Wondering if it makes a difference... we have an aux battery under the drivers seat that was installed years ago by a PO... I believe it is connected to the main starter battery via a Sure Power.  I know that when the ignition is off it drives the radio, 12v adaptor, kitchen wiring etc...

I would like to put a battery charger/maintainer on the starter battery for winter storage but am not sure how that interacts with the aux battery or vice versa if I was to attach same to the aux battery.  Left the van idle for a couple months and went in this week to find both batteries dead.  Can anyone comment on whether having these batteries combined/separated affects or is detrimental to the use of a maintainer?

Barry 

Jim Arnott <jrasite@EONI.COM> , 1/10/2015 10:02 AM:
When my 2/10 amp trickle charger died ~20 years ago, I bit the bullet and bought a real battery charger. Expensive? Yes. Worth it? YES! I can start an American diesel engine with completely flat batteries in about 5 minutes. I can start a Vanagon with a completely flat battery in the time it takes to slide the seat forward and attach the leads. I can charge my 7.5 AH Honda 70 battery without boiling the electrolyte.  I can test a starter motor on the bench. (Which I intend to do in about an hour.) Spend the money and never worry about a battery charger again. 
 
Mine is similar to this: <http://www.amazon.com/Schumacher-SE-4022-Wheeled-Battery-Charger/dp/B00030BFQA/ref=sr_1_1?i> 
 
I use a booster battery (hot start) when I’m traveling. 
 
A real battery charger is one of the best tool purchases I’ve ever made. I use it at least every couple months. It turns what was a couple day job into a couple minute job. 
 
Jim 
 
 
Men are not prisoners of fate, but only prisoners of their own mind. 
-- Franklin D. Roosevelt 
 
> On Jan 10, 2015, at 3:26 AM, Dennis Jowell <dennisjowell@GMAIL.COM> wrote: 
>  
> Good morning to all 
> My 20 year old Sears craftsman battery charger went south yesterday trying to trickle charge my Westy main battery! Does anyone have a recommendation for a new charger? Reading all the reviews of all the ones out their sure is confusing. Many horror stories of the Chargers burning etc. batteries exploding etc. any thoughts? Any suggestions? 
> Dennis 
>  
> Dennis Jowell 
> Scotch Hollow Farm 
> Newbury Vermont