The way I roll
I opted for a ping battery with a 9 lead jst xh connector to run directly into any popular balance charger. These are usually meant for rc hobbiest but work wonders if you want to feel 'at one' with your battery. So my end voltage is 3.60v per cell when hot off the charger and 3.5v after sometime sat doing nothing. The standard charger did put most the cells to 3.9v but found out there is almost no gain (maybe 50ma) in capacity after using a better charger with cell read outs.
When they got charged to 3.9v they dropped down fast in minutes to lets say around 3.6 but now I charge them well to 3.6v they just sit there. So if you have a big voltage pack your going to see 0.3vx16 cells drop that equals almost 5 volts.
I have noticed none of my cells are perfectly matched in speed of charging and often go out of sync at the end of the charge. If my charger says full/end and any of my cells drop down to 3.38v I give them another quick charge (sometimes with a single feed to that cell via my jst lead adaptors) and all is well sticking at 3.50 for days. I think one cell doesnt get fully saturated every time. But I have had the odd panic where I was sure I had a faulty cell but an extra .5ah pumped in has it rebalanced for weeks.
My cellpro10s charger shows my internal resistance is pretty varied throughout my pack causing slightly random behaviour at times. I think the difference is I get to see exact voltages of each cell throughout the charge cycle and got to know the process far easier than you might do with a cheapy basic charger with no read outs other than a few led's.
As for pumping them up to 4v I see no actual capacity gain in that, just battery wear. The only reason most cheap chargers go to 3.9 (like ping) is it makes it possible to keep bouncing them up and down untill the low ones catch up. Pumping up, bleeding down etc etc didnt sound good to me so have barely used the ping charger. Plus I can charge off any 12v source or solar set ups.
If I set my charger to storage mode (lowers the voltage for long term storage) It goes from 3.6v to 3.33v per cell and reports I used around 150ma to do that. So to pump it from 3.6v to 4v is going to be about 50ma max. Not worth frying your cells.
I picked 20ah as I only need 13ah per trip and dont have to deplete the cells too far. I did once do a 55 mile round trip on a 24v 20ah ping and 500w conhis motor at 17mph average (I like to pedal allot btw). I started hitting 2.9v under load as I pulled into my road. My battery still had some pull in it and recharged with a full 20ah (measured bymy balance charger). not bad after two years getting pampered, will I ever need to replace this thing lol.
Further to this I use no bms. I have a micro voltage monitor that can be set to alarm at any voltage. So it beeps at 3.1 volts and I know Im in my last quarter of the battery and to pedal hard rather than just have it cut out on you and have to fight your motor the rest of the way home. http://www.cmfhobbies.com/details.asp?ID=1894
voltage alarm(£3 on ebay) and jst connector
Last edited by leggera16; 12-22-11 at 04:30 PM.
Reason: added info