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Battery Removal and Refitting

Apr 28, 2021
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Hi,
I’ve been caravanning for over 30 years and removed and replaced the battery many times. I was taught that when removing you remove the positive terminal first and then the negative. On replacing the negative goes on first and finally finish off with the positive. I’ve never had any issues with this.
Recently at a site I had to replace a dead battery and followed this process, another caravan owner suggested I was doing this the wrong way round.
Am I correct and is there a specific order to disconnect and connect the terminals?

Many thanks. Mike
 
Jun 16, 2020
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I can understand why there is a procedure with a car with an earthed chassis. But see no reason why it makes any difference in a caravan. Probably best to make sure it is turned off in the van first though.

John
 
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Damian

Moderator
Mar 14, 2005
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As far as a caravan goes, it does not matter which lead you attach first or second.

The van is not an earth return, unlike a car where the metalwork is , so it makes sense to disconnect the earth then the positive and refit in reverse.
 
Aug 24, 2020
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I agree with everyone else, earth first on a car, on a caravan it nearly always doesn't matter, but see my last paragraph below!

The reason it's important on a car is that if you do positive first (i.e. NOT earth, on a non-USA car) and your spanner accidentally touches a metal part on the car, you'll complete the circuit and probably have a high current short across the battery.

If you accidentally touch metal while undoing the earth, no problem because the earth terminal and the car bodywork are both at zero volts with respect to each other = no current flow.

If you've disconnected the earth first, then accidentally touch bodywork while undoing positive, no current can flow so no problem.

I was taught earth lead first off and last back. As said it doesn't really matter on a caravan because all the bodywork around the battery is plastic (unless some caravans are different but I'd think that's unlikely), but it's good practice to stick to the same process.

That said, on my ancient folding caravan, the battery sat direct on the metal chassis of the A-frame, with just a plastic cover over it, so in that case it would have mattered!
 
Last edited:
Jul 18, 2017
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If you've disconnected the earth first, then accidentally touch bodywork while undoing positive, no current can flow so no problem.
However if you do that surely you are completing the circuit as you have created an earth for the positive? There will be a big bang.
 
Aug 24, 2020
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However if you do that surely you are completing the circuit as you have created an earth for the positive? There will be a big bang.
No, because you've already removed the earth lead from the battery, then while you have connected positive to car body, the missing earth lead means there's no circuit back to the battery.

The only way you'll get a big bang is if you accidentally bridge the plus and minus terminals on the battery - car and leisure batteries usually have a "bump" between the terminals to stop that happening.
 

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