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Battery Bank in Attic ? (COLD winters)
By DigitalMind, Section Storage Posted on Wed Oct 17, 2007 at 04:16:35 PM MST
Battery Bank in Attic?

Hi all,
I'll just ask the question first before my long story : Other than the pain of getting batteries up there, CAN I keep my battery bank in the attic ? I'm not worried about them getting wet, but the house is in Ontario and winters are VERY cold and the house is heated with wood. (the house does cool down quite a bit while gone to work) Will the cold cold winters ruin the batteries somehow ??? (I'm picturing all the people who can't start their cars after a ridiculously cold night and need to be boosted) We'll be starting with 4 batteries and over time probably end up with 12.
I'm preparing to do my first "alternative power" install ever. I've been reading for weeks on end. (I do have a technical background) My sister is living in a brand new, tiny, 500sq foot "house" in the middle of nowhere in Ontario. Obviously, there's no electricity or plumbing and she's been there over a year now. I have made it my mission to get electricity to her.
Thanks for any and all help / suggestions !

Battery Bank in Attic ? (COLD winters) | 16 comments (16 topical)

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#1)
by nothing to lose on Wed Oct 17, 2007 at 12:25:58 PM MST

You are probably asking for problems if you put batteries in the attic.
Houses vary like cars, so it's hard to know what you have.

A guess though is the attic should be insulated from the house. It should keep out the summer roof heat from the house and also keep in the house warm in the winter. So the attic may be pretty cold in winter.
Any leak will be a BIG problem. You don't want battery acid raining down on your head or soaking into ceilings or walls.

Myself I would not want batteries in most normal attics for many reasons.
.
nothing to lose

Spelin and tpying are my strong points, not electronics.

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#2)
by richhagen on Wed Oct 17, 2007 at 12:26:06 PM MST

Depending upon how cold it gets where you are, the main problem with batteries is that when they are low or discharged, the electrolyte is closer to pure water and it can freeze, bursting the case. The electrolyte in charged batteries freezes at a lower temperature relatively. If the batteries are being used daily, an insulated battery box is likely all that is needed in most locations. If you put them in your attic, remember that a large battery bank can be of significant total weight, and the structure will have to be able to support that weight for the long haul.

I have put a small battery supported in the rafters of a garage attached to a 20 watt panel and a small charge controller for a light. It has been there for a number of years now with no heat, and no problems. I would worry a bit about electrolyte spilling and damaging anything (wood or otherwise) below and nearby, espesially in a worst case scenario of a ruptured case. If you put the batteries in sturdy plastic tubs, or an old cooler that might help mitigate that risk.

Lastly, the batteries during heavy use or overcharging conditions can give off a bit of hydrogen gas do to electrolysis of the electrolyte. Hydrogen gas mixed with air in sufficient quantities is explosive when ignited. Now in a large attic with a single battery and vents this is probably not an issue. If the space is confined, smaller, and not ventilated, then ventilation would likely be in order. Hydrogen gas rises relative to the air. A vent either at the top of the attic (most are already ventilated to prevent moisture build up and remove heat in the summer) would likely be sufficient. Alternatively, if the batteries are in a container, and a vent tube or something similar to collect the gas from the inside top of the container and leading upward, away and outside could be utilized to vent the gas outside.

You can search this site and see some examples of battery boxes that others have built.

Make your project work for you, and have fun, Rich Hagen
'A Joule saved is a Joule made'

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#3)
by wooferhound on Wed Oct 17, 2007 at 12:44:27 PM MST

Here are some other stories about keeping batteries in the cold weather

http://www.fieldlines.com/story/2007/9/19/387/44327
http://www.fieldlines.com/story/2007/8/16/02338/7091
http://www.fieldlines.com/story/2007/6/27/7811/44777
http://www.fieldlines.com/story/2005/6/3/155321/5575

W o o f -={(

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#4)
by ghurd on Wed Oct 17, 2007 at 12:47:55 PM MST

If it is the kind of house I think it might be, maybe sitting on a 50 acre rock, possibly consider a large cooler(s) under the house or porch?
Should be able to find one or 2 that fish or worms were left in too long. Cheap!
G-
Ghurd.info

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#5)
by snowcrow on Wed Oct 17, 2007 at 03:00:03 PM MST

An old chest freezer would work well for your needs, they are already well insulated, and will give you plenty of room for more batteries. Just go to the local recycle center and pick out what will best suit your needs.

Blessings, Snow Crow

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#6)
by DigitalMind on Wed Oct 17, 2007 at 04:10:40 PM MST

Thank you SOOOOO much for all your knowledge. I really, REALLY appreciate it. I will have to think about this alot. Based on the feedback I am starting to think it will be better to somehow put IN the house without being much of an eyesore. (there is no basement, and the whole place is just 1 500sq ft room.)

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#7)
by Volvo farmer on Wed Oct 17, 2007 at 08:43:57 PM MST

In addition to what others have said...

Batteries need maintenance. They need watering, and maybe specific gravity checked from time to time. They also need their lugs checked occasionally to make sure all connections are tight. Put them in a place where you can get to them easily.

A 75% full battery won't freeze until -40F. Cold (charged) batteries lose some of their capacity but are otherwise unharmed.

In your situation, I'd be tempted to make some kinda furniture out of the battery box. I've actually heard of people putting their beds on top of them. That's a little too close for my comfort, but maybe a bench or kitchen table or something. Just vent the high side of the box to the outside and put some low vents to the inside and hydrogen should not be a problem.

Good luck and let us know what you decide!

Volvo Farmer

[ Parent ]

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#8)
by richhagen on Wed Oct 17, 2007 at 09:19:13 PM MST

Looking at the photo, I would be tempted to build an insulated wooden box just outside. It shoud be a cinch to route the cables through the frame walls. Rich
'A Joule saved is a Joule made'
[ Parent ]

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#9)
by erne on Thu Oct 18, 2007 at 05:59:47 AM MST

Build a super insulated box put it outside against the house and drill a 2 inch hole low in the box for intake air to come in from inside the house (thru the wall) put a elbow and pipe it up a bit toward the ceiling to get warmer air. Then vent the box at the top for the gassing. Put a light flap in the gas exhaust to keep the cold air from reversing. That is the way mine is and it works fine. I am at 8500 ft in the Rockies.....erne

[ Parent ]

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#10)
by DigitalMind on Thu Oct 18, 2007 at 11:58:51 AM MST

Thanks Guys. I have decided to build an insulted box on the outside of the house and route the wires through. (I'm a cable guy, so I can do that part easily). Just for the sake of sharing : I have decided to buy a kit from costco, 3 X 80watt, 12volt, Solar Panels with mounting brackets and Charge Controller ($1750 Canadian + tax) with 4 X T-105's (6v 220ah) brand new @ $150 each. (Always Canadian) This sound ok ??? I've been looking for deals from Canadian suppliers but having trouble.

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#11)
by ghurd on Thu Oct 18, 2007 at 12:18:48 PM MST

Seems crazy high for the batteries.
"Sam's Club" up there? $63 each here.
"Costco" should have the golf cart batteries too.
G-
Ghurd.info
[ Parent ]

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#15)
by Kevin L on Thu Oct 18, 2007 at 05:22:23 PM MST

The T-105's are a superior battery to golf cart batteries, hence their cost. But given your load they may be more then you need. Depends on how often you will be deep discharging your bank. T-105's can be occasionally discharged to 20% where I wouldn't take golf cart batteries much below 50%.

[ Parent ]

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#12)
by Volvo farmer on Thu Oct 18, 2007 at 12:38:08 PM MST

Sounds pretty high to me too.

Here's a 125 watt panel for less than $600
http://store.altenergystore.com/p3290/

Here's a charge controller for less than $100
http://store.altenergystore.com/p2069/

Isn't the Canadian dollar worth MORE than the US dollar at the moment? So you could get a 250W system instead of a 160W system, and still have $450 left over for brackets and shipping charges.

http://store.altenergystore.com/info/shipping_to_canada/

Shop harder!

Volvo Farmer

[ Parent ]

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#13)
by DigitalMind on Thu Oct 18, 2007 at 12:52:38 PM MST

Hmmmm ... I will look into those panels a little more.
Question though (about the 125 watt panel for less than $600), it says maximum output 17volts, is that OK for my (future) 12 volt setup ?? Does the charge controller adjust that?

... and no, there is no Sam's club here,(never heard of it) and IF they do have these batteries at Costco, they're not on the website !! I'll keep looking for the batteries a little more also.

THANK YOU ! :)

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#14)
by ghurd on Thu Oct 18, 2007 at 01:09:56 PM MST

A 12V panel works at about 17V.
Might want to look into 80W-ish panels. UPS or DHL will take them.
That 125W will probably have to ship on a skid, and that won't be cheap!

Those batteries are around 60 pounds each and full of acid.
Best bet is to check at golf cart shops.

Are you North of North Bay?
Good luck!
G-
Ghurd.info
[ Parent ]

Re: Battery Bank in Attic ? (COLD winters) (3.00 / 0) (#16)
by disaray1 on Fri Oct 19, 2007 at 05:57:33 AM MST

No intention to hijack...Ghurd, can you drop me a mail dfaith(at)cfl.rr.com...need a couple of controllers and can't find your address.

David

[ Parent ]

Battery Bank in Attic ? (COLD winters) | 16 comments (16 topical)

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