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Need a little inspiration

VenomBallistics

Aug 30, 2018
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Here's my situation.
I fly RC airplanes.
These run LiPoly batteries which tend not to like to be stored fully charged as the internal resistance rises over time (bad deal when you need to whip the minions to get upstairs)
The weather has sucked and when it has not been trying to waterboard us all, my schedule has conspired with the weather.
What often times happens is I will charge several flight packs only to have weather or schedule bone up the whole show, thus depriving me of an opportunity to discharge these packs in the preferred manor.
While my charger has the capacity to discharge, it is a ridiculously slow process at 1A max.
so ... the mission is to waste energy at a reasonable pace, preferably to semi useful ends.
fine point parameters....
dual voltage ...
16.8 start auto shutoff at 14
12.6 start, auto shutoff at 10.5
Capacities range from 1.5 Ah to 4Ah
Lets waste some powah
 

Alec_t

Jul 7, 2015
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A big fat resistor is about as simple a discharge load as it gets, providing you already have an auto-shututoff on the battery. The load WILL get hot, whatever you use!
 

Audioguru

Sep 24, 2016
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My RC Li-PO batteries are at full charge for most of the summer and at storage charge all winter. They last for years.
 

VenomBallistics

Aug 30, 2018
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A big fat resistor is about as simple a discharge load as it gets, providing you already have an auto-shututoff on the battery. The load WILL get hot, whatever you use!
No auto off on the battery. given that we draw welder level current out of them at times, any auto cut has to be after the regulator in the logic of the speed controller where the servo style PPM is locked to 0.
outside of the airplane, its wide open and unregulated
 

VenomBallistics

Aug 30, 2018
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My RC Li-PO batteries are at full charge for most of the summer and at storage charge all winter. They last for years.
Normal, I'd run them in similar fashion ... this season has been anything but normal, thus pressing me into seeking alternatives to making the old B6 charger hot for hours
 

Hopup

Jul 5, 2015
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I guess you could just run the plane on the ground still with fan which would cool the ESC so it won't overheat.
 

VenomBallistics

Aug 30, 2018
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I guess you could just run the plane on the ground still with fan which would cool the ESC so it won't overheat.
I have a 70MM EDF X-29 that I use for this ... Its good for the larger packs .. gets a little sketchy when the draw exceeds C rating as smaller packs are being processed
 

Bluejets

Oct 5, 2014
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Discharge for storage is normally looked upon for long term storage.
Don't see the point really given most packs are Chinese these days for cost reasons and would never live up to claimed specs.

Other than that There are battery capacity testers that can handle over 100w.
If not suitable as such perhaps a modification to the cut off via an Arduino.
Shouldn't be all that difficult.
 

VenomBallistics

Aug 30, 2018
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it's a sort of forced long term situation.
As I tell the club members, this would be hilarious if it weren't happening to us.
First ... our flying field is along the Missouri River. The season started off great, then the Nippleheads in the army corps of engineers decided to eff up the water management at Gavins point.
They lollygagged and bumbled around till they had a crisis which made out field part of the riverbed for about a month. The water receded but the city parks dept haven't been able to clean things up and fully open the park.
One of our access roads is still underwater. Rain has caused several setbacks ...
Meanwhile we've made arrangements with other clubs ... but the rains kept on coming, and of late, these fields have had spotty availability due to condition as well.
in general, I try to pull batteries down to storage after about two weeks if I get hamstrung by this ongoing saga.
I feel its better to to do this than forget them. It is conceivable that the next opportunity to go flying may be after everything has froze over so we can fly off the ice.
Till then, I have no idea when we'll be able to discharge packs through actual intended use.
and that brings me to trying to think of ways to multitask the batteries.
 

WHONOES

May 20, 2017
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Could use them to run a radio or something similar. At least you would get some enjoyment of them.
 

VenomBallistics

Aug 30, 2018
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that's kind of a decent start ... been looking at compairitors and either a PIC μC or Raspberry Pi for power management.
 
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