Advising Skip to install a stronger belt is like doubling the size of
a fuse when the correct one plows. The belt slipping is preventing a
battery fire or boat explosion right now please follow the reported
history, Battery charger meltdown, Alternator belt replaced several
times even after batteries show a full charge. Overloading a shorted
battery or overloading an alternator is bad advice I hope Skip reduces
the alternators output until this dangerous problem is corrected.
Installing a heavy duty Gates belt from NAPA to extend belt life is a
common practice but not a fix for a serious overload, remember the
alternator's output is not fused except by a slipping belt.

On Aug 14, 4:31 pm, Richard Kollmann
wrote:
...The belt slipping is preventing a
battery fire or boat explosion right now ...

You are right that I haven't been following Skip's post as closely as
I'd like (my reader does horrible things to his hard returns). So I
don't know what his set-up is like. Still, I don't follow what you
are suggesting. Are you saying that his controllers are allowing his
alternators to put out more than their rated amperage? I've got AGMs
and they can absorb all the amps my two 120 amp single belt
alternators can put out for up to half an hour when I have deeply
discharged them. Even under those conditions good belts seem to last
and so do the alternators (though my smart controller does add some
protection for them). I don't claim any knowledge of these things but
I've never heard of belts being used like fuses. My car uses a belt
for the timing and I'm having a hard time groking a condition where
having it slip would protect anything. So, I ask in genuine
ignorance, are the belts intended to be sacrificial or is Skip's some
kind of special case?

-- Tom.

Tom, let me describe three actual serious cases where alternators and
a charger tried to produce more amperage than battery could accept:
1. Owner adjusted smart voltage regulator to 14.2 volts for bulk
charging rate. After repeated belt failures it was found that Link
1000 meter had an error on voltage scale of one amp. When the
alternator received a field current asking to deliver a bulk charge of
15.2 volts for a preset time of one hour the amperage went to max and
alternator belt was overloaded.
2. Lightning struck boat while motoring down ICW in poor visibility.
Alternator went wild putting out enough amperage to cause number 4
output wire to turn red hot and started a small fire. The open
question was it the two batteries that shorted out first or the
alternator?
3. Boat left unattended for a day connected to shore power when Heart
25 inverter charger sensed a low voltage caused by a one of six
batteries in the house bank developing an internal short. Charger went
to maybe its max charge rate of 125 amps overheating all batteries
filling the boat with flammable gas fumes.
It would seam from Skip's reports that everything thing points to a
battery problem because charging current from any source, Alternator,
Charger, Solar Wind and Honda generator results in the same poor
battery performance. I projected when the refrigeration was selected
for this boat that the daily amp-hours for total boat would be at
least 200 amp-hrs.

On Wed, 15 Aug 2007 04:49:58 -0700, Richard Kollmann
wrote:

Tom, let me describe three actual serious cases where alternators and
a charger tried to produce more amperage than battery could accept:

I'm not sure that is the case on Skip's boat. He's got a bank of 4
L16s in series parallel which should be about 800 AH of capacity in
new condition. In bulk charge mode they should be able to accept 150
to 200 amps of charging current. Assuming the alternator is rated for
that kind of current, it needs to produce that much plus any house
loads active at the same time. That's too much for a single belt in
my experience even if everything else is perfect.

Tom, What would cause the alternator belt to slip if batteries
indicate they are fully charged? And why do batteries except a full
charge so quickly? Your example assumes the battery bank still has a
capacity of 800 AH and is in good condition.

On Aug 15, 3:23 am, Richard Kollmann
wrote:
Tom, What would cause the alternator belt to slip if batteries
indicate they are fully charged? And why do batteries except a full
charge so quickly? Your example assumes the battery bank still has a
capacity of 800 AH and is in good condition.

Richard, I think that was Wayne's post you were replying to. But,
thanks for the cases. They are interesting and scary. I'm afraid that
I am still missing something though. The belts have to be up to
dealing with the rated loads on the alternator or the system will
never work right. There should be fuses protecting the alternator
wires. So how do you set up a belt to protect the system and also
have it accept the full alternator load in the no fault condition?

As to your questions, belt slip can be caused by lots of stuff
including bad bearings, bad belts and loose or bad brackets... Having
the batteries come up to full voltage quickly does suggest to me that
the bank has a fault.

-- Tom.

He probably changed the AMP lamp on the dash to a prettier blue one,
causing an idle current increase capability in the rotor.

To be fair, I should say "Might have."

This could energize a hopped up output in the alt, working it toward
death. If it gets hot, it might cool down and stretch the belt less,
if a proper, dimmer alt lamp was reinstalled.

Theraputically, if a resistor was put in series with a too heavy lamp,
it's brightness or warmness (not a dashboard bus dimmer control) and
the alternator excitation and workload might diminish.

Removing the lamp might deactivate the alternator altogether.

It would depend on who jerry wired it in the beginning.

Charge voltage versus specific gravity measurements would determine
this parameter.

Pulley belts need to be in line and adequately wrapped and tensioned.

Removing a bank containing a short battery might cure all of this.
Battery terminal voltage out of circuit lies. A load cell is a good
way to test a battery.

Terry K