Okay I'm trying to increase my top balance time on a 16s48v 280ah pack. I broke them down in a 8s 24v with a 8s 24v overkill bms. I set the parameters to the picture shown. When I went attach the power wire from my DC power supply sparks flew and melted the positive terminal on the charger. Have I got a parameter wrong?View attachment 67266
Charging a 8s 24v 280ah
- Thread starter bushi12
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FilterGuy
Solar Engineering Consultant - EG4 and Consumers
That sounds exactly like what happened to me when I got the polarity wrong on the power supply.
Is the power supply still working?
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Keep in mind.... for some unknown reason, the black pads on the aluminum cells are Positive!
Yes Sir mine are marked +&- and I double checked them.
What do I need to set this power supply too?
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Welcome to the club. I about shit my pants when that happened to me.
Is the power supply putting out volts and current now?
Is the power supply putting out volts and current now?
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Something looks wrong there. Are you sure the power supply is pumping out any current? That looks like there is an internal short.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
? Bummer!!
Live and learn. Would it hurt to do this with a 16s 48v set up. I have a EG4 charger.
I have several 16s48v overkill bms.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
I blew up a nearly identical power supply when I did it.... but the symptom was that it would do voltage and no current. I was able to trace it down to a diode on the output that turned into a fuse. Current and no voltage sounds like something different.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Clarification: the power supply was nearly identical to the black 30V supply you pictured. It was white but otherwise identicle.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Yes, you can use that to precharge before top balance...... but you are still going to need something you can set to 3.65V to do the final top balance.
Heck yeah that's awesome!!! I already ordered another and it'll be here Monday for final top balance! That'll let me get them ready this weekend! Thanks man I really appreciate it. I'll get everything ready. And yeah I about crapped three times. I didn't learn the first 2 times I touched it lol.
rio
New Member
Hi @bushi12. If you don't mind me asking, how is your EG4 charger working out for you? I'm building a 16s 48v setup and I'm looking for a charger. I will be using an Overkill 16s BMS. Do you just let the EG4 charge it up to its max voltage of 58.4V? Or do you set the Overkill to go into overvoltage protection at a lower voltage? I'm new to this and trying to learn best practices. Thanks!
Thanks for asking and I have done 2 battery packs this way and will do another 2 in the near future! It's so easy! I had one pack totally top balance in a weekend. Set your overkill on 3550 maximum cell charge. I did the first pack at 3500. That made the other 15 in the 3.4 range. The 3550 setting made them all come up to about 3500 still enough cushion to not have a surge go up over 3.65. I monitored it on my computer. Took about 6-7 hrs I believe. They all showed about 3.30 in the beginning Then I disassembled and ran them in parallel with the smaller charger set at 3.65. It took about a day. But that was not on full time. I didn't leave it unattended.
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