Author Topic: New 15Ah 48V LiFePO4 is now in my filthy paws  (Read 6280 times)

Offline sixty_cycle_hum

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New 15Ah 48V LiFePO4 is now in my filthy paws
« on: May 09, 2013, 02:25:11 PM »
Not really a review, just some scattered thoughts on my new baby.

Got my 15Ah pack from Gary last Saturday.  Rode it a few times to work earlier this week when the weather was FANTASTIC.
Loving it so far, though it is a little heavy feeling on the rear rack.  This is exaggerated by my MPIII also being rear mounted.

I had been using 4 x 7.2Ah SLA cells while I waited for the lithium pack.  Good enough to get me to work (about 13 miles), but I had to be careful not to ride too hard and fast, or the batteries would be sagged terribly by the time I got there.

According to my Turnigy watt meter I am only using about 250 to 280Wh on the trip, and that's riding pretty darn fast the whole way.  I have the controller limited to 20 amps, and the watt meter reflects that almost exactly.  The bike has plenty of power to get up any hill around here (hilly area of SE Michigan) even with the limited current.

I'm terribly tempted to open up the pack and see what exactly is inside for the cells and BMS (I am an electronics geek, what can I say?) and to get a baseline measurement of cell voltage when balanced and how long they are taking to balance, but I don't want to void my warranty.  Gary, I'm sure you're reading this and shaking your head.  Has anyone opened one up yet?  Any idea what BMS GM is using, or have they designed their own?

Also, what's the recommendation for current limiting the Pie on this pack?  Specs say 3C, but surely that much current draw will tax cell life.  Thoughts from some of the more experienced folk?

Anyway, I'm absolutely loving riding with a large capacity battery.  It's very liberating to have the ability to ride so far without the battery anxiety.