DPI Charger Not Shutting Off

[tomtt2]

I have a DPI 48V charger model 48014C19-005.
I use it to charge my 2007 Yamaha Drive. Charger came with the cart and I've had it for about 3 years.

Normally, I plug in the charger after using the cart. It runs through it's charger cycle and clicks to green.

Yesterday, I noticed that the charger had not clicked off or to the 95% charged mode after a number of hour. I noticed that the battery cases were getting pretty warm (very warm actually) so I pulled the plug and let everything cool down.

After running the cart yesterday to the point that the battery meter showed about 50% left, I connected the charger and went on with my business. six or seven hours later, I checked and the charger was still in full charge mode and the batteries were definitely hot this time. I pulled the plug again and let things cool down. There was a lot of gassing of the batteries, but no cells were dried to the point that plates were exposed.

So, is this a case of a fried PC board or is the mechanical relay in the charger dead?

I see that DPI has a replacement PC board so should I replace the board or just swallow hard and order a new charger.

Has anyone ever encountered a charger that won't shut off?

[scottyb]

The charger is looking for a preset battery pack voltage to trigger the shut off. The pack may not be reaching that voltage or the charger circuit board may be malfunctioning. This is a common problem when a battery dies and the pack cant reach the cut off voltage. So do some voltage tests and report back the individual battery readings now and then after they charge up enough to get warm at a time when you think the charger would normally have shut off.


Also you mention running the pack down to 'half or 50%' - what is that voltage reading?

[tomtt2]

Thanks Scotty.
I just checked individual battery voltages and got the following:
12.81
12.82
12.82
12.87

This was with a digital volt meter.
The batteries are warm as you suggested.
I haven't had a chance to drive the cart down to 50% yet, but will post the readings once I do.
Specific gravity is running 12.75 for all cells.

[cgtech]

Batteries are getting hot with SG at 1.275? Not a bad reading in itself, but i would expect higher (1.300 and above) in a healthy battery before significant heat. It is incredibly uncommon for all 24 cells to have exact matching SG readings, what brand/type hydrometer do you have?

[tomtt2]

Thanks for the response. The hydrometer is a glass float type, you know the orange rubber bulb and a thermometer on the side.
These batteries have been very good about maintaining close SG readings. I can double check the cells again with everything cooled down.

[tomtt2]

Okay, rechecked all four batteries. The specific gravity ranged from a low of 12.70 to just short of 13.00. Battery voltages ranged from 12.69 to 12.74 VDC. The total pack voltage measures 50.9 VDC. All of this is after the batteries have sat disconnected from the charger for just short of 9 hours.

The battery charger has the J3 jumper installed. This is the setup for Trojan batteries. There is no specific setting for Crown batteries and DPI didn't have a recommendation for them with this charger. Since this setting has worked well in the past, I don't think the jumper setting is the issue.

Is there any sort of diagnostics for the DPI charger circuit board?

Thanks.
T

[Phil4Yamaha]

Your Dpi charger is one of the best on the market. Your batteries sound fine, and usually just unplugging the AC cord will reset the memory on the charger, and it runs good again. It does sound like the circuit board has failed on the charger. Not repairable, but a new control board is way cheaper than a whole new charger, and can be changed in less that an hour.

[tomtt2]

Thanks for the response Phil.
I did replace the circuit board as you suggest, but it did not eliminate the problem. In the end, I replaced one battery that had a slightly lower specific gravity when charged. After that, the charger worked normally. Neither I nor the tech at the battery distributor have a good explanation for why the one battery would cause the charger to not shut off. The best guess was that the one battery kept the pack from ever reaching the shut-off voltage level required by the charger. Why is still up for debate.
Thanks for responding.

[scottyb]

The charger will keep running so long as the pack keeps drawing amperage. My guess is the one battery had a short which kept a small draw going and thus prevented the charger from seeing a full pack.

[tomtt2]

I think you are right, but I couldn't pick up on it with either a hydrometer or digital volt meter. I think it was off just enough to keep the charger going. After having a lot of people scratching their heads, we all agreed that the one battery was slightly off from the others and decided to replace it and give it a try. It worked, but I wish the signs had been a little more clear. The replacement PC board cost about the same as a battery.