Reinstating Dual battery

[Kevin99]

Hi from the other side of the pond, I’m looking to reinstate the dual battery in the my 92 C2500 long bed. It had a camper conversion which had been removed before I bought the truck. It appears to be a factory or dealership install as there is a GM label in the glovebox detailing loading for a slide in camper.
Anyhow, the additional battery tray & solenoid are all in place & wiring looks to be original, the only thing that i can see is missing is the cable from the solenoid main stud that should go to the secondary battery.
I just have 2 questions, 1- apart from installing the additional battery, do i just need to buy a new positive battery cable for the battery/ solenoid connection.
2- The alternator looks to be original, there are no markings or labels that i can see to tell me the output, I’m assuming that if it is original, it would handle dual batteries. Is there a way to check its maximum output?
I’ve attached a photo of the additional solenoid for information.
Tia

 

[GMCTruck]

I think the factory used 8 gauge wiring. You need positive cable from solenoid to battery and then negative from battery to engine ground. I added auxiliary battery to my 95 several years ago and i used parts from a wreaker yard. After several months, I notice the auxiliary battery wasn't charging. The contacts in the solenoid had a huge resistance. I would get a new solenoid rather than using a 32 year old one. I'm pretty sure it is a 30 amp solenoid, just for charging the battery. Rockauto had the OEM style solenoid

 

[GMCTruck]

Also, i would technically call it an auxiliary battery setup and not a dual battery. Its purpose is to charge a camper battery or run low amp accessories but not to operate things like winches

 

[1998_K1500_Sub]

The alternator looks to be original, there are no markings or labels that i can see to tell me the output, I’m assuming that if it is original, it would handle dual batteries.

The original alternator will function well with dual batteries / an auxiliary battery.

 

[Kevin99]

I think the factory used 8 gauge wiring. You need positive cable from solenoid to battery and then negative from battery to engine ground. I added auxiliary battery to my 95 several years ago and i used parts from a wreaker yard. After several months, I notice the auxiliary battery wasn't charging. The contacts in the solenoid had a huge resistance. I would get a new solenoid rather than using a 32 year old one. I'm pretty sure it is a 30 amp solenoid, just for charging the battery. Rockauto had the OEM style solenoid

Thanks for that, I think that replacing the solenoid is a good idea, just looked on Rock & couldn’t see an OEM style solenoid, the only one I found showed only one terminal for the small wire, mine has two connections + the two main battery studs.
Do you happen to know a part number I could search for?

 

[1998_K1500_Sub]

Do you happen to know a part number I could search for?

Those relays are fairly common, if you look in into parts that are used for RVs and/or trailers you will probably find one, among other places.

 

[Road Trip]

Thanks for that, I think that replacing the solenoid is a good idea, just looked on Rock & couldn’t see an OEM style solenoid, the only one I found showed only one terminal for the small wire, mine has two connections + the two main battery studs.

I went to the Nemiga chevy parts website, looked up the Auxilliary Battery Relay for a '92 C2500, and it gave me part #12135196.
But no parts available for sale. So I took that part number over to Rock Auto, and it gave me the same (non-matching) 1 small
terminal relay? Felt like one of those database dead ends?

Do you happen to know a part number I could search for?

I continued to search from a few different angles, and although I couldn't find the AC Delco part, I think I've come up with a match to what you've got:

You must be registered for see images attach

For what it's worth from personal experience, normally a part from Standard was/is reliable. And by using
the RY-238 part number to search, I now had a lot more to look at. (!)

Curious about this auxilliary battery circuit, I went ahead and looked it up in the '92 Electrical FSM. I found
that the wiring diagram matched the relay you have, for there are (4) connections to the relay showing.
I've attached (3) pages from this manual that might be helpful if after you get it all reconnected that you
end up having to troubleshoot a little after the fact.

EDIT: I added a .pdf file of the wiring diagram so that you can easily read the fine print. See attached.

It's a bit of a head-scratcher that a relay like this isn't easily found on the better parts websites? Maybe this
may be due to a relatively rare option that's a victim of a database error? At any rate, you should be able to
take all this and piece together a solid solution.

Best of luck. And let us know what you discover.

Cheers --

 

[Kevin99]

I went to the Nemiga chevy parts website, looked up the Auxilliary Battery Relay for a '92 C2500, and it gave me part #12135196.
But no parts available for sale. So I took that part number over to Rock Auto, and it gave me the same (non-matching) 1 small
terminal relay? Felt like one of those database dead ends?




I continued to search from a few different angles, and although I couldn't find the AC Delco part, I think I've come up with a match to what you've got:

You must be registered for see images attach

For what it's worth from personal experience, normally a part from Standard was/is reliable. And by using
the RY-238 part number to search, I now had a lot more to look at. (!)

Curious about this auxilliary battery circuit, I went ahead and looked it up in the '92 Electrical FSM. I found
that the wiring diagram matched the relay you have, for there are (4) connections to the relay showing.
I've attached (3) pages from this manual that might be helpful if after you get it all reconnected that you
end up having to troubleshoot a little after the fact.

EDIT: I added a .pdf file of the wiring diagram so that you can easily read the fine print. See attached.

It's a bit of a head-scratcher that a relay like this isn't easily found on the better parts websites? Maybe this
may be due to a relatively rare option that's a victim of a database error? At any rate, you should be able to
take all this and piece together a solid solution.

Best of luck. And let us know what you discover.

Cheers --

Wow, thanks for all this information, really appreciate it.

 

[GMCTruck]

Yep, the RY238 was what i used. My local auto parts stores could not get it for me.

 

[Kevin99]

I went to the Nemiga chevy parts website, looked up the Auxilliary Battery Relay for a '92 C2500, and it gave me part #12135196.
But no parts available for sale. So I took that part number over to Rock Auto, and it gave me the same (non-matching) 1 small
terminal relay? Felt like one of those database dead ends?




I continued to search from a few different angles, and although I couldn't find the AC Delco part, I think I've come up with a match to what you've got:

You must be registered for see images attach

For what it's worth from personal experience, normally a part from Standard was/is reliable. And by using
the RY-238 part number to search, I now had a lot more to look at. (!)

Curious about this auxilliary battery circuit, I went ahead and looked it up in the '92 Electrical FSM. I found
that the wiring diagram matched the relay you have, for there are (4) connections to the relay showing.
I've attached (3) pages from this manual that might be helpful if after you get it all reconnected that you
end up having to troubleshoot a little after the fact.

EDIT: I added a .pdf file of the wiring diagram so that you can easily read the fine print. See attached.

It's a bit of a head-scratcher that a relay like this isn't easily found on the better parts websites? Maybe this
may be due to a relatively rare option that's a victim of a database error? At any rate, you should be able to
take all this and piece together a solid solution.

Best of luck. And let us know what you discover.

Cheers --

Wow, thanks for all this information, really appreciate it.

Yep, the RY238 was what i used. My local auto parts stores could not get it for me.

Just ordered one from Rock Auto, plus a few other things.
Thanks for your advice. Appreciate it