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Will this work?

Posted by DjDemonD 
Will this work?
June 02, 2016 03:11PM
Okay making a lipo pack for a childs ride on train toy. Draws around 3A when working hard, just a simple DC motor. Thought about putting a protection circuit on the pack to prevent over discharge/over current etc..

Bought this module from China, and yes that's a British penny coin in the photo.

They claim it will handle 5A. Its miniscule! Now I know that modern electronics are pretty good, I am still amazed at the current handling of the mosfets on my printer control board but surely the tracks in this unit will melt with 5A at 8.4v going through them???

Quite happy to test it when I get chance but this is just one of those moments when you look at it and think - this will never work.


[www.precisionpiezo.co.uk] - Drop in Piezo Z-Probe, Early birds sold, kits coming soon.

DemonDeltaMicro - Micro Delta Printer [www.thingiverse.com]
Things I've made/remixed.

Re: Will this work?
June 12, 2016 01:30PM
Well I still have not had chance to actually install this battery pack in the children's ride on train that it is intended for but this module does shut the pack off when under voltage. I left it connected with a 5A lipo regulator designed for Rc cars attached, which I did not realise has a small current drain and it ran the pack down to 4.0v (for a 2S pack). This module shut the pack off at the 2.0v per cell, the absolute minimum voltage, and as a result no scary consequences. Charging the cells back up now, no damage done.


[www.precisionpiezo.co.uk] - Drop in Piezo Z-Probe, Early birds sold, kits coming soon.

DemonDeltaMicro - Micro Delta Printer [www.thingiverse.com]
Things I've made/remixed.
Re: Will this work?
June 13, 2016 08:21AM
2.0 volt per lipo cell will damage the lipo. In the RC world we, under power, are not going lower then 3.0V to 3.2V ( 3.2 is the save value for a lipo )

And if you really want to see what modern electronics can do, look at RC, I have a MIG29 3.5 kg that pulls 220A out of a 6 cell lipo.
And we don't call this crazy. That are the F5B guys that pull over 300A.


P3steel DXL, with Due/RADDS/Raps128 dual Wade's extruder
Re: Will this work?
June 13, 2016 08:38AM
Yeah 2.0v was a bit lower than I'd like to see but better than 0v and a sticky mess/exploded cells.

Data for this module says it should cut off at 2.5v per cell. So maybe I just pulled the regulator off manually when it was at 2.0v exactly - seems a bit too precise to be luck though.

So show me the controller etc.. thats got 220A moving through it I'd love to see it.

Edited 1 time(s). Last edit at 06/13/2016 09:17AM by DjDemonD.

[www.precisionpiezo.co.uk] - Drop in Piezo Z-Probe, Early birds sold, kits coming soon.

DemonDeltaMicro - Micro Delta Printer [www.thingiverse.com]
Things I've made/remixed.
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