Help With My Power System

[alz]

I just bought my first van it's an old style (90's?) conversion van (87 GMC Vandura). The previous owner did not use the 2nd battery so he couldn't tell me how to use it. I was wondering if someone here can give me a run down on its operation. Here are some pics and my thoughts.

This is the starter battery, the blue cable (bottom left) you see runs back to the second battery. I assume this means it can be changed form the alternator.


I followed the blue wire to this switch. It appears the I should switch this to 'ON' if I want to charge the 2nd battery. I'm not sure what the 4 options are that are written there - the switch is just on/off. The switch says Cole-Hersee Co. Boston - Battery


Following the wires further it goes under the van and up through the floor to this space. Its a cabinet that has a plastic enclosure for a second battery and a plastic hose that vents to the outside of the van.


Some wires leave this cabinet then branch off to a Circuit Reset (I assume this is a breaker, I didn't see a fuse) and another branch out to an alarm (I'm not exactly sure what these are or what they are for)
Wire Branch-top right goes to breaker

The Breaker Reset

This branch goes to the "alarm"

Alarm (I have no idea what this is)


So those are my assumptions. Can anyone fill me in on this system and how it operates?

Thank you,

Al

 

[DiploStrat]

Free Advice is Worth ...

what you pay for it. But here goes.

Strip out all of the old wiring and start over with a proper dual battery set up.

FWIW - It looks like some previous own wired up a second battery and it even looks like they may have used heavy enough wire. They put in a manual disconnect switch. You can do better with a modern intelligent relay setup. (Cole-Hersee makes them, although I prefer Blue Sea.) And do fuse it properly.

As to the breaker, etc., I can only guess that they were to protect the camper load. No clue on the alarm, but it might have been a low voltage cutout.

I would not bother to try to diagnose the old stuff - set up a new system and be happy. These slides may help as they show your current setup and what you probably want: https://cookfb.files.wordpress.com/2015/11/dual-battery-slides.pdf

Edited to add - As usual, I agree with Verkstad's analysis. Hadn't thought of a CO alarm.

 

[alz]

Thanks for the info!

I'll having my mechanic look it over before I go on my first trip so I'll make sure to have him look at the wiring.

 

[DiploStrat]

Some old South Africans swear by simple second battery on/off switches. The good news is that they work and there is next to nothing to break. The bad news is that you can easily forget to open the switch when you stop and close it when you restart the engine. If you stay with the manual switch (it is paid for, after all) you might want to make some form of bright tell-tale to drape over the steering wheel to remind you to check the switch before you drive off.

Off course, you do have to remember to deploy the tell-tale!

 

[loonwheeler]

Another option that is pretty dead simple (and less costly) is a heavy duty relay / battery disconnect energized by the ignition switch. This is one step "smarter" than the full manual switch that you must remember to actuate depending on the situation. When the ignition is on, batteries are combined. When the ignition if off, they are separated. I so think the ACR from Blue Sea and others is worth the extra $$, but YMMV.