full charge for 48 volt batteries

eznude

There seems to be a lot of different opinions about what is full charge voltage on a 48 volt cart, my 2000 cc carryall 6 has 6 8 volt batteries, my old charger died and I bypassed the obc an installed a new self contained charger. It won't shut off. ( 16 hours) All my batteries read 9.1 volts, 54.8 total, after a couple hours of use they all read the same, ie 8.45.
I have a adjustment that I can lower the shut off voltage on the new charger but some people have said 62 volts is a full charge, the problem I have with this is my new 48 volt axe controller has a high voltage limit and can't be set any higher than 60 volts.
It would seem to me 9.1 volts per battery is a good charge, would someone please tell me if they have run across this problem before? thanks

BGW

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wthompson912

i use this chart to determine state of charge, most 48 volt chargers i've seen peak at about 55 to 60 volts. someone correct me if i'm wrong...

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wthompson912

test

rib33024

Welcome to BGW


What you said about - some people have said 62 volts is a full charge, the problem I have with this is my new 48 volt axe controller has a high voltage limit and can't be set any higher than 60 volts,--- this is true, but when the pack gets above 60v it will be on the charger and you will not be driving the cart, so there is nothing to worry about, when the charger turn off the pack will be below the 60v mark, here's some info



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.

eznude

Thanks for the information, but once again a difference of opinion, I have charged my cart for most of the day, all batteries read 9.5 volts, have been at this level for a couple of hours, charger is still cranking, batteries are almost hot to the touch. My batteries are 4 years old but have had limited use. I can turn down the shut off voltage on my charger, but I'm not sure if that's the problem. I have 57 volts total, should I keep charging to see if the voltage comes up enough to shut the charger off? I'm afraid that getting that extra volt does more harm than good. thanks again for the feedback