2015 E-Z-Go won't move

[ChevyIIragtop]

2015 E-Z-Go RXV 48 volt
Installed light, turn signal and horn kit about a year ago – wired in a down converter and power the accessories through it. Nothing new added in the last 6 months. It is my first cart and while I am mechanically inclined, I am not skilled at the basic troubleshooting that would point me in the correct direction.
My issues began with intermittent stuttering/stumbling when I would accelerate from a dead stop and now it will not move at all. Searching the site led me to think it was a low battery issue and I thought I found one. I went out today and removed all the batteries and checked them all again to be sure I had only one bad battery. After I got them all out, the battery I thought tested bad now shows 12 volts, along with the other three.
I appreciate any assistance!

Thanks

Fred

[BobBoyce]

Originally Posted by ChevyIIragtop

2015 E-Z-Go RXV 48 volt
Installed light, turn signal and horn kit about a year ago – wired in a down converter and power the accessories through it. Nothing new added in the last 6 months. It is my first cart and while I am mechanically inclined, I am not skilled at the basic troubleshooting that would point me in the correct direction.
My issues began with intermittent stuttering/stumbling when I would accelerate from a dead stop and now it will not move at all. Searching the site led me to think it was a low battery issue and I thought I found one. I went out today and removed all the batteries and checked them all again to be sure I had only one bad battery. After I got them all out, the battery I thought tested bad now shows 12 volts, along with the other three.
I appreciate any assistance!

Thanks

Fred

Voltage at no load by itself does not indicate that a battery is good or bad. It is the ability of that battery to hold an acceptable voltage while under heavy load that determines battery condition.

[nickdalzell1]

When you wired in the DC-DC converter did you make it where it only turns on with the key on? Otherwise it might have drained the pack.

[ChevyIIragtop]

Yes, everything shuts off when the key is off.

[basshawk84]

If these batteries are the original ones for the cart, they are 5 years old and due to be replaced.

[ChevyIIragtop]

Should have clarified, I bought the cart in Oct 2018 and new batteries were installed at that time.
Other than the light kit, the only other modifications were when Bob Boyce made some speed updates on his trip through AZ last year

[ChevyIIragtop]

Originally Posted by BobBoyce

Voltage at no load by itself does not indicate that a battery is good or bad. It is the ability of that battery to hold an acceptable voltage while under heavy load that determines battery condition.

Is testing under a heavy load something I can do in the garage or will I need to seek professional help?

Thanks!

[AZgolfcartguy]

Originally Posted by ChevyIIragtop

I went out today and removed all the batteries and checked them all again to be sure I had only one bad battery. After I got them all out, the battery I thought tested bad now shows 12 volts, along with the other three.

When you say you removed the batteries to check them, are you saying you take them somewhere to be tested? If so, I'd highly recommend you buy a handheld multimeter. If there's only one tool you ever buy for your cart, a multimeter should be it. You can get a cheap one for about $20.

Your batteries should be showing close to 13 volts when fully charged. If they are only two years old and never get above 12 volts then they are likely being under watered or have otherwise been damaged. A healthy pack should meter out to about 51 or more volts after five or ten minutes of use.

Originally Posted by ChevyIIragtop

Is testing under a heavy load something I can do in the garage or will I need to seek professional help?

Basically you need to just drive your cart around, but you can't. Instead, fully charge the cart, unplug it, meter each battery, and then turn on and leave on whatever lights or aftermarket accessories you have wired into the pack, anything to use the batteries while the cart is immobile. Double check all your cable connections for tightness, dirt, burn marks, and damaged terminals while you're at it. Come back in a few hours depending on how fast they lose a charge and individually meter the batteries again; you don't need to remove or unhook them. If you notice one has fallen off faster than the rest then that's your weak link. Alternatively, you could invest in a hydrometer.

If you find one battery is just lagging because it never gets a full charge when hooked into the pack, you can balance the pack and bring the lagging battery up to par with an individual trickle charger for about $30.

[kgsc]

Jack it up, put the meter on the pack and hit the go pedal. What does the voltage drop to.

[ChevyIIragtop]

The battery I thought was bad was the rear most battery. So I took all the batteries out to get to it.
Yes, I have a multimeter. I used it to determine the one battery was low but I am not sure how I got the reading of 3 volts when every other battery showed 13 fresh off the charger. It sat off the charger for a few days as I planned to remove them. That is when I got the reading of 12 volts on every battery.
Would checking the voltage while depressing the accelerator pedal still give me any information?
I will be picking up a hydrometer as well.

Appreciate all the advice! I am very much a newbie at this