[SOLVED] Resistors

Apr 9, 2020
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Hi,

Totally new to this! Not even sure if it's in the right place.

I'm trying to fix a car jump starter battery pack I've taken it to bits and one of the resistors is burnt out!

The resistors have:
1st band grey
2nd band grey
3rd band grey
4th band gold

Now I've found out that this should be 8.8G ohms 5%

But this is something I've found with some research on google and means nothing to me. I've tried to find this resistor on google/amazon to replace it and they are nowhere to be found.

Any help would be greatly appreciated.

Thanks in advance.
 
Solution
I would personally say that a car battery and possible connected devices aren't anything to play around with. A car battery can put out hundreds of cold crank (read as kill you) amps.

Chances are strong that the wrong part will just burn out again. Worst case it is arc flashes back and fries the crap out of the device, the outlet, the battery...you...
That value seems ridiculously high.
Even though that's what the colors say...I think it's likely that 8.8 Gohms isn't the value.
If there are other good resistors like this one....you can "try" and measure it in the circuit...but that is hit or miss....as the rest of the circuit can affect that measurement.
Ideally you would want to remove one of the good resistors....measure it...then put it back.
 

punkncat

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I could see it for a battery jump box. I also confirmed the reading based on those colors.

All of the good local places to find resistors and such have closed down. I am not sure than a standard consumer electronics shop would have need of something with this value anyway.
 
I just checked with Newark Electronics.
They are one of the largest electronics distributors in the world.
I deal with them a lot with my job.
They sell 53,606 different resistors.
They don't sell an 8.8 Gohm resistor.
This is one reason why I question the value.
The other reason is...the value is extremely high.
 
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Apr 9, 2020
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Thanks for all the really quick replies, looks like the charger may be done for!

Mind the resistor has been greyed due to being burnt out. Is there anyway to determine what resistance it should have been giving. Or maybe just throw in the best resistor I can find?
 
Thanks for all the really quick replies, looks like the charger may be done for!

Mind the resistor has been greyed due to being burnt out. Is there anyway to determine what resistance it should have been giving. Or maybe just throw in the best resistor I can find?
Usually when the three bars are the same color, they are brown, red or orange.
If they were brown it would be 10 ohms.
If they were red it would be 2.2kohms.
If they were orange it would be 33kohms.

If they are three or any other color....the values get a bit ridiculous.

Don't just throw in a resistor though....you can cause a problem.

Is there another good resistor that looks like the burnt one?
 

punkncat

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Wow, well that was absolutely no help at all.

All I can find online is that they are ALL refurbished and that the parent company may never have existed at all? lol.
I can't find anything useful.

Edit- It appears to be a similar/same unit as a Centech as sold by Harbor Freight here. I found an exploded diagram but nothing is described in a meaningful way.
 
Apr 9, 2020
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Haha sounds like a hoot. I'm just gonna order a pack of the 3.3s and see if I can find the right charger for it. I think that was probably the issue in the first place someone has use the wrong charger.
 

punkncat

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I would personally say that a car battery and possible connected devices aren't anything to play around with. A car battery can put out hundreds of cold crank (read as kill you) amps.

Chances are strong that the wrong part will just burn out again. Worst case it is arc flashes back and fries the crap out of the device, the outlet, the battery...you...
 
Solution

punkncat

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It would seem to me there are a few things that happen. (This one has the pump and all that too, right?)

You have power to the accessories inside. You have power charging the internal battery, and then when set that internal battery is to the leads for the jump power.
With a (proper) meter and some PPE you could check all those outputs.
 
If/when I was to add the resistor would there be a way to find out if the repair was successful barring a (destructive) test?
After I replaced the resistor...I would set it on the floor away from anything flammable...maybe in your garage or something and plug it in.

That resistor may be part of the battery charging circuit and it may fry right away or it may not.

If it doesn't fry I would let it charge and I would also visibly inspect that resistor and check it for heat.

Then if all seems normal I would try it on a battery.