Am I overcharging?

TheOldMan

3 wheel EZ-Go, Batteries new about a year ago. New Heavy cables and programmable controller. Always put the cart on charge when volts got down to about 36 (mounted digital indicator), Next morning, charger would be shut down, never ever saw volts above 38. Melted the plug on the charger, so ordered a new one and installed. 2nd charge, melted again, so ordered new receptacle and plug and installed yesterday. Batteries were pretty low while waiting for parts to come in. Put on charge last nite, and this AM, charger was still indicating 5 amps, and VM read 42 volts. After setting disconnected, an hour or so, still read 39v. I guess it's possible that the charger never has been making good contact, and batts were never fully charged, but never saw 42 & charger still running. I see in one of the other posts that charger can go up to 47v, but sure don't want to burn something up or ruin batts

BGW

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rbuggies48IN

As you know 36 volts is just under 50% SOC, which is the never-go-below figure for your BATs. 1.75VPC (volts per cell) under load during normal is operation is what you want to stay above and going below 1.50VPC is a big NO-NO as damage will occur. I am thinking that as you get to 50% SOC and if you are putting a heavy load on your battery (uphills, etc.) you may get to these heads-up areas. Assuming you are watching your volt meter for these levels then you would be OK. With regard to the charger, look for feedback from others, but the 47 volts during charging seems correct to me.

JohnnieB

If the charger plug and receptacle melted, there was excessive resistance in the connections, so there is a very good possibility your batteries were being undercharged.

The charger you are most likely using, shuts off when the on-charge voltage reaches about 45V, which is 7.5V per battery. However, if there is any resistance in the cable and connections connecting the batteries in series, a portion of that 45V will be dropped across the unwanted resistance and the voltage on the individual batteries will be less than the desired 7.5V, so they will be undercharged even though the charger is operating as designed.

Having 5A of current flow with an on-charge voltage of 42V isn't abnormal, however an on-charge voltage of only 42V after several hours of charging might be. It depends on the storage capacity of the batteries, how far they were discharged and how healthy they are.

The reason the charger is still running is simply because the on-charge voltage hasn't reached the cutoff voltage yet. Just let them charge until the charger cuts off and then initiate a new charge cycle and let it run until it cuts off.

Since your batteries have very likely been chronically undercharged, a few back-to-back charges might recover a bit of the storage capacity they have lost so far.

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The practice of letting the batteries discharge to 36V before recharging is shortening the lifespan of your batteries. They ought to be recharged after each use, or at least each night the cart was used during the day.

Lead-Acid batteries have no memory, so they do not have to be discharge to some arbitrary point before recharging and the higher the average state of charge maintained, the longer it will be before they need to be replaced.