FLA batteries discharged inside living area, charged elsewhere safe?

[lkruper]

I have a grid-connected cabin and am looking to provide some backup capacity in case of power failure. Below the cabin is an enclosed sub-space (not entirely sealed off, but water-proof, not insulated). In winter it can dip into the mid-twenties from time to time, but that is the extreme.

I am considering Flooded Lead-Acid batteries to be stored in the basement and kept on chargers and manually moved to the living area to be utilized with inverters if the power goes out. At some future time I may add a solar panel which can be deployed but I also do have 2KW inverter/generator to use also if necessary.

Is it safe to discharge the FLA batteries in the living area of the cabin? I would likely purchase battery boxes for this purpose. These boxes, when deployed, could also be further enclosed inside of a cabinet while being used.

If I were to keep the batteries in the basement I would likely need to extend the power at least 10-15 feet to where the power would be consumed. I do not want to incur any fire hazard during deployment.

Can I use FLA batteries instead of the more expensive AGMs in this scenario?

[Mike90250]

You will have too much fun moving batteries from basement to indoors.
Under moderate discharge, FLA batteries don't do much, but you are still handling large heavy jugs of acid.
A generator and propane adapter will provide power and not take constant maintaining.

[inetdog]

If moving the weight and the risk of acid spills is not enough for you, detaching and reattaching the interconnect wiring for a battery bank is both tedious and risky, especially if you are in a hurry.

[lkruper]

You will have too much fun moving batteries from basement to indoors.
Under moderate discharge, FLA batteries don't do much, but you are still handling large heavy jugs of acid.
A generator and propane adapter will provide power and not take constant maintaining.

You make a good point. Also, during an emergency I might not perform at 100%. I have considered having an electrician put in a manual transfer switch so that I can use my existing gas generator/inverter and also perhaps add FLA battery/inverter as well for when I don't want the noise. Right now I would need to leave a door or window open for an extension cord for my generator.

[lkruper]

If moving the weight and the risk of acid spills is not enough for you, detaching and reattaching the interconnect wiring for a battery bank is both tedious and risky, especially if you are in a hurry.

You and Mike make good points. I was also considering one of those off-the-shelf battery/inverter on a hand-truck combos or making my own, but I also really don't have a smooth path from the basement to the door inside the cabin either. The manual transfer switch does make a lot of sense to me at the moment.

[Mike90250]

.... Right now I would need to leave a door or window open for an extension cord for my generator.

Not a good plan. About 2 weeks ago, someone was found dead in a trailer, power cord coming in via a window, and dead of Co poisoning from the generator. Just took a minor wind shift for a couple hours and he was a goner.

"If carbon monoxide
poisoning turns out to be the
cause, it will be the third such
death at a Laytonville grow
site. Two decomposed bodies
found in a greenhouse in the
rural Woodman Peak area of
Laytonville on May 12, 2014
were first suspected to be
victims of homicide, but were
later found to have died of
carbon monoxide poisoning. "

[Sunking]

Well first thing is batteries do not generate gas when discharging, that can only happen during charging and does not happen until the end of the charge cycle or charging too fast.

You can have FLA batteries inside. Thousands of Telephone office, Data Centers and just about every large commercial building have large banks of FLA or AGM batteries. To meet codes they use a hydrogen monitor to turn on exhaust fans in the event hydrogen levels get too high. Hydrogen does not become explosive until it reaches 4% at sea level pressures. In my 35 years I have never known personally of an exhaust fan to come on. Rumors and stories, but not personal experience. Normal ventilation takes care of any hydrogen buildup. Even two year son a Submarine never seen any alarms go off, bu tit would take catastrophic failure for that to happen in a sub.

Hydrogen is very easy to ventilate as it is the lightest gas known to man, it always goes up. So whatever design you use, put an exit point at the top of use ventilation.

[ButchDeal]

Well first thing is batteries do not generate gas when discharging, that can only happen during charging and does not happen until the end of the charge cycle or charging too fast.

You can have FLA batteries inside. Thousands of Telephone office, Data Centers and just about every large commercial building have large banks of FLA or AGM batteries. To meet codes they use a hydrogen monitor to turn on exhaust fans in the event hydrogen levels get too high. Hydrogen does not become explosive until it reaches 4% at sea level pressures. In my 35 years I have never known personally of an exhaust fan to come on. Rumors and stories, but not personal experience. Normal ventilation takes care of any hydrogen buildup. Even two year son a Submarine never seen any alarms go off, bu tit would take catastrophic failure for that to happen in a sub.

Hydrogen is very easy to ventilate as it is the lightest gas known to man, it always goes up. So whatever design you use, put an exit point at the top of use ventilation.

It is pretty easy to make a batter box with naturally vented thermal neutral ventilation for batteries. Then you can simply leave the batteries in place. I made mine from 3/4" plywood, plastic liner at the bottom ( in case of acid leak, 2" pvc pipe vented from top of box to outside with 3/4" copper pipe inside the PVC to the bottom of the box. To let hid roger out you have to let air in to the bottom, it is copper to transfer temperature from air moving out to air moving in. Wires going into the box are below battery top level and sealed.

[lkruper]

Well first thing is batteries do not generate gas when discharging, that can only happen during charging and does not happen until the end of the charge cycle or charging too fast.

You can have FLA batteries inside. Thousands of Telephone office, Data Centers and just about every large commercial building have large banks of FLA or AGM batteries. To meet codes they use a hydrogen monitor to turn on exhaust fans in the event hydrogen levels get too high. Hydrogen does not become explosive until it reaches 4% at sea level pressures. In my 35 years I have never known personally of an exhaust fan to come on. Rumors and stories, but not personal experience. Normal ventilation takes care of any hydrogen buildup. Even two year son a Submarine never seen any alarms go off, bu tit would take catastrophic failure for that to happen in a sub.

Hydrogen is very easy to ventilate as it is the lightest gas known to man, it always goes up. So whatever design you use, put an exit point at the top of use ventilation.

I don't think it would bother me to have batteries inside so long as I had a storage box that was ventilated. However my cabin is only 500 sq ft and I don't really have room for anything like that. I just measured the location in the basement where I would likely store batteries and the closest location inside the cabin where I would consume electricity is about 20 ft from there. The distance to the only place where I can get solar gain because of trees is another 20 feet from that location in the other direction. However my electrical panel is about 10 feet from that battery location. So I still think that the extra expense of an electrician to install a manual switch is unavoidable and the best course. This also gives me a place to use my generator without stringing an extension cord through a door or window.

[Sunking]

I don't think it would bother me to have batteries inside so long as I had a storage box that was ventilated.

Put PVC pipe in the top of the box, and route it through an outside wall. Add a couple of vent holes near the bottom on the sides of the box, but not on the bottom to allow electrolyte to leak out.. Use non reactive insulated material like a plastic tote or ice chest. Wood can be used but reacts to acidic gasses and spills.

[inetdog]

You can get specifically acid resistant paint for the wood. Not perfect, but a lot better than bare wood.
Think of the desk tops in your high school chemistry class.

[Sunking]

You can get specifically acid resistant paint for the wood. Not perfect, but a lot better than bare wood.
Think of the desk tops in your high school chemistry class.

Me thinks Epoxy paints is what you are talking about.

[inetdog]

Me thinks Epoxy paints is what you are talking about.

That is the most commonly available, yes.
But this stuff is not: http://www.aircraftspruce.com/catalo...lkfloatbtm.php

[ButchDeal]

Put PVC pipe in the top of the box, and route it through an outside wall. Add a couple of vent holes near the bottom on the sides of the box, but not on the bottom to allow electrolyte to leak out.. Use non reactive insulated material like a plastic tote or ice chest. Wood can be used but reacts to acidic gasses and spills.

This method will likely cause a thermal venting. Warm air from inside venting up through the holes, and to outside.
I wanted the box sealed inside my basement so followed the other method of having a return air in a copper tube INSIDE the PVC pipe.

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[lkruper]

This method will likely cause a thermal venting. Warm air from inside venting up through the holes, and to outside.
I wanted the box sealed inside my basement so followed the other method of having a return air in a copper tube INSIDE the PVC pipe.

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Looks very nice. What made you go with the extra expense of AGM, considering you have the sturdy vented box?