Jumping a dead car battery

What is the consensus:
Put the negative directly on the dead battery or on a metal part of car to ground it? Everything I read always says metal part of car to ground it as to not cause a spark. But I can never get a good jump when I don’t put it directly on. What’s good ol hackettspeoples take on this?

Bigred Bigred
April 8th

You will still get a spark, but to the car body is what you are supposed to do. If the battery has an issue, the spark could cause a fire. So the last connection can be to the car frame well away from there so it would not be a risk.

Best of all - get an inexpensive external battery starter. It has an off switch so you connect it with no electric turned on. Then throwing the switch on the external starter will not cause any spark at all.


Some cars have solid lugs/tabs somewhere on the engine block just for this purpose (as well as sometimes having a large positive terminal somewhere else as well). The thought is that right near the battery there could be a buildup of hydrogen gas so try to keep the sparks as far away as possible...

If you don't have that, just find a big bolt, since other body parts and brackets will likely have paint on them and that won't make a good connection at all. That being said, I have hooked up right to the terminals and never personally had any problem.

Also, the proper order to hook up the cables is Dead (+), Donor (+), Donor (-), Dead (-). That minimizes the opportunities to have loose ends of the cable short out against something they shouldn't... so just remember "Dead Positive" to start, and basically make the electrical loop from there (and remove them in the exact *reverse* order).

Mark Mc. Mark Mc.
April 8th

Also, use thick jump cables - they "transfer" charge (current) faster and "better". These cables are usually heavy.
Some new cars may have computer problems if you jumpstart them directly from car to car - alternator must charge two batteries instead of one.
I've never encountered this "computer problems".


Black terminal is ground red is hot positive. Trickle slow charge add distilled water to battery unless it is sealed. I am retired and I don't use my truck for a couple of weeks and have a battery charger when the battery needs power.

Robert Rowe Robert Rowe
April 8th

Positive good. Positive bad. Negative good. Negative bad.

I never make the last connection to frame. Sparks don’t scare me.

Sacks cousin
April 9th

Mark Mc. said it exactly how I would have. Whether that’s “correct” or not I’m not sure but I too have only connected pos to pos, neg to neg and never had an issue.

That said, I’ve been religious about texting batteries when they get 4-5 years old and replace them before a jump is required. I know how much more complicated they are these days. The last car I jumped was probably 18-20 years ago and both cars were from the 90’s so way simpler in the ECU dept.

Consigliere
April 13th

No point in replacing them needlessly.


Use this to test the battery every so often-

https://www.amazon.com/gp/product/B07Z67MMGC/


And when the % healthy starts to decline, use this on 'repair' mode to desulfate and bring it back up-

https://www.amazon.com/gp/product/B07W3QT226


Scroll down the listings and read the info on both- very versatile and capable features.


Cars, motorcycles, lawnmowers... works great.


Believe it or not there are so many computers now a days that a battery can still pass a load test but cause issues with the vehicle

My buddy has a 2018 Equinox and he was having a issue with the auto start stop and computer communication issues after remote start, I did some reading on it and everyone was saying battery was root cause. I told him this, which he told the dealer and the dealer swore up and down they tested the battery and there was no problem there and they could not figure out the issue. He even showed them the tech bulletins

Fast forward to the third visit for the same issue and he finally told them to just replace the battery, he would pay for it....this fixed his issue....they then offered to cover his rental and gave him half off the entire bill being he was right all along.


There is a lot more to battery testing than just a load test.


Good point Darrin. Just worked on Nissan with an auto lift gate. Everything in The car worked perfectly except for the auto lift gate. Battery was ok. Slightly low on a load test but still good. Swapped the battery and the lift gate problem was fixed.

Sacks cousin
4 weeks ago

That is a good point Darrin. I had a 2012 ML350. Was getting message about some of the safety systems not working. Took it to the dealer, and it was the battery, which, miraculously was covered under warranty (~$500). So makes sense to check if it's covered. I guess being so important to just about everything, the battery is now covered or at least it was under my extended warranty.

And it does pay to have an external battery jumper. The way some cars are set up, it won't let you jump from battery to battery (the 'dumb' way) so as to protect the electronics. Learned this the hard way with my Audi and had to use a jumper pack (or the 'smart' way).

MeisterNJ MeisterNJ
2 weeks ago

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