Batteries and Winter

[skipsmith521]

I have a 36 volt ezgo. After a full charge, pack will settle to around 38.3 or a little above after a day of being off the charger.

I have maintained the batteries always keeping them charged up.

We have had 3 days of freezing temps here in the south.

The temps are back in the 50s now but I notice the battery pack seems to drop below 38.3 after full charge within a day now. It goes down to 37.8 and I have been running another charge cycle.

Water levels are all good...

Do think the freezing weather killed the pack? What would be advised ?

Even though it's above freezing now...would the colder temps run the pack charge down quicker than normal?

Thx

Skip

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[Freckles]

It was -9 degrees here a couple weeks ago and my batteries are working fine.

[BobBoyce]

It's quite normal for Lead/Acid batteries to lose some capacity in cold weather. The electrochemical reactions slow down as temperature drops.

[Tech Support]

Skip, Bob is 100% correct on cold weather and batteries. And while the change even affects newer batteries, a slightly older or partially compromised battery will suffer even more. Attached is a graph showing temp vs capacity. The graph is a reprint from the Trojan Battery website (trojanbattery.com) but would apply to all FLA batteries. Trojan puts out quite a bit of useful battery information and is a good Saturday morning, sit in the Lanai, and have a cup of coffee read. (After you have checked all the latest BGW posts of course!)

[JohnnieB]

Skip,

What BobBoyce said about the lead-acid chemistry being less active in colder weather is the reason why all lead-acid batteries have less storage capacity (Amp-Hours) and a lower At-Rest voltage for 100% SoC during the winter.

The chart posted by Tech Support shows that Trojan deep-cycle batteries loose about 2.5% of their storage capacity for every 10°F below 80°F.

Also, your battery pack contains about 10 gallons of 30% sulfuric acid electrolyte (roughly 103 pounds) and about 270 pound of lead. The SG of lead is 11.34, so that is the equivalent of 3062 pounds of water. plus the 103 pounds of electrolyte, means it takes about 3165 BTU the raise the battery pack temperature 1°F, so it is going to take it a very long time to warm up after being cold, or cool down after being hot.

If you have T-105 batteries they will have a storage capacity of 225AH at 80°F and will effectively have 197AH at 30°F and 180AH at 0°F. I don't have any good data on how much the At-Rest voltage of deep-cycle batteries for 100% SoC decreases as the temperature decreases, but the attached chart shows that it does decrease.

The less active chemistry also slows down the self discharge rate of the batteries.

In a nutshell, in colder weather your cart won't perform as well or travel as far due to the loss of storage capacity. The At-Rest voltage at 100% SoC will be slightly lower, but the batteries won't self discharge as rapidly.

Sounds like there might be more going on with your battery pack than just cold weather.

[Jmzvet]

Is there a “ sweet spot” temperature range for lead acid batteries? Im guessing dry hot weather is the best?

[NCPW]

True 100% SoC is measured at 80°F.

[JohnnieB]

Originally Posted by Jmzvet

1. Is there a “ sweet spot” temperature range for lead acid batteries?

2. Im guessing dry hot weather is the best?

1. L-A batteries have a longer cradle to grave lifespan in cooler temperatures and greater performance in warmer weather, so it depends on what kind of "sweet spot" you are looking for.

2. Only if you want higher performance coupled with a shorter lifespan. For example, in 2011, my 2008 cart came off a 3-year lease at a golf club near Phoenix, AZ, it was on its second set of T-105 batteries and they wouldn't fully charge, so the lifespan was only about 18 months when the lifespan in more moderate climates is typically about 4 years.

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FWIW: Manufacturers tend to pick environmental conditions that produce the most favorable results for their products and Wet-Cell Deep-Cycle Lead-Acid batteries are rated in the neighborhood of 80°F, so that temperature is very likely to be at or near the optimal compromise between performance and longevity.

[slashpine]

Another factor to note is in cold weather there is often very low humidity which will cause water to evaporate a little faster than when the air is humid...so it's prudent to monitor battery water levels more often...

[skipsmith521]

Today I went did some more checking on my pack.

The charge cycle turned off about midnight. I checked the pack about 17 hours later and the pack charge is 38.1

Temperature today is high of 66 degrees and low of 40 degrees.

The water levels were good...all levels were up over the plates....I did add a little more water.

I took volt readings of the individual batteries.

5 of the batteries were exactly 6.33 volts each
1 of the batteries was 6.36 volts

These are numbers after around 17 hours or so off the charger.

Any more feedback welcome...

Thx

Skip

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