Dumb idea? Mixing old lipo with new...

[corkscrew]

So, I'm applying to go to a new college, that is in the next town over. I don't want to move there, so I'm looking at commuting.

Commute would be about 23 miles one direction. (According to Google maps anyway). I don't know if I'll be able to charge it at the school, and to be honest I don't know if I really want to pack a meanwell and my 1420si Hyperion charger with me either... I have a truck and a motorcycle, but the truck sucks the gas and I can't count on the motorcycle being usable all next winter.

I already have 8 of the venerable 6s 5ah turnigy's wired into a 12S 20AH pack. I have room in my battery boxes to add another 4 bricks, which would bring me up to 12S 30ah.

I've read that it's a bad idea to mix old packs (my current packs have 1000 miles on them, and about 54 cycles according to my cycle analyst). I recently broke the pack down and checked every cell with my hyperion 1420si, and they are all still holding strong. Would it be a bad idea to add new (tested and good) packs to my existing setup?

 

[MadRhino]

Your Lipo's are not that old, that new cells wouldn't match them close enough. I have Lipo packs here that have 7 times your mileage, and with those I would be reluctant to match them with new ones.

 

[corkscrew]

Your Lipo's are not that old, that new cells wouldn't match them close enough. I have Lipo packs here that have 7 times your mileage, and with those I would be reluctant to match them with new ones.

Just wanted to ask because I bought the other 8 batteries almost a year ago. I'll go ahead and order up the other 4 batteries, while I have the trike torn down anyway.

Thanks!

 

[dogman dan]

I wouldn't hesitate either. You could use them seperately if you feel the need to.

One 8 brick pack and another 4 brick pack. Or a 6 brick pack of older ones to get there, and 6 bricks to get home, using two of the old ones mixed in.

 

[ElectroSurf3r]

They are going to be added in parallel, so the capacity difference doesn't matter.

The only concern is that cells in SERIES have equivalent capacity. So don't mix old/new in a series string.

I use old cells in parallel with brand new ones all the time. I've even got a Konion VT & RC LiPo pack going right now, paralleled at the cell level. Even though they have drastically different capacities, they act in unison at the parallel connections, as if they were one giant cell.

 

[corkscrew]

2 batteries will be added to each battery box on the trike. Making it two sides of 6, 6S 30AH (paralleled on both discharge and balance wires) . I then series connect the two battery boxes before connecting to the controller. Will this be ok?

 

[neptronix]

no problem.
run them in parallel and each will perform according to their ability.

 

[dogman dan]

Good point there. Have both new and old in each paralell string.