Originally Posted by Deejay
Originally Posted by Mr Mogoo
Today I replaced my battery and decided to swap the ‘croc clip fly lead’ on my CTEK MXS 5 battery conditioner for the ‘eyelet fly lead’ - connecting the lead directly onto the positive and negative terminals on the battery which prompted me to have a quick look at the manual. The manual says for batteries mounted inside a vehicle you should connect the negative (black) clamp to the chassis away from the fuel pipe and the battery. For years I’ve been connecting the croc clips directly onto the battery terminals – are CTEK being over cautious or should I now separate the black clamp?

The advice to connect the earth lead away from the battery is to minimise explosion risk from hydrogen given off by a battery interacting with a possible spark as you make the connection. So it is only really applicable if you are in the act of connecting jump leads or connecting the charger. Now that a firm bolted connection has been established, the danger has been overcome.
However, when I made a permanent connection to mine, I added an inline fuse to the positive wire adjacent to the battery, to protect the wiring in case it shorted out to earth or bodywork, along its route, or if the charger itself developed an internal fault which could then be catastrophically fed by the full capacity of the battery.
Deejay Many thanks for your very clear explanation - I'll also look into adding an inline fuse.

2016 Aero 8 S5