Is an OBC that Smart?

[Hunter450]

Replaced old tired battery pack with new set of Crown CR-190's. I have a PowerDrive charger and OBC. Installed batteries and charged till charger auto shut-off. Been on 3 separate runs taking the pack down to 70-75% SOC. For the first 3 charges the charger voltage would reach approx. 59 volts on pack and take about 3-4 hours before shutting off. Went down today to do the 4th break-in run and the charger is charging and the pack is boiling. I flipped the voltage meter on and it reads 63.4 volts. Is this normal that the OBC starts another charge just after 24 hours of a complete charge? Is the OBC smart enough to do an "Equalization" charge without human intervention?

Thoughts?

[Fairtax4me]

How long had it been plugged in when you checked the voltage?
63+v and some boiling is very normal for a new pack.
After the first few charges the OBC charges by energy count. It monitors how much energy was used and recharges that much plus a bit more to account for imbalance and lost energy from normal self discharge of the pack. It determined you used X amount of energy so it’s going to put that much back into the pack.

[NoleFan4Ever]

If you did not operate the cart or unplug the DC cord and then reconnect it, then NO. The OBC would not have cut it back on to charge again unless it had been either 15 days since the charge completed or the DC plug had been unplugged and re-plugged.

[Hunter450]

Originally Posted by Fairtax4me

How long had it been plugged in when you checked the voltage?
63+v and some boiling is very normal for a new pack.
After the first few charges the OBC charges by energy count. It monitors how much energy was used and recharges that much plus a bit more to account for imbalance and lost energy from normal self discharge of the pack. It determined you used X amount of energy so it’s going to put that much back into the pack.

I plugged in the cart immediately after the 3rd run on Monday afternoon around 5pm. Charger finished it's charge and shut off automatically by 9pm. I checked the pack voltage at 11 pm Monday night and it read 51.1v. Left the cart plugged in as normal. Went to do the 4th run Tuesday afternoon and that's when I found the cart charging and read the 63+ v. I do not know how long it had been charging but it shut off automatically around 10 pm Tuesday night. The last voltage reading is saw was 63.6v.

[Hunter450]

Originally Posted by NoleFan4Ever

If you did not operate the cart or unplug the DC cord and then reconnect it, then NO. The OBC would not have cut it back on to charge again unless it had been either 15 days since the charge completed or the DC plug had been unplugged and re-plugged.

Neither, the cart was not operated nor the DC plug removed. That is the strange thing because normally this time of year the cart sits unused and plugged in and the OBC does the ~15 day storage cycle charge. It just surprised me to find it charging automatically within 24 hours after a complete charge cycle.

[Hunter450]

Just an update:

I just performed the post 12 hour voltage check after the PD charger cycled off after the +63v mystery charge.

Pack Voltage: Cart meter 50.7v / DVM 50.6v

Individual Battery Readings with DVM

8.45v
8.43v
8.43v
8.45v
8.44v
8.44v

My first rodeo breaking in a new pack but it's interesting that the pack voltage dropped to below 100% SOC after being charged to +63v. I hope to see higher voltage readings as I continue the 12-15 break-in run / charge cycles.

[Fairtax4me]

Do you have any accessories on the cart that could be causing a draw on the pack when it's off? Is your charger plug loose in the cart charge receptacle? I had one cart a few years ago that the charge plug would only go in just enough to get the charger started and then if a mouse breathed on it just right it would lose the connection on the sense wire and turn off. I cleaned it out with electrical contact cleaner and blasted it with compressed air and it helped, but I ultimately ended up just replacing the receptacle.

Also check to make sure the sense wire is not damaged on the back of the receptacle. Give it a light tug and see if the wire is frayed or corroded where it goes into the terminal.


Hard to say for sure what and why the OBC does certain things. It was made by Lester electrical so maybe they could answer exactly why it turned on after only a few hours of shutting itself off.

I don't think the OBC will turn the charger back on based on pack voltage. I'm pretty sure it's just done by time (days since last charge). So there must be some other reason it decided to turn back on.

[Mooncarter]

Split second power outage?

[Sergio]

Power outage would not cause another cycle, only an interruption on the sense wire lasting over 20 seconds would cause that, I agree that checking connections and cleaning up the charger socket with contact cleaner and/or wd40 would be the first thing to do.

[Hunter450]

All accessories are powered through a reducer controlled by the key switch so no power drain there.

The DC charge receptacle is 20 years old so it could be the issue. I purposely lightly knot the charge cord around the break pedal so if it gets pulled, it won't stress the plugged connection. I'll check the sense wire and clean the receptacle as suggested.

Thanks!