Sluggish 2002 EZ GO

Blivit

New owner (1 month) of a 2002 EZ GO Matrix (36 volt). Six new batteries have been installed. Have used the cart quite a bit, but automatic charger still won't kick on and I think that's normal (batteries reading 34.5 volts).

Cart has been running like a scared rabbit, but all of a sudden it is sluggish ie- the least little load (up hill, tall grass etc) and it looses power. I installed a new solenoid, but it is still sluggish. Probably not important, but the old solenoid had a diode across the input terminals and a 250,000 ohm resistor across the load terminals. I did not reuse either with the new solenoid.

Thanks in advance for any suggestions.

BGW

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JohnnieB

Stop driving your cart immediately your batteries are being killed, if they aren't already beyond resuscitation.

Your charger is not working, fix it or replace it.

The batteries ought to be recharged after each use, or at least each night if cart is used during the day.

Your batteries are only 10% charged and cart batteries should never be discharged below 50% SoC (36.3V)

What is make/model of charger?

Attached Images

JohnnieB's SoC Chart.JPG (63.9 KB, 0 views)

Blivit

Thank you JohnnieB. My charger is a Textron Model 26984 and I was pretty sure it was good, as it charged fine when I got the cart with (the old batteries) installed. So, being a "automatic charger" when it failed to "come on" with the new batteries, I thought the batteries had not reached a voltage low enough for it to "come on". Cart does not have a battery voltage indicator. I tried many times (b4 posting here) to find out at what voltage the charger is looking for in order to start charging. I found 2 suggestions of 1 25v and 2 34v. Do you know the real voltage ? I guess it's really academic ie just plug it in and if it needs charging, it will come on, if not it will not.

Now, for the answer to my problem. Don't tell anyone, but I failed to connect the wire that provides the - minus voltage to the charger jack
Once I hooked that up, she's charging (at 17 amps) and hopefully the batteries have not been damaged. It's been charging now for about 40 min & it's still at 17 amps. I did not take any SG readings b4 starting the charger, but about 10 min after starting charge I checked SG on 1 cell in 3 different batteries and the SG ranged from 1200 to 1275.

Thanks again.

JohnnieB

An EZGO/Textron model 26984 is better know as a Total Charge III or TC-III. Here is a service manual for it.

It'll turn on if the battery pack is above about 30V and stay on until the on-charge voltage is about 45V.

Technically, there is a relay on the control board whose coil has to be energized by the cart's battery pack to apply the AC power to the charger's transformer, turning on the charger, so the minimum turn on voltage is whatever the minimum contact closure voltage is for the specific relay installed in the charger. Some will close several volts under 30V, but nearly all will close with 30V applied, "so about 30V" is about as specific or well defined as it gets.

Once the relay energizes, a self holding circuit kicks in and keeps it energized until the battery pack's on-charge climbs to 45V +/- 1V. That is a voltage range that was thought to be high enough to adequately charge new batteries without be so high it overcharged old batteries. The technology used is over 50 years old and there have been some improvement is battery charging technology since then, but it still does a pretty good job.

The control board in the TC-III (Which is a semi-smart switch that isn't part of the actual charging process other than turning it on and off) also has a backup timer that shuts of the charger if the on-charge voltage does not climb into the 44V to 46V range withing 12 hours or so. Since this is the first time your new batteries have been charged, and they were severely discharged, it may take 20 or more hours of charging to get them recharged, so unplug the charger from cart, wait a few moments and plug it back in to start a new charge cycle.

FWIW: Battery manufacturers take their products down to 1.75VPC (Volts per Cell) during non-destructive testing and at 34.5V your batteries averaged 1.9VPC, so you may have lucked out and not physically damaged the plates, but I suspect a few months got knocked off their cradle to grave lifespan.

New batteries only have about 75% of the rated storage capacity and have to be broken in. Here is how to do it: https://www.cartsunlimited.net/battery-break-in-.html

Attached Files

Total Charge III Parts and service-1.pdf (3.28 MB, 0 views)

Blivit

Thanks JohnnieB, excellent information. Thanks to you, I may have "dodged the bullet"

JohnnieB

I forgot to mention two things, the chart I posted is for voltages taken about 12 hours after charger shuts off, or about an hour after cart was last driven. And the higher the average SoC maintained, the longer the batteries last (lifespan not driving distance on single charge).

orangeman6

JB, you are priceless to this forum.