Want to build a resistor bank for my charger. Gurus step on in.

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LicketySplit

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Arrma RC's
  1. Limitless
  2. Outcast 6s
If I wire 4 of these up in series, will this work? The Hota D6+ has the ability I just want to make sure my math is correct. I should be able to discharge at 400w max. I’ll build some sort of enclosure for cooling, of course.
Edit. Amazon links suck it seems.

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Wiring 4 of those in series will give you a total resistance of 16Ω which will be a slow discharge in most setups. With 3s you'll get somewhere around 0.75A average discharge, taking more than 3 hours to discharge a fully charged 5000mAh pack to storage charge. With 6s you'll get around 1.5A average discharge, taking more than 1.5 hours for the same capacity and scenario.

I would suggest the 2Ω resistors with series-parallel wiring might be best. Two series circuits of two resistors in parallel (four resistors in total) would give you 2Ω total resistance, 6A/72W discharge on 3s, 12A/288W on 6s. This is a reasonable maximum current and theoretically the resistor bank should handle up to 400W.

Those resistors are intended to be mounted on a chassis or something that will act as a heatsink, and are unlikely to survive ~72W dissipation each for long without. You'll need a big heatsink and active cooling (fans) to keep four of them at a decent safe temperature.
 
Wiring 4 of those in series will give you a total resistance of 16Ω which will be a slow discharge in most setups. With 3s you'll get somewhere around 0.75A average discharge, taking more than 3 hours to discharge a fully charged 5000mAh pack to storage charge. With 6s you'll get around 1.5A average discharge, taking more than 1.5 hours for the same capacity and scenario.

I would suggest the 2Ω resistors with series-parallel wiring might be best. Two series circuits of two resistors in parallel (four resistors in total) would give you 2Ω total resistance, 6A/72W discharge on 3s, 12A/288W on 6s. This is a reasonable maximum current and theoretically the resistor bank should handle up to 400W.

Those resistors are intended to be mounted on a chassis or something that will act as a heatsink, and are unlikely to survive ~72W dissipation each for long without. You'll need a big heatsink and active cooling (fans) to keep four of them at a decent safe temperature.
Yea that makes more sense. I figured I messed up somewhere. Where do you get 288w on 6s? I got about 317 on a fully charged 6s lipo. I’m basically making this since it’s storm season here. I charged a couple 4s batteries and it was sunny out. When the batteries were done it started storming and I had to discharge. Took 4-5 hours or something like that at .3 amps.
 
If I wire 4 of these up in series, will this work? The Hota D6+ has the ability I just want to make sure my math is correct. I should be able to discharge at 400w max. I’ll build some sort of enclosure for cooling, of course.
Edit. Amazon links suck it seems.

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never thought I'd see those on this forum lol

I play with stereo stuff (amplifiers) and like "testing" / benchmarking.

So ventured how to test amps and of course need a "dummy load" so ended up with 12 100w 8ohm resistors. I mounted them to an amplifier aluminum heatsink.

Pay mind to the resistor circuit and the wiring / resulting resistance.

note, and this is CRUCIAL, the 100w rating is IF the resistor is mounted to a heat sink. They will get too hot if just using the resistor case for heat dissipation.

I don't have a DOTA, but of course you'll need someway to control the power delivery to the resistors.

just me but if I were looking to build a "discharger" I would probably go the route of invertor and just power a monitor / charge other devices. totally not "automatic" though / would need to stop discharging manually.
 
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There are a lot of ways to put a load on a battery than resistors. I get the convenience of using the microcontroller in the charger to manage discharge, but wouldn't it make more sense to run the batts down more efficiently, like powering a blender and making daiquiris?

nerd_sniping.png
 
There are a lot of ways to put a load on a battery than resistors. I get the convenience of using the microcontroller in the charger to manage discharge, but wouldn't it make more sense to run the batts down more efficiently, like powering a blender and making daiquiris?

nerd_sniping.png

1. build small to medium water tower, with a head of approx 50 feet.
2. fill water tower, power water pump with lipos
3. build and attach watermill to water tower, attach generator / alternator to watermill
4. drain water tower and use generated power to charge lipos

infinite energy loop! lol
Rube Goldberg lipo discharger?
 
those 100w resistors in this context just reminded me of my first RC car.


imagine having batteries so weak this resistor is sufficient....and was the "other half" of the speed controller lol.

b_50212.jpg



omg, mechanical speed control power a 3 phase motor (like our RC brushless motors)?

Sure! use a motor to power 3 phase mechanical switch to create pwm for brushless motor.

surely there's an idle 3d printer and ee brain out there that wants to make this quality RC content! lol PLEASE :D

transistors....pffft. give me sparks!
 
There are a lot of ways to put a load on a battery than resistors. I get the convenience of using the microcontroller in the charger to manage discharge, but wouldn't it make more sense to run the batts down more efficiently, like powering a blender and making daiquiris?

nerd_sniping.png
Rezus, this comic just totally hit that part of the brain that makes you lose your poop for two minutes in a fit of uncontrollable laughter. Thanks, I needed that :ROFLMAO:
 
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