Date:         Wed, 30 May 2007 09:00:48 -0700
Reply-To:     Don Hanson <dhanson@GORGE.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Don Hanson <dhanson@GORGE.NET>
Subject:      aux bat.  install
Content-Type: text/plain; charset="Windows-1252"

There have been tons of different posts about problems and procedures having to do with aux. battery installations.  I put one into my 84 semi-camper recently that was simple and works pretty well..Here is what I did. 

 Since '94, I have been using a Ford diesel truck with an Alaskan camper..the kind that telescopes up..In that truck, I have one of those mechanical battery switches, looks like a silver salt shaker, mechanical, it seems. Installed at the dealer as part of a 'trailer package', but used to keep up my camper batteries... A relay of sorts, I guess.  That one has been perfect for all these years, and we've spent months at a time in that camper down in Baja..So I decided to go that route. 

 Went to my local auto parts store and asked em for a "battery relay switch like came from Ford"...They knew exactly what I wanted and pulled one right out..about $20, if I recall..
  The 'can' (switch/relay) has three connections..Two for the main current and one to switch the current path off and on.  When the switch works, you hear a "clunk", "clonk" or "clack", which is why I say it seems sort of like a mechanical switch..

  I put the aux. battery and the switch under the drivers seat, mounting the switch on the door side, right onto the metal of the wheel well.  The switch has to be in good ground contact, so I used a wire wheel to take off the paint.  I ran a big (about 1/8" thick (8gauge?) wire from the main starting battery across under, behind the wheel wells and into the second battery box.  Into the switch, and out to a fused terminal block, which I mounted inside the cabinet under the sink...I put a 30 amp fuse between the batteries, and between the aux battery and the fused terminal block..

  To the third terminal on the switch, the small one, I brought a lead from the Van's fuse panel.  I used a terminal that is powered up when ignition is switched on.  In this line, about 14 gauge, I stuck a lighted toggle switch, which I mounted on the front of the compartment under the drivers seat.  So all the wires and switches are accessible in the same place.

  My truck has worked for 13 years with that switch simply powered up whenever the ignition is on, but on the van, I put in the additional small toggle switch so that If my main battery ever gets really low on charge, I can keep the alternator's output going only there by reaching down and flipping that toggle...I usually leave it on so that you start the van, the big can switch "clanks" and the both batteries get 'juice'...But if the ignition is off, all the accessories that are wired to the terminal block inside the sink cabinet..the one powered by the second battery, they take nothing from the starter battery..I like the audible 'clack' coming from the relay to tell me that, indeed, all is working under my seat...You can leave the little extra switch right out, like my truck is wired..

  Dunno what the term is for that can-style switch..but they work great..simple, dependable, proven.  The fused "terminal" I got from an RV supply online and it has about 6 spade fuses with double output spade connectors for your electronic 'stuff' .

  Sorry for the lack of brand names..I am not that good with electrical stuff.

  Don Hanson