Shout out to Byron

Much much more than this but take a look at the battery tester he gave me.
Wow, this thing is great. Now i can load test on the bench.
@AssyRequired .17 ohms if you have more. Only 1 connected. I can do 600 amps or 150 amps by using both.
Or 300 amps at 100 volts.


My reluctance to build this has been finding a safe way to disconnect 300 amps.
Doh, fets in the bms.

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Open circuit after test. This 2p14s gen3 Volt is disappointing. Then a few days ago it was at 5 volts.:persevere:

@djgabriel2004 @LithiumGods

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If there was anybody that could figure out a good use for them I figured it had to be you.
Yes, I have a few more. How many do you need?
I figure setting up a rack and select how many you need depending on what you were testing.

How warm did it get at 300A? (Those poor FETs)

Too hot to touch after 15 seconds, but not glowing. 1st test only.
You could connect 4 in series parallel to double capacity. I think it’s fine as is.
A fan if needed.
I’m also thinking of welding with it. Fixed 150a dc welder in the field would be pretty sweet. Or two for 75a. This battery goes in a buddy’s ranger, He could weld equipment on the farm. Or blow something up. Who knows?

I guess 3-4v drop at 300a is not terrible. Only a 110ah 5yo battery.

That should warm your garage up!

18s tesla doesn’t like a .17 ohm load. The bms took it though. Big pop when breaking the circuit. Sketchy as hell.

Thought the Tesla would do better. I totally see why lifepo4 don’t perform. This may be the best battery out there and it looks marginal with a big load.
Crap, hope I didn’t blow up the Tesla. :kissing_heart:

Confused on what you are doing/testing? Are you just looking for a way to load test a big battery?

What do you mean by “doesn’t like it”

Big voltage drop. I just thought it would do better.

Based on specs, 1000 A discharge rate for 10 seconds
1C continuous. (280A based on my math)

did you use the same JK?

I would do 2 more tests… one Bypassing the BMS.
and then same test with Goliath :wink:

Doing the sameDoing the same thing today , building the new battery pack for my 2018 and didn’t realize the modules were way off and voltage. Dave’s resistor bank is way bigger than mine

New test at a more reasonable current.

Post test.

The Volt seem to be better. ??
2p14s gen 2017 Volt 3.69/14=.26 per cell drop @299 amps
Versus Tesla 4.63 drop @200a=.25v per cell. 8v drop @387a .44v per cell
Volt 3.69/14=.26 per cell drop.

there is definitely no way that the old volt performs better than Tesla, something must be wrong IMO.

Modules are 6s right? are you planning to go 12s, 18s maybe in your 2018 ?

I think I know. Different soc maybe.
Volt was 3.79 average
Tesla 4.04

I need to charge Volt to 4v and test again.
Both dropped the same amount. .26v per cell.
Volt @ 299a
Tesla @203 amp only

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These are 8s, tapping back to 15s for now

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