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Safe To Trust Esc Low Voltage Cutoff?

Old 12-27-2007, 05:33 AM
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Default Safe To Trust Esc Low Voltage Cutoff?

I am using a great planes silver series 25 amp brushless ESC with my 11.1v 1250mah 20C packs. Having only recently switched over from gas, I was wondering if it is safe to run the batteries until the ESC kicks in or if I should be using some other method of monitoring voltage during my flights to prevent battery damage?
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Old 12-27-2007, 12:26 PM
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From experience, and advice from others, I have learned that it is NOT a good idea to use the ESC low voltage cutoff as an indicator of when to land.

Most ESC cutoffs are somewhere between 2.7v to 3.2v per cell. However if you discharge this low you will cause damage to your LiPo that will significantly decrease it's life span.

The current wisdom on Li-Po batteries, if you want to get the maximum life you can from them, is to not discharge them more than 80% of their total capacity. Thus from a 1250mAh pack you should never draw more than 1000mAh.

Also the standing voltage after a flight (say 10 mins later when the battery has cooled and voltage has recovered) should not be less than 3.75v per cell.

It will not kill your pack straight away to exceed these levels, but if you do it regularly then you will start to notice pack degradation (cell imbalance and/or loss of capacity) after only a few dozen cycles.
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Old 12-27-2007, 01:38 PM
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I agree, I go with the 80/20 rule also. Once you know your plane well enough set your timer and fly to the buzzer. Most planes that use the same battery pack size can generally be set to the same time if the power systems are similar. With the pack you have depending on amp draw and flying type do a 6 minute flight on a full pack and see what is left in it. Then you can adjust accordingly of course if it's a really low amp draw system you'll be able to go much longer.

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Old 12-27-2007, 06:19 PM
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Absolutely NOT!
This is the spec for that unit (quote):
Low Voltage Cutoff: Battery voltage x 0.67

12.v x .67 = 8.5 (much too low). Shouldn't trust anything under 3.0v/cell, 3.3v is much better.

IMO these should not even be sold along with similar miserable ESC's.

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