Yes, you can usually jump start an EV, but not in the way you jump a gas car. You are not starting an engine; you are restoring power to the low-voltage system so the car can wake up and connect its main battery. The procedure, connection points and precautions vary by model, so follow your owner's manual, use a jump pack where possible, and never touch the high-voltage system.
This guide explains what the 12-volt battery does in an electric car, why it fails, how to recognize the symptoms and what a safe jump-start looks like. It also covers why many manufacturers advise against using an EV to jump another vehicle.
What the 12-volt battery does in an EV
Every EV has a large high-voltage battery that drives the motors. Most also have a separate low-voltage battery, usually 12 volts, that powers door locks, screens, computers, lights and the relays, called contactors, that connect the high-voltage pack. When you press the brake to start, the low-voltage system must wake the car and close those contactors. If the small battery is flat, the big one stays disconnected and the car appears dead.
Some newer vehicles use lithium-ion low-voltage batteries instead of traditional lead-acid or AGM types, and some use different nominal voltages. These have their own management electronics and replacement requirements. While the car is on, and in many cars periodically while parked, a DC-DC converter charges the low-voltage battery from the main pack.
Why EV 12-volt batteries fail
- Long periods parked without the car topping up the low-voltage battery.
- Frequent wake-ups from apps, sentry or security modes and connected services.
- Age; low-voltage batteries wear out like any other.
- Heat and cold, which shorten battery life and reduce available power.
- Accessories plugged into power sockets or a door or trunk left ajar.
- A main pack so low the car cannot recharge the 12-volt battery.
How to jump start an EV safely
Procedures differ by manufacturer, so read the section of your owner's manual titled jump starting or low-voltage battery before you begin. The general principles below apply to many vehicles, but your manual overrides them.
- 1Find the jump points: some EVs give direct battery access, others have dedicated terminals under the hood or in the front trunk.
- 2If the car has no power, follow the manual’s procedure to open the hood or front trunk; some require a hidden release or external terminals.
- 3Use a portable jump pack rated for the vehicle. Connect positive first, then negative to the specified ground point.
- 4Turn on the jump pack and wait as directed, then try to wake the car.
- 5Once the car is on and in ready mode, disconnect in reverse order.
- 6Leave the car on for a while so the DC-DC converter can recharge the low-voltage battery, if the manual recommends it.
Never connect to any orange cables or components; orange typically marks high-voltage parts. If you are unsure about any step, stop and call for help.
Should you use your EV to jump another car?
Many EV manufacturers advise against it. The low-voltage system in an EV is designed for the car's own electronics, and a gas car's starter motor can draw a large current. Some manuals explicitly prohibit using the vehicle to jump another, and doing so could blow fuses or damage the DC-DC converter. Check your owner's manual. A portable jump pack is the safer tool for helping other drivers.
Symptoms: low-voltage battery or something else?
| Symptom | Likely cause | Next step |
|---|---|---|
| Car will not unlock, screens dark | Flat low-voltage battery | Jump-start |
| Screens on, will not enter drive, 12V warning | Weak low-voltage battery | Jump or replace, then test |
| Screens on, low range, reduced power | Main pack nearly empty | Mobile charge |
| Fault message about high-voltage system | Possible high-voltage fault | Do not drive; arrange service or tow |
| Both: dark car after weeks parked at low charge | Both batteries low | Jump-start plus charge |
After the jump
A battery that went flat once may simply have been drained. A battery that keeps going flat is usually worn out. Have it load-tested; many roadside services and parts stores can do this. If the battery is under warranty, the dealer may replace it at no cost. Note that some vehicles need a new low-voltage battery registered with the car's computer, and lithium low-voltage batteries usually have specific replacement parts.
To reduce future drain, limit unnecessary app wake-ups when parked for long periods, check that doors and trunks are fully closed, and avoid leaving accessories plugged into power sockets.
Choosing a jump pack for an EV
A portable lithium jump pack is the most convenient tool for EV owners and many gas car owners. Because an EV does not need to crank an engine, the current required to wake the low-voltage system is usually modest, but you still need a pack designed for automotive use with proper clamps, reverse-polarity protection and a rating suitable for your vehicle. Check the owner's manual for any specific requirements; some manufacturers specify a minimum or maximum voltage or warn against certain types of chargers.
Keep the pack charged. A jump pack left in a hot trunk for a year may be flat when you need it. Many owners keep it in the cabin or recharge it every few months.
Lithium low-voltage batteries
Some newer EVs replace the lead-acid 12-volt battery with a lithium-ion low-voltage battery. These often have their own battery management system that can disconnect the battery to protect it if it drops too low, which can make the car seem completely dead. The manufacturer's procedure for these vehicles may differ from traditional jump-starting, and in some cases there are external terminals designed for exactly this situation.
Do not attempt to charge or jump a lithium low-voltage battery with equipment designed only for lead-acid batteries unless the manual says it is appropriate. If you are not sure what type your car has, check the manual or ask your dealer.
When to call instead of DIY
If you cannot find the jump points, the car requires a procedure you are not comfortable with, you do not have a suitable jump pack, or the car still will not wake after a correct jump, it is time to call. The same applies if you see any high-voltage warnings, smell burning or notice damage near the battery. A roadside technician has the right equipment and follows the manufacturer's procedure for your model.
Can an EV jump-start another car?
Many manufacturers advise against using an EV to jump-start another vehicle, because the low-voltage system and the converter that charges it are not designed for the high currents a gas engine starter draws. Some vehicles explicitly prohibit it. Check your manual before offering help; a portable jump pack is the safer option for helping someone else.
Frequently asked questions
01Can you jump start an electric car?
Yes, most EVs can be jump-started through the low-voltage system. Follow the owner’s manual and use a jump pack.
02Can I jump another car with my EV?
Many manufacturers advise against it because the low-voltage system is not designed for starter-motor loads. Check your manual.
03Why does my EV 12-volt battery keep dying?
Common causes include age, frequent wake-ups while parked, heat or cold, and accessories left on. Have it tested.