72V off-the-shelf LiFePO4?

[marvingalaxy]

I finally got my 5304 (for my first build) and I have yet to finalize my battery decision. I've been thinking of a 28AH Ping battery but I now see how efficient 72V systems are on this motor. I am not highly capable with electronics so something close to off-the-shelf is probably as far as I can go considering I don't even know how to wire this thing yet. Is 48V the highest mere mortals should attempt at this time in ebike evolution?

Oh, my budget may be limited to as little as $1000 for the pack but the possibility is there for up to $1500 if I wait a couple of paychecks. I also need at least 1KWH. A 24AH 48V Ping pack is currently in my budget but I would prefer more WH if possible.

 

[Ypedal]

If this is going on a 26" wheel, 48v is plenty for your first rig !! honestly ! it is ! :wink:

I run my x5304 in a 20" at 48v and get 40 km/h, at 72v it's frickin insane, now step that up to a 26" wheel and weeeeehaaa

 

[pwbset]

48v is plenty for your first rig

Plus it'll be a heck of a lot easier/cheaper to get a charger for. Unless you're series-ing toolpack batts and using their chargers or using a customized high voltage DC power supply there don't seem to be any off the shelf chargers over 48v... that I know of anyway. Liability issues I'm sure... after all those higher voltages/currents can kill you.

 

[dogman dan]

Just buy what you can afford now, like the 28ah 48v ping. Later you can sell it if it's not enough, or the 72v off the shelf gets avaliable next year. Most chargers max out at 48v these days anyway unless you get into big ones for cars.

Another way to approach it would be to get a 36v 20 ah, and a smallish controller so you don't kill the pack right away. Then get another 36v 20 ah asap. By then a bms that allows paralell connections may be avaliable or run with a lvc instead of the bms.

 

[dirtdad]

Another way to approach it would be to get a 36v 20 ah, and a smallish controller so you don't kill the pack right away. Then get another 36v 20 ah asap. By then a bms that allows paralell connections may be avaliable or run with a lvc instead of the bms.

That was similar to the approach I took. The little Wilderness Energy controller I have will drive the 5304 around ok. I added a 2nd 36V 20AH Yesa in series when I could and upgraded to a 72V 45A Infineon controller. It moves the 5304 around with authority. 40+ mph on the flats is realizable, the limits become braking, suspension, and tires at that point.

There are some nice things about this arrangement. I end up with 2 3A chargers, so charging is fast. I keep the Wilderness controller around and even carry it with me as a spare. If the controller, bms, or single battery fail for any reason, I can revert to a 36V system and continue.

Hmm...What about 3 24V packs in series? 3 chargers, 9A charging power, 3 voltage levels. Maybe for the next project.

 

[recumbent]

I run 48 volts on a 70 lb bike loaded, plus my 190 lbs and it works great.

 

[dogman dan]

Yeah the yesa's bms is supposed to allow series connections.