EZGO Cart charge does not last long

[djcvet]

I have a 1996 EZGO 36 volt cart that I just bought and installed 6 brand new Rolls batteries in it. They were fully charged at 38.2 volts. We took it out last night and had 2 adults and a 70 lb dog on it. We road around with the lights on for about the distance of a 9 hole golf course. 1/2 mile from home I started noticing the power diminishing until it finally quit altogether. I towed it home and checked the battery voltage and it was at 37.2 volts. What am I missing here? I thought that with new fully charged batteries it should go a lot further.

[JohnnieB]

What Model Rolls batteries?

Are lights LED or Halogen?

Are lights powered by separate 12V battery, or by a 36 to 12V voltage reducer, or from tow of the 6v batteries in the 36V pack?

Which drive system? (Series or DCS)

How many miles are in your local 9 hole golf course?

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New batteries only have about 75% of their rated capacity until they are broken in and it takes a couple dozen charge cycles to break them in.

The charts that say 38.2V is 100% SoC are for Trojan brand batteries, Rolls batteries use a different SoC chart.

[ThreeCW]

Originally Posted by JohnnieB

New batteries only have about 75% of their rated capacity until they are broken in and it takes a couple dozen charge cycles to break them in.

JohnnieB is correct that new batteries start out at only about 70 to 75% of their rated capacity but develop more capacity as they "break in". But breaking them in should be done carefully; you can read more about breaking in batteries here: https://www.cartsunlimited.net/battery-break-in-.html

CGTech recently posted this Trojan T-105 Battery Test Plot which shows new T-105's taking 100 charge cycles to get them up to 100%.

This plot dates back to 1993 ... but I'm thinking that it is still valid today.

Here is some more on the subject of breaking in batteries from the "Battery University";
"Formatting is most important for deep-cycle batteries. They require 20–50 full cycles to reach peak capacity and field usage does this. During breaking-in, manufacturers recommend going easy on the battery."
Read more at: https://batteryuniversity.com/learn/...acid_batteries

And finally, have a look at this Trojan Battery Video to get more information on battery capacity. In this vidoe, Trojan indicates 75 to 150 charging cycles to reach full capacity: https://www.youtube.com/watch?v=O-iW...ature=emb_logo

[djcvet]

The batteries are model 6 FS GC. The headlights are halogen but I have LED's on order. I have the lights hooked to the first two batteries in the group which gives me 12 volt. Not sure what drive system (how do you tell)? 9 holes is equal to about 2 miles.

[JohnnieB]

Tapping the battery pack for 12V imbalances the pack and will shorten the battery's cradle to grave lifespan. Better to use a separate 12V battery of accessories, or a voltage reduce that draws evenly from all the batteries in the pack.

Rolls 6-FS-GC (without the HC suffix -- spec sheet attached) is a 215AH 6V battery, which is about 5% less storage capacity than the standard 225AH batteries typically used, but that should only reduce the range by about 5%.

Golf carts can typically carry two golfers and their clubs for two to three rounds (18 holes/round) on a single battery charge, so only going 2 miles is definitely nowhere near normal, even with undersized batteries and being tapped for 12V.

Attached is a chart that can be used to tell which drive your have.

[djcvet]

Can a defective solenoid cause this problem?

[JohnnieB]

Originally Posted by djcvet

Can a defective solenoid cause this problem?

Possible, but not likely.

Short runtime (range) is typically a battery issue, either the battery charger or the batteries themselves, or something associated with the two.

You implied the batteries started out at 38.2V and stated they had 37.2V after towing it back home.

The voltage of a lead-acid battery drops rapidly when amps are drawn from them and they recover their voltage slowly after the amp flow stops. The amount of voltage drop is determined by the number of amps drawn, the storage capacity of the battery and the battery's SoC (State of Charge).

I suspect there was upwards of an hour between the time the cart stopped running and you got it home and measured 37.2V on the battery pack, so the battery voltage was well recovered, which means the pack voltage was significantly lower when the cart stopped running.

If the batteries were fully charged when the 2 Mile trip started and about 75% charged when you got the cart back to the house, your new batteries are in poor health.

What make/model of charger are you using?

Charge batteries overnight and at about noon the next day, measure the battery pack voltage and the individual battery voltages.

According to the chart on the 6 FS GC spec sheet I attached to an earlier post, the 100% SoC voltage should be at least 37.8V for the pack and 6.30V for each battery. Also, all 6 batteries ought to be within 0.1V of each other.

Then drive the cart around close to home while monitoring battery pack voltage with your DVM.

When the pack voltage drops to 36.0V, stop and measure the individual battery voltages. They should all still be within 0.1V of each other.

If the pack goes below 28V, stop and let the batteries recover for half an hour before heading back home.

[DaveTM]

You may want to pick up a Hydrometer just to see what it says about the battery acid.

[djcvet]

I had a cart mechanic stop by and discuss the problem with me. He said he really doubted that it was a solenoid or battery problem. He said he was almost certain that the controller was the problem. I am going to go with his experience and send the controller out to be bench checked and repaired if possible (can't afford a new controller right now). Anyone know of a company where I can get this done?

[Doubles Shooter]

Did your mechanic do any voltage tests? If not, do as JohnnyB suggests. A few minutes testing will eliminate the batteries as the problem and could save you a few weeks of waiting for your controller to be tested needlessly.