Re: Voltage stability in old truck
From: gothika (Vampyres_at_nettaxi.com)
Date: 09/11/04
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Date: Sat, 11 Sep 2004 00:20:06 -0500
On 10 Sep 2004 17:26:40 GMT, Ol' Duffer <DontSend@MeSpam.com> wrote:
>In article <r9f2k0ls3icodo9t6hnulo60g1a7s59vfm@4ax.com>,
>Vampyres@nettaxi.com says...
><snip>
>> (The main reason the industry switch to 12v systems, 6v batteries just
>> could not hold up under constant use and the variable charge rates as
>> well as being limited in the amount of loads from the ever increasing
>> number of system accessories that were being added to cars.)
>
>Actually, the underlying reason is that you need more
>current to do the same amount of work at low voltage.
>It was taking like 2 ga. wire for starter motors on
>some of the larger engines, but at 12V you can do the
>job with 4 or 6 ga. All the connectors had to be
>beefier at 6V, corrosion and wire/connector resistance
>were more problematic.
>
>Copper wire being an expensive and [potentially] short
>supply strategic material, the military bumped most of
>their systems on up to 24/28 Volts.
>
>And we may have not heard the last of it. There has
>been talk of going to 42 Volts to power the increasing
>demand of proliferating electronics in automotives.
>It is unclear how this might be implemented, as this
>is above what is normally considered "consumer safe"
>low voltage. Check one of *those* with your tongue!
>
>> There was a time when a solid state 6v regulator could be
>> had, as well as a decent 6v altenator.
>
>Check the rebuilders, like Jebco and Triodiode. You can
>still get 6V regulators, reverse polarity diode packs, etc.
>
Yes NOW, but at one time, especially in the late 70's and most of the
80's you'd have to go service that specialized in parts restoration
for antiques. 6v regulators couldn't be had at you're local auto parts
store.
and yes you could find a cross at your local farm implement and
tractor shop, maybe.
>> BTW if you take a look at the electrical design of virtually any auto
>> made in the past 30 years you'll see that the function of the
>> altenator is not to run the entire electrical system of the
>> engine/car, but to simply charge the battery.
>
>Now here you are just dead wrong. Nearly all automotive
>alternators since the early 70's are equipped with remote
>sensing so that the alternator will maintain a nearly
>constant voltage at some point other than the battery.
>This is done both to reduce the amount of charge/discharge
>cycling on the battery, thereby improving longevity, and
>to minimize dimming of lights and similar problems that
>would be associated with running from a battery in varying
>states of charge. Turn something on, the alternator picks
>it up right away. The only times significant current is
>drawn from the battery is for starting, or at idle if you
>have so much stuff turned on that the alternator won't
>carry it all. Watch your ammeter if you don't believe me
>(if you have one - ammeters are becoming extinct as modern
>electronically regulated alternators do such a good job
>you don't have to worry about it). The battery still acts
>as a huge water dielectric capacitor to smooth alternator
>ripple, but this is AC which has no net effect on charge
>and is not hard on the battery.
Well.. if I'm so wrong try and jump off any auto with a computer/solid
state ignition and see what happens.
You HAVE to leave the jumpers on long enough to get a base charge on
the battery. i.e. you can't just jump it off and disconnect the
jumpers and have the motor run. The car being jumped IS running off
the battery of the other car, period.
In autos going back as late as the 70's the regulator acted as the
trap isolating the charging circuit from the secondary electrics, in
later models with computers they took over this function.
As for load sensing that too is a function of the computer, unless
you're referring to some of the altenators with internal electronics
for load balancing and timing. Just talk to any other mechanic about
these and you'll get the same consensus, total crap.
I mod alot of electrical systems and when I run across these, mostly
mitsubishi or nippondenso altenators, I either cross reference them to
a good marine grade non-electronic alt. with matching solid state
regulator or modify the exsisting alt. and put in an after market
brain box to match.
>
>There are one-wire alternators made for simpler electrical
>systems, like tractors, where charging the starting battery
>is about all it has to do. These are not well-suited for
>automotive applications, but a lot of backyard mechanics
>use them in error because they are easy to hook up without
>having to understand how the electrical system works.
>Performance varies from fair to poor. Don't even think
>about using one of these with a high-power sound system,
>you won't get good results. They are disappearing even
>from agricultural use as more high-demand electronics
>make inroads.
>
You need to get up to date on your training, virtually all autos now
run on "isolated charging" electrical systems.
Don't believe me, rip out the dash board electrics of anything made in
the past 20-25 years. All low value solid state components that would
fry in a New York minute if you wired them into the charging circuit.
>> Doubly so with those with computer systems/fuel injection etc....
>> The regulator and/or the onboard electronics "traps" the charge coming
>> from the altenator to prevent it use in the system.(this is to prevent
>> damage to the electronics and engine from using fluctuating voltage.
>
>Smoke and mirrors and fuzzy thinking. Nothing in those
>sentences solid enough even to poke at.
>
Nothing fuzzy about it, just standard design in todays auto electrics.
>> A real no-no when you have an onboard computer, fuel injection and
>> variable valve controls. They must have smooth, clean constant voltage
>> to perform properly.)
>
>That's a bit misleading. Modern engine systems have
>built-in filtering and regulation where needed. They
>are well hardened against anything even a poor charging
>system is likely to throw at them. They may perform a
>little *better* with clean power, but it usually takes
>some kind of major deficiency to bring them down, and
>most of the time they don't even seem to care.
Dead wrong. I've seen injector manifolds blown clean off when when
things go horribly wrong.
You have an computer it runs the injector pump, controls timing and in
the more sophisticated engine controls valve timing.
Get any of this out of sync more than a bit and you start blowing
seals.
Even more and you'll have alot more flying off.
I run Bosch Jetronic "J" type on one of my current autos, the standard
pump pressure is 85psi, however the pump I run can range as high as
150psi. You get the valve timing off or have the computer go
haywire(OR set it up wrong) on this all you'll have left is so much
scrap metal.
Seen it happen time after time.
As for most of the stock oem stuff, you're incorrect they're very
touchy when it comes to having clean power.
In fact most of the GM, Ford or Chryslers out today have safety
interlocks to prevent the engine from running on low batteries.
I Stopped just the other day to help a lady with her 04 model
Cadillac.
Her battery went down and someone was trying to help her jump it off.
Neither new what they were doing.
I had them leave the jumpers on for about thirty minutes and she
finally got it to start.(The Caddy wouldn't even start with the jumper
cables on, the computer locked the system down entirely.)
- Next message: Jerry G.: "Re: Sony 41" intermittent convergence"
- Previous message: Eugen T: "Re: TECHNICS SU-CH900"
- In reply to: Ol' Duffer: "Re: Voltage stability in old truck"
- Next in thread: James Sweet: "Re: Voltage stability in old truck"
- Reply: James Sweet: "Re: Voltage stability in old truck"
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