2000 C2 Coupe 6 speed - battery back-up

[Philip54]

I am considering keeping a jump starter portable external battery  in the car.  I am wondering if this battery could be used, when connected to the car electrical system through the cigarette lighter socket, to power the car electrical system to allow me to drive back home in case the alternator fails and the car battery is low.  Vendors claim that the car could even be started using the external battery connected through the cigarette lighter socket.

 

Is there any risk of damaging any car electrical system components doing this?

 

Thanks

[JFP in PA]

4 hours ago, Philip54 said:

I am considering keeping a jump starter portable external battery  in the car.  I am wondering if this battery could be used, when connected to the car electrical system through the cigarette lighter socket, to power the car electrical system to allow me to drive back home in case the alternator fails and the car battery is low.  Vendors claim that the car could even be started using the external battery connected through the cigarette lighter socket.

 

Is there any risk of damaging any car electrical system components doing this?

 

Thanks

 

Absolutely no way.  The cigaret lighter socket is connected to the electrical system by a relatively light gauge wire, your starting battery used cables many times heavier to deal with the tremendous amperage draw that occurs during starts; if you tried to pull that kind of amperage through the lighter, you would instantly destroy your dash wiring harness and probably burn the car to the ground.  VERY bad idea............

[Philip54]

Thanks for your reply.  The vendor I was referring to sells jumper cables that include a fuse that are used to charge the car battery for 10 minutes.  According to the vendor the car can then be started using the car battery.  The vendor does not recommend to start the car directly from the back-up battery.  In any case, my question was more related to being able to drive back home, if the alternator fails and the car battery is low, using a back-up battery connected through the cigarette lighter (with minimal electrical load, just the lights, if it is night).  Does that seem possible?  What would be a fuse size that would ensure sufficient protection?  I assume that the car has its own fuse to protect the cigarette lighter cable.  Is that correct?

 

Thanks

[Ahsai]

Yes, there's a 15 amp fuse protecting the cigarette lighter. In the event of alternator failure, it's likely your car will need more than 15A of current to power its engine, DME, headlights, etc.

 

If your battery is healthy, it should last you some miles. A healthy battery should have tens of Ah reserved capacity.

[Philip54]

Thanks, Ahsai.  I guess the back-up battery could still be used to travel a little further, if necessary, if its use does not cause any issues.