lipo cutoff

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Old 09-08-2010, 05:04 PM
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Default lipo cutoff

i have a bone stock blitz. i need to know how much run time i can get on these packs.

5000 mah 3s 11.1v 30c lipo
4800 mah 2s 7.4v 20c lipo

i dont have a lipo cutoff so how do i go about determining approximate runtime so i dont destroy these cells?
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Old 09-08-2010, 05:40 PM
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What esc are you using ?

If it is a stock esc designed for nimh's only I doubt you will be able to run 3s lipo on it

You can buy a cheap lipo warning buzzer from ebay that will flash a light and make a noise if cells drop below 3.3v or so, they work fine

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Old 09-09-2010, 03:22 AM
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BTW the esc is an old lrp ics digital speed control no motor limit 10 cell max but on a factory hpi motor. maybe 3s wont work too well on that motor... lol
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Old 09-09-2010, 04:54 AM
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If you don't use something like a Novak Smart Stop, easiest thing is to make a short timed run like you would be running - prob no more than 5 min. Then see what the charger puts back in. This lets you calculate a mah/min. Base your time estimates on 80% of the pack capacity - you don't want to use more than that since its basically the same as running the pack below the voltage cutoff.
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Old 09-10-2010, 01:22 AM
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so the idea on a 4800 would be not to have to put in more than 3840 mah into my pack?
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Old 09-10-2010, 04:49 AM
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Originally Posted by wow View Post
so the idea on a 4800 would be not to have to put in more than 3840 mah into my pack?
Correct....otherwise you're basically overdischarging.
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Old 09-11-2010, 07:04 AM
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Originally Posted by wow View Post
i have a bone stock blitz. i need to know how much run time i can get on these packs.

5000 mah 3s 11.1v 30c lipo
4800 mah 2s 7.4v 20c lipo

i dont have a lipo cutoff so how do i go about determining approximate runtime so i dont destroy these cells?
Go and get a used ESC from another racer that is Lipo capable. Why mess with the effort of Lipo cutoff. A low-level ESC with Lipo cutoff is cheap. Probably cheaper than the Lipo you are putting at risk.
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Old 09-11-2010, 10:52 AM
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^^^ There's a lot to be said for doing that too....
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