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Old Jun 07, 2009, 09:19 PM
41North is offline
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Dumb lipo charger question - 1s, 2s, 3s battery chg rates


My DN Power balance charger fills 1-4 cell lipos at .2A to 2A rates in .2A increments.

Now, I get that lipo's like to see rates of 1c or less. I have some 1s, 2s and 3s batteries. I've been selecting charge rates of 1/100 of the mAH rating or less on all of them. But pondering what's going on... Isn't the mAh rating of a muli cell series wired battery the sum of all the cells?

The charger display seems to indicate the charge rate per cell. If I'm dumping .8A per cell into an 800 mAh 2s battery, isn't that 2c?

Or have I forgotten basic electronics?
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Old Jun 08, 2009, 12:40 AM
sparkie624 is offline
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Quote:
Originally Posted by 41North
My DN Power balance charger fills 1-4 cell lipos at .2A to 2A rates in .2A increments.

Now, I get that lipo's like to see rates of 1c or less. I have some 1s, 2s and 3s batteries. I've been selecting charge rates of 1/100 of the mAH rating or less on all of them. But pondering what's going on... Isn't the mAh rating of a muli cell series wired battery the sum of all the cells?

The charger display seems to indicate the charge rate per cell. If I'm dumping .8A per cell into an 800 mAh 2s battery, isn't that 2c?

Or have I forgotten basic electronics?
In regards to the MAH rating to multi cell. I think you see it wrong if I am interpeting you correctly... For an 800 mah 3 cell, each cell is 800 mah being in series, at 3.7 volts each makes it 11.1 volts. In series Voltage adds up, in parallel current adds up and volts remain the same.
Old Jun 08, 2009, 05:27 AM
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Originally Posted by 41North
Now, I get that lipo's like to see rates of 1c or less. I have some 1s, 2s and 3s batteries. I've been selecting charge rates of 1/100 of the mAH rating or less on all of them. But pondering what's going on... Isn't the mAh rating of a muli cell series wired battery the sum of all the cells?
I hope you mean 1/1000th of the mAh e.g. 2A for a 2000mAh battery, because 1/100th is 10C and could be deadly .

Anyway in a SERIES connection the VOLTAGE is the sum of the individual cells and the capacity (mAh) stays the same. E.g. 3 x 1000mAh 3.7V cells in series gives 11.1V @ 1000mAh

In a PARALLEL connection the CAPACITY (mAh) is the sum of the individual cells but voltage stays the same e.g. 3 x 1000mAh 3.7V in parallel gives 3.7V @ 3000mAh.

Steve
Old Jun 08, 2009, 10:40 AM
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41 - Also keep in mind that your DN charger charges cells seperately so what you see, regardless of the # of cells in a pack, is what you get. Your display even shows you the amps going into each cell during a charge.

Also, the DN's (and CellPro 4S's) chargers can safely charge at 2C and 3C without any issues as each cell is charged seperately so all cells are balanced when the charge is complete.

Rick
Old Jun 08, 2009, 06:28 PM
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Thanks, all. It makes sense now.


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