Suggestions for troubleshooting aux battery not charging

[Elliott]

Sorry if this is covered elsewhere. There are clearly a ton of threads on the aux battery, but I couldn't find an answer.

The short of it is my aux battery installed with the go westy kit does not seem to be charging, and I'd love some advice on the best way to troubleshoot this. It's my third aux battery.

A little background...

I originally installed the Go Westy kit and the SLA1161 under the driver's seat a few years ago. After a couple weeks on the road, it died completely...I assumed because I was careless and ran too much power off of it when parked.

Took me a couple years to finally suck it up and replace the battery. A week after installing the new one (and a day after going to the car wash), I discovered the workers had left the interior light on. It never gave me much life again after that (I yelled at the manager of the car wash, and he gave me a free detail).

Finally, a month ago I sucked it up again, this time shelling out the extra for the SLA0190.

Now a month after the install, the LEDs on the stove are telling me the battery is low, and the stereo won't run at all when the engine is off.

I definitely haven't overused any of the components this time around...I've barely driven the thing.

So I'm wondering if the problem has been with the setup all along.

Please can anyone offer any advice on the best way to troubleshoot this so I can get to the bottom of what's going on? And if by any possibility there might be some sort of a quick fix (I'm taking the wife and our baby boy on his first camping trip this weekend).

BTW, the components work fine when the engine is running so I guess that means the isolator is working? I know next to nothing about electronics, so hopefully you kind and generous souls can help guide me.

Thanks so much!
Elliott

[PDXWesty]

The very first basic test you should do is to measure the voltage at your aux battery when the van is off then when it is running. Buy a $10 volt meter at almost any store to do this. Don't trust the LED meter on the van. Measuring the voltage will tell you the state of the charge of the battery.

Do the same at your starter battery.

Measure the voltage at the output terminal at your alternator while the van is running.

Record the voltages and report back. Then you will know where the weak link is in your system.

You can also go to almost any auto shop to have them test your charging system. Either the alternator output is low, the wiring is weak at some point, or your charging relay isn't functioning. The measurements above will let you know which it is.

Good luck!
_________________
89 Westy 2.1 Auto

[buildyourown]

[MidwestDrifter]

You need to get a quality 3 stage charger on the battery. The alternator is not designed to fully charge a deeply cycled battery. The fastest way kill a lead acid battery is to chronically under charge it. It must be brought to 100% on a regular basis. IIRC the gowesty kits use tiny wires and a long charging path. This limits charging current quite a bit as well.
_________________
2004 Dodge/Mercedes Sprinter (Custom Camper)
2000 Jetta TDI
1982 Diesel Westy W/ ABA I4 hybrid (Sold)
Epic Road Tripping since 08/05/12 | http://VagariesAbound.blogspot.com/
My Current Build | http://sprinter-source.com/forum/showthread.php?t=41215

[Elliott]

[jmranger]

[Elliott]

Thanks for the advice! I actually have a decent battery charger from my days as a street performer

I'll pull the beast out of the van tonight and see if I can give it a full charge in the house before hitting the road tomorrow.

I will look into getting a digital multi-meter too so I can get more accurate readings.

Think it's worth using my wife's AAA membership to have them send someone out who can test the battery?

Once I figure out how to test the alternator hopefully I'll get a better picture of where the problem is.

Thanks for the help!

[kamzcab86]

[pdm777]

I just replaced my alternator and battery.

Easy to test alternator, put red (positive) lead from multimeter
on the big red wire connection on the alternator, the black (negative) lead
anywhere on the body for a good ground (I used the coolant tank bracket).

My old alternator was barely putting out 12V, killed the main battery.
The new alternator should put out about 14V at idle.

In any case, if your battery is older than 4 years old, time to replace.

See post:
http://www.thesamba.com/vw/forum/viewtopic.php?t=657677

[jmranger]

[Corwyn]

I just remedied the same problem - it turned out the wire going from the starting battery to the house battery was WAAY to small (14 gauge). I upped it to an 8 gauge wire and all is well!
_________________
'90 White Westy ("The Longship")
FAS Gen V 2.0
The Annual Baja Rally
https://www.thesamba.com/vw/forum/viewtopic.php?t=604813&highlight=baja

"If anything's" gonna happen, it's gonna happen out there"
~ Captain Ron ~

[Elliott]

Thanks for all the tips.

AAA guy came, and did a bunch of tests.

Discovered that one side of the isolator that came with the Gowesty kit (the side going to the main battery) was pumping out plenty of voltage, but the other side (that goes to the aux battery was putting out zero voltage when the engine was running.

So it would appear that the problem (or at least part of it) lies in the isolator....right?

Any suggestions on a replacement isolator?

Thanks again!

[tgraham]

I think I've got one in my garage collecting dust, pm me your address and I'll ship it down to you.

Cheers,

-- T

[Elliott]

[Bills85Westy]

I interestingly have a similar (if not the same problem). I have a Noco Genius battery tender and solar setup kit that I usually keep the batteries up with, but realized with some testing recently that the Aux battery is not getting adequate voltage when the engine is running / charging.

Time to replace a component (or two)

Thanks,
Bill
_________________
89 Tristar Syncro Doka - White
85 Westfalia Syncro (conversion)
SAH 1.8T Conversion - 2005 AWP
Engine Conversion Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=612144&highlight=
85 Doka L345 Grey - 1.9L

[pdm777]

what was the result of the AAA test?

If your battery is 5 years old, you are due for a new one.
I just replaced my old battery today.
See my post on Interstate battery that fits Vanagon.

[jmranger]

[fxr]

The Gowesty 'isolator' is just a large solenoid (relay). Its coil is powered from the fridge relay, which in turn has its coil powered by the blue 'D' wire from the alternator.

So those feeds should be checked, along with the respective relay coil grounds.
_________________
Jim Crowther
1984 1.9l EJ22 Westy Wolfsburg Edition
Vespa GTS 300

[Vanagon Nut]

re: the meter shown in this thread. @ the OP. this likely isn't needed,
but the meter may need to be "zero'd". At very least, set it to Ohms, hold
probes together. If needle swings to 0, great. If not, the meter is out of
adjustment. I don't see an adjuster pot on the meter so am assuming the
adjustment is at the small screw with green paint on it. Google is your friend
here.

If you replace the isolator solenoid with same, be sure to get one that's rated
for continuous duty.

Make sure the isolator has a good ground. It likely grounds itself via the case
to vehicle frame (somewhere in battery box)


Neil.
_________________
1981 Westy DIY 15º ABA

1988 West DIY 50º ABA

VE7TBN

[Elliott]

Hi all...finally getting back to this. Yes, family got in the way. Thanks again for all your tips and insight.

Just realized one other thing, and I'm wondering if it really is the isolator. If not, tgraham I will gladly send your isolator back.

So when my Vanagon is running, the stereo which is connected to the aux battery works. When the engine off the stereo no longer turns on at all.

The aux battery has gone completely dead unfortunately.

So, if the stereo runs when the engine is running but not otherwise would that be an indicator that the issue is not my isolator and that the isolator is working fine?

Obviously still open to the idea of it being the isolator, and tgraham has kindly sent me one. But before I pull the seat out yet again and start "screwing" around just wanted to run this one last bit of info by you all.

Thanks so much!!