Addendum on the charger / welder

The new welder arrives!

I ordered one of the cheapest inverter welders I could find on Amazon that had a decent power output and duty cycle.

"Arc Welder Dual Voltage 110V-220V IGBT Inverter DC Welding Machine 200A High Frequency Household Smart Welder for Novice Welders fits below 3.2mm weling rods"

Cost was $119.00 not including tax. For comparison, the battery charger I previously had (which I went through two of them!) was $179.00. It also had no monitoring or charging customization (which I have via the MPPT). It also was not nearly as efficient in converting grid power to charge power. It was also limited to 40 amps.

While the previous charger was using around 15 amps, this was drawing a little over 9 amps for the same output to the MPPT. This makes it safe to use with a "smart plug" which is rated for 15 amps.

Results

The graph above is what I would call a "mixed day". I had solar input, but it was spotty and because of this and my old batteries, I had to top them off with the welder. What you see in the graph is input from the panels from 9:00am until dark at 6:00pm and then the welder coming online at around 6:30pm until around 9:00pm.

Note that I am still running parallel MPPT's. Because of this the welder began the full 4 stage cycle all over again because it was a different MPPT. Another thing I will bring to your attention is the voltage drop at about 5:30pm. This is very indicative of a bad cell or battery in the chain.

Summary

As long as things keep up like this, and there are no surprises, I doubt I will ever go back to a separate grid charger. Not only was my experience with that horrible, but the experience with this is so far wildly better than expected.

Addendum 1-11-2020

Yesterday I had windows installed on my house. Because of this I had to disconnect and move the panels. This gives me a "trace" on the system with only the welder as a charger (without suppliment from the panels) for a 24 hour period.

There are a couple "telling things" from this trace. The biggest thing is the overall condition of the batteries.

What this has been telling me about the batteries is I somewhere have a weak or dead cell. This can be seen by how the quickly voltage pulls down but then stabilizes. The other telling thing is the intervals of voltage drop. I still dont know for sure what these are but my speculation is that is the defrost cycle on the fridge (the only load on the system).

As for the charge cycle, this tells me that this setup will be very good for litium batteries. What you are seeing is what the batteries can readily absorb. This is shown by the low voltage and high wattage (blue being volts, green being watts). As the voltage reaches its peak you can see the wattage dropping off rapidly. This is followed by welder shutoff and then the fall off of the "skin charge" on the batteries (most likely by another defrost cycle).

Since its a crappy day weather wise, I think I will leave the panels disconnected. Tonight I will run a charge cycle but will keep an eye on the voltage level. After the "peak" I will then shut down the welder and see how the batteries hold up without a long "equalize" cycle. If my hunch is right, then I may be able to reach a "full days charge" with 1 1/2 hours of charging. That would actually be closer to what I saw with charge versus discharge wattage.

Addendum 1-16-2020

Below is the 12 hour trace of todays power. The first item of note is the PV panels and the welder/charger running at the same time. with a low light day the second is the evening top off with only the welder/charger providing power.

This is what the readout looks like when running the two MPPT's in parallel

Dont overlook "waste heat" especially in lighting!

We've all most likely hear of the term "waste heat". You will have most likely have heard about it concerning incandescent light bulbs. We all have heard that LED's "efficiency" comes because it delivers mostly light and not heat. The problem with this though is we need to temper our idea of "waste heat".

What truly is "waste heat"?

We really need to take a look at what we consider as waste heat. We need to rethink the whole concept and put it into perspective. What waste heat really is, is heat that is brought into a space we are trying to cool, or dumped out of a space we are trying to warm. With this in mind, is an incandescent light bulb really as inefficient as advertised?

Now this isn't really about incandescent light bulbs versus LED's. I use this as the example that is most likely known to the most diverse audience. If it is the middle of winter, and you are heating a space, the electricity that is being "lost" to heat, is going as heat into the space we are heating. This somewhat reduces the load on our other heat sources. In essence, the light bulb is working in conjunction with our main heater to warm our space. In essence, that bulb is working not only as a light source, but also as a restive heating element (like an electric space heater).

Now likewise, in the summer when we are trying to cool our space, that light bulb is like having a space heater running. Under those circumstances our cooling system has to work harder to get rid of that unwelcome heat. It is under these circumstances where incandescent bulbs are inefficient and LED's "win the day".

One "tool" two purposes

With winter upon us, we have a much larger need for two things. These would be light and heat. Most people of the younger generation are likely to think that this would require two separate "tools". Incandescent bulbs are not going to significantly contribute to heating our space. Additionally, if you are "off grid" you understand that electric heating would be very expensive indeed because of the extra capacity in generation and storage of electricity necessary.

There is a solution though that provides both heat AND light. This solution hearkens back to the days of camping (before you took your whole house with you to "camp"). This would be the mantle lamp. Despite there being different types and manufacturers, most would refer to these as "Coleman Lamps". When you use this term though, most will picture the old green lantern that you had to constantly pump up.

Not only does this lamp provide (maybe harsh) light, but best of all it provides light AND heat. The problem is though that people think this (or its propane canister version) is the only option. 

Fortunately this is not the case. There are not only other options than the old green Coleman lantern, but there is at least one other option from pressure lamps altogether.

Front and center is the liquid fuel Coleman table lamp. Most people (including myself at one point) had no idea that Coleman made "table lamps" for use in the house. It seems these were particularly popular in Canada (Im assuming for the same reason I am featuring them here). They operate in the same way as the camping lantern. If you can use a Coleman camping lantern you can use these.

CAUTION!

Keep in mind that most of the coleman table lamps will be from the 50's or earlier and may need some repair or at least maintenance. The one pictured above is a 1948 model. One thing to note, some come with a built in pump but the really old ones use a separate hand pump. Try to stick with the ones with the built in pump. Also keep in mind that these were built long before government had to protect us from everything. They are dangerous if mishandled. For this reason dont ever light one inside or on a flammable surface.

The "other" option.

Note the lamp behind and to the left of the Coleman. This is an Aladdin brand kerosene wick type lamp. These are not quite as bright as the Colemans. On the positive side however there is no "pumping" required. They are basically just a standard kerosene lamp with an efficient burner and a mantle. One other very positive note is that they dont stink like a cheap kerosene oil lamp (at least until you blow them out for a short time as it cools).

Other items of note concerning the Aladdins. The wick must be kept in good order or it will burn and light unevenly. There is a special wick cleaning tool that I HIGHLY recommend you have on hand. Also NEVER burn one unattended. They tend to be a bit sensitive to wick position. The will also change and need to be turned down as they heat up. The reason for this is that as soon as you start getting a little bit of carbon buildup on the mantle, they will begin to "smoke" and need to be turned down. I learned this the hard way and had a big black soot spot on the ceiling of my living room as a result of being careless and not keeping a close eye on my lamp.

One last note concerning the Aladdins. THEY ARE NOT CHEAP! A new basic model will set you back $125.00+. You can get lucky however and find them second hand. I just picked one up in the south for $100.00 complete with shade. I saw the same one in the store new for $299.00. With that in mind, keep an eye open in antique and second hand stores. Many times these people dont realize what they have.

One last word on the Aladdins, these get so hot that you can light a cigarette by holding it at the top of the chimney. Because of this, leave plenty of room between the top of the chimney and anything that can burn.

The other candidates

These are variations on the Coleman burner. I have so far found two types of these.

The first (white tank) has a bunson burner type of mantle holder. This unit runs on propane. You will note that it mounts directly on and uses the tank as a base. This one is by far my favorite. It is simple to use and other than changing the tank or a broken mantle it is maintenance free. It also has two advantages over the other models. First is there is VERY little odor when it is in operation. Secondly, it puts out plenty of light AND heat. In fact this lamp alone is enough to heat and light the box with no other heater running!

The second, brown tank, is a (reproduction) Coleman type burner and uses Coleman Fuel (white gas) as its source. Operation is the same as a Coleman lamp except you need a separate pump to pressurize the tank (I run 15-20 psi).

One note on these two. They are hard to come by as they are essentially "home made". Prior to LED's solar panels and batteries, these were the mainstay of Amish household lighting. The first generation was the brown white gas model. Second generation was the propane version. Because of this these two are essentially "cottage industry" made lamps. With this in mind, I found this particular Coleman fuel lamp to be on the very dangerous side when lighting it. There is no small diameter pickup tube inside the pipe between tank and burner. Because of this, a LOT of fuel comes out when first started. Its actually a quite spectacular sight to light this one with all the burning fuel not only in the burner but also dripping on the tank.

Final thoughts

With the Coleman lamps and burners I seem to get the best of both worlds, heat AND light. The best of these is the propane tank mounted unit. The downside of this is I dont know a reliable source for these. I found mine by word of mouth through Amish country at an Amish store. It was of course used as it had been replaced by LED's in someones home. It did however sell me on propane as the best all around fuel source.

I found this tank mount propane distribution tree on Amazon however. Note that it is also direct tank mount and has an outlet at the top for a propane lantern. You could also buy a refill adapter and some propane mantle lamps if you dont want the bulk of the tank to carry around.

WARNING!

I keep  a carbon monoxide detector in the "box" just in case. It has not gone off until yesterday. What I found is that if you turn down the propane lamp too far, it WILL produce carbon monoxide. In all this time I have had this only once. That one time was when I was throttled too far back. USE CAUTION with these lamps indoors!

Charging solar backup batteries with a welder

BEFORE I START, DO NOT TRY THIS WITH AN AC WELDER!!!!

For the past weeks, Ive been considering and designing for ultimately going to LiFePo4 (Lithium) batteries. One of the biggest hurdles I have found is finding not only a high amperage backup charger, but also one that I can get data from for my control system. As it stands my MPPT has all the charge and condition data I need on my batteries. With this not only can I see current state, but also trending of (at the moment) solar input and battery voltage over time. These are the only two parameters I care about at the moment.

I happened to be browsing Quora today and came across this question. In it they ask about using the output from a welder as the input to an MPPT. Ive done some experiments with a converted alternator, bypassing the voltage regulator and using a larger external 3 phase rectifier. With that I would then vary the field to control power output. This was a pain but it worked. My issue is that I have this nice 3 Kw military diesel generator already. Problem is last time I put a charger on it, the charger failed. After this I went back to the engine driven alternator experiment.

Seeing the post linked above and having "napped" on the subject, I realized I have all the pieces to throw together a test. I have a Miller 152 DC (DO NOT CONNECT AN AC WELDER TO AN MPPT!) old model inverter stick / TIG welder. I also have a spare MPPT from my tests with the alternator. Well after tossing it around in my mind, I decided to setup for a test.

I dialed it in to 40 amps and checked the output voltage. ~88 volts DC was what I got, well within the spec of the MPPT (which is around 125 vdc, 40 amps or total (I think) 1050 watts) and within the continuous rating of the welder. I then wired the "welding leads" into the MPPT. I threw the switch. What I saw was nothing short of worth breaking out the Champagne!

The MPPT was staging and dumping 1087 watts of power into the batteries at 28.88 volts (equalize stage). Best of all, there was no undue heating of the batteries nor of the MPPT. Best of all, the "magic smoke" stayed inside all of the electronics!

Next to see what actually happened. this is the chart of the whole experience

In the chart, blue represents the battery voltage. The line where it starts is 25 volts (had decent sun today). The green line is the input wattage. it is 0-900 in 100 watt increments. As you might guess, I was at first a bit dissapointed at the output. Then I remembered that the batteries were already at full charge (or close). The first "dip" was from turning on the washer and oil filled heater. The welder was easily powering everything and not putting power to the batteries. With the second dip, I had shut off the welder to let the batteries draw down from the heater. Keep in mind my batteries only have about 20% life left in them so it didnt take long to dip down to 22 volts under the load.

After discharging the batteries some, I fired the welder back up. Note that it immediately went to full power to the batteries to bring them back up. As they were taking charge, you can see the wattage (green line) dropping off as the internal resistance of the batteries increases. Being dark out and running out of time, I went ahead and shut things down having proven it will work.

My next test is to do it over about an hour or two. During this, I will know more about heating and how the whole system reacts under real world conditions. At this point I am confident it can be done without damaging anything. The only real question I have is if the welder will "throttle back"far enough so as not to require a dump load. The basic principle has been proven to my satisfaction, now its just "details".

Addendum 1-3-2020

Today I did a more thorough test. This time I ran for about 7 hours. I couldnt be more pleased with the results

Nice clean charge with the wattage tapering off just fine. At the end of the run I was up to about 93 volts going in and around 100 watts. I also bought a contactless thermometer and noticed nothing unusual with the batteries running at around ambient temperature. The MPPT was running about 72 degrees at its hottest point. At this point, I consider the results better than even what I got out of my original grid connected charger.

I cant comment on other combinations, but I now know my welder with my MPPT has been a complete success. Next to test the welder with the generator, but that is an unrelated subject. If that works I then have a portable welder that I can also use as a backup charger around the homestead.

Addendum 1-4-2020, The Welder and MPPT

Some have wondered about the methodology I used to determine if or how this was going to have a good chance of working. Here I will review a bit about what I checked first before I even connected the wires.

The MPPT

In my system I am running an Epever 4250BN MPPT. Now to me the datasheet is a bit confusing. Some of the ratings just dont add up. Because of this I went with the lowest individual rating values. First of all we have different values based on the battery voltage. This tells me that the MPPT finds current (amperage) as the most important value. This you can see in my other posting about "Amps,Volts, and Watts". Long story short, the electronics care more about the current passing through (wire and electronics sizing) than the voltages. My battery pack and inverter is 24 volts (in my opinion the minimum voltage for a serious system). So now to look at the datasheet....

• Rated charge current 40 amps (discharge @20 amp I believe is for the dump load)
• Maximum PV input power 1040 watts. This is what your welder should be set to supply as maximum.
• Maximum input voltage 138 vdc. (for some reason this is not on the datasheet but in the amazon ad).

It should be noted that I monitor my values from the data bus of the MPPT. You can get approximate values during setup and test with a volt meter and a DC clamp on amp meter. NOTE: not all clamp on meters will do DC. If you are doing a solar system, a DC clamp on amp meter is a MUST in my opinion. Do not use your normal meter in "amps" as most are fused to around 10 amps. A clamp on will take you into the 100's of amps.

The Welder

Next, I look at the data sheet for the welder in question. In my case it is a Miller 152 Maxstar. Everything you need to know is on page 9 (in my case). Here we find

• 100% duty cycle (meaning it can run continuous) of 125a at 25vdc.
• Open circuit voltage 95vdc. This is the "no load voltage" verified with my meter.

Next we look at the volt-amp curve. This one is very important. Remember as you draw more amperage the voltage will drop. For the test, I set my current limit to ~40 amps on the welder so as not to accidentally overload the MPPT.

Looking at the output curve, at 40 amps the voltage will drop to about 65 volts. This is still well within the spec for the MPPT. The maximum I saw during my testing on flat batteries was 73.78 volts at 14.74 amps, for 1087 watts. This is slightly above maximum for the MPPT but it was not significantly over rated. I suspect the MPPT was burning some of this off as heat. If I had run at that wattage for a longer period of time, I would have first tried turning down the amperage setting a bit. NOTE: I do NOT know this for a FACT!

Other DC Inverter welders

I just finished searching for other welders of this type. Nowhere could I find a detailed volt/amp curve for the welder in question. I did find some that listed their open circuit voltage. This was usually around 70vdc. The other thing you need to know which I couldnt find is the "duty cycle" at the amperage you need.

What the duty cycle is (in case you dont know) is how long you can power at a given amperage before the machine needs to cool down. Some of what I saw was listed at 75 amps but a 20% duty cycle. What this essentially means is you can run at 75 amps for 2 minutes and then the machine needs to cool for 8 minutes (roughly). All I will say without having the actual data is firstly this is not a "linear value". In other words 37.5 amps will not necessarily give you a 40% duty cycle.

Personally, I wouldnt look at anything below 150 amps or so rating. After all, you may want to also use it as a welder. Most serious welding work is going to happen in the 80-120 amp range.

Update 1-6-2020

My new welder / charger just arrived. I purchased a cheap one off of Amazon. It is a 110/220 vac inverter type. Other than a little lower voltage running on 120vac vs 240vac of the Miller, there was no difference in performance in initial testing. 

The only issue I did see is I had paralleled 2 40a MPPTs last night in preparation. One is on the panels (900 watts) and the other on the welder. Both were connected to the same batteries on the output. There seemed to be some "contention" over which MPPT was going to "run the show" (after a good day of sun).

Despite that minor issue, no magic smoke was released and everything returned to normal when I isolated the input of one or the other. One very pleasant surprise was the power draw of the welder. My previous dedicated charger would pull close to 15+ amps to charge batteries directly. With this method it was pulling only around 9 amps for the same power. In this regard the welder is MUCH more efficient.

Final Thoughts

In todays installment, I pulled my batteries down heavy before starting. I did see the input wattage to the MPPT peak up around 1100 watts for a while. This isnt all that much above MPPT spec. On the other hand it does make me think that the security of having a dump load would be worth the minor expense. Since I dont have a dump load, I cannot tell for sure. Dialing down welder amperage didnt seem to have a lot of effect (neither did dialing it up for that matter) on anything other than voltage.

This gives me an educated guess that the MPPT will only take what it can use off of the welder (MPPT regulating the overall charge side). I did notice some heating (76 deg/f with ambient being around 60 deg/f) of the MPPT. Note that the MPPT does have overtemp protection with shutdown around 150 deg/F.

After testing with another DC inverter welder and 2 40a MPPTs in parallel and seeing the contention between MPPT's, I think I will end up making a minor change to the overall plan. I will go back to one MPPT of higher output capacity with a source transfer switch on the input. I will then set it up so that it is "motorized" for remote switchover. I know I could use relays or contactors but I dont want to waste the power on holding contactors and cant find anything high amperage that is latching.

All in all, I stand by my initial overall conclusions.

The learning experience with batteries

How not to go about selecting batteries!

Ok, so I admit, I have a tendency to go cheap and improvise until I know that doesnt work. Well, on batteries I have learned the most expensive batteries are cheap (used) batteries. This knowledge cost me $2000.00. Here is my journey and lessons learned.

Pricing batteries (sorta) apples to apples

The most important lesson I have learned is to not simply look at the price of a battery. It really pays to do your homework here. Before I get into the nuts and bolts of comparing apples to apples let me reiterate something you will find in ANY alternative energy battery posting on the net. DO NOT BUY CAR STARTING BATTERIES. Click HERE for a google search that will tell you all about why this is a waste.

With that out of the way, lets look at what is important in pricing a battery. First off is the total storage capacity of the battery. This is the (Kilo) Watt hours the battery will hold when new. To get this figure multiply the voltage of the battery and the rated amp hours of the battery.

Example:  

12 volt battery with 255 amp/hour capacity AGM type. Capacity 3.060 Kwh. Cost $339.00

12 volt battery 100 amp/hour capacity LiFePO4. Capacity 1.2 Kwh. Cost $342.00

Think the choice is obvious? Not by a long shot! To give us a more fair comparison, lets break that down some more. How much does 1 Kwh of storage cost us. For that we do the following calculation:

(Price / Capacity) / 1000

With this the AGM comes in at $110.78 and the Lithium at $285.00. The choice is still looking obvious in favor of the AGM to the consumer. Now we add some "art" to this.

The AGM battery cannot be discharged on a regular basis below 50% of capacity without shortening the life of the battery. AGM in general is good for 2000 cycles before they should be replaced. With this in mind we have roughly 3.060*.50 (50%) or 1.53 Kwh available to us for approximately 5.4 years. With that in mind our battery will have cost us about $63.00 per year.

Now we turn to the "expensive" battery, Lithium. A Lithium battery cannot be discharged 80% of capacity without shortening its life span. Lithium is also good for at least 4000 cycles before you need to think about replacing them. So here we have 80% usable battery or roughly 1.2*.80 (80%) or .96 Kwh available for us to use for approximately 10.9 years. This brings the cost of our battery to $32.00 a year.

Now the last piece of the puzzle is the storage capacity. Maybe you noted that for our $63.00 / year we had 1.53 Kwh available and for our $32.00 we only had .96 Kwh available. Because of this, and to keep things simple, lets buy 2 lithium batteries to our 1 AGM.

We have now doubled our capacity to 2.4Kwh (total with 1.92 usable Kwh) of battery. We still have the 10.9 year lifespan but we have doubled the cost. With this in mind our yearly cost is now $62.00/year.

We come out $1.00 per year BUT we have 0.39 Kwh/day or 142 Kwh/year available for us to use (if we use each battery to its full capacity daily).

I have intentionally not calculated industrial batteries. The reason for this is while the overall cost MIGHT be competitive, they weigh in around 1000 pounds per pack. This makes them pretty difficult to move around. Additionally, I do not consider them safe for residential or RV indoor use and would not recommend that (been there done that).

My thoughts on used batteries

First off dont buy used! You have no real idea how much life is left in the battery. When I bought my panels, they guy selling them also had some beautiful looking AGM type batteries. They were Interstate 12MQ2400 12 volt rated at 94 amp/hour each. Cost $100.00 each (I bought 10). This came out to $88.65 per Kwh. The problem is that Ive had the full pack now 2 years. 2 of the batteries have a shorted cell and had to be pulled out of the pack. The 8 remaining batteries can now barely get me through 24 hours with a 1 Kw/day load without needing recharged. I estimate them to be at about 25% of their new capacity.

I dont consider my mistake to be all that earth shattering. The system was built as an experiment / learning tool and not because I absolutely need it. All of the mumbo jumbo I just wrote may not mean a lot to the reader. Because of that I will just say this, if your system is critical, DO NOT BUY USED OR EVEN "RECONDITIONED" BATTERIES. It is a complete roll of the dice.

Where do I go from here?

What all of this has basically come down to is what do I do now that I will have to replace my battery pack soon. I used to be a firm believer in lead acid technology (AGM is a specially constructed lead acid battery!). I had turned my back on Lithiums as being too expensive and too high tech.

A couple things changed that idea. First among those was actually crunching the numbers. Next I came across this video. The video outlines how to create a litium battery pack from individual 3.2 volt cells. From there I turned to Amazon and China to price cells. Basically without being "conservative" I can do lithiums for approximately $250.00 per Kwh or less using individual cells.

Basically what it has come down to is two choices. You can either spend less now but more over time, or you can spend more now and less over time. As for me the lifetime cost and the weight factor, has finally pushed me into the lithium battery made up of individual cells court.

Of Volts, Amps, Watts, and Batteries

Its been some time since Ive updated this. In that time Ive sidetracked into solar power. WOW, what a learning experience! I will try to keep the "politics" of solar out of this and just stick with my experiences. I will however say this much. To anybody who thinks solar is the be all end all of alternative energy, I challenge you to build a small system and live with it long term! That being said, on to the facts and experiences.

Electricity Terms

Before I begin all this, I will do a brief explanation of the terms of electrical measurement and flow. Electricity is very much like water. The electrical equivalent of a molecule of water is the electron. All an electrical system does is move electrons around in varying pressures and quantities through the wires which can be thought of as pipes to water. All of the following is GREATLY simplified just to give an idea of what we are talking about.

Voltage - Everyone knows the word, few knows what it means. Voltage is the "pressure" pushing against the electrons. Its hydraulic equivalent would be pounds force, or Bar.

Amps - These are the electrons. You can have a whole bucket of amps, but if there is no pressure they dont do anything.

Watts - This is the real number you need to pay the most attention to. This is the system POWER or power potential. Often it is expressed in Kilowatts (watts x 1000) for the purpose of residential power. There are also a couple related terms you may come across in AC power. These are "VA" or volt/amp, and "KVA" or Kilovolt/amp. Setting aside AC power theory, simply think of them as Watts.

Watts are the equivalent of Amps x Volts. The same amount of power is produced by 120 volts at 10 amps, as is produced by 240 volts at 5 amps - 1200 watts. So, the next big question might be, if its watts that matter, why do we even pay attention to volts and amps? The reason for this is that wire sizes are based solely on Amps (the insulation is based on volts). Lets look at this a moment from our batteries point of view.

For the sake of discussion, we will consider a 100% efficient conversion through our inverter (which is FAR from 100% efficient in real life!). Below is a "wire ampacity chart". This is the safe wire size for a given amperage flowing through the wire. As long as the amperage for a given wire stays below what is shown here there is no danger of the wire overheating due to resistance.

Using our previous load example of 120 volts at 10 amps moving 1200 watts we first look at the minimum wire size for the AC side. This shows us the minimum safe wire size is 14 gauge. This is pretty much the standard size for American household wiring (although some run 12 gauge to lower the power lost in moving through the wire).

Now we look at the DC side of things. We know we need to move 1200 watts (at least!). We will assume a 24 volt battery pack first. To size our wires we need to know how many amps will flow through the wires from the battery to the inverter. For this we divide 1200 (watts) by 24 (volts). The result of this is 50 amps. If we go strictly by the chart, we will need an absolute minimum wire size of 6 gauge wire to the inverter. Assuming for a moment that our battery pack is 12 volts we do the math and find we will be conducting 100 amps. The minimum safe wire size to the inverter is now 1 gauge wire.

An important note to all of this is wire distance. The longer the wire run the bigger the wire needs to be to compensate for resistance in the wire. This is only important when the batteries are far from the inverter, or the inverter is far from the circuit. This is only the basics. We need to look at the system as a whole.

Wiring and circuit protection

We are all familiar with circuit breakers and fuses. What many fail to realize is that those are there to protect the wires and not the devices attached to them. Because of this, we need to size everything to the potential of how much power the inverter is capable of. In my case I have a 24 volt input 120 volt output 2500 watt inverter. Wires and circuit protection should be based on that. I chose a 2500 watt inverter because it is only capable of supplying 20 amps at 120 volts AC. This is the average amperage of a single branch of a household circuit. Going back to our chart, this means we are still safe with our 14 gauge wiring.

The REAL issue comes on the DC side. To make those 20 amps on the AC side we need to draw 104 amps at 24 volts from the batteries. Because of this we look at our chart to find that we need 1 gauge wire minimum along with a fuse or circuit breaker around 100 amps. I can tell you first hand that the wires to connect to your batteries that come with the inverter are of a laughable size at best and downright dangerous at worst.

DC system size selection

A question many usually have is what DC voltage to use. Using the above example, simply from a wiring size I would say anything above 1000 watts or so should be 24 volts DC. At 1000 watts DC, we will be moving 83 amps. This keeps us in the 3 gauge side (still manageable). However if we built our 2500 watt system at 12 volts DC we would need to size for 208 amps! This means a minimum of 3/0 copper line! My suggestion, ANY off grid system should be 24 volts DC or higher. Any vehicle mounted 12 volt (by necessity) system should be MAXIMUM 1000 watts.

Batteries

The care and feeding of batteries is a whole subject in and of itself. Its not something I am going to get deep into here. I will simply add a few notes on. All I say here will be in very general terms just to get an idea of how much battery might be acceptable.

First of all, STAY AWAY FROM AUTOMOTIVE STARTING BATTERIES! There are plenty of sources out there that will explain why I say this. Secondly, the most "expensive" batteries are "cheap" batteries. What I mean by this is that you will replace used or cheap Walmart deep cycle" batteries multiple times before you will if you simply buy new good batteries from the beginning.

Do not buy flooded lead acid to use inside unless your space is well ventilated. Ignoring this runs the risk of burning down your house as these can vent hydrogen gas during charging. If you dont want to experience the last moments of the Hindenburg, just dont do it! Also, no matter what "voltage" your battery is, it has the potential to injure or even kill you if you disrespect it! Treat your batteries with the same respect you would a full gasoline tank.

Educate yourself on batteries through Google. What I write here will be simply the bare basics. To get a rough idea of what I needed for capacity, I first looked at my loads. In my case I have only a refrigerator rated at 1.1 Kilowatts per day. I wanted capacity to go 3 days without a proper charge while not drawing the batteries below 1/2 charge (going lower can dramatically lower the life expectancy of the battery). 

With this in mind I needed (1.1 * 3) * 2 Kilowatt hours of battery. There, I threw a curve with kilowatt hours. I do this because thats how to figure the capacity of the battery. They are rated in amp hours. To get Kilowatt hours multiply voltage and amp hours. This means my BARE MINIMUM requirement is 6.6 kilowatt hours of battery.

A quick search showed this https://www.optimabatteries.com/en-us/bluetop-dual-purpose-deep-cycle-and-starting . We will look at the largest capacity available. In this example it is the "Bluetop D31M". Taking the Amp hour rating and multiplying by the voltage we come up with 900 watt hours each. This means we need 7 of them to meet our criteria. Since I am running a 24 volt system I need 8 (4 rows wired in series, with each 2 battery combination wired parallel. This will give me (under ideal conditions) 7.2 kilowatt hours. Lastly using their pricing I come out to a cost of $2648.00

Summary

All of the above is simply a rough overview under ideal conditions. So far I have found my system to be about 50% efficient. Since it was for experiment and development, I went used on the batteries. I know they are not optimum and of the 10 I bought at $100 apiece I have lost 2 so far to dead cells over about a 2 year period. They are 1.1 KW each (12 volt 94 ah) giving me currently 8.8 Kw/hr.

These are charged by 3 300 watt solar panels fixed facing south. We had an optimum day today sunshine wise. With this the panels produced 1.42 Kw/hr. This gives me about 300 watts to charge batteries above what the load is taking. Considering inefficiencies in batteries, charging and inverter, this is about what I need just to run the fridge for 1 day.

All in all, you be the judge. I have ~$3500.00 invested. Just replacing the batteries will wipe out any energy savings. The only benefit I see in solar is for an off the grid system where no options are available. For me though that is what its all about. As for solar being a viable alternative, I say live with it like I have and see for yourself. The "economics" simply dont make any sense unless you're the power company and have government mandating panels on your roof (for essentially free) and grid inter-tie inverters (which by the way dont work during a "blackout").

GOVERNMENT!

What to expect from small minds in a small town

Well, this posting is a bit late, but I wanted to take a moment to show what you may be up against. I live in a small town in Ohio. I also live in a part of town where my lot is zoned industrial! Behind me is an active railroad track, and a former one that was converted to a walking path after I moved in.

It seems a city councilman was walking there and took exception with my "box". To be clear, I not only have the "box" detailed here, but I also have a 40' unit that I plan to also work on in the near future. Currently I am just using it for storage until I decide how I wish to proceed. The only improvements I have made to the 40' is a coat of paint the same color as my current unit.

Below I present the city council meeting minutes that pertain to what has been said. I do this so you may have some idea what you may come up against should you decide to "try this in your own home". I have put the main part of this section of the minutes in bold font. My comments (not presented to council as I was not even aware of this until it made the local shopping paper) will be in bold italic font. So here it is in its entirety:

Workshop 

a. Discussion of Accessory Structures City Manager Boggs advised one of our Council Members pointed out that they felt at one time the zoning regulations stated that there could only be one accessory building and requested it be brought for discussion. He indicated the current language for an accessory use were included in your packet and he advised he felt it was plural in nature and he didn’t see anywhere (in the regulations) where it states only one accessory building permitted. Boggs advised an accessory use is described as many different things including garages, sheds, tennis courts, swimming pools, etc. He advised he wasn’t sure what they (Council) would want to do, if anything, to regulate them (accessory structures). Boggs advised he believes the concern was over how many sheds should be allowed on private property. He advised he didn’t know if Council wanted to discuss it further or have it brought up at a future meeting. 

Council Member Lynn Beaumont advised if you drive around town and you look at the condition of a lot of the residential properties and the abandoned properties he felt this was the least of our problems. He advised there are a number of abandoned properties and dilapidated properties and he has talked about this a number of times with (City Manager) and he felt at some point they have to do something. Beaumont advised he didn’t know if this was the start or whether we devise a program, but over the years that he has served on Council this is what most of the calls he receives are about the dilapidated properties in town. He advised it is just awful right now. Beaumont advised but, someone who has 2 structures on their property and their property is otherwise in good shape he’d have a hard time going after them when we have junk everywhere and junk is a nice word. He suggested others to just drive around and look. 

Mayor William Robertson advised some houses that were previously some pretty nice houses have fallen into pretty bad disrepair. Beaumont advised right. He advised we have people living in their cars. Beaumont advised it is ridiculous. He advised he doesn’t have a problem with this (topic) if it is our ordinance then we should enforce it, but there are some serious issues that we really got to deal with when it comes to properties and it was just a matter of putting it in place. Beaumont advised Rick (Hanlon) worked really hard on the Property Maintenance Code and we don’t do anything about it. He advised that is not a criticism of Larry (Boggs) as he understands it is a personnel issue and it is implementation of our policy. Beaumont advised there are a lot of issues and if we start here then that is fine, but he would have a hard time lowering the boom on somebody that may be technically in violation of this ordinance when we’ve got people that own properties that are uninhabitable.

Robertson advised the list of things included (as accessory uses) are a garden, a swimming pool and a garage etc. 

Council Member Darrell Carey advised he felt as long as they (accessory structures) are maintained well he doesn’t have an issue and doesn’t care how many they have. He advised they own the property and they should be able to put buildings on it. 

Council Member Dave Williams advised the issue he has is that while walking along the trail he saw a particular residence that had a shipping container on their property converted into a living unit. He advised there was electricity run to it and an air conditioning unit. Williams advised there are public safety concerns if (any of the safety services) were called out to this location if it would be the main residence by the road or would they be (dispatched) to a shipping container. He advised if it were in the middle of the night and trying to find addresses and he felt there was a certain public safety aspect for our safety services. Williams inquired if this is a taxable habitat on top of the main residence.

So, they are concerned for my "safety". Its funny how often this excuse is used to justify government meddling in our lives. You may also see from the rest of this that this individual knows absolutely nothing about it, its purpose, whats inside, NOTHING other than it has an electric cord going to it, windows and an "air conditioner". The REAL reason however for his "concern" is made evident at the end....MONEY! This last statement makes plain what the main resistance is to affordable housing. Not only did I not pay "tribute" to the building department and banks, but they cannot TAX it. Remember, the more expensive the "dwelling" (NOT implying this is a "dwelling") the more tax money the government gets. Think about this the next time you look at the lack of affordable housing!

Beaumont advised it is amazing what you see from the trail that you don’t see from Sterling Avenue.

Robertson advised he believed that was illegal to have a second residence on the property. 

Boggs advised he sent the police department out to check on that and they didn’t see what you (Williams) saw, but they (PD) better double check it. 

They sent the POLICE to check it out! I should note that not ONE SINGLE TIME was I contacted in all of this. Also note that none of my neighbors has complained in any way. All of this was started by someone who came down from on high, and didnt like what they saw!

Carey advised he felt that was an entirely different type of issue than sheds, swimming pools and gardens. Robertson advised if someone put up a garage and moved into it then… 

Beaumont advised he didn’t feel it was fair to people who really try to make their properties nice. He advised there are people trying to make their property’s look nice and then others who (it appeared) they just don’t care. Beaumont advised he doesn’t think it is fair to the people who care. 

Williams inquired if they were looking to be more definitive with the rules. 

Boggs advised he was asked to bring it in front of Council. He advised at this point he wouldn’t know what to change it to. 

Boggs advised he felt the concern was how many sheds and he hasn’t done any research with neighboring cities on this particular issue. He advised he didn’t know if the answer was for structures with a roof to allow a maximum square footage total per lot. Boggs advised when he started working on the other workshop item and was doing some preliminary studies on streets looking at GIS mapping data, there were a lot of properties with more than one shed. He advised to go back and try to enforce it (to allow only one shed) would be a nightmare. Boggs advised it might be better to attack it on the property maintenance (end of it). He advised he could do more research and see if neighboring cities have anything different and bring it back at a future meeting. 

Just a side note here. What this means is that they look for you and what you are doing via areal photographs. Be aware that if you put something up, no matter where it is, it WILL be found and questioned.

Robertson inquired if there was any desire among Council to have Larry (Boggs) look at it further. He advised it sounded to him like they were okay with the way it is (currently). 

No additional comments were made.  

Water (experience and lessons)

Lessons from living with my "water system"

"how NOT to do it"

If you have read through this blog, you will see that a large portion of it was devoted to "water". You will also see that I had a lot of "bright ideas" and plans. 

I have now had some time to actually live with it. Some things worked well, others not so well, others turned out downright ugly. About the only part of the system I have not been disappointed with is the tank and tank filling system. My only desire there is to come up with some other location for the tank. It takes up quite a bit of room in such a small space. What I will likely do is somehow integrate the filters with the tank by either mounting them on top or around the tank.

Issue 1

The fist big issue I had with the system, was the pump. It was a 2 gallon/minute 12 volt diaphragm pump. This was necessary for the pressure it can reach to be able to push water through the "reverse osmosis" filter. I had it turned down to produce 70 PSI through the filters.

Pump failure (AKA Use an expansion tank at the pump outlet!)

The pump I had chosen lasted about 4 months. The biggest reason for this is that I did not put an expansion tank at the outlet of the pump. What this meant was that the pump was constantly cycling on and off as the water flowed through the RO system. It also pulsated on the output side very badly. In the end it was simply too hard on the pump and it burnt out prematurely.

Another issue in regards to the expansion tank is with the water heater. I did not install the tankless water heater in here. Instead I had bought a motorhome to use while I was gone for work and installed it there. In this way I am able to give a review of the performance of that. 

First off, the motorhome also used a pump of about the same type and capacity. What I found is when I was on "pump water" (without an expansion tank), the water heater would constantly cycle on and off. It was unusable. The reason for this was the intense fluctuation of water flow and pressure from the pump.

When water was sourced from the camground, the water heater worked as well as, if not better, than expected. It was perfectly acceptable for everything from doing dishes to showering. I would HIGHLY recommend it for a container or cabin as far as the water heater itself! I am hoping to get another one in the near future and try it as a source of heat for a hydronic heating ("hot water") system for the entire "box".

Solving all problems

I believe that if I had added an expansion tank at the pump outlet, this would have solved all my problems. The expansion tank would very much dampen the output from the pump. What this means in this situation is that the pump would have lasted much longer (as it would have run less and more smoothly and had a more consistent pressure at the outlet) and the water heater could be used on pumped water (because of the lack of fluctuation in pressure and volume). In summary, I cannot stress enough the need of an expansion tank at the outlet of the pump!

Have a backup pump (and plan) ready!

Here I am speaking of the need for at least a hand pump. For a while I reverted back to the 5 gallon water container with a hand pump. This I had from before I put the tank in. As I tried to decide my next move, I still needed drinking water. With the 5 gallon water container (the type used on a water cooler), I at least could refill it from a clean water source for drinking water.

The picture is representative of what I am talking about. These are available on ebay quite cheap. They also snap on to the top of the jug.

Until I get a final solution to the whole setup, I have set the hand tank and pump aside and simply installed this pump inline with the filters

This is a $6.99 "Harbor Freight Special". All I can say "good" about it is that "its a pump". It has some slight leakage at the pump shaft and it produces very little pressure. It is also easy to "blow the hoses out" if too much pressure is applied. Because of this, I am currently only operating on the normal filters and the UV light "disinfector". I had to remove the RO filter from the system as this would not produce nearly enough pressure to push water through that filter. Basically, right now, the main water system is only good for a clean drink of water :-( 

Where do we go from here?

Well, four big modifications I plan to make to the system.

• Somehow combine the tank, pump and filter system to save space. This will also have the added advantage of making the entire system "portable".
• Add an expansion tank at the outlet of the pump or pumps so the pump does not have to work so hard.
• Add a hand pump inline with the electric pump for backup. Right now the whole thing is simply "rigged" together to get drinking water. If I have a hand pump permanently installed on the inlet side of the electric pump, I will not have to make any modifications to the system if the electric pump should fail (you can "push" or "pull" water through a diaphragm pump without modification).
• Add valves to bypass the RO filter when using a hand pump. As it is now, I had to physically change the tubing to bypass the RO filter for use with the hand pump. A couple valves and some tubing would be better so I can simply change the valve settings and flow water around it if using the hand pump.

Well thats the summary of where the water system stands. I hope somebody can learn from my mistakes!