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Battery Question

Posted: Mon Feb 11, 2013 2:21 pm
by sha786
So,

Let's say I was driving along and the negative wire on the battery terminal became loose and came off, would this cut the engine? Or would the car stay on until the next time I switched the engine off and simply not come back on?

Excuse the silly question :oops:

Posted: Mon Feb 11, 2013 2:33 pm
by NafemanNathan
Yes, your circuit would be incomplete and you'd loose ignition amongst other things.

Posted: Mon Feb 11, 2013 2:46 pm
by Merlin
:lol: Yup you'd be a rolling brick with no assisted brakes. At least with the key still in position II your steering lock wouldnt be on but you would have no power steering. My engine cut off switches (breaks the negavive battery line) will also be my main anti-theft device.

Posted: Mon Feb 11, 2013 3:15 pm
by sha786
This is strange as last night I was driving along, stopped at Tesco, went to restart the car and nothing. No hazard lights, no power at all. Opened the bonnet and the negative battery terminal had come off :shock:

So that must have been a coincidence that it just came off when I came to a standstill. Scary stuff :shock:

Posted: Mon Feb 11, 2013 3:20 pm
by Merlin
Bizarre!

Posted: Mon Feb 11, 2013 3:21 pm
by 4thgenphil
see i thought after start the engine/alternator wouls sustain the engine :?

like race bike, they dont have batteries?!

Posted: Mon Feb 11, 2013 3:32 pm
by NafemanNathan
4thgenphil wrote:see i thought after start the engine/alternator wouls sustain the engine :?

like race bike, they dont have batteries?!
Do they not?! :?

Without the negative connected on our cars you're effectively removing the battery from the equation as it needs a complete circuit to effectively allow the power to be drawn from it. That's be like jump starting a car without a battery (which is obviously doable) and then removing the jump leads and expecting it to still run.

Posted: Mon Feb 11, 2013 3:33 pm
by Merlin
You have me questioning it now :? For instance the main relay and hot start issues.

Nafe, could it be that it is running purely off the alternator?

Posted: Mon Feb 11, 2013 3:36 pm
by NafemanNathan
I'm trying to think what cables are attached to the negative now :think:

Try it! ;-)

Posted: Mon Feb 11, 2013 3:36 pm
by sha786
Like I said, I think it came off when I went over a bad pothole but the car continued to run fine.

I wonder if I should test the theory, whats the worst that could happen? :lol: