bmsweb wrote:kaptain_zero wrote:If I noticed that the cells were quite far apart to start, I would do a charge on each cell individually first, to bring them all up to the same level and then use the balance charge for the pack to keep them in balance.
Thanks for the info Christian, a lot of food for thought. However I don't understand why you would need charge them individually. Isn't a Balance Charger like the Accucell 6 supposed to do this automatically when connected via a balance plug? Sorry if this is a silly question but I come from the old Nitro Powered models days and electrics are all still very new to me.
Cheers
Paul
Paul, I did write
I would, and not
have to. <smile> My reason is simple, even inexpensive chargers such as the accucell can charge an individual lithium cell in about 2 hours if you select anything close to 1C of charge rate. If you attempt to charge a pack with cells that are far apart, such a charger simply charges at the set rate but has to apply a discharge on the higher charged cell, once it reaches it's maximum voltage, to keep it from going too high in voltage. This resistor drain is quite small, which is fine if the cells are nearly balanced but when they are far apart it can take what seems like forever to get the pack fully charged. Many times the charger will run up against the safety timer and shut down, leaving you with an unbalanced and not fully charged pack.
So, if the cells are out of balance by a significant amount.... just charge the one cell first and when it's full, charge the second cell and the total should be less than 4 hours. Now that they are both fully charged, they should remain close to each other and only require normal balance charging which should not take much more than charging a single cell.
Another point I should mention in case I forgot is that all Lithium rechargeable batteries prefer shallow discharge/charge cycles instead of deep discharge and full recharge cycles. It's the nature of the chemistry. Charge your pack up, use it for the day and then remember to charge it shortly before your next outing and you will get the maximum lifespan from your pack.
For a lot more information about all manners of rechargeable batteries, I'd suggest a visit to
http://batteryuniversity.com/ which has a wealth of information and I have read the original "Batteries in a portable world" and it was well worth the read, but I have yet to read the updated one. Still, there is much to read on the website itself...
Regards
Christian