A manual Isolator

[Boyntonstu]

Possible isolator solution: Use one of these cheap manual switches in the van to connect/disconnect the secondary battery.

https://www.harborfreight.com/catal...eatured+Weight,f,Sale+Rank,f&q=battery+switch


I prefer the simple version.

 

[John61CT]

Cheap HF stuff is fine for low-amp non-critical use.

For a full-bank isolation switch it's worth paying more from marine-grade vendors like Blue Sea or BEP/Marinco.

Even a second-hand of the latter will be safer and more reliable than cheap stuff new.

IMO

 

[Boyntonstu]

Cheap HF stuff is fine for low-amp non-critical use.

For a full-bank isolation switch it's worth paying more from marine-grade vendors like Blue Sea or BEP/Marinco.

Even a second-hand of the latter will be safer and more reliable than cheap stuff new.

IMO

Good suggestion.  Thanks.

How many Amps does your alternator deliver to your van batteries?

A circuit breaker may be be a better isolator:

http://www.ebay.com/itm/12V-Car-Aut...hash=item360782b6b3:m:mgQB6zQtfatw3sMFDnEIWRA


I  like these switches that you recommended for high currents,

http://shop.pkys.com/BEP-Panel-Moun...qjB1HeVuAb6fKghNJ6yJO4w5WgqBmL7RoChYcQAvD_BwE

Looks like it can handle anything that you would throw at it.

As will:

https://www.amazon.com/Blue-Sea-Sys...38820&sr=8-4&keywords=blue+sea+battery+switch

 

[John61CT]

Don't rely on consumer "car stereo" stuff for critical systems.

eBay new stuff can be counterfeit, and Amazon-sellers are often pricier than trusted marine sellers like maine sail and bay-marine that give personal levels of service and valuable advice.

Not saying don't buy from eBay or via Amazon, just do your research elsewhere

https://www.bluesea.com/products/category/2/Battery_Switches

then ask for confirmation and advice in forums, only check Amazon/eBay pricing as a last step, IMO avoid unless lots cheaper.

Talking new of course, eBay's great for buying quality secondhand gear if you know how to do it right.

 

[highdesertranger]

"Don't rely on consumer "car stereo" stuff for critical systems."

I will add don't rely on it for anything and don't let car stereo/alarm shops do any wiring on your vehicle. highdesertranger

 

[Boyntonstu]

If it has a fuse and/or a beaker, I believe that the only two failure modes; short or open would not be a major problem.

For $30 go marine..

 

[John61CT]

There are lots of very poor quality circuit protection devices out there too.

Even shocking to Beaker!

 

[DLTooley]

A hard disconnect is very cheap!