Are these batteries bad (Crown Deep Cycle)

[L11Hill]

Need some help identifying whether my batteries are dead/dying.

The cart (2005 precedent IQ) will go for for a very little while, but then dies quickly. I want to make sure I am measuring them correctly, and take any advice regarding replacing or fixing the issue. What is odd, is that the batteries are less than 2 years old (Crown deep cycle).

I set the multi-meter to DC 200, and below are the measurements for each battery (NOT under load)
Battery 1 (driver front): 11.8
Battery 2 (driver back): 11.8
Battery 3 (passenger front): 10.9
Battery 4 (passenger back): 11.7

I then test them under load at about 80% throttle, and measured:
Battery 1 (driver front): 11.3
Battery 2 (driver back): 11.8
Battery 3 (passenger front): 6.1
Battery 4 (passenger back): 11.1

I am pretty sure that battery 3 is bad because of the significant reduction while under load. But what about the other 2 that hand reductions as well? Battery 1 went down by .5, and battery 4 went down by .6. Battery 2 didn't go down at all... If it is just that one battery that is failing significantly, what are the risks with just changing out just Battery #3?

The date stamps on each battery show that these were manufactured in December of 2018, so I may have some warranty opportunities.

Any suggestions would be appreciated!

[kgsc]

Bat 3 is toast. I would also put a car charger on the other 3 one at a time and see if they will come up to a full charge. Charger may have some issues also.. Did your bat 3 happen to have the lights connected to it alone?

[L11Hill]

The previous owner wired a solar panel on top of the cart and the negative of the battery is hooked into that system. The positive has a blue wire that runs into the main wiring harness, and I am not sure what the deal is there. The guy I bought it from had a farm and was into solar and whatnot, I am not, so when I fix this I may take the solar panel off and cut that out of the equation.

Would one failing battery cause the issue? This thing won't make it around the block. If it's toast, I may as well start with replacing that one battery, but do I need to consider switching them all out?

Thanks!

[kgsc]

I would try charging the other 3 first then if they come up replace the one with a good used one if you can find one. Low voltage will cause the issues you are having.

[rib33024]

At 11.8 volts you batteries are only 10% charged. A fully charged 12 volt battery will read around 12.75. You can NOT fully charge a battery pack with a solar panel only. You need a golf cart charger to fully charge the batteries. Are you batteries golf cart batteries? Or deep cycle batteries? And it sounds like you don't have a golf cart charger? What batteries and charger do you have?

[L11Hill]

The batteries are 12v deep cycle batteries by Crown. I will be honest, I never have used the solar panel and have only used the golf cart charger that came with it. I charge it overnight, and have never tried using the solar panel. That said, the solar panel IS plugged into the system - so it could be the culprit.

[rib33024]

What batteries and charger do you have?

[Mooncarter]

Originally Posted by L11Hill

The batteries are 12v deep cycle batteries by Crown. I will be honest, I never have used the solar panel and have only used the golf cart charger that came with it. I charge it overnight, and have never tried using the solar panel. That said, the solar panel IS plugged into the system - so it could be the culprit.

If you charged overnight, and that is the voltage you have, those batteries are toast.

[meimk]

What you're labeling battery #3 should be the pack negative battery. The blue wire on the (+) terminal of that battery should be for the lights, so that one battery may have been discharged significantly more than the others over time. Are you charging after every use? Do they have sufficient water in them? Do you let the charger run till it shuts off on it's own? Does the charger show high amperage when it first turns on? Have you ever checked what voltage the pack is near the end of the charge cycle? Sorry to ask so many questions, but there's many things involved in battery care an condition.

[yawood]

Here is a good table. As you can see, your batteries are only 30% charged at the best of times. Try the car charger method to see if you can get them higher but if they won't go much above that, they're toast. No 3 is toast anyway.

If you decide to replace just no 3, see if you can get a second hand one from a battery shop that is about as good as the others. Don't be tempted to replace No 3 with a new battery, you'll just ruin it very quickly. Either replace No 3 with a cheap second hand one to try and buy some time or replace them all with new.

No 3 is the one that is stopping the cart from having any distance. If it was as good as the others, you still wouldn't have a great cart but at least it would go further.