A/C fans pull battery voltage way down

[RBEmerson]

The show continues...

Cleaning up the metal around the point of contact for the ground braid has helped. But I'm still seeing under 10A (at least it's over the 5-6A seen before) even with the A/C running. On the road, with no lights, A/C, radio, etc., the battery hit something like 13.65 after a while. Turn on the radio, not so good but OK. Turn on the A/C and the voltage drops, but only to about 12.7 but continues to slowly drop further. The alternator's output still isn't properly reaching the battery.

Oh, and here's a really weird point: sitting at idle, the battery comes up to about 13.65. Rev the engine the least bit (or run at road speeds) and the voltage drops to 13.45-13.5. Get off the gas and it's back to 13.65. Say what???

I'm going to replace the ground braid, sand the grounding point a bit more, and re-check the wires on the starter. If that doesn't do it, all I can think of is the engine ground.

Has anyone added an engine ground on a WBX? How did you do it?

Beyond that, I'll see about replacing the alternator. it may just be DOA.
_________________
Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[Terry Kay]

[quote="RBEmerson"]The next steps: 1) reinstall the battery cable, 2) personally haul the battery off to be re-tested, 3) replace the battery if it's marginal (on a 6 month old battery???).[/quote]

How much of this do you have done??
_________________
T.K.

[Terry Kay]

<<The alternator is a new (re-manufactured) alternator. I have the test slip for it. Volts and amps are fine. Probably the core was OK, too.>>

How much of this is true?
You changed the alternator or "somebody" told you it was new?

There for sure is a bunch of back pedaling going on in this post.

Get a new battey in the Van.
Get a new cable from the starter to the battery.
Get a new Alternator in the Van.
Clean all of the grounds.
Get a Milton charging system tester and then report back.

You are just spinning your wheels until you get all of this dialed in.
_________________
T.K.

[RBEmerson]

[RBEmerson]

[crazyvwvanman]

Automotive batteries usually have 2 amp numbers like 650/810
The first is CCA, COLD cranking amps, when the battery is at 0 degrees F.
I doubt they put your battery in a deep freeze over night.
The second larger number is CA, cranking amps.

http://www.interstatebatteries.com/p/automotive-tr...2147384903

http://www.interstatebatteries.com/p/automotive-tr...2147384903

Mark

[RBEmerson]

I don't fully believe 778 CCA number, either. The reported ambient temperature (I kept the tape with the test results) was 78F. NTL, that puts the battery further down in the list of suspects. Remember that, standing completely disconnected, there was virtually no voltage drop after after something close to 12 hours. If a cell was beginning to short out (plate warpage, for example) the voltage wouldn't be so stable. For now, I'm focusing on grounding.

The disaster with the battery box ground (painted over ground plate, corroded terminal) has me thinking I haven't found all of the wiring "Easter eggs" the PO left behind. Given his poor electrical work in general, I'm sure they're around. All I need to do is find them...

Also, remember the engine and transaxle were replaced about 5 years ago. I don't know anything about who did what parts of the work and how well they did it. That means that they may not have done the right things electrically. I'm still new to Vanagons, so I'm having trouble distinguishing original VW work from later work of varying quality. Some of it is "no brainer" easy: 2-3 cable ties strung together to hold a coolant hose in place is probably not something done in Wolfsburg. But there's some stuff I'm not so sure about. Anyway, I'm focusing on making sure the grounds are as good as the wiring from the alternator to the battery. "Circuit" is the name of the electrical game.
_________________
Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[Terry Kay]

Well Rick,
I've been pretty calm here, with your mamby pamby information, and cave man repair proceedures.
In one post you retorted with : it's all been done, the next post it's going to be done & I'm spending your money, without even mentioning you refuse to to do the job with the correct tools.
Perhaps you haven't figured out yet that you jumped into this bottomless pit on your own, I had nothing to do with that, and after you ask questions refuse to follow plain & simple instructions.

I'm done pointing my finger at, and dragging you to the water hole, but yet you refuse to drink.

Thanks for the invite--I'm outa here--"Check Please"
Wander aimlessly on your own--you've got all of the answer's plugged into your grey matter--and not getting anywhere quick.
That's called in this neck of the woods being stuck in the mud with a bald tires, aka; Spinning your Wheels.

On 8/5/14 you posted it was the TPS creating the problems, and from there you've moved everywhere but the front wheel bearings , and it still ain't right--Go Figure.

Adios,
_________________
T.K.

[RBEmerson]

This is what passed as the engine ground:

For whatever reason, this URL should sit in between a pair of IMG tags and produce an image. I get [img]https://www.dropbox.com/s/ab8eio1vxcfthbj/20140822161332.jpg?dl=0[/img] instead.

The left side is the engine side, the right side is the chassis sheet metal side. Note the corrosion and the burned insulation. And, of course, the wire's a little light for the job. The bolts and whatever those things are at the ends of the wire look cleaner than they are.




I checked the resistance between the alternator case and the transaxle housing. The numbers are all over the map, meaning I can't tell what's resistance from surface crud and what's resistance due to gaskets, sealer, and so on between the transaxle and the engine. The ground strap for the transaxle probably isn't doing much for the charging system.

Both bolts will be replaced along with the wire (for now 4 AWG is all I can get my hands on in a hurry - I want something heavier). Everything will get a scrubbing, be bolted together, and then gets a coat of dialectric grease to seal things. The fun will be to see how the electrical system behaves after that.

BTW, one simple test that was missed: run a jumper cable from the alternator frame to the battery return. That rather steps around any ground faults.
_________________
Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[Dampcamper]

[RBEmerson]

[thatvwbusguy]

I was going to suggest the HID's as a possible problem, but figured you would get to them sooner or later since it was something you installed and would want to check out. When a ballast starts to go south, it can make for some interesting troubleshooting conditions to say the least.

The electronics inside the average set of $29.00 generic "slim ballasts" that come with most "plug and play" HID kits are converting 12VDC to 20,000+VAC as the igniter heats up the salts in the HID capsules, then they kick down to about 90VAC when running. The high voltage at startup is primarily what is responsible for the audible whine when the ballast starts up.

After a few months of use, it is not out of the ordinary for moisture to start getting into these ballasts and then things tend to get really interesting, really fast. A guy I work with had a ballast catch on fire in the engine compartment of his Acura a few weeks ago. He said he was having some problems with his battery going dead and had to have the car jumped to get to work the day before it happened.

Take a good look at your ballasts and look for any signs of excessive heat or moisture infiltration. If anything looks out of the ordinary, please proceed with extreme caution.
_________________
Jay Brown
'85 Zetec Westfalia
Newmarket, NH


If you want others to be happy, practice compassion.
If you want to be happy, practice compassion.

[Wildthings]

If what you did to the small ground strap on the left side of the engine bay made any noticeable difference then the much larger ground strap coming off the nose of the tranny must be bad. The smaller ground strap is just there to try and reduce transient voltages from messing up the various signals for the FI system. It isn't designed to handle the much larger starter load which will choose to go that way if the main ground strap on the tranny is bad.

I really don't understand why your engine is starting as your bad engine/tranny grounds would be expected to be preventing it from doing so.

[RBEmerson]

Well, the engine has been ...um... less than consistent about how it starts. That is, sometimes it spins quite briskly, sometimes it acts as if the battery is almost dead. If the return engine ground is mainly to ground the EFI and sensors, that explains why the ground point seems rather inadequate for charging and running the starter.

I am still puzzled by what seems to be significant resistance between the engine and transaxle. As I said in an earlier post, I'm not confident about those readings. I may have not really gotten past the dirt and corrosion on the cases. At any rate I'll replace the ground strap on the transaxle.

Is there anything I should watch out for when I change the strap?

Given that charging last night was vastly improved, but still a little ...what?... sluggish, the strap may well be the last piece in the puzzle.

Without trying to sound obsessively paranoid about the PO and his electrical work, if the PO wired it, I am have my doubts about the work done. I know the transaxle was replaced, so it seems reasonable that the wiring is suspect. Aside from the ground strap and reverse light switch, is there any other wiring I need to check?
_________________
Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[kamzcab86]

[RBEmerson]

I really should have worn goggles when messing with the battery cable. My glasses didn't do a good job with falling crud. At least with the transaxle braid, I could stay out of the way. [/grin]

Things are getting better but still not 100%. I can hit voltages in excess of 14 VDC but too often it's hovering between 13.5 and 13.7. Suddenly imposed loads (e.g., radiator fan) drop the voltage; it recovers but far too slowly.

On the good side, the starter spins like a top instead of grinding, and the engine catches fast enough that I have to get off the key in a hurry. [/two thumbs up]

Since the battery tests out as healthy (again, the CCA number seems too high for a 650 CCA battery - at least it's not so low as to condemn the battery), I'm going to replace the alternator under warranty. I'll also find a grounding strap for it, tying to the reinforcing brace between the power steering pump and the alternator bracket. There are a couple of bolts I can get to easily.
_________________
Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[RBEmerson]

It's still broke, it ain't fixed. Charging is better than before. I saw 18A at one point, instead of 5-6A. OTOH, depending in which A/C fan speed I pick, the draw varies from about 5A to about 10A (speed 3 IIRC), and then drops back to 5A for speed 4. The fastest fan speed needs less current than a slower speed??? Speeding up the engine shows the now-typical 0.1A drop. The main battery never comes up to 14VDC for any real length. In short, as far as I can tell, there's still more work to be done.

And the (now replaced) house battery? Sigh... Time permitting, I'll put in an echo charger. The stock (and now the GW) relay setup sucks.

Fix the charging issues? I ain't doin' it. I have a boat to prep for ocean cruising. Time and tide willing, I'll let a friend's shop have the electrical job, or it'll wait until we're back.

Meanwhile we'll use the Westy to camp out while we work on the boat. At 165 miles each way, it'll be interesting to see how the batteries' voltages fare.
_________________
Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[crazyvwvanman]

The A/C system electrical setup has some nuance to it. Fan speeds 1 and 2 use power from the starter battery feed to the dash fuse/relay panel. Fan speeds 3 and 4 use an entirely different power feed path that is in the engine compartment area only. So OF COURSE the power draw can seem to be less on high fan speeds than low fans speeds depending on where you are measuring the power draw.

Mark

[RBEmerson]

Interesting but confusing. When I looked at the diagram for the fans, it seemed as though 1-3 went through the power resistors, and 4 came, as you say, via different path that bypasses the resistors altogether. So maybe that has some influence on the draw. In general, though, I expect draw to be proportional to fan speed. [/head scratch] Anyway, I'll reread the diagram in hopes of understanding why the draw isn't consistently proportional to fan speed.

All of that said (and thank you for pointing out how the A/C fans work), the fact remains that a draw of only a few amps can seemingly drop the battery voltage, with, most importantly, no sign that the alternator is supplying power for the load. Simply put, the battery is carrying the loads and the alternator seems to be partially recharging it when it can get around to it. That's not how I understand automotive charging systems to work.

My expectation is the battery comes up to full charge or very close to it after spinning the starter, drops again as loads come on, but recovers as the alternator supplies the power consumed by the loads, and recharging the now slightly discharged battery. I've always thought that a battery was in the car only long enough to spin the starter, and fill in the odd drops when the alternator doesn't catch up to the loads fast enough. I am not seeing this happen in our Westy.
_________________
Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[kamzcab86]