Voltage reading question

[la-boy]

I just installed new Trojan 875's and put in a new voltage meter/reader, I've read scotty b's post on batt. break in and would just like to know when do I judge the pack to be 50%. Is it while the cart is running or at rest. thanks, I just finished my first build and will post pics soon. Need to GPS the speed, but it is plenty fast for me........

[Colbyntx]

What meter did you put in? I would go off of my DMM and check it with your meter several times and go from there. Remember, you need to charge these batteries each day you use it.

[easydoesit]

Think his question is, that for break in period, he shouldn't drain the new batteries to less then 50%. Is that 50% reading taken while the battery pack is at rest? Anyhow, I would say that the answer is when the cart is at rest otherwise you would be doing a load test instead if you take the reading while (movin) accelerating.

[Colbyntx]

That is why I said to use the DMM to get the voltage reading and compair it to the new meter to see where exactally it is on his meter compaired to the DMM. Do it several times until you feel it is accurate. Dont run them below 50% anytime and charge them fully after each use.

[easydoesit]

Colby, think you missed a part of his question again. "Is it while the cart is running or at rest"....

[golfcarfixer]

just run it but dont run it till it quits and charge it. Its like filling it up with gas.Just keep topping it off,it will be better each time you do it.

[Colbyntx]

At rest! Just the same as you wouldn't check the state of charge while the charger is still on or just shut off.

[scottyb]

I thought the 2nd part of his question was just exactly where is 50% of state of charge?
This is the state of charge chart as taken from the Trojan Battery Co. It is fairly accurate

[la-boy]

I probably made a mistake and bought a cheap state of charge meter, it is the 48 v model. I was looking at the meter at rest and thought i was getting close to 50%, but after a afternoon trip w/ kids the cart suddenly started going slower. I did make it home and voltage tested the pack and got 46.?? I will need to remember that 50% on my meter is about 20-30% in reality. Do yall think I hurt the pack by doing this one time. I am only on the second full charge now. thx.....

[scottyb]

Sulfation of Batteries starts when specific gravity falls below 1.225 or voltage measures less than 12.4 for a 12v battery, or 6.2 for a 6 volt battery. Sulfation hardens on the battery plates reducing and eventually destroying the ability of the battery to generate Volts and store Amperage.



Any time this happens isn't good. The damage is small but accumulative each time this happens.
Buy good quality meters and always check them against one or better yet 2 good DVM.

You do not need to take the batteries down to 50% when new to recharge. 75% and recharge does the same thing. Actually it is better as it the recharge not the draw-down that you are trying to get done 10-20 times to break them in....