Best / Fastest way to discharge lipo to storage volts

[Zoea]

Hi

I find myself charging excess lipos or not using each enough when I go out with my RCs. I'm fed up with "1a" (0.2a more like) 5w discharging a full lipo to storage - this can take 3 hours with balance to 2*3.8v .

I need a 40w+ discharger or balance storage charger - ideally much more... Anyone know one specced to this? Since my 2s are rated at least 30c (8*30 amps) I should be able to quite quickly discharge each to 7.6v, then put it on a cheap charger for final balance. However there is nothing on the market to do this. Can I make something ? I don't mind manually watching the voltage drop.

Creative solutions welcome. Yesterday I spent 4 hrs storage charging and I have a couple of better chargers even.

Thanks
Zoea

[mark christopher]

No one on the market makes a stand-alone lipo discharger the best way is to invest in a good quality charger with a high discharge rate this will then allow you to put them in storage mode quicker

[mattr]

Best way to discharge is to actually drive..........

My "best" charger only goes to 30W/8A according to the specs, and that was near enough 150 quid with a Powersupply thats up to the job.
Cheapy one will do 20W/7A. And thats near enough 70 quid including the PS.

[Northy]

I'm actually thinking of making a discharger to do the same at the moment.

G

[tonydevon]

I picked up a used LRP charger, only 50 quid, charge at 12A discharge at 20A

doesn't seem to take long if I need to take a pack down.

I run 5 packs so typically at a meeting I used to charge it, run it and then put it back in box, I have always used that end of run voltage as my storage, never had any issues, zero swelling after 6 months of weekly use in this manner

now I run 2 classes I tend to miscount or be cautious and charge an extra 1 or 2, so use discharge function to take them down

[Zoea]

Thanks for the replies everyone. Useful information here.

Elsewhere I have heard of people putting a beefy resistor (heatsink, maybe fan) in series with their lipo when storage charging and getting a good result. Resistors are very cheap. Has anyone tried this and got first hand feedback or recommendations for me? It seems to me that the charger would continue to set the amps discharge, it would just do it much quicker. Might be ideal for me.

Again, thoughts and creative solutions welcome. I ran 6 packs today and we ran them good, still took 70 mins to storage charge them all - not ideal

Also, is it ok to leave a lipo 2s at 7.4-7.8v (within 0.2v of storage charge) or do they *have* to be exactly 3.6v per cell? One of my newer chargers does a range, something like 3.6-3.8 per cell....

thanks
Zoea

[mattr]

Rule of thumb is "a chunk under 4V per cell."

I check mine before they go back into the bag and anything under 7.7-7.8 ish i leave. 7.9 i might discharge depending on how rushed i am.

Though to be fair i only charge the batteries just before i use them so the only time i get a charged battery needing discharge is if i break a car badly enough to give up for the day.........

[Pushead]

Originally Posted by mark christopher

No one on the market makes a stand-alone lipo discharger

ISDT makes 100W discharger,
http://www.isdt.co/fd-100.html

[mark christopher]

Originally Posted by Pushead

ISDT makes 100W discharger,
http://www.isdt.co/fd-100.html

Ok fair enough but not of any significant discharge power.
Only 6 amps though, most decent chargers will do that, my charger will do 20, or 40 amps regen mode

[Zoea]

Me and my brother have been looking at this for a few days and found these;

150w halogen discharge harness no auto stop or monitoring...


https://www.banggood.com/AOK-CellMeter-8-150W-Multi-Function-Battery-Tester-Discharge-Module-p-1084706.html?rmmds=search

I have ordered 4 and 4 cheap lipo alarms from eBay and will report back when it all eventually arrives.

Thanks for the help all...

Nav

[mark christopher]

Originally Posted by Zoea

Me and my brother have been looking at this for a few days and found these;

150w halogen discharge harness no auto stop or monitoring...


https://www.banggood.com/AOK-CellMeter-8-150W-Multi-Function-Battery-Tester-Discharge-Module-p-1084706.html?rmmds=search

I have ordered 4 and 4 cheap lipo alarms from eBay and will report back when it all eventually arrives.

Thanks for the help all...

Nav

1 slip up or distraction and you have puffed/blown lipo, dont leave them alone for one second

[D20MCK]

I use my old Trinity DPD to discharge fast if I need to, discharges at 30 amps.

you might be able to get one cheap second hand.

[Aire valley]

I have an Etronix Powerpal 200 that discharges at, up to, 5 amps...works for me.
seems consistent and a reasonable price.

[Northy]

After thinking about this I think it would be best if the discharger discharged one cell at a time using the balance port.
So I'm going to make one that does just that.

G