Ping charger

[hippiehunter]

Ive got 2 36v ping packs and I did some dumb stuff to destroy one of my BMS's. Now im left having to manualy unplug the battery just before it goes over 45v. Otherwise the trickle charge gets it up to 55. Im pretty sure that is really terrible for the pack health so my question is can i mod the charger to disable trickle charge?

 

[dogman dan]

Put it on a timer, or just use an sla charger that will shut off at a lower voltage. Lifepo4 is pretty tolerant of overcharging so there is not as much harm anyway. Ping can sell you a new BMS. They aren't that expensive.

 

[hippiehunter]

How about maybe a simpler question, can I lower the level it shuts off at? right now it "stops" at 45 and i would prefer that it stop at about 41. I really dont need my batterys fully charged and would like to offset the abuse i deal them when discharging.

 

[Rassy]

Hi HH. I had a similar problem when I purchased two "anna" packs and one of the BMS's was bad. So while waiting to get the BMS problem sorted out, and wanting to check out the battery, I made the one good BMS so that it could be used on either battery. The only wire that had to be cut was the large negative between the battery and the BMS. Then a connector was installed where the cut was made. The long narrow connector where the 16 wires (48V) or 12 wires (36V) can just be unplugged and replugged on the other battery (carefully). Then if you need to charge both packs at the same time you can use your SLA charger on one and the LiFePO4 charger on the other, and alternate every so often to keep both packs well balanced. However, I would avoid charging without the BMS if possible.

 

[hippiehunter]

I really would just like to charge only to 41v even on the one that still has a bms.

 

[Rassy]

hippiehunter wrote:

I really would just like to charge only to 41v even on the one that still has a bms.

My 48V charger that is altered for LiFePO4 duct tape packs pushes the 48V packs with about 61V and they come hot off the charger after the balancing cycles are completed at about 59V. Then they taper back down somewhere around 55V at rest. I know these chargers are boosted up to this higher amperage in order to get the LiFePO4 batteries fully balanced and charged. So for a 36V charger stopping at 45V seems about right. I figure since Ping and others go out of their way to boost the voltage for these LiFePO4 chargers that they know more about it than I do? Maybe some of the smart guys on this forum can add their opinions on this.

 

[hippiehunter]

Right, but i dont need a full charge for my normal commute, i use about 33% of my battery and i would like to ubermax their lifespan

 

[dogman dan]

Cheap scooter charger will charge to 43 volts. That is what I'm using now, and my pack is staying balanced. The nicads, like in a prius are more sensitive to overcharging than lifepo4. So they undercharge more, but lifepo4 shouldn't need that much undercharge.