A dead battery is the most common reason a car won’t start. Don’t try and be a hero until you’ve read this article first. I will familiarise you with some tips ‘n tricks to make your jump start a great success!
Is it Possible?
Yes, you can jump-start a dead BMW 330e PHEV. Despite being a plugin hybrid, the fundamentals of a conventional ICE vehicle are all still present. There are a few things to consider:
- Suitable jump leads
- Find the positive terminal for both vehicles (this might not be the battery)
- Safely connect and disconnect the jump leads
- Ensure the drive battery’s plug-in charge lead is disconnected
Can I use a BMW 330e PHEV to Jump Start another Vehicle?
No! Unfortunately, whilst it is possible to jump-start a 330e, you shouldn’t use a 330e to rescue a stranded vehicle with a flat battery. The owner’s manual warns against using your 330e PHEV to jump a stranded vehicle.
Where is the 330e Battery Located?
There are two batteries found in any hybrid vehicle.
- High voltage traction battery (300v powers the drive motors)
- Low voltage conventional battery (12v powers the radio, opens/closes big relays etc.)
For a jump start we need to feed the traditional 12 volt battery. BMW have nestled the 330e’s battery in the boot.
For a 330e PHEV, it is much easier to perform a jump start using the terminal under the bonnet! The alternative would be to access it from the boot, DON’T DO THIS UNLESS YOU LIKE EXTRA WORK!
When setting up for a jump start, give consideration to the location of the battery positive in your rescue vehicle and arrange both vehicles such that the leads will easily reach!
Struggling to find the positive terminal?
Accessing the battery in an 330e is a pain, use the charging terminals instead, check out this brief video to see what I mean:
Jump Start Guide
A set of jump leads is an essential item for the task. Pick up a set here for a great price.
- Park your rescue vehicle next to the stranded 330e, with easy access to the positive terminals on both vehicles
- Switch off the ignition for both vehicles, apply handbrakes
- Connect the red cable to the 330e’s positive terminal, behind the removal red plastic cover, under the bonnet, (see video above, to find the terminal)
- Connect the other end of the red cable to the rescue vehicle’s positive terminal
- Connect the black cable to the negative terminal of the rescue vehicle’s battery.
- Connect the other end of the black cable to the chassis ground terminal on the 330e PHEV. Again, see video above.
- Wait a few seconds, then crank the rescue vehicle to keep the engine on – don’t get your clothes hair etc. caught on rotating belts!
- Attempt to power on the 330e- if you are in luck you will get the green ‘ready’ light.
- I would advise switching off the rescue vehicle and then proceed to remove the cables in reverse order, i.e. steps 6,5,4,3.
Considerations
Short jump leads should be preferred. Whilst longer leads might be more convenient, they suffer more of a voltage drop. These 3m jump leads are an excellent combination of value for money and performance.
Lead acid batteries can explode. They can release hydrogen gas which is flammable. Fortunately, the 330e battery is hidden well out of the way in the boot. Any sparks created during connection are now well away from the battery, minimising the chance of an explosion.
Don’t ever jump-start whilst your 330e’s drive battery is being charged, this could damage the charging equipment or your BMW.
FAQs
Can I Jump Start in the Rain?
Yes you can, it is completely safe to jump start in the rain. The 12v battery has a sufficiently low voltage that it finds it impossible to cause you any kind of electrical shock.
Do you Have to Use the Battery Terminals?
It is advisable that the rescue vehicle use both battery terminals to jump-start your 330e. It is best practice to use the charging posts under the bonnet.
Will a Banana Jump Start a Car
No, OF COURSE IT CAN’T, this is just internet clickbait!
You can start a car with AA batteries though, electroBOOM did it!
There are now products on the market that will essentially facilitate what you see in the video above. If you want to avoid being stranded and not rely upon a second vehicle for a jump start, you could always carry a mini jump pack, like this one.
What Voltage for Jump Start
The 12 volt system is used for a jump start. However, when the alternator is charging the battery, (when the engine is running), expect the voltage to be higher, ~14.5 volts.
What’s a Bump Start?
A bump start is when someone pushes you along and engages the clutch whilst in gear to start the engine. This will allow the wheels to turn the engine over instead of the starter motor.
The energy of someone pushing the car is transferred into the rotation of the engine. Pushing energy replaces the electrical energy required from the battery to start the engine using the starter motor. This technique is impossible with an automatic transmission.
Do not pull or push the 330e to try and start it, always use the jump start procedure instead. The complexities of the hybrid drivetrain render this technique impossible.
Conclusion
Jump starting a car is essentially no different when you have a plugin hybrid such as the BMW 330e PHEV. Reading through this article should give you the tools and confidence to perform a jump start safely and effectively.
Fantastic article pal. I’ve learnt so much about jump starting my 330e in the 5 minutes it taken to read this. This answers so many questions I had.