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cutoff voltage?

Old 03-24-2004, 06:20 AM
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Me-109K4
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Default cutoff voltage?

I've just upgraded my SS to brushless/lipoly; mega 16/7/8, phoenix 10, 2 cell 2100 mah 7.2v lipo. My question is what cutoff voltage should I set for this combo, I'm new to electric systems.
Old 03-24-2004, 07:58 AM
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Matt Kirsch
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Default RE: cutoff voltage?

The rule is 3.0 Volts per series cell. You have two cells in series.
Old 03-24-2004, 11:32 AM
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Trogdor the Burninator
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Default RE: cutoff voltage?

Hola Matt, learned a lot from you past few months lurking.. Anyway, isn't the 3 volt per lipoly cell NOT under load? I've read that 2.5V per cell is the cutoff limit because the batteries will be under load.... and this on a vendor website. Whats your opinion? Is it that 2.5V to 3V is so close because of a sharp voltage drop near end of charge like other batteries or something similar or is 2.5 actually a potential damaging situation?

I guess I should add that in my own limited lipoly experience I don't use cutoff (non-lipoly aware ESC) and just stop and check with a voltmeter... however, the plane gets so slow by 6.5V (after stopping and digging out voltmeter etc to test on ground at least) that I just bring it in because the plane barely flies anymore anyway...
Old 03-24-2004, 02:18 PM
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Default RE: cutoff voltage?

3.0 Volts per cell is under load. Originally, the recommendation was 2.5 Volts, but with all the unknowns regarding LiPoly longevity and failure modes, end users have generally adopted a more conservative 3.0 Volts.

Under 3.0 Volts, there is very little energy left in the battery anyway. The few extra seconds of lackluster flight you'd get by drawing the cells down further is not worth it.
Old 03-30-2004, 11:51 PM
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Default RE: cutoff voltage?

I have a castle creations pheonix 10 and the directions say the cutoff voltage is preset at 5.0 volts. If I am understanding this correctly, that means I am in danger of harming my 3 cell kokam 340mah? The motor has pretty much full power right up until the esc cuts it off. One more question, Is there a way to adjust the cutoff voltage on the pheonix 10? Thanks for any help.
Old 03-31-2004, 12:38 AM
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Default RE: cutoff voltage?

Only if there is a P after Amps. Example Pixie 20P. You can program the cutoff voltage, hard or soft cutout and and something for heli flyers. Hope this helps.
Old 03-31-2004, 11:38 AM
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Default RE: cutoff voltage?

Yes, you can do some significant damage to your Kokam 340 pack. A 3-cell pack should be cut off at 9 Volts. With a 5 Volt cutoff, each cell is drawn down to a dangerously low level, less than 2 Volts per cell!

The "P" suffix only applies to brushed motor controllers from Castle Creations. The Phoenix 10 is programmable, as are all Castle's brushLESS controllers. You should have gotten a set of instructions with it, or you can download them from Castle Creations's website.

Be aware that some older versions of the Phoenix 10 are not programmable, such as the older ones that come with the Astro 010.

Measure the voltage of your battery while it's running, and after the ESC cuts it off. It should never go below 9 Volts.

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