48V charger keeps tripping 15A breaker

[thetoddjohnson]

Originally Posted by cgtech

so, let me get this straight.... everything has been returned to original configuration, and it still doesnt work?

Yes. The only thing I ever did was remove the DC cable to understand how it was threaded through the compartment. I then reinstalled it. That's why this is so puzzling.

TJ

[cgtech]

i'll send a pic of the SCRs tomorrow with testing instructions. i dont have one of these at home. describing the appearance of a scr is difficult. fyi- a Silicon Control Rectifier is basicly a diode that controls the current passing through it with a third "gate" that a typical diode does not have. this allows the charger to tailor the charge rate, as opposed to controling only the charge voltage and time duration, as older or more basic chargers do. i will send more help tomorrow.

[Volt_Ampere]

I would be surprised if any modern charger uses SCR's. They would use Triacs if they are using phase control of the AC. (Same as most lamp dimmers)

[cgtech]

triac is bi-directional, turning ac transformer output into dc battery power is a desirable aspect of the scr.

[shaffer88]

Lestronic great brand been around for awhile and still using scr
http://www.lesterelectrical.com/prod..._list_2012.pdf

[cgtech]

i like Lester as a brand, but a little pricey. BUT, i would never recommend the E-series (Economy = cheap) Lester (Too many failed transformers).

[simple man]

Originally Posted by thetoddjohnson

Hi. I wanted to lengthen the cord that goes from the charger to the cart so that I could leave the charger in the garage (protected from the elements) while charging the cart outside. I figured that an 8AWG cable would be sufficient for a 25' run.

Before purchasing the cable I wanted to see if splicing would be involved, or if I'd be able to run a cable that thick through the same route that the existing 12AWG cable runs. So I went through the exercise of opening the charger and removing the current cable. Confident that I'd be able to use 8AWG I reinstalled the 12AWG cable and planned to purchase 8AWG next time I swung by an electrical supply store.

To the best of my knowledge I reassembled the charger exactly as it was before I did my investigation. The next time I plugged the charger in the lights flashed as usual, the charger kicked on, and I went in the house. In the morning the "abnormal cycle" light was illuminated. I figured that I must have done something wrong, so I opened the charger again and verified that everything was connected properly. Now if I plug the charger into the cart the lights will flash, the charger will kick on, then after 15 or 20 seconds the 15A breaker on the front of the charger will trip.

After on BGW I found a few posts that indicate once one of those breakers trips it tends to trip, so I figured perhaps the breaker was bad. I replaced the breaker, but the problem persists.

So, either I somehow damaged the charger, or there is a bizarre coincidence that it just happened to have problems after I was tinkering with it.

I have two G29 carts and 2 identical chargers. I do not believe this problem is related to the quality of the batteries, because the problem exists regardless of which cart I'm trying to charge, and also both carts will successfully charge with the other charger.

Any ideas on what to do next with the "tripping" charger?

Thanks,

TJ

Just a thought here, I had replaced a dc cord on a charger once and did not pay attention to the location of the insulating washers that isolated the rectifier heat sink from the charger case. Wouldn't hurt to double check your cable installation if you recall having to remove some nuts and washers to remove the eyelet type terminal. I can't recall what charger I was working on, but it did the same thing as yours.

[cgtech]

1- unplug charger from cart and wall
2- unplug large block of wires from control board- VERY IMPORTANT
3-using lowest Ohm setting, check from "long stem" to "heatsink" (should be "out of range" very high)
4- check from "long stem" to "short stem" (should be 30-50 ohm)

[thetoddjohnson]

cgtech, PM sent.

TJ

[thetoddjohnson]

Thanks to all for the help.

Just to close out the thread here is the cause (and solution).

By unplugging the control board and also bypassing the relay I forced the charger to turn on as soon as the AC cable is plugged into a wall outlet. Even without plugging the DC cable into a cart the breaker would trip after 8 or 10 seconds.

I then unhooked from the heat sinks the heavy wires that come off the secondary side of the transformer, reset the breaker and plugged in the AC while I had a volt meter on those heavy wires. It read zero volts. Therefore it seems like the transformer is bad.

TJ