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e-Electric Batteries & Chargers > 208B: why charging ends sooner with lower charge rate?
 
 
Makiedog
Senior Heliman
Location: Minneapolis

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I've been parallel charging 2x 5s 5000 mah 25c Turnigy packs using the iCharger 208B. When I set the charge rate at 6A (0.6c), charging completes in 50 min. When set to 10A (1c), charging completes in 1 hr. Batteries were in the same depletion state. Balancing mode is set at normal.

Is this due to heavy balancing required when charge rate is high?

Pat L
10-25-2009 06:11 AM
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Richardmid1
Key Veteran
Location: Leeds, England

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Yes if the packs are out of balance. Also because of the slight imbalance between the 2 packs.

Eden George born 10/03/08, future 3D Masters winner!
10-28-2009 11:12 PM
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TJinGuy
Elite Veteran
Location: Socorro, NM - USA

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Sounds to me like you discharged the packs further on the 1C charge. Yes it can take longer if the packs are out of balance but if the packs are healthy then it shouldn't take too long. The imbalances between the packs will be mostly negated when they are hooked up in parallel, but balance times can increase, due to the larger pack capacity created, but not by much.

Charge a few more times an see what happens. Note how long it takes at the fixed current and then how long it takes after it starts to drop off.

- Chris

TJinTech
Team New Mexico
10-29-2009 01:24 AM
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GREYEAGLE
Key Veteran
Location: Sioux City IA

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Great Post : say T.J. --

Can you give me a brief explanation on what is taking place during the balance phase in the charge. Are some of the cathode / anode cell's being pushed harder and the others retarded ?

Specifically if one cell reaches peak and the remaining are pretty far behind. Will the remain catch up ? if given enough time at C1 or lower.

During the balance discharge phase is the current pulled from the top cell pack till it reaches the next and so on ??

Like to learn as much as I can --- coping with sour packs.

greyeagle
10-29-2009 02:05 AM
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gvr-4579
New Heliman
Location: Lakeville, MN - USA

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I would also check if your charger has a charge time limit, I know my charger does.
10-29-2009 03:20 AM
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TJinGuy
Elite Veteran
Location: Socorro, NM - USA

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Series lipos like a 3s pack are comprised of several cells in series. So they accept and release current as a team. As such they each stay pretty much at the same level as each other cell. The better the pack then the closer they are matched and the better they stay at the same level during use.

The way these chargers balance is simple, they charge through the main leads while monitoring the voltage of each cell through the balance connector. If a cell is higher than the others then it bleeds of some current off that cell to discharge it until it matches the others. It does this the whole cycle when you do a balance charge, so there is no balance phase to say. Most people call the last stage of charging the balance stage but that is not accurate on mast chargers, it is merely the ramp down stage where it drops the current way down to allow the voltage to finish at 4.2V per cell without exceeding 4.2V.

- Chris

TJinTech
Team New Mexico
10-29-2009 04:03 AM
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e-Electric Batteries & Chargers > 208B: why charging ends sooner with lower charge rate?
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