*

Offline Cole

  • Gear head!
  • *****
  • 464
  • 28
    • View Profile
There seems to be some mystery out there about what the aux battery does, how its hooked up, and what the upgrade options are.

Lets bring all the minds and resources together to create a great thread of information and resources on the topic.

If anyone has good links, diagrams or pictures please post them. If we have enough I will update this first post with all the resources for future owners to find.

The Weekender (poptop) is the only version of the short wheelbase van in the USA to get an AUX battery.

It's located under the driver's seat and was intended to power the rear cabin lights, two rear 12v outlets (except on 1993), and the cool box that was located under the rear facing driver's side passenger seat.

The battery is connected to the vehicle charging system (alternator) by a relay. When the key is on the aux battery, main battery and alternator are all connected and charging. When the key is off, the two batteries are separated so that you don't drain the main starting battery while camping.

One of the mistakes people tend to make is using the radio while camped. The radio is connected to the main start battery and NOT the aux battery. You need to make some wiring modifications to change this.

Because many people remove the cool box, the aux battery goes largely unused. It's a fairly expensive battery to let waste away. For this reason, I think most average users would get more use out of a "solar generator" system like a Yeti 400. (provides 12v/120v outlets, etc.)

The driver's side seat base has a built in battery tray. It will accept a larger battery.Though the stock one is already too tall to run a seat swivel. So you need a shorter battery to do that.

 If you also wanted to add a second house(aux) battery under the passenger seat you would need to source a second driver's side seat base for a factory like fit.

One of my favorite threads on house/Aux battery systems is this one from Expedition Portal. Lots of good basic info and diagrams there. Especially if you wanted to add solar to the van.

http://www.expeditionportal.com/forum/threads/77503-How-to-make-a-cheap-isolated-dual-battery-setup-for-50


Cole

*

Offline fkahlert

  • *
  • 3
  • 1
  • Camps in backyard!
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #1 on: July 31, 2015, 03:48:47 PM »
Ok, i bite and post.

I have recently installed the following:
- Solar panel (100w) on the roof (removable)
- Morningstar charge controller
- replaced aux battery with AGM SLA 1180 Interstate (65Ah) under the driver seat
- added second aux battery (same type) in parallel under the passenger seat
- added additional power outlets
- replaced rear facing driver side seat with ARB compressor fridge.
- added main fuse to protect sine wave inverter and ALL outlets that are driven off the aux battery

On order:
- Low voltage disconnect thingamagig to protect the newly added outlet under passenger seat.

Issues encountered:
- when changing battery to SLA 1180 you need to update the ground wire under the driver seat (original is too short)
- you also need to create / fabricate a strap/bracket to secure the battery. It does not have a lip like the OEM flooded
- when adding battery under passenger seat you need to run 4AWG wires between the seats. No issue in our van but if you have no rubber mat you need to figure out how to do that without tripping
- Also, you need a battery retaining system under the passenger seat. You can try to find an OEM battery tray or fabricate something.
- Its much easier to work it when you remove the seats. For that you ideally need a very low profile hex allen wrench with a small ratchet. the front bolts are half covered by the seat and its a bit of a pain to remove / reinstall.
- If you add fuses etc., make sure you make the wires long enough that you can access the fuse holders from the front of the seat once everything is reinstalled.
After much futzing it all seems to be working fine.


Details here:
http://www.vauweh.com



*

Offline evlove

  • *
  • 7
  • 0
  • Always in Repair
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #2 on: July 20, 2016, 01:49:30 PM »
Im in the process of putting in an aux battery.  I've pretty much got it all wired up, but having some difficulty finding where to put the trigger wire for the isolator.  Can anyone shed some light?  I've tried a few circuits I figured wouldnt have power with key in off position, but each time I've found power there regardless  (probably goes through a relay after the fuse box).  Haven't been able to find much good info regarding the trigger wire either.   If you know, please share, I'd appreciate it along any other fools that keep working on these vans.  :) 

Ill post my final project when its up and running. 
Paul

*

Offline Cole

  • Gear head!
  • *****
  • 464
  • 28
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #3 on: July 21, 2016, 12:14:33 PM »




Cole

*

Offline IdeaNerd

  • *
  • 20
  • 0
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #4 on: August 08, 2016, 06:00:09 PM »
Cole, thanks for posting this -- helpful info.

I recently bought a Renogy solar panel suitcase (http://www.renogy.com/renogy-100-watt-12-volt-monocrystalline-foldable-solar-suitcase/) to supplement and charge our aux system when I'm in hardcore "parked, mobile office" mode. Took it on its maiden voyage this past weekend and like it so far -- simple, easy, and flexible in use.

Unrelated (and prior to) that, it's looking like our aux battery is needing replacement (it not been lasting long at all with the cooler on). My question for any and all: any recommendations re: battery type? i.e. should I be looking for a deep cycle battery / gel / etc.?

*

Offline fkahlert

  • *
  • 3
  • 1
  • Camps in backyard!
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #5 on: August 16, 2016, 10:22:23 AM »
If your seat base is not modified you have some options. Mostly your limitations are height and width.
I have replaced the OEM battery with an Interstate SLA 1180.
It fits nicely and is AGM.  You will need to replace your ground wire with a longer one and need to rig up a simple way to secure it.  Others have used slightly larger flooded batteries. 
http://vauweh.com/wp/2015/07/21/more-on-batteries/


*

Offline rickiellen

  • *
  • 1
  • 0
  • 2 dogs and a Eurovan => Road trip!
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #6 on: August 22, 2016, 04:05:10 PM »
Can I charge this auxiliary battery using an AC battery charger plugged into one of the cigarette lighter receptacles in the cabin?  I'll be camping -- with no driving -- for a week, in a campground with AC, and I'd like to be able to use the battery for charging my electronics (iPad, phone) and running a DC fan (15 watt).  I won't be using the battery to run a fridge or cooler.  Just wondering if it's recommended to 'trickle charge' this battery if it's being used for camping, and the van won't be driven, for say a week or so.
Ricki-Ellen
2002 EV Weekender
San Francisco, CA

*

Offline Cole

  • Gear head!
  • *****
  • 464
  • 28
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #7 on: September 28, 2016, 06:36:35 PM »
Cole

*

Offline wajacobs

  • *
  • 3
  • 0
  • Camps in backyard!
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #8 on: March 20, 2017, 11:29:44 AM »
Hi all,

Cole,  nice job on installing those Yetis.  Do you also use the house battery beneath your drivers seat or are you using the Yetis for all your house power needs?  Also, do you think one could be fit beneath the driver side jumper seat if the cooler is removed?  Thanks, Wes

*

Offline Cole

  • Gear head!
  • *****
  • 464
  • 28
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #9 on: March 20, 2017, 12:34:21 PM »
Most of the vans that got Yetis in them were either MV to Weekender top conversion vans. So they didn't have factory house batteries or they got shortened front seat bases with swivels which takes away the room for the factory house battery.

The Yeti 400 is about 8.5" tall.

The just released Yeti Lithium 400 is about 5.75" tall. So it may fit more places. I'm about to get one for a van I'm building so I should be able to let you know soon
Cole

*

Offline my_bmw_sucks

  • *
  • 13
  • 0
  • Camps in backyard!
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #10 on: July 06, 2017, 11:29:27 AM »


Upgraded my aux battery with a Napa agm group 94R. It's 80ah and requires no modification for it to fit. At $210 it's a bit cheaper than the Interstate; especially when you consider you don't need to buy a hold down or new ground wire.


Sent from my iPhone using Tapatalk

*

Offline SWSL

  • *
  • 9
  • 0
  • Camps in backyard!
    • View Profile
Re: Westfalia Weekender aux battery, upgrades, solar, etc thread.
« Reply #11 on: July 11, 2017, 12:55:00 PM »
I'm upgrading and just bought a lithium battery for mine.   It's a "drop-in" lithium which means it's internal "Battery Management System" is designed to work ok with a lead-acid oriented system. 

I did a lot of research on drop-in  LiFePo4 batteries (the type to use) and finally settled on the 100 ah "Battle Born Battery".
Both "Bay Marine Supply" and "Northern Az Wind and solar" sell it and both currently offer a discount over the US-based mfr's price,  though you do have to ask Bay Marine for the discount.  Bay Marine is a GREAT company to deal with, by the way, very helpful and the best prices around. Nothing against NAWS either, good folks.

100 AH might not sound like any great advantage considering the high initial cost ($850 shipped with discount), but these lithiums should give much more real usage for the AH rating, size and weight. 

- you can draw lifepo4 batteries down all the way if you want with little issue, so 100 ah lifepo4 has more useable power than 200 ah lead.  Most sources indicate that 100% DOD is not an issue when needed, but that 80% DOD will give the most cycles
- they hold their voltage up until the very end, so your fridge won't be cutting out early.
- they charge much faster to 100% and will soak up more amps when available, so smaller panels or shorter drives will still get you your full capacity back sooner.  You don't have to "spoon-feed" them juice over long periods like the AGMs and other lead based batteries.
- unlike lead, they don't care if they don't get fully charged. 
- minimal self-discharge
-longer life in storage
-many more cycles

Caveats:  Just like lead, keep 'em cool to make 'em last.  Don't charge when the the battery is frozen.  Internal electronics on the Battle Born take care of the freeze factor. Mounting inside van keeps 'em cool.

Extensive comparison on value/capacity of lithiums vs AGM
https://www.victronenergy.com/blog/2015/03/30/batteries-lithium-ion-vs-agm/

I'm doing a solar setup as well myself, which I'll detail once I get it installed, but thought I would give a heads up now for anybody who is about to buy and unaware that lithium is maturing as an available tech and seems especially appropriate  for smaller vehicles where small and light really do count.  IF you have the $$$ for initial outlay, they might actually be more economical over the years.

From everything I have seen, these will probably give a long enough run-time for a fridge with no solar, just alternator charging if you are not boondocking for long periods.  And though the alternator should charge the "drop-ins" decently as-is, because lithiums like different voltage levels than lead and mainly, no float charge, it seems that changing the relay over to something designed to work with lithium will get the longest life.   The Victron Cyrix Li-charge is the one I'll using as recommended by Alan at Bay Marine:
https://baymarinesupply.com/victron-cyrix-li-intelligent-battery-combiners-for-lithium-systems.html   I had originally ordered the Li-CT, but he called and convinced me to go with the Li-Charge as it's uni-directional and less issues than the bi-directional Li-CT

cheers