battery storage

sgtalexmom · August 2011

i'd like some input on how you store your battery bank. temp control, and such issues.

i didn't even think about this when we began working on the floor plan for our cottage!

any help and advice you can give would be greatly appreciated

snuffy · August 2011

Re: battery storage

Mine are in the basement and the temps vary with the seasons. Now it's around 70 degrees there but in February it will be in the 40's as it's an unheated basement. They're AGM batteries so I don't have to worry about out gassing and possible explosions from the gas like I would if they were flooded lead acid batteries. Those type need a good vent system.

sgtalexmom · August 2011

Re: battery storage

snuffy wrote: »

Mine are in the basement and the temps vary with the seasons. Now it's around 70 degrees there but in February it will be in the 40's as it's an unheated basement. They're AGM batteries so I don't have to worry about out gassing and possible explosions from the gas like I would if they were flooded lead acid batteries. Those type need a good vent system.

that's the reason we're going with AGM, despite the cost differences. now i need to figure out where to put them LOL no basement.

do you think a small lift-lid box attached to the house would work?

else i could try to carve out a closet area somewhere.

BB. · August 2011

Re: battery storage

Assuming you "treat" your batteries nicely (not too deep of cycling, bring back to near full charge quickly, etc.)...

The "Rated Temperature" is ~77 degrees F (25C).

If the batteries run at +18F (+10C) most of the time, you will get some more power from them (hot batteries are "more active"), but their "aging" life will be reduced by a factor of 2. (20C will be reduced by 2*2=4x reduction).

Conversely, cold batteries will have lower stored power potential (until you warm them back up), but will last 2x longer for every 10C/18F below 25C/77F you keep them.

More or less, if you can keep your battery bank above 0C/32F, you will not loose too much capacity (~20% loss at freezing).

Note that fully charged batteries will not freeze until they are very cold (well below 40C/F). "Dead Batteries" will freeze near 0C/32F. AGM's are almost "freeze proof" from damage even if frozen (All frozen batteries need to be defrosted before charge/discharging).

Some good battery stuff to read:

Battery Faq
www.batteryfaq.org

Insulated box with venting (possibly configurable by season) to keep the batteries in the 0C/32F to 25C/77F range would be best (a bit warmer will not kill them).

I am not in cold weather, and I do not use batteries, but as I understand even in cold regions an insulated battery box with a battery heater--AC Genset-- the heater is only needed to bring battery temperature up from storage--Not usually needed once people are on site and using the battery bank--natural heating from charging/discharging works well to keep them at temperature).

-Bill

icarus · August 2011

Re: battery storage

Keep them cool, water them before you leave, and keep them on float with a good charge controller and they will be fine. We have sets that have been in seasonal service for better than ten years (T-105/l-16s)

A fully charged battery won't freeze until well below -40.

Tony

Vic · August 2011

Re: battery storage

Batteries should be close to the inverter(s). Larger inverters can make a soothing HUMMMm, well, really, many larger inverters really make a BUZZZzzzz. Some charge controllers have relays which click on occasion, and can make other noises as well (these noises are reduced in most of the latest crop of CCs). The CC should be close to the batteries, if for no other reason for convenience of having all of the power conversion electronics together with the batteries.

In a small cabin, you may not have a laundry room, or similar, but, I would make certain t keep the power electronics and batts out of the bedroom(s).

It is not possible for any vanilla members of this site to conjure your location, so the extremes of weather are your secret.

If possible, would suggest that you try to do a Root Cellar type battery cave, if at all possible -- cooler in the summer and warmer in the summer.

A battery box outside the residence may be fine, except in extreme environments. An insulated box will integrate the extremes in temps. And, especially for FLA batts, (which are less effiecient), each charge cycle dumps some heat into the battery box, and some forced cooling ventilation is important if the box is insulated. Customary battery box venting is toatlly inadequate for this cooling. The root cellar type home for batts should elinimate the requirement for insulation in the battery box, so heat entrapment should not be an issue.

Soulds like a fun porject, Vic

Photowhit · August 2011

Re: battery storage

My batteries/now battery, lives outside along with the charge controler and inverter, in it's own little building;

I live in Missouri and my 4 abused, just retired Sam's club golf cart batteries survived almost 6 years in this box, and were still running an air conditioner when they retired yesterday. It lives in the shade of the panels and I never saw the inside thermometer over 100, but this summer it would live in the 90's in the afternoon.

I just put in a forklift battery, and will add a fan to the vent to help keep things cooler, but the ambient temps will limit it to around 95 in the afternoons. This has been a brutal summer.

The box is unheated I don't need the capacity in the winter.

"No pleasure, no rapture, no exquisite sin greater... than central air. "
— Kevin Smith

My golf cart batteries have just been move to a friend who had the former, now 10(11?) year old batteries die now him, he and I have different ideas of when a battery should be retired, then again he just runs a fan and a couple lights on his system.

icarus · August 2011

Re: battery storage

I confess to not reading your original post thoroughly, so I will add:

My batteries live on a rolling cart, under by office desk/work bench inside the house. The rolling cart allows me to pull them out to check the SG and the water levels. The enclosure is 1 1/2 styrofoam on the top of the box (underside of the desk, and the front and sides of the box, all covered with a wood cover that matches the desk. I have a voltage controlled fan in the box, so by closing off the batteries behind the foam and the door, I can't hear the fan running.

Batteries want to be temperature stable, away from any ignition source, and well vented.
By insulating the box with styrofoam board, it evens out the temp swings, and in the winter, the batteries will generate a bit of their own heat when we are away, further keeping them from freezing.

Tony

sgtalexmom · August 2011

Re: battery storage

thank you all, very useful info!

photowit:
YES! this has been a brutal summer. in northern illinois we have been scorched as well.
or having massive t-storms. it's been an odd summer.

vic: sorry, i should have given my location, a "duh" moment

Vic · August 2011

Re: battery storage

Hi sgt...,

Sorry for my (mild)sarcasm.

If I were the site admin, in the welcome e-mail, I would strongly encourage new members to do a profile, or Sig line with location, target interest etc. There might be a way for the Forum software to not allow posts unless something on the Profile, or Sig was input, BUT this is a bit too RIGID. This info allows more meaningful replies. The Moderators and Admin can see the poster's ISP location, which strongly implies the location of the poster fairly closely.

Did not mean to pick at you. I do apologize (for apologizing all the time !).

Realize that when one is planning a new system, some of the fine detail would not apply. And all (of us) new members are anxious to post and get started on the quest for info.

Asking good questions like yours are much better than someone telling about all of the new EQ that they have just acquired, and JUST need to know how to connect all of the (incompatible) EQ, and so on.

Have Fun, Vic, off the soapbox

sgtalexmom · August 2011

Re: battery storage

Vic: no worries. i added my location to signature, for when i forget to mention it in posts.

niel · August 2011

Re: battery storage

vic,
you are correct that requiring the info would be a bit too rigid even though nice to know ahead of time for the general membership's responses. the placement of one's location is more applicable in the upper righthand section of one's posts as there is a place for stating the locale if one wants to. many overlook it there even when people do post their location to it. high accuracy in a location listing is definitely not recommended or necessary in any case so general location info is fine if one wants to post it.

if a poster does not list the info that you want you will have to get used to asking for it no matter how redundant it gets in doing so. in keying on the location aspect, and this holds true for any info from a poster, the poster has the option of not disclosing information on themselves to the forum and may run the risk of us not being able to properly answer a question in doing so. i should mention ip addresses aren't pinpoint either and some only point to the provider's location so this is not always an advantage for mods and administrators in answering questions with enough info. also, we try to respect the poster's privacy if they did not reveal their location by staying very general and only as would be needed for giving an answer. we might say for instance, 'the nearest major city for pv watts is' or say passively something like, 'in that part of southwest pennsylvania'.

battery storage

Comments

Categories