Neighbor needed a jump in her garage, but my cables weren't long enough (c'mon behave, guys). We ended up going out to buy a new battery, but I wondered if putting 2 sets of jumper cables together would work. I know the usual warnings about red-to-red and not letting them touch would apply here, but has anyone ever tried this? Is this ever done?
Join Two Sets of Jumper Cables
- Thread starter JerryBob
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DC current is a lot more affected by resistance so you will suffer a reduction in cranking amps by doing this, but it will work if you have enough power. Heavy gauge cables would help, too. In other words, the longer the distance, the thicker the wires have to be to carry the same amount of current.
It can be done with quality cables. As always, the resistance of the cables matters if the battery won't take a charge and we must rely on the current carrying capability
I like the new jumper cables version; the Battery Jump Starter.
It's been done but it's really sketchy, since you don't have much to separate the middle connection. Wrap a rag around the positive side so it doesn't hit the car body or other cable.
Naturally it goes better if you have a good donor and good cables trying to boost a healthy car that's just down on its luck. You may need to do this to get an electronically shifted car to go from park to neutral, for example, so you can roll it out and then jump it properly.
Naturally it goes better if you have a good donor and good cables trying to boost a healthy car that's just down on its luck. You may need to do this to get an electronically shifted car to go from park to neutral, for example, so you can roll it out and then jump it properly.
Due to the high resistance of using two sets of cables it would be best to let the donor vehicle run for five minutes or more to build as much charge as possible. Of course watching the cables for overheating is imperative.
You're absolutely right. Seems like a must-have and I just put it in my shopping cart.
JHZR2
Staff member
Another thing to degrade and fail in time. But with horror stories about inductive spikes on cars boosting others, probably the best way if you’re not going to just use a spare battery to jump.
I tend to have an old battery on a charger that is good enough to get things going. I’m not keen on subjecting alternators to dead batteries, or putting a less than 100% charged battery into service.
Yes, I've done it, and it works pretty well.
Long ago, back when cars had steel bumpers, if your cable pair was too short, all you had to do was seperate the pair and touch both car bumpers together, that was your negative.
Both jumper cables, singled out, were attached end to end for the positive side. That worked too.
Long ago, back when cars had steel bumpers, if your cable pair was too short, all you had to do was seperate the pair and touch both car bumpers together, that was your negative.
Both jumper cables, singled out, were attached end to end for the positive side. That worked too.
No reason other than safety, and most of that just involves property damage. As mentioned, if the positive connection arcs to a ground you've effectively got high-amp welding cable there. Small wires burn up but heavy cables will get much, much hotter
Got one. Never had to use in three years. Charge it every three or so months, but it never requires much recharging before light is in the green. Go for it cowboys.
I was an early adopter of jumper packs but they're not guaranteed no matter how much you pay.
They're a valuable tool -- especially to self-rescue -- but don't throw away your cables. Cables are (obviously) dead simple old tech that can't really go bad and can be used infinitely in the field. It's the difference between CO2 cartridges for bike flats vs a frame pump.
They're a valuable tool -- especially to self-rescue -- but don't throw away your cables. Cables are (obviously) dead simple old tech that can't really go bad and can be used infinitely in the field. It's the difference between CO2 cartridges for bike flats vs a frame pump.
Longer would mean you need a heavier wire (lower number in the gauge).
With the Li-Ion jump packs being under $100 not sure why everyone does not have one?
One reason is their limited life span. The last one I owned had to be disposed of when it started bulging after several years. They don't tolerate being in a super heated car very well and have limited functionality in cold weather. That's not a big deal where I live, but is for a lot of people.
The beauty of the jump boxes, to me, was the ability to get them in tight spots. Hard to get 2 vehicles bumper nose-to-nose on speedy CA freeways, etc. Or a big fat SUV stuck in the garage.
This was a SLA battery or li-Ion?
I have several jump packs. The SLA stays in my garage and the Li-Ion stays in my car/truck.
However two AGM batteries in PSD is even better.
I'm on my second jump box after the first one bulged. Like most things for emergency use, they don't get used much.
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