I have two GEL batteries 12V/130Ah and want to connect them together in parallel.

Currently I have one battery in the system and it is fused on the positive wire before the isolation switch.

I wonder what is the best way to fuse two batteries together connected in parallel. I came up with three possible solutions to prevent the short circuits:

1) solution 1

2) solution 2

3) solution 3

Which one is the best and why?

  • 1
    \$\begingroup\$ Changing the question after you have an answer? Not cool. \$\endgroup\$ Jul 30, 2018 at 13:26
  • \$\begingroup\$ I edited the question because I came up with additional possibility, please update your answer if you think that changes something in terms of your answer :) Thanks @ElliotAlderson \$\endgroup\$ Jul 30, 2018 at 13:31

1 Answer 1


Use configuration 1. This will prevent damage if one of the batteries fails or is undercharged with respect to the other battery.

Also, you only need to stock one size of fuse, unlike in version 3.


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