Car Battery Jumpstarter - Automotive Wiring and Electrical


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Auto Repair Home>> Automotive Repair>> Automotive Wiring and Electrical

Pales84
New User

Feb 27, 2010, 7:50 PM

Post #1 of 3 (1583 views)

Car Battery Jumpstarter	Sign In

Gday,

Recently bought a jumpstarter for my car battery, and every time i hook it up, it comes up with a reverse polarity alarm. I change the terminals around, same drama. I'm too scared basically to actually give it a go cos i really don't wanna damage either my car nor my jumpstarter.

Anyone know why this is happening? It is a Projecta 900A 17 Amp Hour jumpstarter and wasn't cheap!

Any help would be great...

Cheers.

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 28, 2010, 12:27 AM

Post #2 of 3 (1576 views)

Re: Car Battery Jumpstarter	Sign In

Good one!

I own three such portable jumper boxes, two with polarity lights. I suggest you check the polarity of the unit with a common voltmeter will/should do.

It's possible (back from school days {dark ages} ) to charge a dead battery in reverse! By that I mean when a battery is so low it shows no voltage it will charge either way was the info I was taught. It would show the reverse with a test but wouldn't work well that way was the word of the day.

Maybe reasons: Defective unit or reversed charger for it? Perhaps the car is already reversed - can't know from here.

I'm not familiar with your exact model. I have one that you can hook up with no power transfer but light will say polarity correct or not before you turn a knob to enable it. Others if truly wrong would object horribly and instantly but I haven't screwed up yet to find out.

My guess is the new unit is the issue and not the car. If this is the type that can be hooked up without power until enabled and just that warning I'd try it on a known battery disconnected from a car or machine. If still wrong or tests wrong take it back as the car could really take a hit if jumped with reversed polarity,

T

jensdog
New User

Feb 28, 2010, 5:55 AM

Post #3 of 3 (1570 views)

Re: Car Battery Jumpstarter	Sign In

I agree with tom, try the charger on another " good" battery then you will determine whether the charger has a fault or the battery you have needs replacing( which I think will be the case,sorry) good luck!!
ps. If you hate anyone enough you could ask them to attach while you start the car!!! its win win situation!!

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