Bostig and SA grille and headlights = low volts

buildyourown

I have a Bostig converter van that I just added a SA grill to.
When I turn on the headlight (with no other accessories) the voltage drops to 14v. Im reading this with a dash mounted Ultragauge so its pretty easy to see the drop. Both batteries are fully charged.

This seems too low. If I turn on the defrost and the blower, the van will stall at idle from low voltage. Does this indicate a bad alternator or do I just need a bigger one? Anybody have experience adding bigger alternators to Bostig conversions? Google returns several options for Ford Contour alts but they all seem very generic and I'd be worried about fit and compatibility.

insyncro · Posted: Mon May 18, 2015 10:32 am Post subject:

I just added Jay Brown's relay kit and SA harnesses to Kyle's Bostig van.
No complaints.
I did add an over wound alt as well Wink

kourt · Posted: Mon May 18, 2015 12:22 pm Post subject:

I put this in my Bostig:

http://www.ebay.com/itm/Ford-Contour-Alternator-20...3aa03a0e9f

Around 10,000 miles later and it's still running great--and keeping my starter and 165aH house battery system well charged. I have no complaints.

kourt

buildyourown · Posted: Mon May 18, 2015 1:57 pm Post subject:

kourt · Posted: Mon May 18, 2015 2:14 pm Post subject:

I use UltraGauge and my voltage is pretty stable, FYI--and I have 100w headlights, ham radios, truck fridge, and all sorts of other junk added to my van.

kourt

LemonCove · Posted: Mon May 18, 2015 2:33 pm Post subject:

My alternator is rated at 130A. I have all kinds of loads (headlights, aux lights (all with relays), stereo amp, A/C fans, fridge, etc) which can all be operating at the same time.

No issues with inadequate power . . . . . have a VDO Voltmeter and stays pretty stable at around 14 (measured at dash) with engine running.

If this (voltage drop and stalling) started happening with the SA headlight install, I'd start investigating there. Draw from headlights shouldn't have been dramatically different from stock.
_________________
'88 Bostig Westy

jmranger · Posted: Mon May 18, 2015 2:38 pm Post subject:

Not an expert, but I strongly doubt that the issue is that your alternator is undersized.

Think of it this way: an alternator is an energy converter, from mechanical (rotation) energy to electricity. If your engine stalls due to the alternator load, it means that the alternator is requesting more energy than the engine can provides. Putting a bigger alternator would only allow it to request even more power from the engine, energy that the engine might be able to provide at higher RPM, but not at idle.

Which doesn't mean that your current alternator isn't defective - it may well be. It might also be a bad ground or bad connection somewhere.

Bassyaks · Posted: Mon May 18, 2015 5:16 pm Post subject:

I believe the Bostig instructions suggested to change the alternator to the Contour one.

buildyourown · Posted: Mon May 18, 2015 6:04 pm Post subject:

To clarify, I am already running the Bostig speced Contour alt.
The stalling is not caused by alt load, its cause by voltage drop. Its pretty easy to see with a gauge and its easy and predictable to make it happen.
The voltage drops to ~13.25 as you come off the throttle and the engine dies. At cruise, it can keep up. At idle, it can't.

@lemoncove: I'm not sure how the SA headlights could not draw a lot more power. They are much higher wattage than stock. There isn't any more math to do than that.

wcdennis · Posted: Mon May 18, 2015 6:34 pm Post subject:

Your engine should run fine on 13.25 volts, if not, it would never start. A standard car battery is only at 12.6 volts and the starter will pull it even lower. You say you see a drop to 14 volts, when you turn on the lights, that sound about normal to me. What is your voltage without any accessories?

LemonCove · Posted: Mon May 18, 2015 8:42 pm Post subject:

bluebus86 · Banned Joined: September 02, 2010 Posts: 11075

thatvwbusguy · Posted: Tue May 19, 2015 4:51 am Post subject:

I never experienced any voltage drop with either of my Bostig powered vans, even when running 80/100W 9004 / 100W H3 before I converted my old '87 Wolfsburg to round lights.

To the best of my knowledge, every version of the Ford Contour alternator puts out more amperage than the stock Vanagon alternator, so it shouldn't be a question of needing to add more power.

With an OBDII gauge, you are looking at the voltage at the diagnostic port, not the fuse block, so the reading isn't necessarily going to be accurate.

My guess is that your alternator is failing. You can check your alternator following the steps in this video:

Link

_________________
Jay Brown
'85 Zetec Westfalia
Newmarket, NH

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

alnvilma · Samba Member Joined: March 07, 2002 Posts: 395

buildyourown,
After initial voltage checks on my Bostig conversion showed deviations, I put a secondary ground from the starter mounting bolt to the engine cradle mounting bolt. No fluctuations since....

buildyourown

buildyourown · Posted: Wed May 20, 2015 3:53 pm Post subject:

Had a chance to look at it while driving in this afternoon.
Voltage is pulled from the fuse panel. I'm reading it thru the Ultragauge, but I spliced the wire from the fuse panel to dash mount the gauge.

At idle - 14.47 Seems about right.
Lights on it goes to 14.
Turn everything on. High beams, blower motors, defrost, etc. I can get it down to 12.5
If everything is on and I let off the throttle and depress the clutch, it drops to 11.6 and the engine cuts out. Let the clutch out and it restarts.

thatvwbusguy · Posted: Wed May 20, 2015 4:43 pm Post subject:

Give Jim a call at Bostig. He should be able to have you grab some data with your STC tool and take a look at what is going on. My guess is that your alternator is on its way out, but guessing is not the best method...
_________________
Jay Brown
'85 Zetec Westfalia
Newmarket, NH

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

buildyourown · Posted: Thu May 21, 2015 9:13 am Post subject:

kourt · Posted: Tue Jul 14, 2015 7:53 pm Post subject:

An update on my Bostig alternator:

In an above post I linked to a 200 amp high output alternator bought on eBay.

I no longer recommend this path. I got what I paid for: about one year of 200 amps, and then nothing... it died last week. The alternator was not built to withstand the stress of high amperage and the heat of a Bostig conversion in central Texas (my road trips often result in 12 hour driving days at 70MPH at 90 to 100 degrees outside temperatures).

I should note that my alternator needs are higher than usual due to lots of cooling fans (stage 2 for AC, transmission, engine oil, AC blowers), DC accessories, large house battery bank, and amateur radio equipment in my van.

For most folks the 99 Contour alternator (105 amp) is going to be more than sufficient. For those that want more output, better heat resistance or want a better built alternator, try these folks:

http://alternatorparts.com/6g-series-heavy-duty-alternator.html

In this case, you would be looking for the baseline 140 amp heavy duty "dual ear" mount 99 Contour alternator.

kourt

buildyourown · Posted: Fri Aug 28, 2015 9:36 am Post subject:

New clues to my ongoing puzzle:

Im reading my voltage with my Ultragauge. It's getting power from the dash fuse block, not the OBD2 port. It occurred to me while driving home in the dark that the fuse block may be dropping in voltage while other systems were not. Here's what I found.
At idle, with no accessories running: Ultragauge and battery read 14.4
Turn on headlights: Ultragauge drops to 14 but battery still reads 14.4

That tells me that either my wire size or my grounds on the fuse block are not good enough.


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Bostig and SA grille and headlights = low volts
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