Changing battery... which terminal first?
Changing battery... which terminal first?
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Discussion

Scarletpimpofnel

Original Poster:

1,498 posts

48 months

Tuesday 28th May 2024
quotequote all
On line a web site said when changing a car battery to disconnect the positive first and reconnect it last. But the battery instructions say disconnect the negative first and reconnect it last.

Which is right and why?

bunchofkeys

1,305 posts

98 months

Tuesday 28th May 2024
quotequote all
Disconnect the negative first.

When connecting connect the positive first.

GreenV8S

31,027 posts

314 months

Tuesday 28th May 2024
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When connecting jump leads between cars, you connect the ground last and disconnect it first. This reduces the risk that either end of the positive jump lead can short out against grounded metal on either car.

When installing a battery it probably doesn't matter which terminal you connect first in most cases, but if you connect the ground last it slightly reduces the chance that you short a spanner between the battery terminal and nearby grounded metal.

donkmeister

13,052 posts

130 months

Wednesday 29th May 2024
quotequote all
GreenV8S said:
When connecting jump leads between cars, you connect the ground last and disconnect it first. This reduces the risk that either end of the positive jump lead can short out against grounded metal on either car.

When installing a battery it probably doesn't matter which terminal you connect first in most cases, but if you connect the ground last it slightly reduces the chance that you short a spanner between the battery terminal and nearby grounded metal.
This was my understanding, and "am I possibly going to weld this tool to my inner wing?" is a handy way to remember the correct order.