Remote battery disconnect

I hadn’t seen those before. But makes sense and simple enough. Although for your purpose I believe it would require modification as it is made to simply disconnect one lead from the battery. You’re not trying to disconnect the start battery, you’re trying to combine them when the charger (converter) is providing juice.
Looks like another low buck security solution for, say, an old car.
On a separate note, the quality has to be horrible for $25 and I wouldn’t trust it to work as designed very long. And in the proper use, you’d be running starting current through it which may be marginal with only a 250a rating if you were starting the engine in the cold weather.
I bought a similar ching Chong made headlight relay kit for our old truck. It works but it’s worth about what I paid for it. And it doesn’t work great.
There are several other ways to accomplish what you want to do but in a more preferable manner IMO.
From a simple Perko type cutoff switch to an ACR type switch for automatic combining or cutoff.
Also I’d make sure you’re not creating some sort of ground loop or other issues as your rig should already have a charging circuit from the start system to the house batteries.

jjrbus,

Interesting link. Thanks.

I think I'd spring for a dc to DC charger instead of just a switch.

Thanks for the responses. I would not be running starting current through it. A simple mod and a piece of heavy wire to jump the isolator for charging vehicle battery on shore power. I have a battery switch in my junk, I do not see a convenient place to put it.

The more I look at it the less confidence I have so will use a relay/solenoid.

I am not sure if I am understanding what you would like to do, but it seems like a BIRD and an Isolator Relay from Intellitec would work for your purposes. My apologies if I misunderstood your intention.

https://intellitec.com/bi-directional-isolator-relay-delay/

jjrbus wrote:
Thanks for the responses. I would not be running starting current through it. A simple mod and a piece of heavy wire to jump the isolator for charging vehicle battery on shore power. I have a battery switch in my junk, I do not see a convenient place to put it.

The more I look at it the less confidence I have so will use a relay/solenoid.

What you posted, however you use it, if it’s hooked to the start battery it will have starting current going through it when you hit the key. However you’re correct in believing that what you posted is not part of the equation to get you charging your start battery off of house shore power (converter).
Nor is a dc dc charger that was suggested. I think they mis understood what you want to charge and when.

jjrbus wrote:
I have a 02 Roadtrek built on a Chevy 3500. Looking at adding a selector switch so when van is sitting I can charge the van battery also. Simple enough to add a couple wires and switch to the isolator. But no where convenient to put the switch.

OK, no big deal I will use a solenoid, relay something like that and started looking.

I came across something new to me, a remote battery disconnect, never saw one before. Has anyone used one of these, are they any good, junk ??

https://www.amazon.com/Battery-Disconnect-Upgraded-Anti-Theft-Prevent/dp/B09WVBHBHG/ref=sr_1_1_sspa?crid=186USQXROLQBD&keywords=remote+battery+disconnect&qid=1688384345&sprefix=remote+battery+disconnect%2Caps%2C108&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

Guess I am too much of a KISS theory guy to want a remote, key activated solenoid.

Thanks for the responses, I will find a place for a switch!