[Vwdiesel] Alternator - Battery - jumpstart questions

[Milton Kaplan]

On Wed, 19 Jun 2002 13:42:31 -0400 jon.sykes at ps.ge.com writes:
>
>
> I have a couple of questions:
>
> now the battery has been drained so much could it
> have
> been pretty much worn out?  can they be drained so much that the
> alternator
> isn't enough to get them back to normal?

A good way to weaken a battery is to discharge it completely. If you use
a deep cycle battery, it can take more discharge punishment.

> b. a voltage test on the battery with engine running gave approx
> 12.5 V.
> I'm thinking it should be over 13 V.  if the battery is almost flat
> but
> still has the alternator charging it, should I expect the voltage to
> be less
> than normal or should the current from the alternator as recorded at
> the
> battery be the same regardless of the battery's condition?

When battery is discharged the alternator will put out high current to
charge it back up. At first the voltage will be low but as the battery
charges the voltage should increase toward 14.8 volts. As the battery
gets charged the current (amps) will decrease.

> c. does the battery have to be removed from the van in order to
> charge it?

No need to remove battery to charge it. Do not run engine while charging
as damage could occur to some electrical systems.

> this sounds like a big no no, but reason I ask is that one of my
> terminals
> is stuck and I can't remove it on my own.  i don't want to spend $80
> or more
> on a new battery until i know my battery is shot.  i'd like to
> recharge my
> battery first and then see if it maintains a charge or not.  in
> order to do
> this though i have to charge it in situ.  could this do some damage
> to the
> electrical system, cause a fire, etc?

Just connect charging cables correctly and do not run engine as I
mentioned. Did you inspect the water level in the battery? You need
battery fluid filled to proper level before charging. While charging
check for bubbles in each cell. If some cells are not bubbling while
charging, the battery probably needs replacement. Most car parts places
like Shucks can test battery in the vehicle free.
>

> d. if all else fails, i'm out camping and the van won't start, can i
> jump it
> from the camper battery under my seat?  hook up the jumper cables
> from that
> battery to the engine one?  the camper battery is almost new.  again
> though,
> could there be nasty consequences of doing this as they are both on
> the same
> circuit?  i'm not really sure how the isolator works and whether
> altering
> the circuit from the camper battery to the engine battery while they
> are on
> the same circuit could damage something?

Shouldn't hurt anything to bypass isolator and jump from one battery to
the other. By the way, isolators can go bad and this could be a reason
why your battery doesn't charge.
>
> Any help much appeciated.  I know it's a 10 year old Vanagon but I'd
> be a
> lot happier if I could be pretty certain that the van's going to
> start!
>
> Thanks!
>
> Jon
> _______________________________________________
> vwdiesel mailing list
> vwdiesel at vwfans.com
> http://www.audifans.com/mailman/listinfo/vwdiesel


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