HELP me with dual Battery fuse (1 Viewer)

[maasa2002]

Hi

I want to add aux battery for camp light.
I'm using a Cole hersee solenoid.
I want the two batteries get charged only when the engine is running, and get them disconnected automatically when the engine is off. So the crank battery is not getting drained.
That's why I need to find a fuse live only when the engine is running and alternator is charging each battery.
Here is a picture of my suggested diagram.

Thank you all.

 

[maasa2002]

No one got an idea? ..

 

[maasa2002]

I assume you are looking for a fuse in the underhood fuse box that is only hot when the ignition is "on". You don't state what year your 100 is, so I would suggest testing a fuse that would be convenient to add a tap to with the key "off" and "on" to determine when it is hot. I would expect most of the circuits will only be live when the key is "on".

FYI - I have a similar dual battery setup in my 100, with the exception of a switch in the cab to control the solenoid, and it has been flawless.

Thanks for the reply.
I have tested all the fuse box underhood, nothing was suitable for the project. Most of them were live while the ignition is on 2. The others were live all the time. Same with cabin fuse.

The switch you are referring to, doesn't work with. I did it before, but I forget it all the time. It makes the 2 battery get draining together.


Thanks anyway.

 

[hoser]

Perhaps a better idea would be to use a “smart” isolator. It is triggered on by 13.3v (like when the alternator is charging) and off at 12.8v (Engine off).

 

[maasa2002]

You can see page 3 of my build linked in my signature to see how I wired my batteries.

In my 1999, I have two empty fuse slots in the fusebox under the hood. Both of these are dead when the key is off and hot only when the ignition is on. This would be a good choice to trigger your solenoid, unless I am misunderstanding what you are trying to achieve.

View attachment 3072680

Thanks for the reply
No. I want something only live when the engine is running. I've tested what u refered to, it is live when the ignition is on, which I don't want, cause the cracking will depend on both batteries.


Thanks anyway.

 

[numby]

This.