I am buying a geared hub motor kit to replace/upgrade my old Bionx. I want to go lipo, but i don't want the one from my kit dealer. I would like some direction on a simple setup from Hobbyking.... 50v +/- and 11-15 ah should be fine. What's the simplest setup for bms and charging? I don't really want to be soldering cells, but i'm ok with making a harness for multiple packs, splicing, etc.
Simple battery question (i think)
- Thread starter ssmith711
- Start date
Among other things, a solution might depend on a) the controller's power capabilities and capacity to be reprogrammed and, therefore, I won't be much help because I don't know the bionx controller at all b) how much anxiety you've got about joining the stuff together. I sense that you'd like a relatively easy solution so offer that below. I know that the bionx controller reportedly has a whole lot of additional capacity because it uses mosfets that are rated higher than the usual case (something like 72V - not that you would push it near there but rather 50V might indeed be safe at the max end)
Anyway, the first solution which came to mind: four x 6s rc lipo (these are expensive in 6Ah capacities but still cheaper than some alternatives. If you could make do with 10Ah the 5Ah packs are much cheaper) - paralleling and placing them in serial to create 12s2p will give you about 50V fresh off the charger. If you really aren't keen to parrallel the packs for charging, this arrangement could be used easily with a Tunigy 4x6s charger. Unhook the discharge harness made from, say, 12guage wire and andersons, then plug four pairs of connectors in to charge. A little fiddly in terms of connecting and reconnecting but not too daunting.
That's what I've done for my wife's bike. The weak point is that I'm not using a BMS. I have 4 x BM-6 alarms and I've repogrammed her controller so that the LVC is quite high. I suspect that the second protection there is uncessary. Because I'm not using the harness for charging, I've added some schottky diodes to stop each pair discharging into the other if they get out of balance.
Anyway, the first solution which came to mind: four x 6s rc lipo (these are expensive in 6Ah capacities but still cheaper than some alternatives. If you could make do with 10Ah the 5Ah packs are much cheaper) - paralleling and placing them in serial to create 12s2p will give you about 50V fresh off the charger. If you really aren't keen to parrallel the packs for charging, this arrangement could be used easily with a Tunigy 4x6s charger. Unhook the discharge harness made from, say, 12guage wire and andersons, then plug four pairs of connectors in to charge. A little fiddly in terms of connecting and reconnecting but not too daunting.
That's what I've done for my wife's bike. The weak point is that I'm not using a BMS. I have 4 x BM-6 alarms and I've repogrammed her controller so that the LVC is quite high. I suspect that the second protection there is uncessary. Because I'm not using the harness for charging, I've added some schottky diodes to stop each pair discharging into the other if they get out of balance.
dogman dan
1 PW
Simple battery question. :lol: Wouldn't it be nice if it was always simple?
http://endless-sphere.com/forums/viewtopic.php?f=14&t=19956 There's the best I can do for a starting point without typing it all again over and over.
In my opinion, the simplest set up is either 36v or 42v nominal voltage. 10s lipo for 36v or 12s lipo for 42v. That way you buy four 5 ah lipo bricks, and connect them in pairs paralell to make 10 ah packs. Connect again in series to bike voltage. Disconnect to pairs again to charge with a charger from HK. 12s lipo is right about 50v when fully charged to 4.2v per cell. You wouldn't want to ride it any lower than 3.5-3.75 v per cell, so you'd have about 42v minimum on 12s lipo. Just about halfway between 36v and 48v nominal voltage.
True 48v, 63v when fully charged, is only slightly more complicated. 6 batteries, pair them up, and then series connect three 10 ah batteries instead of two. That is a 15s pack. If you want to keep the voltage closer to lifepo4 48v, at 60 v fully charged, do the same thing exept with 14s lipo. So that's four 5s packx and two 4s packs. another option would be 8s packs combined with 6s packs, but the 8s packs are harder to get in stock. Most of us choose either 5s or 6s lipo and build a pack with one or the other.
In the batteryspeak, 5s means a pack with five cells in series. Rigging up means to connect paralell and series is not too hard, some make their own stuff with andersons, others buy pre made connectors. Personally, I went with converting my packs to andersons, and half of them have two connectors making paralell or series connections possible without additional adaptors. I break em down to individual packs to balance charge when needed.
I charge with the regular lipo chargers from HK, but I can take days to charge if I want. My lipo is on "fun" bikes, and my commuter bikes run on ping lifepo4. Like any bms, I only trust each buzzer after I have tested it's function, and know it actually does go off at the right voltage.
My bms is nothing fancy, charge side is handled by the lipo charger. So all I need on the bike is a low voltage warning buzzer on each paralelled set of lipo blocks. Using a Cycleanalyst helps a lot too, but really, with some experience I don't need it every ride. Just the buzzers to alert me of the unexpected problem is mandatory.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=19956 There's the best I can do for a starting point without typing it all again over and over.
In my opinion, the simplest set up is either 36v or 42v nominal voltage. 10s lipo for 36v or 12s lipo for 42v. That way you buy four 5 ah lipo bricks, and connect them in pairs paralell to make 10 ah packs. Connect again in series to bike voltage. Disconnect to pairs again to charge with a charger from HK. 12s lipo is right about 50v when fully charged to 4.2v per cell. You wouldn't want to ride it any lower than 3.5-3.75 v per cell, so you'd have about 42v minimum on 12s lipo. Just about halfway between 36v and 48v nominal voltage.
True 48v, 63v when fully charged, is only slightly more complicated. 6 batteries, pair them up, and then series connect three 10 ah batteries instead of two. That is a 15s pack. If you want to keep the voltage closer to lifepo4 48v, at 60 v fully charged, do the same thing exept with 14s lipo. So that's four 5s packx and two 4s packs. another option would be 8s packs combined with 6s packs, but the 8s packs are harder to get in stock. Most of us choose either 5s or 6s lipo and build a pack with one or the other.
In the batteryspeak, 5s means a pack with five cells in series. Rigging up means to connect paralell and series is not too hard, some make their own stuff with andersons, others buy pre made connectors. Personally, I went with converting my packs to andersons, and half of them have two connectors making paralell or series connections possible without additional adaptors. I break em down to individual packs to balance charge when needed.
I charge with the regular lipo chargers from HK, but I can take days to charge if I want. My lipo is on "fun" bikes, and my commuter bikes run on ping lifepo4. Like any bms, I only trust each buzzer after I have tested it's function, and know it actually does go off at the right voltage.
My bms is nothing fancy, charge side is handled by the lipo charger. So all I need on the bike is a low voltage warning buzzer on each paralelled set of lipo blocks. Using a Cycleanalyst helps a lot too, but really, with some experience I don't need it every ride. Just the buzzers to alert me of the unexpected problem is mandatory.
