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What's the cut-off voltage for a 9.9V 3s A123?

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Old 09-18-2007, 10:02 PM
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hobbygoblin
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Default What's the cut-off voltage for a 9.9V 3s A123?

Hi! I have a Mamba Max ESC that has the ability for the user to set the cut-off voltage for lithium batteries. My question is... Since A123's are rated at 6.6V for 2s, and 9.9V for 3s, it fools the MM ESC because the MM ESC's auto lipo cut-off is custom programmed for 7.4V for 2s, and 11.1V for 3s. But I can also choose what cut-off voltage I want with the Castle Link software. Is there a specific voltage I should set the cut-off to for a 2300mAh 9.9V A123? Thanks for any help with this.

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Joe...
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Old 09-18-2007, 10:18 PM
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Default RE: What's the cut-off voltage for a 9.9V 3s A123?

Cut-off voltage for A123 cells is two volts per cell. I set mine about 2.2 volts per cell just to be safe. I try and not fly to lvc but use my timer to time my flight.


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ORIGINAL: hobbygoblin

Hi! I have a Mamba Max ESC that has the ability for the user to set the cut-off voltage for lithium batteries. My question is... Since A123's are rated at 6.6V for 2s, and 9.9V for 3s, it fools the MM ESC because the MM ESC's auto lipo cut-off is custom programmed for 7.4V for 2s, and 11.1V for 3s. But I can also choose what cut-off voltage I want with the Castle Link software. Is there a specific voltage I should set the cut-off to for a 2300mAh 9.9V A123? Thanks for any help with this.

Thanks,
Joe...
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Old 09-18-2007, 10:36 PM
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Default RE: What's the cut-off voltage for a 9.9V 3s A123?

Thanks for the quick help Bob. I'm guessing that since I drive an r/c Monster truck that a 6V cut-off would be fine since I would notice it slowing down before it actually goes down to 6V? Since you fly a plane, I'm assuming you'd have to give yourself enough extra time to land, hence the reason for the slightly higher LVC setting?
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Old 09-18-2007, 10:39 PM
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Default RE: What's the cut-off voltage for a 9.9V 3s A123?

I don't use any cutoff voltage. I just stop when I loose power. The drop in power is huge, so you can't miss it. But in the beginning I did set the voltage at 2 volts per cell. But it got annoying after a while since used 2, 3 and 4 cells packs.
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Old 09-18-2007, 10:43 PM
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Default RE: What's the cut-off voltage for a 9.9V 3s A123?

Ok, good to hear. Thanks snellemin. I'll be using the 3s primarily so I'll try the 6V cut-off. I won't be using my 6-cell IB4200 pack much any more, lol.
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Old 09-18-2007, 10:51 PM
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Default RE: What's the cut-off voltage for a 9.9V 3s A123?

Yes the like the extra time to land, but I also don't like pushing the limits, even if they are A123 cells.

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ORIGINAL: hobbygoblin

Thanks for the quick help Bob. I'm guessing that since I drive an r/c Monster truck that a 6V cut-off would be fine since I would notice it slowing down before it actually goes down to 6V? Since you fly a plane, I'm assuming you'd have to give yourself enough extra time to land, hence the reason for the slightly higher LVC setting?
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Old 09-20-2007, 11:46 AM
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Default RE: What's the cut-off voltage for a 9.9V 3s A123?

Do you guys store your A123's at whatever voltage they ended up at after the run, or do you charge them back up part way?
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Old 09-20-2007, 01:17 PM
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Default RE: What's the cut-off voltage for a 9.9V 3s A123?

sometimes I store them depleted. But I usually fully charge them before storing them. Sometimes I use them after a week and it still has all its "power".
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