Battery temperature in winter + chemical agents for maintenance

jimskau · November 2006

My battry store is exposed to low temperatures now that winter is setting in. The location is frost free though, but temperatures down to 3-5 degrees Celsius is common at night. How ever my location in Southern Spain makes the days pretty warm (about 18 C ). The lesser voltage late at night is obvious, but the thermal mass of the 1000 Ah store takes some time to cool down, so I don´t have any problems with that. My question is whether the battery bank is wearing quicker due to this change in daily temperature.
Secondly I have seen adds on batterystuff for a chemical equalizer for lead acid batteries. This should reduce the sulfating of the plates and give better performance/longevity to the batteries. Have any one got any experience with this? What is the actual chemistry of the equalizer?
Would this be recommended for a new battery store?
As allways thank you for your interest and help - great forum site.
Jim Skau

crewzer · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

Jim,

My question is whether the battery bank is wearing quicker due to this change in daily temperature.

The ambient temperature swing (~2 C to ~18 C; ~36 F to ~64 F) should not be a problem for the batteries. As you suggested, the battery bank’s thermal mass will keep the temperatures of the batteries themselves from reaching those extremes.

The good news about cool ambient temperatures is that useful battery life is usually extended. However, cool temperatures reduce useful capacity. Based on battery temperature, figure on a 1% loss for every degree C below 25 C. Also, cool batteries require a higher charging voltage, so using a charger with built-in temperature compensation and a remote battery temperature sensor is recommended.

Secondly I have seen adds on batterystuff for a chemical equalizer for lead acid batteries. This should reduce the sulfating of the plates and give better performance/longevity to the batteries. Have any one got any experience with this? What is the actual chemistry of the equalizer?
Would this be recommended for a new battery store?

I’m not aware of any chemical additive that works. Bill Darden is an on-line battery guru, and here's what he has to say about this subject: http://www.uuhome.de/william.darden/carfaq14.htm#pulse

HTH,
Jim / crewzer

mike95490 · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

Any thermal cycleing (cold - hot - cold) will slowly degrade anything as the expansion/contraction swings back & forth. That's one way we life test spacecraft parts, is with hundreds of thermal cycles, eventually we get something to break. Batteries would be the same, so strive to keep the temps more stable.

Cooler is better for battery life than hot.

I know of NO magic dust to add to a battery that makes them stronger, last longer, or feed the cat for you. I'm pretty sure you could do something to a sick battery to get another week of use out of it, but I would only add distilled water to a battery.

crewzer · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

In general, I'd agree that thermal cycling should be minimized, but space standards (-250 F to + 300 F?) are probaby a bit severe for Jim's application. Instead, and considering the the environmental swings experienced by batteries in RV's and under the hoods of cars and trucks, I'd project that a daily ambient temperature swing of ~28 F will have less of an impact on Jim's battery life than will proper charging and maintenance protocols.

Regards,
Jim / crewzer

niel · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

i too will chime in here saying they should be fine and a controller with a battery temp sensor is a must. the only additive should be distilled water or possibly a bit of acid if too much boiled out. if your batteries are on their last legs and you're trying to buy some time until replacements arrive or until that you can afford them, then ok take the chance on an additive. like everybody else i have not seen an additive other than the distilled water or acid that works. proper maintenance does the best in giving your batteries long life and being sulphation free.
if you ever feel the temperature is falling too far then an enclosure with some insulation is ok, but give the batteries plenty of breathing room.

jimskau · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

Well that should conclude this session for me. I will keep on feeding the cat myself! :-D
I should be able to make it through the winter with a few polystyrene plates round the bank. My Mppt charger has temperature sensor. I expect far bigger problem when summer arrives. In a period of no less than 3 months, the ambient temperature round my houses reaches 35 - 40 degrees Celsius for several hours every day. In this environment insulation won´t be a good idea unless I get some kind of DC cooling device, as the excess heat will be at PV production peak, leaving amble surplus energy to run a small airconditioner. Does anybody have an idea of where to search for 12V DC airconditioners of a reasonable power consumption? My array is of 500W.
Another matter of concern is that my bank is located between two wooden houses in a space of app. 5 ft. width.Will the gases affect my wooden walls? I know by now, that wearing nice work clothes is a bad idea. Even an hour around the batteries makes nasty holes in anything of cotton or similar.
Thank you for your kind advice and thoughts on the previous matters.
Jim Skau

crewzer · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

Jim,

Check this company in the Netherlands for small DC air conditioners: http://www.dcairco.com/

HTH,
Jim / crewzer

mike95490 · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

jimskau wrote:

My array is of 500W.
Another matter of concern is that my bank is located between two wooden houses in a space of app. 5 ft. width.Will the gases affect my wooden walls? I know by now, that wearing nice work clothes is a bad idea. Even an hour around the batteries makes nasty holes in anything of cotton or similar.

With a 500W array, and a decent charge controller, I don't think you will have much of an overheating problem. Even a simple 12V in-cab truckers fan should be fine
However, the problem you mention about holes in clothes, that sounds like acid outside of the batteries. How's that happening ? The batteries work best with the acid inside.
The only gasses you should have would be oxygen and hydrogen so that should not matter much

niel · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

However, the problem you mention about holes in clothes, that sounds like acid outside of the batteries. How's that happening ? The batteries work best with the acid inside.
The only gasses you should have would be oxygen and hydrogen so that should not matter much

if he is overcharging his batteries there could be electrolyte escaping into the air along with the hydrogen and oxygen. this is evident when the batteries are boiling hard, but some escapes over the normal lifespan of a battery. most batteries do contain more acid than is necessary, but should he lose too much it is recommended some be added back into the cells with specific gravity readings taken to assure there is enough and it is done in a manner to equalize all of the cells.

System2 · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

Re holes in the clothes, I took it that he was giving us a joke, a chuckle, like when I posted about having the negative cable to my battery bank, run outside the shed and along the north wall for about 10 feet, before returning to the battery terminal, thus acting as a heat sink to "cool off any hot electrons", so they wouldn't heat my batteries. LOL. Sorry, I seem to have an evil sense of humor.
:evil:
Wayne

jimskau · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

Well I will have to admit, that the holes in my pants emerged after moving my newly acquired batteries to their new location. When I picked them up from the delivery truck in town, one of the 4 batteries had fluid spilled over the cardboard. Little did I then know - now the wiser, and a pair of sturdy workpants poorer

Jim

jimskau · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

Oh!
I almost forgot. Thanks for the Dutch link Crewzer! :-)

niel · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

jimskau wrote:

Oh!
I almost forgot. Thanks for the Dutch link Crewzer! :-)

make that ditto from me. they seem to be fairly efficient as 1w equals about 3.4btus. the units are nice looking too, but pricing on such ac units are usually very high just as they are for rvs. if anybody gets or has one of these units, please chime in on it.

crewzer · November 2006

Re: Battery temperature in winter + chemical agents for maintenance

You're welcome! 8-)

System2 · January 2007

Re: Battery temperature in winter + chemical agents for maintenance

Charge battery and equalize. Then some folks that I know are acid balancing the batteries and getting much longer life out of them. They check the specific gravity and add acid if needed to get the level up to equal on all of the units, somethimes even hotter and the batteries work much better. The batteries that they deal with are the fork lift type (Flooded) and they also salvage the telcom products. Another batch coming in 2 weeks (I'm crossing my fingers)

I have (2) 48 volt strings of 6VF11 Hawker batteries. 100 AH @ the 10 hour rate. I don't think even Jim can find out the 20 hour rate (But he is pretty good!) These are VRLA sealed batteries BUT!!!!!! the top POPS off (there is an O ring, and the rubber caps come right off and PRESTO you can add distilled water!!! So I might give them a heavy equalization charge. The worst thing that will happen is that I trade them back in equal weight for equal weight and I buy the battery man lunch then I get different ones that are of the same age and type. These were $700 each new and I am paying $41.20 each and I'll be able to load test them after the Trimetric arrives from NAWS. I'll keep you posted. Oh, I might add acid if the cells are very different to acid balance. I buy acid 5 gallons at a time. I have also purchased EDTA, but haven't had any luck so far.

Skip

James · January 2007

Re: Battery temperature in winter + chemical agents for maintenance

Use care with the VRLA sealed units.
Yes, you can add distilled water, but I would be careful with regards to an equalization charge.
they should absolutely be in metal "jackets" (cases), as they plump when you cook'em!
I've done it.

Battery temperature in winter + chemical agents for maintenance

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