dumbass said:
Jeff,
Take a look at theses. I was quoted $2.60 each from the supplier. Note they are cell bleeders and not chargers. I was told they can be used in parallel while the pack is wired in series. I am looking at these because I am having problems with the single cell chargers actually balancing the cells properly. I find that while charging 8 cells (each with it's own 3,6v 2a single cell charger) the cell voltage is all over the place. Some cells are over charging and I have to disconnect that cells charger. And other cells are turning off early. The problem is each charge or pack is different. Yesterday they charged pretty well. But today it's a PITA. So I am looking to build a set of 8 of these and plug into my balance plug while using my bulk charger.
I just hope they understand my question about using them in parallel while the pack is in series. Your better electrically so please give me your thoughts on these. Please note the current bleed is adjustable via jumpers.
http://www.szsmartec.com/EN/productsview.asp?PID=752
Bob
Geez never seen separate balance boards before, throw away price 8)
Each of those 39 ohm resistor's across a cell, should be around 0.3W dissipated in each resistor.
Trying to work out how they get those current values?
I see there is a few other components on board, but no circuit diagrams.
Possibly a voltage sensing chip, controls the bleeding process?
That would be a very cheap option, per cell.
I can't find any operation details or specifications!!
I had a very similar problem to you when charging, the voltages are all over the place
Maybe you have mismatched cells in your packs like me?
As you're only charging at under 0.5C, I would think a BMS might be a better option.
I had a 'evassemble' capacitor BMS on my pack for a while, charge/discharge, but it got smelly after a while.
I was sucking about 4C, out of the battery, on my gokart, so I don't think it could keep up with shuffling the charge around and smoked a channel.
Hope you have more luck with the charge bleeding.
My manual resistor balaning was burning my fingers Ouch.
Cheers Jeff