LiOn battery draw tester

canadmin

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Canada
Is there a draw tester available for LiOn batteries similar to a draw tester for lead acid car batteries?
 
The only one I'm familiar with is a product from Grin Tech in Vancouver. It's called a "Grinspector" but unfortunately, it was discontinued in 2022:


There was an EBR member selling one in the classified section last year. You might try to PM him to see if he sold it:


If you're a DIY'er, you can make a crude tester using old incandescent light bulbs and a multimeter:

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The load can be adjusted by adding or removing bulbs from the string. I can get a 20A load using some old 300 W bulbs. By measuring the voltage drop as you add load, you can get a fairly good idea of the battery condition.

Capacity loss can be checked by timing how long it takes to discharge using a known load. Care should be taken so as not to over discharge.

I added a timer so the rig can be used to discharge batteries to the proper voltage for storage:

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One of the tricky parts in making such a rig is tapping the battery discharge connectors. My batteries all use the flat spade type. It was simple to cut the plug in half on an old extension cord. The prongs on the plug fit the battery perfectly.

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Check out the big brain on @6zfshdb!
Cutting an extension cord in half is pure genius!
I might have to do that this weekend to bench test a battery/motor... 👍


To the OP... my battery failed this draw test 🙃

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I used four 5 ohm 225 w resistors connected in series and parallel as a load to test a 48 v battery. 10 amps at 50 volts. My battery had .250" flag terminals on wires. I used 14 ga wire with flag terminals for connections. A parallel voltmeter will detect the garbage. I had one battery drop to 11 volts during this test, then snap back to 53 v immediately after disconnect. https://www.digikey.com/en/products/detail/vishay-huntington-electric-inc/FVT20020E5R000JE/257612
I bought my resistors for $6 each at surplus house Apexelectronic but he is out of that business now. Were also useful for testing PA amplifiers at 300 watts.
Do this test on concrete or dirt surface in case of fire. Wear safety glasses and do not touch the battery or resistors during test. the computer looking part mounts a 30 amp switch from the auto supply. The white plastic wrapped in aluminum angle was the battery.
 

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Digikey is a great source for anything electronic. They've got just about everything that you can think of, and they are based in the USA so they don't sell junk that gets returned.


I bought a 5 amp 60 volt bench power supply on AliExpress that lasted a year before it crapped out.

I replaced it with a 3 amp 60 volt bench power supply from Digikey that cost twice as much.
It was the cheapest 60 volt power supply they offer at $170 CAD plus tax.
It's still made in China, like everything else, but it's from a vetted source that Digikey stands behind.

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This 60 volt 24 amp programmable bench power supply is pretty cool, but at $3,700 CAD it was a little out of my price range. 😂

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