Battery voltage over 100% SOC

SW FL CC

I bought a 48v 1998 cc with T875s about a month ago. Batteries are one year old. Been using it daily and charging it every day. Almost 48 hours ago charged cart. Charger took about 5 hours to shut off which is about twice as long as it had been taking. Voltage near the end was over 65. Amp meter indicated 3 amps. Temp here is about 70F. Water is 1/2 inch over plates in all cells. Cart runs fine. Cart has been driven a couple of miles since charge.

Voltage now measures 51.7v. Trojan says equalizing charge should be 62 volts. 100% SOS is listed as 50.93v. Checked voltage with second meter. Exactly the same results. All batteries measure the same.

Is 65 volts too high? How can the voltage be greater than the 100% value?

Is something wrong or am I missing something? Comments please. Thanks.

BGW

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rib33024

Welcome to BGW


every thing is ok, 5 hours is normal, and a 48 volt battery pack can get to 67 volts before the charger turns off,

Stevegrmich

. . . check your pack voltage about 12 hours after the charge is finished . .

SW FL CC

Update: I know why the voltage is so high. Something is causing the charging system to do an equalizing charge every day! Voltage goes to 66 volts, batteries gas, etc.

Connections are clean and tight. Water levels are good.

What should I check next?

gsf35099

Sounds like you are charging just fine. My charger takes my pack to just under 66 volts each time before it shuts off. I think as others are saying, your charging system is doing okay. I have the same Trogan's and they are performing great holding a charge throughout the day driving and even when I do quick charges for just a few hours after driving. and they are 3 years old now.

SW FL CC

I thought equalizing charges were only done occasionally. Seems awfully hard on the batteries to overcharge every time but if that what everyone's cart is doing I will quit worrying. Thanks all.

rib33024

Who said they are over charging

rib33024

Here's some more info



"when your cart is fully charged the battery pack will get up to 60 - 65 volts", is correct.
In fact, the charger may have to take a 48V battery pack up to 67V, or above, to fully charge it.
On the other hand, 59V may fully charge a 48V battery pack.
The voltage it takes to fully charge a 48V battery pack depends on who manufactured the batteries in the pack as well as their age and condition.

By definition, a lead-acid wet cell is fully charged when the specific gravity of the electrolyte ceases to increase while a charging current is passing through it. Since open-circuit voltage increases/decreases as the electrolyte's specific gravity increases/decreases, open-circuit voltage is an indirect or secondary means of monitoring the electrolyte's specific gravity and is often used to do so.

An ideal charger would monitor pack voltage and when it ceased to rise over a predetermined period of time, it would stop the regular charging mode and go into a float charge mode, however few, if any, chargers typically used by golf cart owners are ideal. Most of them simply shut off at a predetermined voltage that is high enough to almost fully charge most battery packs without being so high that repeated use would significantly harm battery packs that are fully charged at the lower end of the typical voltage spectrum needed to fully charge a battery as determined by empirical data.

Here is Trojan's recommended charge curve for a single (2V) deep cycle wet cell. There are 24 cells in a 48V battery pack, so do the math and you get 58.80V to 66.96V. However, Trojan uses an electrolyte that is 27.7% sulfuric acid by weight (SG = 1.277) and other battery manufacturers use different concentrations, so the on-charge voltage that is typically reached when their batteries are fully charged, will be higher or lower.



Quote: JonnieB

kantuckian

Good info