Date: Mon, 2 Jan 2017 11:39:48 -0800
Reply-To: Don Hanson <dhanson928@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Re: Delay on charge/o2sensor indicators after starting..?
In-Reply-To: <BY1PR20MB00220E9D16EE67277D59C5F0A06F0@BY1PR20MB0022.namprd20.prod.outlook.com>
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Thanks all. I'm now a bit more knowledgeable about how the charging system
works, though I still don't quite understand the "delay" with the
alternator light "activating" the alternator.. But, I've gone back and I
saw I posted my "coach" battery at 13.6 v, when I should have said
"auxillary" there...I re-tested just now...and indeed, just a few moments
after startup, I'm reading 13.9 13.92.. at the coach(main vehicle) battery
and still the 13.6 at the auxillary battery...after my fusable link and
large mechanical relay that is controlled from a small relay and the one
under the dash powering the small relay.. not sure maybe the "X" relay?...
So I assume I'm getting good output from the alternator, but the 13.6v at
the secondary battery is due to some resistance...Not concerned about that,
as it's been adequate for a few years now...What I worry about is that "one
time" the alternator light lagged before going out.... But I've got some
hints now and I'll look around at connections, etc... DH.. thank you
On Jan 2, 2017 8:47 AM, "Dennis Haynes" <d23haynes57@hotmail.com> wrote:
> It's OK to disagree and no offense is taken. I was merely trying to
> explain that 13.8V is not a sign of a defective alternator and why that is
> a chosen design point. Yes that voltage does not fully charge a battery. In
> fact you can't properly charge a battery on any fixed voltage system. The
> biggest problem is that with a properly discharged battery a fixed voltage
> system will try to charge it too fast. This is why batteries are often
> ruined after an accidental discharge and jump start. Maintenance free or
> low maintenance batteries is a compromise situation to begin with. Part of
> their function is to operate at lower charge voltages, off gas while losing
> less electrolyte, and last for some reasonable length of time. As they age
> their peak charging voltage also drops as some of the plate alloys go into
> the electrolyte suspension. At too high a voltage these older batteries
> will continue to draw current and heat up. As a battery heats up the
> resistance goes down further and draws even more current causing it to get
> even hotter. Thermal run away. Yes this can reach a point of causing an
> explosion. In normal operation you only need about 3-5% of a starting
> batteries capacity to get the job done. This why sudden failures are common
> near their end of life.
>
> As for battery experience I have specified all the way to 48 volt 1,000
> A/H and worked with UPS systems pushing 80kw. At work I also operate a near
> 600kw solar system (utility intertie). I am also well versed with emergency
> generator/transfer switch systems.
>
> Dennis
>
>
>
> -----Original Message-----
> From: Alistair Bell [mailto:albell@shaw.ca]
> Sent: Monday, January 2, 2017 1:18 AM
> To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
> Cc: vanagon@GERRY.VANAGON.COM
> Subject: Re: Delay on charge/o2sensor indicators after starting..?
>
> Dennis
>
> We've disagreed before about charging voltage, and I have to do it again
> :-)
>
> Couple of points, I've had new Bosch voltage regulators produce from 13.8
> to 14.1 volts. I don't think the tolerance on the regulators are as precise
> as you say.
>
> If we all drove our van like trucks and buses, that is long haul with
> ample amperage output from alternator for loads seen, and scheduled
> maintenance, then 13.8 V is fine.
>
> But we usually don't use our vans that way. Many of us use them for short
> hauls most of the time. We call on the battery for starting, we drive
> relatively short distances and then we stop.
>
> I assert that a lot of the time the starting battery is not getting fully
> charged during driving. This is ok if you plug in a good battery charger
> once in a while to do a full charge profile. Otherwise you have a
> chronically undercharged battery.
>
> I prefer to have an adjustable voltage regulator which I can dial up a
> higher voltage for the day to day short distance driving. I can dial it
> down if I was to do a long haul.
>
> Up here in winter, night driving in the rain and cold, I can easily have
> the wipers working, the headlights on, the front and rear heater blowers
> going and the rear defogger working. Not saying all at full all the time,
> but you get the idea. A 13.8 V alternator ain't going to be supplying 13.8
> V at the battery with those loads.
>
> Alistair
>
>
>
> > On Jan 1, 2017, at 8:02 PM, Dennis Haynes <d23haynes57@HOTMAIL.COM>
> wrote:
> >
> > From the factory 13.8 volts was the setting. 2.3 volts/cell keeps the
> battery just below the gassing limit and is desirable for extended travel
> operation as it avoids boiling out the electrolyte and grid corrosion.
> Most trucks/busses operate here. Yes there are vehicles that operate close
> to 14.2 volt. My point is that 13.8 was the VW design choice.
> >
> > 13.6 volt is slightly low but that could be due the a bad battery
> drawing excess current combined with older/undersized wiring having an
> excessive voltage drop. Proper diagnoses includes measuring current and
> taking voltage measurements to locate the drop.
> >
> > The alternator warning light does more than indicate that the alternator
> is working. That circuit provides the excitation current needed to get it
> started. You need some current in the rotor to get a magnetic field so the
> stator can create some current. A low battery after startup can cause this
> delay. So to can modifications of this circuit such as the wrong relay for
> the fridge/aux battery circuit. The light/diode in this circuit is
> critical as they also prevent the back feed form the alternator from
> keeping the ignition system energized when the ignition gets switched off.
> I would begin by testing this circuit for proper voltage at the alternator
> with key on, engine not running.
> >
> > Dennis
> >
> >
> > -----Original Message-----
> > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
> Of Stuart MacMillan
> > Sent: Sunday, January 1, 2017 9:27 PM
> > To: vanagon@GERRY.VANAGON.COM
> > Subject: Re: Delay on charge/o2sensor indicators after starting..?
> >
> > I'd like to see closer to 14v at the battery at idle with no load
> (lights, heater fans, etc.) from a good alternator. Check voltage at
> alternator and battery to be sure the cable and connections are good, but I
> think your alternator is undercharging. Get an OEM Bosch rebuilt
> alternator from a major chain parts store so you can take it back if it's
> bad. I got one that was charging at 75% out of the box, which is where I
> think yours is right now and took it back. I don't like ordering
> alternators and starters on-line for this reason.
> >
> > Another test you can do is turn the headlights on and rev to 2000 rpm,
> you should still have close to 14 v at battery. 14.2 is about as good as
> you can expect.
> >
> > I've also added this to eliminate that revving annoyance with the light:
> http://www.gowesty.com/product-details.php?v=&id=24031 The older I get
> the less tolerant of annoyances I am.
> >
> > Stuart.
> >
> > -----Original Message-----
> > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
> Of Don Hanson
> > Sent: Sunday, January 01, 2017 2:10 PM
> > To: vanagon@GERRY.VANAGON.COM
> > Subject: Delay on charge/o2sensor indicators after starting..?
> >
> > 84 Digifant (inline) with previously correct behavior ..
> > I know it's normal for these two lights to remain illuminated until I
> rev the engine and activate the alternator... The present alternator is
> perhaps 3yrs old...maybe 60 k miles. I've replaced it one time, and I may
> have installed new brushes in this one at some time past... can't recall if
> it was this one or the last one. I also recently re-tensioned the one
> belt...no power accessories..and I have a new belt expected any day, not
> bad, the current belt, but I think it is time...Anyway, everything is fine
> in the belts, the waterpump and the alternator bearings, I checked when I
> tightened the belt...But this afternoon after a day of no driving, I fired
> it up...normal cranking, no squeal, but the two indicator lights remained
> on as I drove off... I saw right away and blipped the throttle and the
> charging system kicked right in...But that is NOT something I like to
> ignore, since I may soon be heading back north through winter Nevada and
> Oregon...
> > So...What should I check? I have some new brushes with me, but I'd
> rather not remove the alternator here...In the desert sand....I will be
> putting on the new belt when it arrives... I'm reading the usual charge
> > voltage, same as ever, at the coach battery 13.6v at idle... Anything
> > else I should check that might cause a "sticky" charging system? A
> relay, or something? I've got lots of those under my seat..😃.
> > Otherwise, once I fixed the missing expansion tank rubber grommets, to
> keep the fuel dry, the van has been like a champ thanks DH
>
>
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