Wouldn’t it be fine with insurance/ liability for the batteries to be removed from the valuable property, as Bill Schiller is doing? Or is that just common sense opposing the “rules are rules” people?
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Around here the insurance companies are good at finding any loophole to avoid paying. I am probably over sensitive to the topic because I had to deal with one not wanting to pay for water damage in a house when a pipe burst. I got them to pay in the end but it wasn’t easy.
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I sympathize, sounds like the issues around heating your home with a home built boiler stove, though it may be 100 feet or more from a house, insurance companies seem pretty immune to common sense.
It is just business to them any claim they don’t pay is profit they keep.
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Insurance is the main reason for the popularity of outdoor boilers around here. I don’t think most people actually insure the shed they are in.
The cycle life is higher then lead acid. I think what attracted me was the 97% efficiency.
My parents ran into an issue where the insurance company wanted to charge them for having a wood fired heating system in their house, though it is a boiler 150 feet away. Rules are rules… 
But in common sense land, always a great idea to keep potential hazards like battery banks, or fire at a safe distance from valuable property. The shed is no worry compared to a house full of belongings and people.
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Maybe they aren’t insuring it for wood heat and just risking it…
I might put the aquions in my house but that is about it. I know they probably offgas some hydrogen but it isn’t going to explode or leak acid.
there are the other MIT/Samsung cells that are solid that won’t explode and should be coming down the pipeline in about 5 years.
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I lean towards Bill Schiller’s approach. I have a small off grid system, the batteries are in a pressure treated plywood box set in the ground just outside my cabin. That addresses space issues, safety, and keeps the batteries relatively warm compared to minus 20C. I would use the same general approach for a bigger system, then you’re free to tackle any system, home brew or other. Also simplifies accessing and moving of heavy batteries.
And, I have to wonder if a big lithium ion bank might just burn the house down one day…
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It is a risk, but definitely less of a risk if you let the factory do the circuitry, it has a cooling system and it is sealed. most of the fire risk is from thermal runaway from discharging too fast, or overcharging and damaging them. Then you have a few accidental things that could happen if your shop is in the garage too.
The box outside isn’t a bad idea if you get it deep enough and cover it with insulation. but you do have to worry about off-gassing hydrogen with like lead acid batteries or edison batteries since it won’t have air circulation and there is potential for spark.
Actually size of the battery bank will go a long ways towards safety with lithium ion of the aquion batteries. Both have limits to how safety you can discharge and charge but the calculation is based on charge per battery cell so the bigger the storage system the safer it is. It is non intuitive as the larger the battery the more stores energy the bigger the disaster if something does go wrong. Of course with lithium ion there thermal runaway that simply doesn’t exist with aquion.
Lower then aquion or the powerwall 2. As to the 97% I will wait and see if it holds true once they have a design that has made it to mass production. It is often easier to get good results in small scale lab designs built by engineers or scientists then it is in production. There are tradeoffs in the production process that could effect that 97% I hope they succeed but I try not to get too excited before I see a finial design.
Pretty easy to rig up a small computer / 12v fans for ventilation, or better, 2 combined in a heat recovery ventilator. For my micro system im not overly worried, if I build it any bigger it’s a consideration. I understand a tube of a certain diameter is considered adequate ventilation for such banks?
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I would guess a tube would work, but the you are letting cold air in which is what you are trying to avoid in the first place. I haven’t looked at other people’s designs for it. My original idea when I was like 8 was to bury like a septic tank to store edison batteries in. That idea promptly got shot down by my dad.
Because hydrogen is such a light gas, it will rise to the top of any enclosure and out threw a small diameter pipe or tube that slopes up from the enclosure. In normal use solar batterys charge and discharge slowly compared to a auto battery so the gas is released at a slower rate even in a larger system. The vent tube doesn’t need to be large enough to carry away much heat and doesn’t need a fan that could fail or worse yet cause a spark to ignite the hydrogen and air mix it would be pulling. I have set up several systems that used the large L16 batterys and never had a problem and was able to get approval by the inspector who used the national codes.
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Anytime you make a hole be careful some gasses are heavier than air. It is very easy to make a confined space which can be deadly when you enter it. I built a 700 gallon water tank for my wood gas boiler and it sat empty for about a month while I waited for the coils. The plumber showed up with the coils during the day and told me he almost passed out before his helper got him back up the ladder. This tank was only 6 feet tall so I really don’t know what he was doing inside it but it scared the crap out of me because I told him to be careful it was a confined space. I have a feeling he didn’t realize that a hole with the top open to the air could end up without any oxygen to breath in it.
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A modest proposal.
I have four different lead-acid starting batteries that hard experience had shown me with winter-time idle down time I need to removed and top-up charge at least once every four weeks. Do not do this and is replaces at least one of these set-aside ignored, every, next use season.
The John Deere/Yammar three cylinder diesel tractor has had it group 30H go time/age bad last year. NLA on group 30’s anymore. I replaced with a slightly larger Group 31. A post version versus the more common stud terminal type’s.
Measuring up it will be easy for me on the Miller/Kohler welder-generator to replace out the small Group 28 for a Group 31P.
Group 31P will fit easily in any one of the three Ford pickups. Group 31P can be squeezed into the Hyundai versus it’s rare group 121R. Easy to fit a Group 31P into the wife’s current Ford Edge replacing it’s group 58 come the time. Group 31P can even be grafted into the Club Cadet riding lawn mower when it’s becoming 3 year old U1 fails.
My needs are Grid-backup, Grid’s Failed Us (four timed now since late Nov.)
2,3,4 of these Group 31’s in parallel put my two 500 watt, two 1600 watt Rediline motor-generators into play.
Puts my Trace 2512 big’ol herky inverter into play.
Group 31’s are available from low capacity/amps cheap, to high maps flooded plates, to high-amps vibration resistant AGM’s, to pure lead stationary storage types.
THE most common, over-the-road diesel truck battery group size are 31’s. Lots of backup there.
A practical, today use, suggestion.
J-I-C Steve Unruh
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I know it happens, and I know that wouldn’t have been my first thought either. He might have been down there a while too.
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He said there was a dead mouse down there he tried to get out. I told him to fill it up anytime down there would float.
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Steve I sold my trace 2512 and I’m still upset about it 7 years later… a tank still makings ac 24/7 now on its 4th owner original manufacturer 1997…
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Steve,
I get what you are getting at: Standardize your vehicle batteries so they can become an emergency back-up array. I don’t think I can stuff a 12.9" long battery in my lawnmower, though! Where is my tape measure? 
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