Charging Question

Old 03-20-2011, 09:46 PM
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Ive been using Thundxer AC-6 for a month now with no problems. Today I'm balance charging a 5300 mah 2 cell @ 5 amps and just happened to look at it when voltage hit 8.4 v. Charger did not shut down so I unplugged and checked battery with meter and it only showed 8.22v. Has anyone seen this before? Is there any way to calibrate this charger? BTW, Im new to lipos.
Thanks in advance.
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Old 03-20-2011, 09:55 PM
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Normal for voltage indicated on the screen to be slightly higher than actual pack voltage

Let it complete the charge then check the individual cells, they should be 4.2v

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Old 03-20-2011, 10:02 PM
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Thanks and cheers to you.
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Old 03-20-2011, 10:43 PM
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Per Cell, LiPos should be @ 4.2 nominally. When new they will be around 4.17/4.19. Once they break in (@ 20 cycles) they will more than likely show 4.20/4.21. Then when the battery gets a lil worn it will creep back down to the 4.17 mark (booo).
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Old 03-21-2011, 08:38 AM
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thanks Lapper. I guess the biggest concern is at what point should the charger shut down? Is it the instant it sees 8.4? I've never watched it that close.
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Old 03-21-2011, 05:35 PM
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Lipo charges in two stages, you'll see referred to as CC/CV. The 1st part is Constant Current (usually the 1C charge rate you selected) and it will charge at this constant current until the cell max voltage of 4.2v is reached (8.4v for a 2S). Then charger switches to Constant Voltage part of the charge where charger holds max voltage on the lipo while the current decreases as the lipo tops off.

You'll see the current fall to low value, close to zero before the charge is properly terminated. Stopping when charger reaches 8.4v for a 2S will not give you a fully charge lipo.
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Old 03-21-2011, 06:38 PM
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Thanks for info Duster 360, I appreciate it.
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