Know how to determine the battery info, but what to do with it?

[shmo]

I just pulled my 48V cart off the charger, then checked for voltage in the Interstate Workaholics. Out of the batteries, 5 are within 8.42 and 8.49. One battery however has a voltage of 8.25, indicating a 60% state of charge. Later today I will check voltage once again, after the cart has some miles on it, but I am sure that reading will be somewhat grim. I have no idea how old the batteries are. I was told they were "pretty new" when I purchased the cart a few months ago. My charging cycles are typically every night or every other night depending on the amount of use the cart is given.

For obvious reasons, I would like to get the most life and performance from my cart. With that said, I have seen the battery charge graphs and a lot of discussions about how to determine if a battery is bad, but I have not read much in regards to what to do after you have come to a conclusion on the batteries condition. Does this reading indicate a shorted cell? With this reading, Is the battery completely junk or is it just low on life? Would it be O.K. to just run it and replace the whole set of batteries at a later time, or would it be in my best interest to replace just the weak battery? The cart "feels" to be working just fine. Perhaps slightly lower on the available torque comparing it to my other 48V cart. Top speeds are exactly the same however. I hope this is enough information for suggestions on what to do.

Thanks,
SHMO

[SpoiledRotten]

How much run time are you getting off of the pack? I waited until I barely made it around 18 holes on the golf course and decided I was tired of taking the chance. Man, did the new batteries make a difference. You might be just buying time, but then you have to decide if you have enough ride time to satisfy you for a while. Some golf cart dealers sell used batteries so you might be able to find a replacement battery that is about the same condition as the 5 better batteries that you now have.

[scottyb]

A voltage test after charging only tells you the charger is charging and the battery appears to have taken a charge. I say appears because the real question is can they hold a charge. So, check voltages when the charger is done. Number the batteries & write the readings you got for each battery down. masking tape and a pen works good for this if your batteries are not too wet. If they are too wet they are over-filled and that is a different problem.
Let the batteries set, unused for 12 - 48 hours and then recheck your voltage. Note the before and after readings and post the results here along with the test time span & test area temperature.... Meanwhile get a battery hydrometer for the next test

[shmo]

Going to do that...thanks Scotty. I will post my findings and get that hydrometer purchased today.

SHMO

[shmo]

Here is another (maybe stupid) question. Is it OK to put it back on the charger after putting a full charge into it last night?

SHMO

[scottyb]

If it has sat ans settled then recharging is okay, the charger will shut off when the pack reaches a preset limit. Now~ if you had one dead battery and the pack could not hit that limit then you could overcharge the remaining healthy 5



That's why we need the hydrometer and not the voltmeter, next.

[shmo]

So,

I plugged it in....it reached 80% quickly, but it is continuing to run...roughly 15 minutes now. Should I continue to charge it?


SHMO

[shmo]

I feel confident that the entire bank should be charged fully, or as fully as it will get.


Here are the findings at 2:00

1) 8.64 volts
2) 8.64 volts
3) 8.41 volts
4) 8.5 volts
5) 8.62 volts
5) 8.62 volts

SHMO

[shmo]

Two hours later and the temperatures have been roughly 70-75ish most of the day.

1) 8.51
2) 8.52
3) 8.30
4) 8.42
5) 8.46
6) 8.47

SHMO

[smallblock450sl]

I hate battery carts...the battery acid puts holes in my jeans Scotty is an expert, take his advice, I'll just throw in a couple of ideas. As far as I know, all battery's should have a letter and number stamped on one of the lead terminals for a date code (ie; c7 would be march 1997 or 2007). Volt meter will only read surface voltage. The hydrometer can show differances in the cells taht could help decide if a battery is bad (1275 to 1175 in one battery differant cells would show a problem), and the color of the water/acid in the hydrometer...is it clear or muddy colored? Muddy-bad!. I really beleive the best test is a download machine, it works to drain the batteries like if driving the cart and tells you minute reading of battery pack run time capacity. After the machine quits, quickly turn the machine back on (before they have a chance to (what do you call it Scotty?) regain voltage and volt meter each battery to find a bad battery or more in the set. I myself do not recommend replaceing 1 or 2 batteries in a set that is over 3 years old, after charging and discharging several times, the new batteries will equalize within the set and basicly will be as old as the old batteries (wasted money?). Lastly, Mac or DPI chargers, if plugged into a fully charged battery set, will go to 80 % quickly, but normally will still run for 15 to 30 minutes before it shuts off and green lite comes on. WHEW...I'm tired Hope this helped alittle, but as I said, take Scotty's and Roady's advice very seriously...they know there stuff