Charging Issue/Blinking Guage

[tyetsko]

I have a 2018 Tomberlin E-merge 48v.
My son recently got his license so we started letting him use the golf cart around the campground. He drove it most of the day and ran the battery fairly low. The gauge started blinking so he brought the cart back to the camp site.
This was probably the first time the batteries were ever run that low and it was certainly the first time we ever saw a blinking gauge. We plugged it in to recharge but after a while we noticed the status of the gauge remained unchanged.
I measured each battery and they were all over 6 volts. I disconnected the positive terminal of the pack and reconnected it and the gauge then registered full.
We drove it again and ran it down to 1/2 charge. We tried to recharge but the gauge did not change from the 1/2-way mark. We also noticed that the charging extension cord was hotter than we recall it usually being.
Any thoughts would be appreciated.

[ojo]

What batteries do you have, 6 x 8v or 8 x 6v? My older Tomberlin had 8v batteries and If a 8v batt. shows 6v+ only, it's dead in the water...
Never discharge below 50% SOC! That will irreversible damage your batteries.

[tyetsko]

Sorry for the delayed response.

My E-Merge has 8 6-volt batteries. Individually they all appear to be at full charge.

The pack total reads over 50 volts when the gauge says full.

One other bit of info: when the pack is charging the light on the charger blinks slowly (like it does when there is still a long way to go to a full charge) Normally when approaching a full charge the light would blink a lot faster but now it continues to blink slowly.

[ojo]

Ok, slow blinking means < 80% charged, faster blinking > 80% charged. It could be a problem with the batteries. What is the individual voltage of each battery, how old they are?

[tyetsko]

Batteries are the original but have been well maintained. Water is topped off in spring, mid-summer, and fall. The cart is stored in my garage in the winter and kept plugged in.

I did check the batteries individually and they all measured ~ 6.5. Total pack voltage while charging is ~53 or 54 and close to that when charged.

I am able to charge it by monitoring it with a meter to make sure I do not overcharge the batteries. However, the gauge does not change. When I think it is close to being charged I disconnect the pack and hook it back up to get a more accurate (hopefully) reading on the guage. I am then able to drive it.

I think my next step is to try and find a trouble shooting guide. I guess I suspect the charger but maybe it is just the gauge. One thing I may try is to plug it back in when once the gauge indicates a full charge (after the disconnect hack) to see if I get the fast blinking then.

[ojo]

Could be a faulty gauge also... Enclosed a SOC chart to verify the actual state of charge with a volt meter.

[tyetsko]

Thanks for that info. It will be very useful. I will do some more testing this weekend when I am in Maine.

On a side note, we close up the camp mid-October and I bring the cart home. If I do not solve it by then (or if I am able to just limp along until then) I will have a lot more time during the week to try and properly resolve the issue.