Discharge unbalanced battery

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Hummina Shadeeba   1 MW

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Discharge unbalanced battery

Post by Hummina Shadeeba » Mar 13 2019 7:24pm

I’m forgetting. Can I hook an incandescent bulb (or something that will discharge faster than leds) directly to my p groups to balance them? I’m
Remembering a toaster. Can I directly hook the toaster up to the 4.2v pack to get it down to 3.9?

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liveforphysics   100 GW

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Re: Discharge unbalanced battery

Post by liveforphysics » Mar 13 2019 8:03pm

An incandescent car headlight bulb, or a bunch of car headlight bulbs with both high beam and low beam wired all together in parallel is a crude but functional method.
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Hummina Shadeeba   1 MW

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Re: Discharge unbalanced battery

Post by Hummina Shadeeba » Mar 13 2019 8:50pm

I hooked the overcharged pack up to my toaster! Nothing happened that I noticed and don’t think they were discharging, maybe they were. 4v. And then I tried to hook it up to a couple different bulbs and nilch. Is the voltage too low? I’m surprised. Maybe need a much higher wattage bulb? Thanks Luke. Are there other options as I don’t have a bunch of car bulbs. Maybe some super high resistance conductor or something? Make a heater.
It’s this or using a phone charger to increase voltage on the low packs which I’ve done before.

Or all in paralllel but don’t want to make that contraption and they’re all snug built into a complete battery already.


I did parallel the extreme cells to balance them. Should’ve finished the job. They were spaced really far at about 3.4 and dare I say (3) at 4.65!!! Don’t ask. They didn’t get but a bit warm surprisingly though when I threw them together in parallel and it took a lot longer then I thought it would to balance.

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Re: Discharge unbalanced battery

Post by amberwolf » Mar 14 2019 3:21am

Say toaster is 1000w.

1000w / 115vac = 8.69 amps

115v / 8.69a = 13.23ohms

4.2v / 13.23 ohms = 0.313a

So discahrge will be pretty slow for a big back, but fairly quick for a single small cell.


parallel more loads for faster discharge.

Hummina Shadeeba   1 MW

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Re: Discharge unbalanced battery

Post by Hummina Shadeeba » Mar 14 2019 10:26am

Aha. There’s the math. Thank you.

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Matador   10 kW

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Re: Discharge unbalanced battery

Post by Matador » Mar 14 2019 6:55pm

I used my 1800W hairdryer...

Hummina Shadeeba   1 MW

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Re: Discharge unbalanced battery

Post by Hummina Shadeeba » Mar 16 2019 8:05pm

amberwolf wrote:
Mar 14 2019 3:21am
Say toaster is 1000w.

1000w / 115vac = 8.69 amps

115v / 8.69a = 13.23ohms

4.2v / 13.23 ohms = 0.313a

So discahrge will be pretty slow for a big back, but fairly quick for a single small cell.


parallel more loads for faster discharge.
would you use the full 115 in the equation or would it be the root means square I think it's called?

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dogman dan   100 GW

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Re: Discharge unbalanced battery

Post by dogman dan » Mar 19 2019 6:26am

For field balancing of lipo packs, like when on a camping tour, I carried a 12v turn signal light bulb. Plug it into the right two pins of the balance port, and that one cell starts discharging. Took some time, but it would work, quicker than running a balance charge on a 150w RC charger.

This method just let me get crudely balanced, if one cell was way out of whack. But in reality, that weak cells capacity still limits the whole pack capacity, so I did not get any more usable wh. The aim was to just let the rest of the pack charge without actually flaming that one cell while using a dumb bulk charger.

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Re: Discharge unbalanced battery

Post by Hummina Shadeeba » Apr 08 2019 5:11pm

I’d like to discharge at maybe 10 amps from the single 4v packs to balance.




https://www.ebay.com/itm/New-6x-5-Ohms- ... xyi3FRzaAv

.5 ohm resistor w 4v battery should get about 8 amps current draw and stay under the resistor’s rated max of 50 watts. I assume the resistance rating is accurate but the wattage rating would be a max based on its ability to rid of heat and stay consistent and not burn.


household stuff Id need something like at least a 30,000 watt rating to get about 10 amps with my little 4 volts right? It’s not out there. Isn’t 115 the peak voltage ac though and maybe to figure power you would do the math with the voltage’s root mean square?

I’d like to find a Ferris wheel or something else that can get me at least 8 amps draw. Something more fun. I’ll be curling up with my resistor in the dark till then

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Re: Discharge unbalanced battery

Post by Hummina Shadeeba » Jun 12 2019 1:43pm

What you think of my link will it work as I think? I’d rather use something high wattage. What about niochrome wire or whatever that heating wire is called? Don’t want to spend long discharging and the cell can individually put out 15 amps no prob
Last edited by Hummina Shadeeba on Jun 12 2019 3:18pm, edited 1 time in total.

dustNbone   10 kW

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Re: Discharge unbalanced battery

Post by dustNbone » Jun 12 2019 2:16pm

Should work fine, you'll be running it at around 30W or so. As long as you can't smell it cooking it's probably not too hot. You could series/parallel 4 of them to keep the same resistance but spread the dissipation out.

Hummina Shadeeba   1 MW

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Re: Discharge unbalanced battery

Post by Hummina Shadeeba » Jun 12 2019 3:49pm

https://www.homedepot.com/p/Everbilt-45 ... /205681009
4500w/ 240 volts= 18.75 watts per volts.
4v x 18.75w =75 watts id be discharging from a single 4 volt cell. that would be 19 amps. that sounds good to me. for a burst just to balance.

maybe it wont need to be submerged in liquid if putting out that amount of heat. maybe the heat would increase the resistance and a balance of output will be hit. Making tea is as exciting as discharging gets so far.

im liking hooking a voltmeter and a jst plug on it

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