how do a I test a jump box

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Jul 14, 2020
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a freind asked me to test their costco cat jump box. i used my chinese battery tester and it said it was good , but the resistance was 45 milli ohms. i hood it up to my HF toaster tester which is supposed to put a 100 amp load on it and it read bad battery. went down to 9 volts from 12.6 .

i know these things jsut have a small battery in them , but how do i test them other than what i have done? the compressor and led light etc all seem to work

 
Those things aren't magic-- they have a pint-sized lead acid battery inside that barely works for a couple of years.

If your friend thinks it's toast, it probably is. Your load test proves this.

It can be disassembled and the battery replaced if stuff like the inverter is important to your friend. The battery is a commodity item.
 
the resistance is partially because you arent testing at the battery.(unless you removed the battery)

Those will barely put out 150amps..
when they say 600 or 1000amps they mean peak amps for .002 seconds.

Probably needs a battery if its over 3 years old.
 
For a Clore SLA based jump pack, the test (at a battery temp of 77F) is to apply a 100A load for 6 seconds and then read the voltage. 9.5V or higher is considered acceptable.
 
This is the OEM 22Ah battery from my Clore JNC660 jump pack. When new, it could provide 385A at 60F, but the voltage after 6 seconds would be below 9V . A 200A load test would end at 9.4V . It died a very premature death. A new battery from Clore costs as much as a new jump box, so I bought a $45 SLA battery at Amazon. The replacement battery is not as powerful as the OEM , and is 2lb lighter.

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took it out and tested it. no change . numbers the same. gonna order a new batt form amazon. just for giggles i tested the li ion jumper pack i have with the toaster to see how it would react . the thing did not even flinch. stayed close to 12 volts for 10 seconds .
 
I’m currently charging up a jump box that loses it charge quickly. I think the best bet is purchase a 2000 amp lithium jump pack and throw the other one out. ( recycle the battery if you can.)
 
Here is my old Motomaster branded jump box. I pressed down the test button with a pencil after fully charging it. I’ll report back how many days it lasts. I used to take it out when we went out in the boat with the kids and they would crank the stereo.

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Here is my old Motomaster branded jump box. I pressed down the test button with a pencil after fully charging it. I’ll report back how many days it lasts. I used to take it out when we went out in the boat with the kids and they would crank the stereo.

View attachment 137905View attachment 137906
It’s Friday today and my old jump box is down 1/3 from Monday.

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SLA batteries in jump packs dry out. I believe that’s what causes them to “die”. Not very well Sealed. I’ve taken to popping the top off those batteries and adding distilled water to re-wet them. My garage door opener back up battery was revived that way. Took a few weeks of charging (installed in the garage door opener itself), but seems to work well now.
 
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