brightspark
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- yarm stockton on tees
it would be simlar to towing or bumping a car off giving a good power surge when the battery is flat
not really coz alternator is set to 14v ish whereas a boost/start charger go to 18v ish and with no battery voltage can go to 20v because they are unregulated off the tranny especially if mains are high .it would be simlar to towing or bumping a car off giving a good power surge when the battery is flat
On Old group 4 escorts it used to be standard practice to have two batteries, one for the normal running, and the slave battery was in series with the starter to give 24v even though it was a 12v inertia starter, the principle was simple they would not start when hot on 12v because you didnt have the cranking speed but would start in less than a second, easily on 24v, so the lesser of two evils was to start them 24v, the motors suffered less in the long run. then on a long event you would swap the batteries round, I did it with relays to get both batteries to charge parallel but the batteries didnt like it long term.
whats floating above earth teacher ???The O2 sensors etc are screened devices which being metal bodied, are at earth potential. There is more risk in unplugging them than leaving them alone. Low impedance is the key, in the event of the mythical induction damage, it would only affect anything floating above earth. That's why you don't need to bother disconnecting anything.
Dynamos were pretty much unaffected by anything (apart from wear/tear and generally not being very good at coping with demands) and their control box was electro-mechanical, so not much affected either.I have welded with both the battery on and disconnected. Never had a probloem or know anyone who has. Could all of scaremongering etc not have originated in the days of positive earth and dynamos?
i can see some o2 sensors being potentaly vunerable . mainly older desings where the exhaust provides the ground connection for the sensor or the sensor and its heater.
most of them are now 4 wire sensor or widebans where the actual sensor can isnt connected to anything inernaly
I do loads of welding repairs on alternators (mounting lugs ect)
Never had any problems at all