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Auxiliary Battery Q&A via E-mail

The following text is a compilation of questions we receive from customers on auxiliary battery related issues. Our responses are usually quick and to the point as we receive scores of e-mails throughout our business day. They are not designed to be historically and/or technically complete, As always, please drop us a line if you have any technical questions involving your Westy.

...received via e-mail May-06

Hi Lucas-

I was scanning the go westy web site and came across a 95 eurovan that you guys sold- It has a nice aftermarket fridge installment- It was solar powered and also with the mod was a new little cubby-

It was sold in July 2008 and item # is 834 with pictures-

I wanted to see if this is a mod gowesty did and what the cost would
be- I also have a 1995 eurovan-

Also what are the power requirements for the Norcold you used- I assume when it is not getting solar in kicks into the 12v system- Did you upgrade the RV battery and how long can it run that fridge without solar? I know some of the new marine Norcolds have very low amperage draw?

Thanks in advance-



Hey Dale,

Yes, we can sell you what you need to replicate what we did for our customer to whom we sold a 95 EVC--he wanted the built-in style frig.

But in general, the whole idea of a built-in frig does not make good sense. Please read this:

Instead of a built-in, all-electric frig, you may want to fast-forward to an Engel type, solar powered frig.

We call it a "solar powered frig", which is true. But, there is actually no direct link between the solar panel and the frig itself.

Rather, the solar systems we install produces energy that is stored by the auxiliary battery system. The energy in the auxiliary battery system can be used to run whatever. One of the things it runs is an all-electric frig.

The amount of time you can run off the auxiliary battery system depends on the amount of stored energy you have (size and number of batteries), and how much power you consume. In general, a fully charged EVC auxiliary battery will run an Engel frig for between 24 and 48 hours without a charge--depending on ambient and selected inside temperatures.



...received via e-mail May-06
Lucas, a few times over the past couple months I heard what I thought was the smoke detector, kinda like when a battery is going low. I was parked at extended parking at the airport Memorial day week and when I got back I heard a repeated 4 beeps for about five minutes about 20 seconds apart, and it seemed to be coming from the sink cabinet behind the drivers seat. Nothing in the manuals I have as to what it is, but although it did stop, I haven't a clue as to what it is, that i should be responding to! Any help would be appreciated.
Thanks and All the best!
Mark Huckel

There is an LP gas detector at the front end of the sink/frig/stove cabinet assembly, down low, behind the drivers seat, in between where the tables stow. When the second battery gets really low on voltage, the LP detector starts to beep. There is a separate fuse for it in the rear electrical panel, below where you add water to the storage tank. It is labeled "LP detector". If you remove that fuse and the beeping stops, your second battery is probably low. You can double check the battery condition on the stove panel. Either the second battery is no good, or not getting a charge.


...received via e-mail May-06
I own a 2003 Eurovan Weekender that comes with an auxiliary battery. I am heading down to Baja camping and want to better understand how this battery relates to the car battery.

If I use this auxiliary battery heavily, can I exhaust both the [Aux] battery and the car battery?
Also, do different 12v outlets use the two different batteries?


Chad & Ellen
The second battery in your Eurovan MV is located under the drivers seat. It is isolated from the primary battery (located under the hood above the transmission) by a relay.  Whenever you start the engine, the two batteries are bridged by a relay located next to the 2nd battery, also under the drivers seat.  When the engine is shut down, the relay separates the two batteries.   The second battery is there to power only the small cooler under the rear facing seat behind the driver, and the two 12V outlets on either of the rear bent seat (no on 1993 models).  The cooler and two outlets are protected by a separate fuses, located next to the aforementioned relay.  So, while stationary, the auxiliary battery can be exhausted while the main battery is unaffected.

NOTE:  It is not a good idea to fully exhaust a lead-acid battery.  See our library article on the subject, click here.


...received via e-mail January-04

The charging system on my 78 Westy does not seem to recharge the batteries adequately. Do you know of an upgrade to the existing charging system that would help? I'm not sure if it has a generator or an alternator but it seems to charge better at a higher rpm. My second question is what kind of batteries should I use to replace the dual batteries. Do deep cycle marine batteries work better for camper use or should I stick with the std automotive batteries? Let me know if you have these products for sale or if you could advise me on what I should get. Thanks, Peter

The battery on the right side is only for starting the vehicle. The best choice for that battery is an Interstate 42-50. The battery on the left is for the camper related stuff. The largest deep-cycle battery you can fit in there is the best choice. There is a little relay inside the engine compartment that controls the re-charging of the second battery. If it is bad the second battery will not charge properly. We sell replacement relays. The alternator fitted to the engine should be more than adequate to keep both batteries charged. Thank you.

...received via e-mail October-03

Hello - We've been admiring your website and were wondering if you have any recommendations for deep cycle auxiliary for 91 vanagon westfalia? thanks in advance... Axel

Axel, there are no deep cycle batteries that we are aware of that fit a Vanagon battery box without modification. We have seen people install Optima sealed batteries successfully after removing the top posts (then connecting to the side posts), laying the battery down and making modifications to the compartment lid. Obviously it is not a slam dunk, but anything can be achieved if you want it bad enough. Our approach is much simpler. We utilize a Interstate battery (part# MT-41) in both the starting and auxiliary positions. It is a powerful, long lasting battery that fits perfectly. Having two of the same batteries of the same age aids in the recharge cycle and adds to their overall life span. While it is not a "deep cycle" design, it works well to power your fridge and other accessories while you are driving as it is being continuously charged by the alternator. While you are camping you should be running your fridge on LP which relieves your 12V system of that primary load. Then the MT-41 is more than capable of running the fresh water pump/faucet for quite a while as the electrical demand is minimal. Hope this helps.

Cheers, Taylor

...received via e-mail October-03

I have a 1982 Vanagan Camper and I bought the 2nd battery kit along with the relay.
I know it is not the kit for the 1980-1984 van. However, I would like to try to fix it myself. If you could just tell me which wires go where on the relay switch, (which color wire to which number) because the instruction on the kit is for vehicles with pre-existing relays already set up. Can you please assist me because I am going back to Africa in 3 weeks and I want to try to make it work.

Thanks for your help!!!!!!!


Basically, to link the second battery to the first battery, and therefore to the alternator, it is necessary to hook up to two circuits under the dash, circuit 30 which is a solid red wire with at least 10 guage from the first battery to the fuse box, and circuit 61 which is solid blue wire that comes from the from the alternator that runs the charge light, which runs near the fuse box and up to the instrument panel. You can mount the relay near the fuse panel under the dash. The circuit 30 wire (red) goes to pin 30 on the relay, the circuit 61 (blue) wire goes to pin 85 on the relay, pin 86 goes to ground, and either of pins 87 on the relay go to the second battery positive post. You will need to run at least a 10 guage wire to the second battery positive post from pin 87 on the relay. Got it? If you need a wiring diagram, refer to the Robert Bently Workshop Manual CLICK HERE

Regards, Lucas

...received via e-mail October-03

I own a 1987 Vanagon Weekender Syncro and I discovered the place for an auxiliary battery under the drivers seat. I was aware of the characteristics of the aux. battery with camper models. Does it work the same with Weekenders? Will the aux. battery be charged by the engine when running. Also will all electrical equipment be operated by the aux. battery with no key in the ignition? I have all the complete connections under the drivers seat.

I also had another question concerning the operation of the 12v cigarette outlet on the bottom left hand side of the passenger seat. The one on my vanagon is currently not functioning even though all the connections and the fuse seem to be there. Do you have any ideas or tips as to why this outlet may not be functioning? Is there a second fuse or is there a switch that needs to be activated?

Thanks for taking the time to answer my questions.


L. Ventolini

The Vanagon Wolfsburg pop-top weekender came standard with a second battery under the passenger seat. This second battery is charged by the engine while running via a relay located near it, also under the drivers seat. The sole purpose of this battery was to power a cigarette lighter outlet located in isle way next to the passenger seat. The sole purpose of this outlet was to run a small 12/120v refrigerator which also came standard on this model Vanagon, and mounted via a pair of small brackets and wing nuts on the floor behind the passenger seat. If you look closely at the floor, you will find two 6mm threaded holes into which these wing nuts were fitted. There is no switch to activate that outlet, so you will need to trace the short and determine why it is not receiving power.

Regards, Lucas

...received via e-mail May-02

I am considering adding a second battery under the driver's seat of my 1987 VW Vanagon. I see that your Part #GVW-253-700 - Auxiliary Battery Installation Kit is used for this purpose. Your description of the kit states the following,"The existing relay under the seat is used to isolate the two batteries when the engine is not running, but allows the alternator to charge both batteries while the engine is running. That way, you always have a charged battery to start the car even if the second battery is completely discharged." I don't have any relays or wiring in this compartment, will this kit still work for me? Are there parts included that will still accomplish your description above? And does the kit come with instructions and wiring diagrams?

Any assistance you may offer is greatly appreciated.

J. Bogle

This kit is for the Westfalia camper, not the regular 7 passenger van. To add a second battery under the drivers seat of your van is much more complicated. You would need the relay you are missing, plus you would have to run wiring to the other battery, and one wire to the alternator. We could put together a kit for you with instructions for about $100. Let me know.

Regards, Lucas


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GoWesty! Camper Products is a privately owned company specializing in parts, accessories, sales and service of Volkswagen (R) campers. It is not affiliated in any way with Volkswagen of America or Volkswagen AG. "Vanagon", "Bus", "VW", "Volkswagen", and "Eurovan" are registered trademarks and should be considered as such throughout our entire website.


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