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Sat Aug 09, 2014 8:31 pm

This issue began in this thread. The problem has turned into an electrical problem, not an A/C or EFI problem, as I originally thought.

The problem: running the A/C fan at 4, the battery voltage(*) drops to somewhere around or below 12.4VDC and drops from there (maybe 0.1 VDC in a minute?). At speed 3, the voltage is a bit higher (around 12.5VDC) but the voltage also drops albeit not as fast as at speed 4. At speed 1, the voltage is about 12.8VDC. I can't tell if the voltage will drop, given a long enough wait. With the A/C off, the battery voltage jumps up to about 13.2 VDC and increases (typical for any 12VDC vehicle electrical system).

The present Bosch alternator is about 4 years old. Belt tension is good (1/4" deflection in the middle). The alternator to starter cable was just replaced with 8 AWG stranded wire. I installed a new alternator bracket and GW bracket reinforcement kit at the same time. The original bracket's pivot holes were beginning to look a little on the oval side.

The question is how is the A/C fan able to pull the battery voltage down by at least .8VDC, and clearly the battery is still being discharged from that point. Are the fans (two motors in this system - the evaporator is over the back seat) pulling that much current??? Or... is the alternator unable to meet the demand?

At this point, I think the main grounds need to be checked. But maybe I'm seeing a failing regulator? When I replaced the alternator output cable, I also checked the field wire connection. I cleaned it and clamped it down tight. The terminal is a copper ring terminal that looks to be crimped on correctly.

I need some pointers on the problem, keeping the peculiarities of the Westy in mind.

(*) Read on a DVM tied directly to the battery. All voltages were read while the vehicle was running at typical road speeds (engine in the 2500-3000 range).

Sat Aug 09, 2014 8:36 pm

Your alternator's on the way out...have it checked at your favorite FLAPS...

Sat Aug 09, 2014 8:40 pm

It's certainly something I've thought about. But failing after only four years?

Sat Aug 09, 2014 8:48 pm

Does the output voltage on the alternator itself mirror the voltage drop at the battery? You could try to clean up the brushes on the regulator and see if that changes anything.

Good Luck,
Mike

Sat Aug 09, 2014 8:48 pm

Yeah, maybe...stuff happens. Go ahead & have it checked. If it's bad, it's bad.

Sat Aug 09, 2014 9:06 pm

Aren't you also burning up belts?

Sat Aug 09, 2014 10:38 pm

The alternator is supposed to be putting out 14.3 volts--
Minumum 13.9 with all of the accessories on.

The dynamo is going Bye-Bye, hasta lavista baby, arriva derchi Roma --

And your anal about a solinoid stud rubber cover????

Get your horse pointed in the right direction here Tonto--

What the hell else is wrong with this thing???

Sounds to me it time to call in T.A Edison, Marconi, Tesla, Enrico Fermi , Dyno Don Nickelson, & Smokey Yunich to cure it's electrical ills.

Your worried about the starter solinoid lug shorting out by mysterious flying desbris,(which BTW will newer happen in 1000 years) and the alternator isn't working no where up to par?

I'd yank the anchor and do some sailing on dry land with the Captain, and then get a new alternator.

Years, time in use equates to nothing as far as output--who rebuilt it?
Got his name?
Forget about it--get a new one in there, or go and buy a Milton load tester and see what it's actually going on, you've got something really screwed up here.

Sun Aug 10, 2014 3:44 am

Terry, I love your posts!!
Glad you are back and hopefully better.

Sun Aug 10, 2014 6:01 am

I can't see how the battery would have enough oomph to start the engine even once if the AC fan could draw the voltage down much below 12v in such short order, even if the alternator wasn't putting out at all. At this point I would guess your alternator is likey shot, your battery is likely shot, and there is some other problem like a bad ground hiding under that shiny sheet metal exterior somewhere.

Sun Aug 10, 2014 6:18 am

Pure poetry TK :lol:

Sun Aug 10, 2014 6:37 am

Here's the kind of story that doesn't make any sense;
Ricks been bouncing all over the engine compartment to find out why the Van isn't running right, with or without the AC on, and then wants to know why the 4 year old alternator is short winded, and only putting out 12 volts.

Hello---

I've bought re-man alternator's that have lasted 5 minutes.
It happens, and there isn't anything you can do about it but remove the junk one you just bought-get on your scooter and return it for another unit
that may or may not work.

Nobody know's if Juan or Pedro re-built the alternator's before or after lunch.

Perhaps all of this Vans ills is due to low or no voltage.

Who know's???

Get the Milton battery tester on the battery put a load on it--see if it is worth doodley--and then check out the alternator for actual output while the tool is connected.

This is a pretty flat out simple discovery operation.

Sun Aug 10, 2014 6:51 am

Farf wrote: Does the output voltage on the alternator itself mirror the voltage drop at the battery? You could try to clean up the brushes on the regulator and see if that changes anything.

Good Luck,
Mike
I'll look at the alternator voltages, but I expect them to be effectively what I saw at the battery on a touch higher (voltage drop between the alternator and battery). I'm also going to measure the voltage from the alternator (when it's running) and the battery to get handle on the voltage drop. If all's well, it should be around 0.1 VDC or less.

Sun Aug 10, 2014 6:52 am

dhaavers wrote: Yeah, maybe...stuff happens. Go ahead & have it checked. If it's bad, it's bad.

True dat.

Sun Aug 10, 2014 6:53 am

insyncro wrote: Aren't you also burning up belts?

Nope. They're fine. I'm about to replace all of them, but only because it's part of my maintenance schedule.

Sun Aug 10, 2014 6:59 am

TK. I hear you. :)

BTW, on the to-do list is carting our anchors from the barn back to the boat (off for boat storage under a cover which doesn't like anchors poking it). Who knows, we may just need them in a couple of months, for a long while. (/BIG grin]

1000 year thing - some things I ignore, some things cost sleep. Having already gone through one short (cooked voltage regulator on the boat) that was very, very, very expensive to clean up, I'll stop moaning and do the job so I can sleep better. :)

Sun Aug 10, 2014 7:08 am

Wildthings wrote: I can't see how the battery would have enough oomph to start the engine even once if the AC fan could draw the voltage down much below 12v in such short order, even if the alternator wasn't putting out at all. At this point I would guess your alternator is likey shot, your battery is likely shot, and there is some other problem like a bad ground hiding under that shiny sheet metal exterior somewhere.

The battery is about 6 months old. Without the AC, the starter turns over well enough. But... because the Westy can sit for a while sometimes, I have the main and house batteries on trickle chargers.

That said, on the road there have been some slow starts (on the Blue Ridge Parkway, we tried to park nose downhill, Just In Case - never needed it, though).

I'm going to check at least the engine ground (the battery ground is good). It's cheaper than an alternator to fix.

Finally, the PO's electrical work was generally ...um... substandard. I'm constantly finding new examples of this. The alternator-battery cable, for example, had a brutally ugly booger job on the ring terminal. That it worked amazes me............. UH OH! Run an alternator into an open circuit and diodes start to die. Damn! I gotta check that. It would explain lazy alternator output. Hmmmm...

Sun Aug 10, 2014 7:27 pm

It's the alternator. At best, I can get about 6A with the engine spun up to 3K. Bentley calls for 74A (rating less 16A) at that speed, with no loads (fans, etc.). I'm off to the FLAPS tomorrow.

Why the alternator failed is still a puzzle. Unfortunately, I don't know of anyone locally who does alternator and starter repairs and rebuilds. Oh well, the alternator will go off, as a core, to be someone else's headache.

Sun Aug 10, 2014 8:44 pm

RBEmerson wrote: ...Why the alternator failed is still a puzzle...
Longevity of any component is in direct proportion to the quality of materials and/or care of assembly.

It's just a machine - they only work until they don't... :roll: :wink:

Sun Aug 10, 2014 9:01 pm

Or... "Uncle Harry was doin' real good right to when that truck hit 'im".

Tue Aug 12, 2014 5:25 pm

It ain't the (new) alternator.

Basta. I'm turning the job to a friend's shop. I just punched a hole in my right calf; climbing around the Westy is over for a while. :-(