Precharge resistor burning up

[kjackmail]

Im going to put the newer controller in it today. Try it again. The newer controller ran the cart for about 45 minutes and then quit. I will be back!

[kjackmail]

Ok so today I didn't get a chance to swap controllers however, I had left it to charge yesterday. Everything with that is fine so I checked the resistor and its still good. I am thinking I might be a little too quick to unhook everything once the resistor starts to heat up. How hot should it get normally? I am trying not to leave it in the run position so long that it melts the plastic over the resistor.

[Kashmir]

The cart is ok to charge in the run position, if things start to melt when charging in run mode, you have another issue that should be addressed.

[kjackmail]

With the motor connected in the tow position the precharge resistor burns. With the motor disconnected it doesn't burn in tow or run. I also noticed when the white wire is disconnected the controller will click when i switch between tow run. I believe it has beat me. I swapped the solenoid first. The controller second and actually got a ride out of it only to burn it again during a charge cycle when i turned the key on. Then I swapped the OBC because it burned when I turned the key on while charging. This may have burned the second controller up. Then i swapped the plum quick for a known working stock motor. Still burns resistor but i believe the 2nd controller is bad now. I found another used excel controller on ebay for $174. I just dont want to buy another controller to test it. I have a 2011 cart that I can take parts from but im not 100% sure it has the excel controller. The parts manual for the 2011 lists 2 different controllers where the 2013 only shows an excel controller. I am debating taking it to a shop and making it their problem.

[kjackmail]

I spoke to another golf cart guy today and he says it sounds like I have voltage back feeding from the LED lights and or the voltage converter. The controller is definitely toasted but I should be able trace my problem with the current set up before dropping in a new controller. I didn't disconnect the aftermarket accessories until after I had already fried the new controller. He also said to leave the stock motor in it for now because he has seen a Plum Quick motor fail and cause the same problem. I did some testing prior to talking with him and I do get 3 volts across the key switch in the tow position. On my personal cart with the same setup I get 1.2 volts across the key switch in tow position.

[whit71]

Originally Posted by kjackmail

With the motor connected in the tow position the precharge resistor burns. With the motor disconnected it doesn't burn in tow or run. I also noticed when the white wire is disconnected the controller will click when i switch between tow run. I believe it has beat me. I swapped the solenoid first. The controller second and actually got a ride out of it only to burn it again during a charge cycle when i turned the key on. Then I swapped the OBC because it burned when I turned the key on while charging. This may have burned the second controller up. Then i swapped the plum quick for a known working stock motor. Still burns resistor but i believe the 2nd controller is bad now. I found another used excel controller on ebay for $174. I just dont want to buy another controller to test it. I have a 2011 cart that I can take parts from but im not 100% sure it has the excel controller. The parts manual for the 2011 lists 2 different controllers where the 2013 only shows an excel controller. I am debating taking it to a shop and making it their problem.

I'm not sure what year they stopped using the IQ drive system, but if your 2011 has a serial number starting with PQ it is an IQ not an Excel.

[kjackmail]

RESOLVED. I think i finally got it. I bought a 2nd used controller online and disconnected all the aftermarket accessories installed. Per advice from a local golf cart guy he claimed the led lighting will backfeed the system thru the factory grey ground wire under the dash thus bypassing the lockout while charging. Turning the key on while charging would backfeed and burn up my controller. The volt converter i have has a remote wire hooked to the 48v key switch. My next step is to isolate the 12volt system from the 48 volt system. My plan is to wire both positive and negative wires of the transformer directly to the batteries. It would bypass the OBC but it should also eliminate my backfeed. The 48v remote wire concerns me too so i may use the switched 48v relay to turn it on. Any advice going forward?

[mrgolf]

You can hook your 48 volt input wires to thr b- and the solenoid battery side large post to keep them away from th acid battery area. If you have a trigger wire you can run it through a relay operated by the key switch, it could also be hooked on the solenoid.

[Sergio]

The issue with power back-feeding on the gray wire at the 12-pin harness connector has to do with not connecting the bucket harness negative wire to the Controller B- negative.

If that negative wire is connected to a different battery post, the existing diode on the Precedent brake relay harness will back-feed power to the gray wire when the key switch is OFF.

Turning the key switch ON while the charger is plugged is not a problem.

The only thing some LED bulbs have an issue is with back-feeding brake/turn-signal power to the headlights.

If that is an issue You have to put a diode in series with the taillight/marker light positive power wire, with the striped end of the diode (cathode) pointing towards the LED bulb.

What brand 48v->12v reducer do You have?

Are the LED lights 12v or are they connected directly to the pack?

[kjackmail]

Originally Posted by Sergio

The issue with power back-feeding on the gray wire at the 12-pin harness connector has to do with not connecting the bucket harness negative wire to the Controller B- negative.

If that negative wire is connected to a different battery post, the existing diode on the Precedent brake relay harness will back-feed power to the gray wire when the key switch is OFF.

Turning the key switch ON while the charger is plugged is not a problem.

The only thing some LED bulbs have an issue is with back-feeding brake/turn-signal power to the headlights.

If that is an issue You have to put a diode in series with the taillight/marker light positive power wire, with the striped end of the diode (cathode) pointing towards the LED bulb.

What brand 48v->12v reducer do You have?

Are the LED lights 12v or are they connected directly to the pack?

I am not 100% sure where the back-feed is coming from however, I have an idea. At this point I can only assume its a back-feed issue. I burned up a new controller by not fixing the problem. I replaced the original controller thinking I just had a bad controller. I installed the new controller and drove the cart around just fine. I put the cart on the charger and it charged just fine. I thought the problem was fixed. I tested again the next day and did a few victory laps around the neighborhood. This time while it was still charging I turned the key and instantly fried the replacement controller. All of the 12v wiring was still connected and working 100%. This was the same thing that fried the original controller. (rewind to the beginning) My aunt drove it home late one night and couldn't see to plug it in so she left the key switch on with the headlights so she could connect the charger. As soon as it bumped the charger she smelled the precharge resistor burning.

Here is where I am at now... I disconnected everything and started from scratch. I installed a 2nd controller. Put the stock motor back on it and a known working OBC. Tested and it runs and charges fine. Even cycled the key switch while charging and everything is as its supposed to be. I put the Plum Quick motor back on it and tested again. Everything is perfect and a lot faster. I have drove and charged it everyday since with no problems at all.

This is where I stopped and I need help before going forward. I have not reconnected any of the 12 volt stuff and I am terrified to do so. I have a 48 volt reducer that I have used on several carts in the past. It's a made in china converter from East Coast Carts. I like it because it has the 12 pin molex connector that goes between the bucket harness and the light harness. Plug and go! The converter has a trigger or remote wire that turns on and off all of the 12 volt accessories when I turn the key. The 48v trigger is supplied thru the 12 pin molex. I am pretty sure it's powered by the factory switched grey wire with the red butt connector already in the dash. This grey wire is also where I think I am getting the back-feed from converter when I turn the key while charging.

http://www.ebay.com/itm/Club-Car-Pre...53.m1438.l2649

All of the 12v accessories have plugs. There are no cut or spliced wires anywhere in the dash. The bucket harness power wire is plugged directly to the 48v positive battery and the negative to the yellow butt connector in the battery box that goes to the OBC. The light kit came complete with LED lights, turn signal, brake lights and horn. Oh yeah!! I did splice in a LED license plate light to the driver side tail light. There are no other 12v accessories (radio, etc.). Everything has worked for several months wired as described. But I never tried the switch while charging. I never had a reason to try. Now I think I have a bad or back feeding volt converter.

My thoughts now are to the isolate 48v trigger on the converter with a 48v relay just like the brake lights have or replace the converter.

THANKS again for everyone's help on this project so far. Without it I would still be scratching my head and spending money.