Derekdrew says>  
> It is not advisable to use a dual battery isolator with you VW van. This is
> because isolators typically reduce the voltage by about 1 volt. On an

This again is something I was waiting for someone else to confirm:) Thanks!

> This characteristic of your VW is not a defect. VW simply felt that 15  volts
> was too much and would overcharge your batteries. The USA car makers don't
> feel this way.

Not positive, but I know the vw alt has a different level of mechanical 
advantage (engine rpm vs alt rpm). Think this is to provide a reasonable amount of 
power at low rpm's. If the alt's output were greater than it is, you would
'dry out' your battery when running at highway rpm's. US tanks don't have this
feature because the mechanical advantage is different. 

> The solution is to use relays. There are 200/500 amp relays that you can buy
> and connect up to disconnect your batteries automatically for various
> scenerios. Wrangler Power products of, I think, Scottsdale, AZ has a great
> catalog with various wiring accessories for this purpose.
> 
> Think twice before using an isolator in a VW!

DO you have any idea of their address?? Any info or diagrams of the setup???
Data are appreciated!) 

P.S. I think Y'all have provided just enough data to get my final design in 
progress, but I'm still considering alternatives.
> 

*Werner Hellmer		whellmer@icaen.uiowa.edu