Total Charge charger not working

[z71red]

Hi guys. I have read a bunch but posted very little over the last couple of yrs. and have to say i have been able to find out how to fix my problems by that method until this month. My pa-in-law bought an older ezgo cart that needed batteries but cam ewith the charger. He put new batteries in the cart and went to hook up the charger got no output. the charger has a built in 12 hour timer plus the relay board for auto shut-off so i bypassed the board and charger started to hum. With cart hooked up to charger I was only getting 1.5 amps out but have 44 volts coming from charger. Told him to run the cart a day or so and lets get the battery pack down. Oh yeah it is a 36 volt cart. He discharged the batteries and they were down around 30 volts so we hooked charger back up and had same issue voltage at 44 volts and only 1.5 amps current. I disconnected the meter thinking it may be bad(?) and connected my amp meter in series and was truly only getting 1.5 amps even though the batteries were weak. I have tested all components based on manuals I have found on here and all test fine. Both diodes good. Capacitor is 20mf( have a cap checker since my dad was an old ac repair guy he had one I could use) and then verified the transformer voltages based on an article JohnnieB had for Lester troubleshooting. Transformer outputting 87 vac with cap and 64 vac without cap connected and diodes both disconnected. ANy ideas on where to go from here? I do appreciate your help in advance!

[JohnnieB]

Ouch, discharging a 36V pack down to 30V is a bad thing to do, especially new batteries.

Never, ever, discharge the pack below 50% State of Charge, which is 36.30V.
Hopefully, the new batteries are salvageable.


The transformer and capacitor test okay, so the problem is either bad diodes or bad batteries or high resistance in the charging loop.
You've already checked the diodes, so measure the voltage drops around the charging loop while the charger is connected to cart.

First, measure the charger output voltage between Ammeter post with 3 wires on it and the stud on the heatsink.
Then, measure the on-charge voltage across each battery. (Lead pole to lead pole)
Each battery should have 1/6 of what you you read between Ammeter and Heatsink. (IE: it the charger output is 44V, each battery should have 7.333V +/- 0.1V across it.)

If batteries' on-charge volts vary more than about 0.1V, the battery may be bad, (New batteries can be fail, especially one that have been deeply discharged)

If batteries are close to equal in voltage, but total voltage of the six doesn't add up to charger's output voltage, measure the voltage drop across each and every cable and connection between Ammeter and Heatsink.
Fix or replace any cable or connection that has a voltage drop across it.

------------

The timer on some, but not all, of the older Totalcharge chargers had to be turned to the "Start" position before they would come on.
The timer served two purposes.
1. Tells you how long it took to charge batteries
2. Back up timer that shuts of charger is the turn off voltage isn't reached in 12 hours.

[z71red]

Thanks JohnnieB.
I had just read your post when I got a call from the pa-in-law that he was going to change the diodes and heat sink from another old charger he had. Before I got over there I saw the lights go out at his shed. Walked up and asked what happened. He said "Not really sure I hooked everything up like it was before and as soon as I turned the timer on I heard a loud pop and then the main breaker for the shed tripped." I looked at the charger and he had not put the insulators back on the heat sink where it connects to the housing and one of the transformer leads was also grounded. I checked and found that the primary fuse was not blown but the secondary of the transformer was open so forget trying to fix this one...... Needless to say pa-in-law is a good guy but knows absolutely nothing about electrical......

[JohnnieB]

Bad things can happen when you Poke & Hope.

Glad your pa-in-law didn't burn down the shed.

Suggest you charge those new batteries in pairs with a 12V charger while waiting for the new charger to arrive.