Weekender Auxiliary Battery Upgrade

[omacs]

I bought a Weekender recently, and have been having a great time with it.

One of the things I really want to do is to get the auxiliary battery system operational again.

It has the auxiliary battery system with the battery under the drivers seat. It has some juice, because I see the fluorescent bulbs *almost* turn on with the engine off. With the engine on, they operate fine. So it seems like this is just about an old battery.

All I really want to do is get the existing system operational again. I've read through a lot of the threads about this. A lot of them point back to the grand daddy thread on the subject.

http://www.expeditionportal.com/forum/threads/7750...tup-for-50

Lots of ideas on how to build the system from scratch, add solar, add a voltage gauge, charge controller, which is all great info, but is different from what I'm trying to achieve.

So my question is (finally!), what are the basic components I should replace/upgrade just get my house battery usable again?

I've ordered the battery which everyone seems to use:

http://www.interstatebatteries.com/p/sealed-lead-acid-sla/yuasa/yuasa-np65-12i-sla1180

I've seen the notes about needing a longer ground wire for this battery, since the +/- points are switched and will buy one locally once I get in there and see how long of a ground I really need.

I've ordered the strap from Go Westy to secure the battery under the drivers seat.

I'm going to replace the existing stock relay with a good solenoid:

https://www.amazon.com/gp/product/B001YIPXR2/ref=c...PDKIKX0DER

Is there anything else that I *must* do? Charge controller? New fuse (and where)? Low voltage disconnect?

I'm handy - just haven't had to deal with electrical before.

Thanks,
Omi

[markcm2]

When I bought my 93 the stock relay was melted and the aux battery was long dead.

I did a little spruce up to my system without getting carried away. I simply replaced the relay with a solenoid and added a low voltage disconnect to protect the battery from over discharge which seems like a must have. I used a cheap $15 solar controller from Amazon that has Low-volt disconnect built in, I'm not using the solar charge part. I also converted my rear cabin fluorescent to dimmable LED which was a HUGE improvement with controllable light level and super low power draw. I also bought a cigarette USB charger that has an LED volt meter built in so I can visually monitor the voltage. There are some nice watt meters available on amazon for about $12 that will show current levels and accumulated usage.

Examples:

https://www.amazon.com/gp/product/B00L37KZI6/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

https://www.amazon.com/dp/B00SXZDKTW/ref=wl_it_dp_...&psc=1

https://www.amazon.com/dp/B013PKYILS/ref=wl_it_dp_...&psc=1

[jjvincent]

For my Weekender I bought a NAPA Group 94R size AGM battery. It's the largest battery you can get in a Weekender without any modification at all (the battery tray is made to accept it and there are no height issues). Then ran 2 gauge wire out to the battery, uses a Sure Power 1314A battery Separator to charge the battery and ditched the stock one. It charges the battery under the seat when it needs it. Plus, I hooked up a button to do a manual override to where it will jumper the two batteries together (in case the main battery is dead). With the 2 ga wire, it's thicker than most jumper cables.

The main problem I had was that the stock system was losing a pretty good amount of voltage to the coach battery. In the end, it took forever to recharge the coach battery if you ran it all of the way down. Plus, I rewired the 12v socket for the 12v cooler and put a low voltage bypass on it. Now it runs way longer than it ever did. Then out a battery maintainer/12v supply so if I'm camping when there's 120V, I can plug the van in and run it indefinitely.

[fkahlert]

The weekender setup is actually pretty straight forward and easy.

If you bought an 1180 sla and put it in the current spot, you should be pretty much set.

Things I would check:
Voltage you get at the coach battery post when the car is running. Should be btwn. 13.8 and 14.5, steady. This should be the same as you get in the front. If its erratic or low maybe your alternator voltage regulator is on its way out - cheap to fix and good instructions around.

Test your voltage at one of the power plugs at the rear bench and see how much voltage you lose there. This is your loss in the coach system. It should be pretty benign.

Also, keep in mind your "full" charge on the new SLA is going to be higher (around 12.9V at rest).
Good luck,
Florian
03 MVWK with 2 1180s under the seats.

[jjvincent]

Here's the battery I have (it's rated at 80Ah):

https://www.napaonline.com/napa/en/p/NBP9894R/NBP9894R

[Abscate]

I'm not sure I would replace the stock relay unless there is a known problem?

My 2002 aux battery is still original and runs my fridge for 12 hours at least and will start the car from dead main , in winter.

Just replace the battery with your choice of properly fitting one.

What is your intended use? Long camping or just weekenders ?
_________________
.ssS!

[jjvincent]

The stock harness is fine if you are not going to use the battery that often and using a regular lead acid battery. The main issue is that you just can't get past the wire diameter when it comes to charging the battery. Plus, I know mine had a pretty good voltage drop from the main battery to the coach and then another voltage drop to the 12v cooler.

A few things, the coach battery would never be fully charged and the fridge shuts off too early (it shuts off at 11.5v). Thus, the reason why I rewired it with some old BMW battery cable, a battery isolator and rewired the 12v socket (I eliminated the goofy German plug and put in a regular lighter socket). Even that German plug had it's issues because it gets loose deep inside of it even if it feels like it clicks in.

I'll have to find the link but I spent last spring redoing the whole thing and even disassembling the 12v cooler (plus bypassing the low voltage shutoff). In the end, the cooler will run for 4 days straight and the delta compared to the outside temp was increased. That was good because you can shoehorn 23 beers into that cooler so I don't have to go on a 12 hour drinking binge just to get it all down before it goes warm then have three days of no beer and just camping.

[fkahlert]

I wish I would have seen the 80Ah battery you use before I put in the slightly smaller one. BTW your writeup how to clean the cooler is pretty neat too.

The 65Ah one the OP talks about is pretty awesome as replacement and lasts a lot longer than the OEM lead acid. Particularly the deeper discharge ability without killing it after a few cycles makes a huge difference.

As it is, I have now 2 65Ah running in parallel and in the summer they are fed by a solar panel. Enough power to run anything electric plus an ARB / Engel / Waeco compressor fridge for weeks with the occasional sunshine without moving the car as much as an inch.

For anyone changing from regular batteries to AGM its important to know that the charts you find on the web showing charge % based on voltage are slightly different for AGM.

http://vauweh.com/wp/2015/09/04/state-of-charge-for-agm-batteries/

Florian
03 MVWK

[jjvincent]

The NAPA batteries are made here locally by East Penn Manufacturing. It's literally a rebranded Deka. Plus, East Penn makes the Braille Battery but Braille just jacks up the price. A group 49 is just a tad too big so I went with the 94R (which is the same battery in my TDI Jetta). You might be able to shoehorn in a Group 49 but I never tried.

I went to the Deka factory store but they didn't have a 94R in stock (they stock blem batteries) and told me to just buy a NAPA as it's the same (plus it comes with a NAPA warranty that makes it easy to return it to any NAPA if it fails). In case you want to look at the dimensions, here's the Deka spec sheet.
http://www.eastpennmanufacturing.com/wp-content/uploads/Intimidator-Automotive-Flyer-1737.pdf

[fkahlert]

yep that 315mm gives you just a hair of room to get it in. Nice find. I guess i am good for a couple of years right now but i like this one.

[omacs]

Thank you *all* for the superb advice! Some comments and questions:

Charge controller: Seems like a good idea to me. Some questions though: how do you determine what the low voltage value should be at which to disconnect? Same question for the overload value? Also, do I route the voltage coming in from the alternator into the solar panel leads in a device like this:

https://www.amazon.com/gp/product/B00L37KZI6/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

If (when?) I do add a solar panel to the setup, does it also just connect to these leads, in parallel with the alternator?

The NAPA 80Ah battery looks sweet! I think the 65Ah Interstate will do the job, however. I’m just planning on long weekend trips (for now).

The fluorescent bulbs are on my list to replace with LEDs. Anyone have a good source for these? I’ve seen the ones carried by eurocampers.com but they’ve been out of stock for a while.

[jjvincent]

For the florescent lights just DIY:
https://www.thesamba.com/vw/forum/viewtopic.php?t=653285

More LED:
https://www.thesamba.com/vw/forum/viewtopic.php?t=663177&highlight=led

[fkahlert]

yes, solar just adds in parallel to the posts. A solar charge controller will make sure you are not overcharging. Its pretty easy. I added a switch to disconnect the solar charge controller entirely from the system. that way, when the panel is off the roof, i can disconnect the rest of the solar setup and it runs like the oem Weekender system.

In my setup I added an additional switched circuit so i can actually use the solar to charge/"top off" the starter battery if I am inclined to do so.

Have fun
Florian
03 MVWK
www.vauweh.com

[omacs]

Did the upgrade to the SLA 1180. Was just as simple as you folks described. Used the strap from Go Westy to secure it. Didn't replace the relay or add a charge controller. Those will be projects for another day. House lights can finally turn on! Right on time too, as we head out to Death Valley early tomorrow morning.

Florian, voltage readings were as you expected: 14 V at the main battery with engine on, 13.9V at the secondary battery with engine on, 12.6 V at secondary with engine off (although this could just mean the battery was shipped not fully charged. Will take another reading after a few hours of driving/charging.) Drop from secondary to house power outlet was negligeable (0.01 V!?).

Before pic showing the original battery:

And after. 4 ga. red wire is the new ground wire.

Thanks again everyone!

[chansuresh]

[chansuresh]

[markcm2]

[IdeaNerd]

Very interesting -- thanks for posting the info + pics, @markcm2.

[Abscate]

Mark - thanks for those posts

Ive never had mine out - is it an easy removal from the seat?
_________________
.ssS!

[markcm2]