Generator charging question

[hippieforever3]

I've looked at the charging system diagrams and if I interpret them
correctly the way the generator battery gets charged is either from the
alternator or the generator produces AC which than goes to the
converter and this indirectly charges the generator battery.

I never seem to be able to get a full charge on the generator battery
either off the alternator or the converter. Unless I'm missing
something the generator will always get charged to one diode drop less
than the main battery bank. I think I see evidence of this when I hit
the Aux. Battery switch and the dash voltage meter drops about one half
volt.

Does the charging voltage come into the generator compartment through
the "mystery control box"? or go direct to the battery. What is in that
box? Awful big for just a fuse holder and start switch.

I know I can trace it all out but if someone happens to know, I can
save getting a bad back stooping over for a few hours.

Regards,
GPSGary
1984FC35

[freewill2008]

Gary - Given that the wiring on your bus is original and stock, the
genset +charge comes from one side of the charge isolator and goes
directly to the genset battery. There are 3-4 connections but no
control boxes or other components after the charge isolator.

There should be a small voltage drop due to the charge isolator, but
still plenty of voltage to charge the genset battery.

If all the +12V wiring and connections have been checked and found
good, then start checking grounds. Ground connections are the other
half or the 12V system and just as likely to cause problems. In the
generator compartment, follow the ground cable from the battery to
the bus frame and the generator engine. Take each connection apart
and make sure everything is "shiny clean". Also consider that lugs
on the ends of cables can have high resistance after 25 years. Twelve
is a very low voltage for an electrical system and it does not take
much resistance in a cable lug or connection to cause a voltage drop.

Bob Griesel '84 FC31 WLII WA

--- In WanderlodgeForum@yahoogroups.com, "hippieforever3"
wrote:
>
> I've looked at the charging system diagrams and if I interpret them
> correctly the way the generator battery gets charged is either from
the
> alternator or the generator produces AC which than goes to the
> converter and this indirectly charges the generator battery.
>
> I never seem to be able to get a full charge on the generator
battery
> either off the alternator or the converter. Unless I'm missing
> something the generator will always get charged to one diode drop
less
> than the main battery bank. I think I see evidence of this when I
hit
> the Aux. Battery switch and the dash voltage meter drops about one
half
> volt.
>
> Does the charging voltage come into the generator compartment
through
> the "mystery control box"? or go direct to the battery. What is in
that
> box? Awful big for just a fuse holder and start switch.
>
> I know I can trace it all out but if someone happens to know, I can
> save getting a bad back stooping over for a few hours.
>
> Regards,
> GPSGary
> 1984FC35
>

[sfedeli3]

Gary,

If you are coming to Q- we can troubleshoot the charging circuit
there. I replaced the *&%$#*% diode with a "battery link ACR" from
blue sea systems. All has been right with the world since then! Just
pull the diode or isolator out and put this little puppy in its place.
No voltage drop and adjustable make/break settings- Life is good!

Shane Fedeli
85PT40
Hershey, PA

--- In WanderlodgeForum@yahoogroups.com, "hippieforever3"
wrote:
>
> I've looked at the charging system diagrams and if I interpret them
> correctly the way the generator battery gets charged is either from the
> alternator or the generator produces AC which than goes to the
> converter and this indirectly charges the generator battery.
>
> I never seem to be able to get a full charge on the generator battery
> either off the alternator or the converter. Unless I'm missing
> something the generator will always get charged to one diode drop less
> than the main battery bank. I think I see evidence of this when I hit
> the Aux. Battery switch and the dash voltage meter drops about one half
> volt.
>
> Does the charging voltage come into the generator compartment through
> the "mystery control box"? or go direct to the battery. What is in that
> box? Awful big for just a fuse holder and start switch.
>
> I know I can trace it all out but if someone happens to know, I can
> save getting a bad back stooping over for a few hours.
>
> Regards,
> GPSGary
> 1984FC35
>

[hippieforever3]

Not coming to Q but you and Bill confirmed what I suspected. I think
I'm going to replace all the battery isolators with a custom relay
control panel. I've found all sorts of solid state relay components
with ultra low drops that are far less expensive than some of
these "Marine" components.

I just need a place to work on it.

Regards,
GPSGary
84FC35

[GARY MINKER]

A properly operating diode isolator should have a voltage drop across it of between .45 and .8 volts. typically .5 to .75 volts. Just measure across the isolator to see the drop per segment. Any good hand held voltmeter referenced to the chassis works for down the line voltage readings. In an older or dirty vehicle, bad connections at high amperage draw is a typical culprit to charging problems barring bad batteries. --- On Sun, 12/14/08, sfedeli3 <sfedeli3@...> wrote: From: sfedeli3 <sfedeli3@...> Subject: [WanderlodgeForum] Re: Generator charging question To: WanderlodgeForum@yahoogroups.com Date: Sunday, December 14, 2008, 5:42 PM Gary, If you are coming to Q- we can troubleshoot the charging circuit there. I replaced the *&%$#*% diode with a "battery link ACR" from blue sea systems. All has been right with the world since then! Just pull the diode or isolator out and put this little puppy in its place. No voltage drop and adjustable make/break settings- Life is good! Shane Fedeli 85PT40 Hershey, PA --- In "WanderlodgeForum%40yahoogroups.com", "hippieforever3" wrote: > > I've looked at the charging system diagrams and if I interpret them > correctly the way the generator battery gets charged is either from the > alternator or the generator produces AC which than goes to the > converter and this indirectly charges the generator battery. > > I never seem to be able to get a full charge on the generator battery > either off the alternator or the converter. Unless I'm missing > something the generator will always get charged to one diode drop less > than the main battery bank. I think I see evidence of this when I hit > the Aux. Battery switch and the dash voltage meter drops about one half > volt. > > Does the charging voltage come into the generator compartment through > the "mystery control box"? or go direct to the battery. What is in that > box? Awful big for just a fuse holder and start switch. > > I know I can trace it all out but if someone happens to know, I can > save getting a bad back stooping over for a few hours. > > Regards, > GPSGary > 1984FC35 >

[freewill2008]

A Schottky isolator is also an option. These have much lower loss than
the garden-variety isolator used by BB. It fits (or is close to) the
stock isolator mounts and cable connections and only takes a few
minutes to swap out. It looks exactly like the stock isolator from the
outside.

Schottky isolators are required equipment in ambulances where correct
voltage is a matter of life or death. An Internet search will find
plenty of vendors.

There are other good options, however the change to a Schottky is fast,
simple and reasonably economical. Ours has performed very well for
several years.

Note that a different isolator will not help much if there are other
problems with the charging system.

Bob Griesel '84 FC31 WLII

--- In WanderlodgeForum@yahoogroups.com, "hippieforever3"
wrote:
>
> Not coming to Q but you and Bill confirmed what I suspected. I think
> I'm going to replace all the battery isolators with a custom relay
> control panel. I've found all sorts of solid state relay components
> with ultra low drops that are far less expensive than some of
> these "Marine" components.
>
> I just need a place to work on it.
>
> Regards,
> GPSGary
> 84FC35
>