FJ 60 - battery power drain

just curious as to why disconnect the negative only rather than both. And curious as to why you would leave the positive on ? Am thinking you'd disconnect both. Remember some time ago someone saying that, well that doesn't matter really so just interested in your response. I mean, do you mean that something in the vehicle could hold a charge and you touching it means you take the current to the earth terminal at the battery ?

Hi porslprado, there are a number of reasons for doing it this way but it’s especially handy when working with 4x4’s as you don’t always know if there is a second battery somewhere else in the vehicle, so by leaving the positive on the main battery, you don’t risk grounding the second battery’s positive. Even when you know your own vehicle has only one battery, it’s still a good habit to get into.

Cheers

I was told to disconnect the negative first and connect last.
If the spanner should short between the terminal and the chassis no harm done.
If the positive terminal, one gets a hot spanner and damage to the battery.
once the negative is disconnected the battery is isolated so cannot short between the positive and negative.
Techie

Hi techie, that’s exactly the way any decent auto electrician works and as I posted, it’s a good safety routine to get into especially when working on a 4x4. There is not only the potential of having a second battery in the 4x4 but if there is a camper trailer or caravan hooked up to the 4x4, you have an even greater chance of another battery being connected to the vehicles electric's.

Most dual battery set ups have some type of electronic isolator and should have some form of protection such as a fuse or circuit breaker in the system but there are still a lot of set ups that simply use a battery switch and this leaves the set up very vulnerable to shorting out the second battery.

It’s a simple safety routine that can save you a lot of money as well as averting a potential danger.

Cheers.