Jumper Cables and Low Voltage Batteries?

We recently became a 100% EV family ('23 Model Y and '20 Bolt, woohoo!), and as I was cleaning out my last gas car during trade-in, I found the jumper cables and thought, ‘Does carrying these around make sense anymore?’

Most EVs have low voltage 12V systems for accessories, but the battery power rating seems lower than gas cars since there’s no engine to crank. So, I doubt I could jump a gas car with my Tesla, and if my EV’s 12V battery was going bad, I’d probably get an alert before it left me stranded.

Any thoughts? Has anyone had their EV’s 12V battery die and leave the car inoperative? Has anyone successfully jumped a gas car with an EV? Thanks in advance!

Get a jump pack. I’ve carried one for over 10 years, and it’s about the size of a laptop battery. Costs around $60 (though there are fancier ones now), and I only charge it once a year. It’s great for jumping your car without risking damage to electronics by jumping others. Also, it doubles as a portable power bank.

@Amelia
This! I’ve used mine to help others where moving cars wasn’t an option. Plus, it’s handy for helping yourself when no one’s around.

@Amelia
I bought this one, and it works great: https://www.amazon.com/Imazing-Portable-Car-Jump-Starter/dp/B07L5HPVJZ

My car’s manual says it can receive a jump if the 12V dies, so jumper cables could still be useful. But it also says not to jump other cars.

Gabriel said:
My car’s manual says it can receive a jump if the 12V dies, so jumper cables could still be useful. But it also says not to jump other cars.

>also says to not jump other cars.

That’s a dealbreaker for me. I jump cars often with my TDI, which has a 120amp alternator.

@diallo
You could carry a jump pack instead. They’re affordable and safer.

Gabriel said:
@diallo
You could carry a jump pack instead. They’re affordable and safer.

Jump packs don’t handle extended cranking well. If I’m jumping a car, it’s often because I already drained the battery trying to start it.

A dead 12V can leave you stranded, even in an EV. I keep a Li-ion jump pack in my car, just in case, and it’s handy for helping others too.

For my 2018 Model 3, Tesla says it can be jumped but never used to jump another car.

We gave our jumper cables to a neighbor when they asked for a jump. We weren’t sure if it was wise to jump their car with our EVs. Now we just carry a jump start battery pack for safety and convenience.

Power rating doesn’t matter. It’s still a 12V battery, so you can jump it like any other.

Yes, my 12V died when my SO left the car in accessory mode overnight. Also, I’ve jumped a gas car with my EV when her power bank drained the battery. EV 12V systems are still robust enough to power essential electronics like lights, steering, and brakes.

12V batteries dying on EVs is surprisingly common.

chozen said:
12V batteries dying on EVs is surprisingly common.

I had to use a jump pack to revive my 12V after leaving my car’s doors open while cleaning. The battery needed replacement soon after.

chozen said:
12V batteries dying on EVs is surprisingly common.

Probably more common than on ICE vehicles, actually.

Keep the cables in the Bolt, as it has a traditional lead-acid battery. The Model Y’s lithium-ion low voltage battery is less likely to go flat.

You can jump a Tesla in a pinch, but it’s better to use a jump box. Never use a Tesla to jump-start another car, as voltage spikes could damage your EV’s electronics.

Yes, keep the cables for helping others. For your EV, a small jump pack is a better choice, as it takes very little power to start the EV.