Car charger manuals quite often suggest not to charge a battery in situ. They recommend that if you do so, you should earth to a point on the chassis / engine and not have both poles connected to the battery for charging.
They suggest it's because a spark might ignite hydrogen gas from the battery.
How likely is this ?
The bonnet is open, there is lots of airflow around the battery, no direct sunlight.
(After 8 hours of charging, battery showed no charge, so I removed it from the car and connected it to the charger (both poles connected) and it charged fine. So I can only assume the earth point I found originally wasn't an earth point...but that's another matter).
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By (user no longer on site)
over a year ago
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Do not take battery off if a modern car if you do there be a lot things to ree set and if like mine some will need laptop to reset
Yes safer to earth to car body but won't earth if painted where you put earth clamp. |
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By *TG3Man
over a year ago
Dorchester |
"Car charger manuals quite often suggest not to charge a battery in situ. They recommend that if you do so, you should earth to a point on the chassis / engine and not have both poles connected to the battery for charging.
They suggest it's because a spark might ignite hydrogen gas from the battery.
How likely is this ?
The bonnet is open, there is lots of airflow around the battery, no direct sunlight.
(After 8 hours of charging, battery showed no charge, so I removed it from the car and connected it to the charger (both poles connected) and it charged fine. So I can only assume the earth point I found originally wasn't an earth point...but that's another matter).
"
exactly earth is only as good as the body you connect it to just detach battery connections and charge it  |
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"Do not take battery off if a modern car if you do there be a lot things to ree set and if like mine some will need laptop to reset
Yes safer to earth to car body but won't earth if painted where you put earth clamp. "
It's just an alarm that goes off when I reconnect it, but I can stop it pretty quickly. Thank you for your advice. |
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connect the red lead to each of your.batteries then connect the black lead to 1 battery and last connect goes to metal in engine bay but away from the battery some have posts just for that disconnect in reverse order starting with the 1 in the engine bay in over 30 years as mechaniconly had 1 blow up |
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Thank you folks for all your sensible advice. (Checks URL address bar...yup, definitely FAB) 
Found an interesting YT video going in detail on how a spark can ignite hydrogen, from a charging battery. It was possible to extrapolate from the video why charging in situ calls for an earth away from the battery and not to use both positive and negative ON the battery itself. |
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"Isn't that's what the AA are for?"
Yes the AA are an exemplary body of men & women that work tirelessly through the night to bring satisfaction to all members.
Join the Alt Alliance now
15 % off if you can guess this members deepest desire. |
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"Do not take battery off if a modern car if you do there be a lot things to ree set and if like mine some will need laptop to reset
Yes safer to earth to car body but won't earth if painted where you put earth clamp.
It's just an alarm that goes off when I reconnect it, but I can stop it pretty quickly. Thank you for your advice."
Lucky you, on some new Nissans you can't change the battery as the car needs setting to it by the main dealer or various warning lights won't go off. |
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