Battery light on a 1996 48v (sn-A9649) is staying on

[Sergio]

While You may have a bad diode assembly (aka: Heat-sink), that would not cause the relay not to click.

That test you did only checks 1 of 4 possible failures for the diode assembly.

If You did not remove the wires from the outside posts when you tested, all you did is test the continuity of the transformer secondary windings.

You need to disconnect the wires from the outside posts (each diode) that goes to the transformer.

Set the meter to diode test (preferable for high current diodes) or continuity.

Put the meter probes between the center post and one of the diodes, note the reading.

Switch the positive and negative probes around and note the measure.

Do the same for the diode on the other side.

The diode should conduct in only one direction, so for a good diode, Your meter would either show a voltage (diode test mode) or continuity with the probes in forward bias and 0v or no continuity with the probes switched.

As long as the DC cord was unplugged from the cart for more than 30 seconds, the OBC should have activated the relay again once you plug the DC plug back to the cart.

With the AC plug disconnected, If the relay does not click but you have voltage at the relay coil, the relay is bad.

You can temporarily run a wire from the yellow fuse holder behind the charger receptacle directly to pack negative.

Open the fuse holder and leave it open, run a wire from the receptacle side directly to pack negative.

The charger relay should click every time you plug the DC cord to the cart regardless of how long it has been unplugged since the OBC activation is by-passed.

If You still have an issue with the relay not clicking, it is either a bad connection on the cables or the relay itself.

[UGA_FAN]

Ok, because I had limited time to troubleshoot the charger, I just bought a new heatsink. I also used some jumpers to check the relay. Both the old and the new relays are working fine. I had bought 2ga wires for the pack; so I replaced all the wires except the one going through the OBC because I need on more cable to use the OBC “through bolt” I made. I then put WD-40 in the charging receptacle and worked the plug in and out for a bit. After doing that, the charger would come on, but would cut off once the charge reached ~ 54v. I wondered if the cable going through the OBC was bad. I decided to cut off the cable going through the OBC, put in the ‘through bolt’, use my 2ga piece from the OBC to the battery and a recycled 6a battery wire from the OBC to the controller. After doing that the charger came on, ran at ~15a to begin with and is now down to charging at ~4a. The current charge across the pack is 59.4v. I am getting the same number in front of and behind the OBC. It has been charging now for ~12-13 hrs and I can hear the batteries bubbling. Is 12-13 hrs excessive? I think the battery bubbling is ok. Just looking for confirmation on that. If the charge time and bubbling are ‘ok’, hopefully we’ve solved my charging issues. What do you think?


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[mrgolf]

Sounds like you got it. The charger can run up to 16 hours, the voltage will be high but the charging amps will be low.

[Sergio]

That is good, just make sure the current does not get below 3amps as that would indicate the OBC is not in Control.

Since that cable through the OBC is the same one that conducts current when the cart is moving, it is unlikely it was the cause of the problem.

The 10ga black wire output from the OBC to the same Controller B- terminal where that cable is connected can definitively cause issues if it was not making a good connection.

Let it finish the cycle and check the pack voltage a few hours after is done.

[UGA_FAN]

[emoji1303]. I did have to take the 10ga black cable off the controller bolt to get the battery cable off. Maybe there was a connection problem with that wire that was resolved when I tightened everything back up.


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[UGA_FAN]

Ok, I had to leave the house before the charging cycle finished. Not sure when it actually turned off. It was charging at 4a when I left. Even if it went near the max 16hrs, that means that it stopped charging ~ 12:00 est. So, after what I am going to assume is a minimum of 5 hours, I’m seeing 52.0v across the pack.


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[UGA_FAN]

Well....back to the lab again. Went out for a 30 min ride today. When I got home, I plugged the cart in. The relay clicked. The charger came on for a few seconds. It turned off for a second. It then came back on and started charging at ~16a. I started to clean some stuff in the garage. 10 min or so into the charge, it cycles on and off a couple of time and eventually stopped charging after maybe 20 min. The pack at the time it stopped was at 53.2v and the battery light came back on and stayed on. I got my dmm, some jumpers and started checking stuff.
1)Voltage across pack: 51.4v.
2)Voltage between red and blue wires inside the charger: 50.7v.
3)Voltage between red and black inside the charger 38.3v.
4) Voltage at the cart plug input match readings inside charger
5) Both relays will click when I use jumpers directly off the pack (51.4v)
6) Neither relay will click when red/blue wire from charging cable is used (50.7v). 🤷🏼*♂️
7) Because I was only getting 38.3v between the red/black at the plug, I disconnected the negative battery cable and the black cable that runs to the OBC from the controller and connected them directly together to see if the low voltage was a connection issue.
Still got 38.3v between red/black at plug. Same number before/after fuse.
9) I used a jumper between the negative on the plug and the negative on the pack to get full voltage so see if that had anything to do with anything....Negative, Ghost Rider. No click when I plugged in the charger.

I decided to come in, watch some Olympic skiing and ask the experts. I do not know exactly how the OBC works, but I do not understand why I’m losing ~ 0.7v in the system somewhere. Why the relay is not clicking between red/blue @ 50.7v and why the red/black at the charger only has 38.3v? I’m so lost with this thing.




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[UGA_FAN]

Ok, last post on this for the night. I got frustrated and started scouring bgw for a solution. I was looking at wiring diagrams to see what I might be able to glean from them. I read a post from Sergio saying that the yellow wire out of the OBC is negative and connects to the solenoid. The solenoid on my cart is a stock Club Car one. I do not know if there is a difference in polarity between the two small posts; but according to the diagram, the yellow wire connected to the “front post” and the red & white/black connected to the rear. Because I have been under the cart so much, I remembered that my wires were on the opposite posts. I went out and switched them. When I reconnected the negative battery cable and measured the voltage onthe red/black at the plug, I got 50.7v. I plugged in the charging cable and the relay clicked. I removed the cable; waited a minute and plugged it back in two more times. Each time the relay clicked. I am going to hook everything back up tomorrow and see if it will charge properly. Anyone know if the solenoid thing really made a difference or if I am still going to be chasing a ghost in the system when I get home from work tomorrow?


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[Sergio]

The charger receptacle black wire goes into the OBC where an SCR controls the current that comes out and goes to the Controller B- terminal.

It is normal for that voltage to be lower than pack voltage.

It seems like the OBC is failing, but I have a question about the test:

"2)Voltage between red and blue wires inside the charger: 50.7v. "

Where exactly were the meter probes connected, right at the relay 3/16" terminals with the wires still attached to the relay?

[UGA_FAN]

Originally Posted by Sergio

The charger receptacle black wire goes into the OBC where an SCR controls the current that comes out and goes to the Controller B- terminal.



It is normal for that voltage to be lower than pack voltage.



It seems like the OBC is failing, but I have a question about the test:

"2)Voltage between red and blue wires inside the charger: 50.7v. "

Where exactly were the meter probes connected, right at the relay 3/16" terminals with the wires still attached to the relay?

When I disconnected the red and blue wires from the relay, I got 50.7v between the red/blue female spade connectors. I also am getting the same reading between the red/grey at the cart side charging plug receptacle.



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