Battery with low voltage - Will it charge in pack?

ajbrown

Background
The cart I just bought has a three year old pack of T875s. When I got the cart a couple of months ago one battery had SG readings of 1.25, 1.25, 1.26 and 1.17. The pack itself seemed to charge to about 90% and I could drive 26 miles.... I figured they were fine until next fall. The other day I noticed a drop in performance. I charged the pack overnight and late the next day took some readings. My suspect battery now has SG readings of 1.25, 1.27, 1.26, ZERO, like I was sucking up straight water from last cell . I decided to replace the battery with a spare T875 (5 year old) battery my Dad has as a test.

That battery was only at 7.99 v when I got it. My pack was at about 8.30 v per battery. I dropped this lower charged battery into the pack and charged. I monitored the charge and near the end the voltages were about 10.xx of all batteries except this new one which was 8.65.

To me, the battery was not coming up to a decent voltage....

Questions:
Will the battery with a lower voltage (7.99) get enough of a charge during a normal charge cycle in a pack with higher voltage batteries (8.30)?

This is an '02 DS series cart, will it help to reset the OBC?

Should I first bring the voltage up on this new battery using a 12v charge to match the voltage of the other batteries and then try a normal charge?

Thanks for any experience shared,
Alan

BGW

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OLD MEC

Give your charger time to do its thing unless 799 V is also fective? I assume you have a CC Power Drive charger with OBC mounted in cart for control? By allowing charger to do its thing and allowed to turn off on its own your pack will balance out over a period of time UNLESS the new battery is defective? It will over charge a few cycles the old batterys but they are probably on the way out like the one replaced anyway.
NOTE I am happy to see a cart owner willing to take the time to do a hydrometer test as Voltage alone is not fool proof?
Voltage tests should be done after waiting at least an hour for accuracy. The normal full charged voltage T-875 is 8.49 and 1.275 SP, pack should be 50.96 V.

ajbrown

OldMec, Thanks. It does have a power drive charger and OBC. I did let the charger do its thing twice, full charge and shut off automatically. Before second charge I took cart out for 8 miles ride. The "new" battery could be defective, the max voltage I have seen after charge is 8.13 (55%) and SG is consistant with that reading in all cells at around 1.15 - 1.18.

I just was concerned that this battery was not getting a full charge it required as the other 5 batteries and the OBC have no idea there is a weak sister in there.

scottyb

I had luck once with a pr of weaker batteries. They had had a pr of lights and a radio on them like some people will do. Well, when they are drawn down lower and come back up less, it tends to over charge the good ones as all the charger knows is a preset finished voltage. It's bringing the pack to that voltage whether all 4 are even or one is low and 3 are high, see? Anyway I had luck bringing my weak ones up quite high and then cycling them back into the pack a few times and everything balanced out. Not saying this won't happen for you over time, without boost charging the weak one.... I was wanting to level the pack immediately and it stayed there. Hope this helps also.

ajbrown

I am going to try this. I will borrow a 12v charger and have read some threads on that subject, so will try to boost this "new" battery. The charger is a Diehard 6/12 volt 10/2/60 amp charger.

If I read the other threads correctly:

• set charger on 12 volts
• set charger on 2 amps
• set charger on manual
• Keep an eye on it and be careful, paying close attention to the voltage and heat.

Sound about right?

Thanks again.

shadowman

those SG readings on that battery arn,t at all should be 1.25 to 1.50..................................

scottyb

2 amps is a maintenance charge. Set it on 10 and check it every 30 minutes. Take it up to 14.25v and let it sit for 12hours. Give us the reading after it sits for 12 hours.

ajbrown

This charger shuts off after 15-20 minutes at 10 AMPS. It gets pretty warm to the touch and must have an auto shutoff for heat??

I have it running at 2 AMPs. Voltage while charging is at 9.8. Will monitor to see if it goes higher before I take off charger.

Scottyb, did you mean 10.25 volts instead of 14.25?

sonicj

i have a charger similar to this: link

it will charge every battery i own; LiIon, LiPo, LiFePo4, NiMh, NiCd, & Pb! it may take a while as it tops out at only 5 amps, but the peace of mind knowing im using the right settings for a particular battery chemistry makes it worth the wait! anywho, imo its a super handy tool to have around the house/shop!
-sj

*for Lead Acid it charges configurations up to 20V.

scottyb

I am sorry, I thought you had 12v batteries.
If you use a 12v charger on the 8v you must use the 2 amp setting and do not bring it up over 9.8 v reading you have. see where it settles from here.