Charging time - 3 month old batteries

[SaltLifeCC]

I bought new batteries a few months ago - Trojans. I made sure to put them through as many charge cycles as possible before taking it to the campground for the summer. While at the campground, anytime it is going to be parked for more than an hour or so, we plug it in. I've been super-anal about maintaining the water levels, and when we leave it unattended for a week or two at a time, we leave it plugged in.

One of the benefits of brand new batteries was, hopefully, reduced charge cycle times. And, it seemed at first like that was the case. However, over the past few weeks, I seem to be right back to 12+ hour charge times with no other real variables from the norm like riding it longer, further, differently than usual. The cart has to be parked by midnight every night. We park it and immediately plug it in. I've been going out the next morning around 8:30 or 9 and find the charger still humming and the meter hovering around the 3 mark. I check it several times over the next couple of hours and it's still the same. Am I doing, or have I done something wrong here? Or was the promise of reduced charging times just a gimmicky promise?

[Golfdog]

A couple of things to check. When you plug in the charger do the amps go up to 15-20a where the bulk of the charge will take place.? Take a multimeter reading across the pack when the amps are at 3a. The charger should switch off when the voltage gets to +-64v on newish batteries. The deeper the discharge the longer the recharge. When the OBC does an equalisation charge it will run for a lot longer than normal.

[SaltLifeCC]

Thanks. I didn't have my meter with me last time I was down there. I will take it and check it next trip. But, yes, the meter on the charge goes up as usual when the cart is first plugged in. Everything is basically normal except that it seems to have started taking longer to cut off.

[jdunmyer]

SLCC,
If the battery pack is heavily discharged, it can take 12 hours to bring it to full charge. My first cart came with a Lester charger that had a simple 12-hour timer and instructions on the top of the case:

For lightly discharged batteries, set timer to 7 hours. If batteries are heavily discharged, set timer for 12 hours. To do a rough check in the morning to see if batteries are fully charged, set timer for 1 hour and see if the charge rate goes down into the Green within about 15 minutes.

"Green" being under 5 amps.

Does your charger ever shut off by itself? When topping off the charge it is normal for the charge rate to sit there at some low value for quite some time.

[SaltLifeCC]

Originally Posted by jdunmyer

Does your charger ever shut off by itself? When topping off the charge it is normal for the charge rate to sit there at some low value for quite some time.

I have a power drive II charger, so there are no timers. And yes it cuts off by itself. I always make sure it gets a full charge at the end of the day when it has been ridden. No, I don't take a meter and test the pack voltage everytime the charger shuts off - but I make sure the charger runs until it shuts off. The cart does see a good amount of use on a typical day.

[jdunmyer]

SLCC,
It sounds to me like your charger/cart/batteries are working in a normal fashion, albeit not quite what you expected. Monitoring things with a good DVM should verify that, along with monitoring the water usage. If it's truly overcharging, water usage will be excessive.

[SaltLifeCC]

Originally Posted by jdunmyer

If it's truly overcharging, water usage will be excessive.

It has required so little water, I was starting to wonder if that's an issue in itself. With my tired old batteries, I was having to add water all the time.

[Sergio]

This may be a good opportunity to check how well your battery pack is balanced.
The next time you find the charger at 3 amps after 9 hours or so:
A) Set your meter to 200Vdc and measure the pack.
B) Divide that measurement by 6 and round to 2 decimal places.
C) Set the meter to 20Vdc and measure each battery.

The voltage you get from "B" will be the approximate voltage each battery should have in a well balanced pack.

For each battery in "C" below that value, another battery will have to make up the voltage. If You have a battery that is much lower than the average, You may be cooking a good battery that is overcharging to make up the difference.