main batt to second batt and thrid batt

[Audio Master 10+ year member]

well as it stastes this is weird as 20 diffewrnt peeps have said almost 20 differnt things about

A isolateing main batt before connecting to rear bats then puting fuses between each one also

basically what im asking is i have three batts 1 starter batt main

and 2 rear batts OYT how do i connect them safley do i use fuse at eityher end and just series them or do i isolate main from the 2 rear and then series the rear and ground in rear to chassis

i hope somewone understands my typeing and can help cheers

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[Audio Master 10+ year member]

up and help me

aaaarrrrgggghhhh

 

[funkyab 10+ year member]

why do you want to isolate? I do this on my boat for security. No reason to do it in a car unless you plan on running system only on batt power for long periods of time. If not,, run all three in parallel. +to+to+ and -to-to-.

For extra safety you can fuse between all three to the rating of the wire. This is what I do but others do not.

Problem solved!

 

[Audio Master 10+ year member]

why do you want to isolate? I do this on my boat for security. No reason to do it in a car unless you plan on running system only on batt power for long periods of time. If not,, run all three in parallel. +to+to+ and -to-to-.
For extra safety you can fuse between all three to the rating of the wire. This is what I do but others do not.

Problem solved!

so there is no need for an isolater even if the main battery is different from the rear batterys

as i have a normal starting batterry up front and 2 opt yt in the back

if i isolate the main it will never discharge fully would it be prudent to run caps

 

[Low_e_Red 10+ year member]

You need a 200A relay (to act as a isolator while vehicle is off.) Minimum of 3 fuses. And a bit of wire.

Take the 200A relay; wire 85 to ground, 86 to ign, 87 to the Starter B+ and the 30 to the back bats. Then fuse w/in 12" of both front to rear and rear to front. Then of course between rB+ and the load.

(I do expect to get many arguments against this, but this is the correct way.)