Use of 'jump start' terminal

[Ken Butcher]

Good morning,
I use a high-pressure inflator for the tyres on my trailer. This is rated at 15 amps, which is too high for the various 12 V outputs inside the car, which I believe are rated at 10 A. I usually connect the inflator directly to the trailer's own battery (which is also used for the winch). But if for some reason I can't use the trailer battery, would it be OK to connect the inflator to the 'jump start' terminal under the bonnet? Is this likely to blow a fuse or drain the aux battery? There is a huge amount of experience out there, so any thoughts welcome. Thanks.

 

[kpetrov]

At least turn the PHEV ON in ready mode so you won't drain the battery.
Regarding the amp rating on that terminal, don't have idea but won't be on low side.

 

[AndyInOz]

I can't remember if it was here, but I remember a conversation where members stated that they had damaged their batteries by trying to jump start another car.

This is because the little 12V battery is really not up to much more than running the car's electronics.

If the current draw for running your compressor is similar, you could easily damage the 12V battery.

Members here have recommended carrying a small 'power bank' so that they can jump start someone else's car in an emergency. Could a small device like that suit your needs?

 

[Daixiwen]

IIRC the jump start terminals on the PHEV are behind a 30A fuse and that's the reason why it is a bad idea to use them to jumpstart another car. In theory 15A should be fine, but your inflator could have a much higher in rush current when starting and you could still blow your fuse so I wouldn't recommend it. You can also open the car boot and remove the floor to have direct access to the battery terminals.

A jump start power bank is just designed to give a short power boost to start a car, it is not designed to provide 15A continuously during a significant amount of time.

 

[kpetrov]

An starter for a 4 cylinder engine draws way more than 100 amp and we should not jump start conventional vehicles, definitely.

15 amp won't hurt the battery especially when the vehicle is ON... the power comes from main traction battery.
Moreover a lot of those vehicles are fitted with 1500W inverter that draws (when in READY) continuously way more than 15amp
All that in regard to the battery only...

 

[Ken Butcher]

Thanks, all, for your advice and suggestions.

 

[siteboss2024]

I can't remember if it was here, but I remember a conversation where members stated that they had damaged their batteries by trying to jump start another car.

This is because the little 12V battery is really not up to much more than running the car's electronics.

If the current draw for running your compressor is similar, you could easily damage the 12V battery.

Members here have recommended carrying a small 'power bank' so that they can jump start someone else's car in an emergency. Could a small device like that suit your needs?

I once came back from holiday where i had to postpone the home trip and luckly had left my PHEV outlander at home because the small battery in the back which powers the central locking ect had run flat so realised that the positive terminal to the battery was not accessable without removing the boot liner so on to Utube to discover that you can charge the battery by conecting the positive feed from the battery charger to the terminal in the fuse box (look for what looks like a red switch lift this cover up to expose the terminal ) connect the earth wire to your engine mounting and plug the trickle charger into the mains this shoulddo the trick otherwise remove the boot liner cover to expose the three bolts to the back and two within the liner this will allow th rear section of the tray to be removed to access the small battery should you need to replace it but the previous method of charging is less work

 

[RobertGrover]

At least turn the PHEV ON in ready mode so you won't drain the battery.
Regarding the amp rating on that terminal, don't have idea but won't be on low side.

Get a battery operated air pump….

 

[Stevepl11]

I'd question the need to inflate the trailer tyres so much that this is even a concern at all. If there's an underlying problem with tyres going flat, fix it. Pump them up at home or a service station (allthough I know that can be unreliable).

And what do you mean by "high pressure"? I carry a 12volt compressor that is slightly bigger than the one that came with the car but it's still ok to plug in to 12volt outlets. The original is limited to about 3.5 bar and slow, it even failed the first time i tried to use it in earnest after getting off the beach where I had lowered the tyre pressures.