'92 E-Z-Go Marathon Electric 36v Charging Issues

[Mezzy]

36v setup not charging fully.

I'm using an E-Z-Go "Total Charge" charger to charge my battery bank.

On my first charge cycle the charger ran for approx 3hrs according to the timer. Per the voltmeter on the cart (with the charger not running) the state of charge was just below the minimum charge.

I wiggled the charger connecter and the charger then ran another 3 hrs (timer then read 6hrs total)

Several times I've gone out to check the charger to find that it's run an additional 45 minutes to an hour if I just wiggle the connector. The initial few times I did this, the ammeter sat at 20amps after wiggling the connecter and didn't really fall off.

The past few times it's fallen down below 10 amps within a few minutes of wiggling the connector but doesn't shutoff righta way either.

I plan to check water levels in the batteries once I get as much of as a charge into the battery bank as possible.

My concerns are:

Is there a potential for damage if I continue doing as I have and "wiggling" the connector to see if the charger will continue to run, or will the controller in the charger keep that from happening?

I just purchased the cart used from a family friend and it sounds like it sat over winter...potentially without a charge. Is it possible that my batteries are slowly coming back? I bought the cart knowing I may have to replace some or all of the batteries but to my surprise it appears to be taking a charge.

Yesterday I was able to cruise 8-10 miles with no issues and the carts voltmeter only indicated a minimal usable charge was present.

Also, the voltmeter on the cart reads in the red during charging. I assume that is due to the additional input from the charger. As soon as the charger is disconnected it drops down to about the mid level in the "charge" indication of the gauge. Just wanted to make sure this was safe/normal.

I'll attach some pictures to describe what I'm seeing.

I do not have a DVM, but I am going to order one as well as a hydrometer to check the batteries.

Any input would be appreciated.

Glad I was able to find this resource...I've already made use of several pieces of information I found here. Hopefully I'll be able to contribute as well!

[JohnnieB]

Wiggling the plug in the cart's charger port and having the charger initiate a new charge cycle might mean there's some loose contacts in the plug or port.

That model charger turns off at 45V +/-1V, or after 12 hours if that voltage hasn't been reached. Since it is turning off in about 3 hours and the batteries are not being fully charged, the batteries are sick.

Back-to-back charging like you are doing may bring back some capacity, but if they sat for months without being charged, there is little hope for them.

The analog battery level meter you have is an expanded scale voltmeter and the green area between E and F is something like 36.3V at E and 38.2V at F. The on-charge voltage goes up to about 46V, so the meter may be pegged at the upper end while the batteries are being charged.

The amps out of the charge star out at about 18A or so and decrease as the on-charge voltage increases. Specifically, it follows the attached charge profile.

I've also attached a SoC (State of Charge) chart. Measure the pack voltage about 12 hours after charger shuts off to get a SoC estimate.

[Mezzy]

Thanks for the detailed response!

There are three separate pairs of matching batteries that appear to have been purchased together.

Trojan T105s, Trojan T605s, and a pair of black batteries that I didn’t notice the brand or model of. They appear the oldest.

My hope is that I might be able to replace them 2 at a time if the other four are still serviceable.

My plan is to cycle the batteries a few times and then, with as full of a charge as possible, see which batteries are maintaining a charge, and which ones are not. I’ll also check their solutions for clues.

Thanks again for the help.

[JohnnieB]

Mixing batter brands and mixing battery models shortens battery cradle to grave lifespan.

They are charged and discharged in a series circuit, so the need to be the same make, model and age to get the max usable lifespan.

A T-105 is a 225AH battery while a T-605 is only 210AH, so they won't charge evenly.

That said, try to find some used Trajan batteries roughly the same age as the T-105 or T-695 batteries.

The two digit date code is stamped in the negative terminal. The letter is the month and the number is the last digit of the year. IE: C6 is March-2016.


Start saving for a complete new set.

[Mezzy]

My local Trojan retailer is 119.95 with cores for t105s. Is that A decent price?

I’ve looked online and haven’t found any cheaper, but that doesn’t mean I’m not overlooking another possible source.

[kernal]

Pretty good. $109 locally. You pretty much have to buy them locally because shipping cancels out any on line savings.

[JohnnieB]

Originally Posted by Mezzy

My local Trojan retailer is 119.95 with cores for t105s. Is that A decent price?

I’ve looked online and haven’t found any cheaper, but that doesn’t mean I’m not overlooking another possible source.

That better than I can find locally.

I got my Exide batteries through Rural King.