Effect of ambient temperature on battery capaity

Salaam friends,

I feel some capacity decrement since the weather has become cold in my home. I found that the lower temperature has negative effect below 20C.

Can friends share their feedback to enlighten others.

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Source: http://www.leoch.com/pdf/reserve-power/agm-vrla/lp-general/LP12-7.0.pdf

thanks for info mysterio92.

is this for agm or gel?

AGM

amazing that at high temperatures its capacity is at maximum

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i am not sure about the values above.. all batteries are designed to be at max performance at room temp. which is usually 25C. modern gel batteries can withstand much lower temps than AGM .(in majority brands) but higher temp will reduce battery capacity in almost all cases.. majority manufacturer specs state that battery should not be subjected to temps higher than 35 for optimal performance.anything above will drastically reduce battery performance and charging capacity. the graphs for all batteries drastically slope downwards in terms of charging and backup at higher temps.. and also heat will kill everything and reduce its life...extreme low temps will reduce battery performance but wont have as much negative impact on battery life unless you are freezing the acid in it.

batteries should ideally be kept in an open space well ventilated area, preferably away from sunlight.. which is why under the stairs is a good place.

PS: just saw that this value is by Leoch batteries..

i am not sure, why does a 103 % value even exist... if thats the highest capacity, then 40C should be 100% and 25C should be 97%.. meaning it would be best to put these batteries on the roof in summer for optimal performance (makes no sense to me, but i am not the manufacturer )

Thanks all for the valuable input. This will help understand members any abnormality if it happens during coming winter as the temp may fall as low 3C or so.

Mine are under shaded area but on first floor and it is highly ventilated place so I have already felt change in the capacity.

[quote=“farhan_ds, post:7, topic:22361”]

i am not sure, why does a 103 % value even exist… if thats the highest capacity, then 40C should be 100% and 25C should be 97%… meaning it would be best to put these batteries on the roof in summer for optimal performance (makes no sense to me, but i am not the manufacturer )

[/quote]

It makes perfect sense. Batteries are rated by following a certain test regimen (temperature, discharge rate, etc) and battery capacity (100%) is defined under same parameters. That allows one to make valid comparison between batteries from different manufacturers. 103% is merely relative reading showing that temperature increase will result in higher capacity (at same discharge rate).

Batteries produce current as a result of Chemical Reactions inside it.
Heat increases the rate of Chemical Reactions(for most of the reactions, if not all). That is why higher rating of battery at higher temperature(for e.g. 100Ah battery giving 105Ah).
But beyond a limit, high rate of chemical reactions eats up the active material inside the battery too soon. Thus the short battery life at continuous elevated temperatures. A rough guideline, for every 10 degree C the battery is above its design temperature, the battery life is reduced to its half.

Most of the sealed batteries are rated for 100% capacity at 20 degree C. Some(agm-gel hybrids) are rated for 25 degree C. The closer the batteries are kept to their rated/design temperature the more life can be extracted from them.