markvanhaze said:
I recently changed my HK Lipos from 6 4S packs to 2 6S packs. While I was using 4S I could charge all of the packs with my 80W RC imax B6 clone charger using a parallel board but now with 6S, my charger is struggling to balance the packs, even when charging one at a time. The cell voltages displayed on the charger are off by up to 0.3V so the cells rarely get charged to 4.0 volts.
So now I am wondering if I should invest in a stronger RC charger with an external power supply or get a BMS per lipo and then charge with a standard e-bike 48V charger off Aliexpress.
Any suggestions would be very appreciated.
Forget the RC "toy" chargers and bulk charge.
For 12S, you would want the Mean Well HLG-320H-48A. It's a 120 Volt input LED lighting(Like a store window display) power supply and avail. from many industrial electronics suppliers. That's the charger I use and it's awesome. It's fully potted, waterproof, CC/CV, dead silent(no fan) and Voltage adjustable 45V to 52V. As it approaches the set top Voltage, the Current attenuates to mili-Amps, where it will safely stay,....forever. Only a very soft "switching" can be heard. It's faster than one would think by the spec.s. Unlike a balance charger, it does not go thru switching cycles to read the cells. W/ a steady 300 Watts, it will put back approx. 5 Ah/hour.
You will need to add a mini Voltmeter(to adj. the Voltage/Ebay) and add connectors on both ends. Make sure you get the one w/ the suffix A.
Since you only have two bricks, you will need two Battery Medics to ck and balance the cells:
https://www.amazon.com/Targethobby-Discharger-Voltage-Balancer-Battery/dp/B01ET33R5S/ref=sr_1_11?ie=UTF8&qid=1510238448&sr=8-11&keywords=battery+checker+discharger
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Mean Well and 2) Battery Medics charging 2) 6S/5000 mAh bricks.
By bulk charging, you will not have to "break the string" to charge and that, in itself, will help he cells stay balanced.
On the subject of your pack and the number of bricks, I would say your pack is too small. One of the great advantages of LiPoly is it's small size and low weight, allowing a larger capacity, for a given space, than other chemistries. If you have space for 2 bricks, I'm sure you could find room for two more. Here, I have 12S/11,400 mAh (2S/2P) in a very small frame bag;
By doubling the capacity, you will not have to discharge as low as you probably are now, extending the service life of the batteries. Not to mention, lessening "range anxiety". Going to 4 bricks means you would need 4) Battery Medics.
Store charge to 3.90 to 3.95V, top charge to 4.10V and try not to discharge below 3.65V for maxium battery life.
P.S. I might mention that I recently changed that sm. pack to 14S/11,400 mAh, adding 2 to 3 mph top speed. I went from 6S + 6S = 12 S to 6S + 4S + 4S = 14S. Since you already have those bricks and assuming the are the same brand and C-rate, you could do the same. But note that by going from 12 S to 14S, the LVC in my controller became useless. But that's ok, I use a voltmeter on my pack and have a low-Voltage alarm on it as well. I usually don 't recommend relying on low Voltage alarms buried in a frame bag, but my pack is right in frt. of my face and I can't hardly miss it if it goes off.
I also had to go to a HLG-320-54A Mean Well, that has a top Voltage adjustment to 58 Volts, but I already had one on hand.