Wayne.B wrote in
:

On Thu, 26 Jul 2007 01:51:23 -0000, Skip Gundlach
wrote:

We've already got massive batteries. The issue is properly keeping
them charged. At 750 nominal (less aging) AH, we can go for a long
time with no charge input. But if we don't put in the charge,
eventually the biggest battery bank will be flat, even if nothing is
drawn from it, out of normal charge dissapation (flooded = ?%/
month)...

To recharge 750 AH in a reasonable length of time you need a 3 stage
charging source of 150 to 200 amps (25% of capacity). Don't let Larry
tell you anything different. Wiring of appropriate size is also
required of course.

If you had a generator you could do that the way we do - use the
charger half of a high powered inverter/charger. Since you don't, you
will need a seriously high powered alternator with an external
regulator. An alternator of 200 amp capacity will typically be a
large frame Leece-Neville, require two drive belts, and quite possibly
some custom work on your engine drive sheaves and alternator mount.
All of this is not cheap of course, and it will take some shopping
around just to find someone qualified to do the work. Nothing less is
going to get the job done however.

And don't forget cooling. A 200A alternator is going to generate a lot
of heat and will need to be cooled. You just can't throw it into an
enclosed engine space and expect it to crank out 200A without burning
up. You need to have a 3 stage controller with a thermocouple on the
alternator and you need to pipe air into the engine space.


-- Geoff

On Fri, 27 Jul 2007 05:21:01 -0500, Geoff Schultz
wrote:

And don't forget cooling. A 200A alternator is going to generate a lot
of heat and will need to be cooled. You just can't throw it into an
enclosed engine space and expect it to crank out 200A without burning
up. You need to have a 3 stage controller with a thermocouple on the
alternator and you need to pipe air into the engine space.

Good points. In the end you may find that a generator coupled to an
inverter/charger has a lot to recommend it.

Wayne.B wrote in
news
On Fri, 27 Jul 2007 05:21:01 -0500, Geoff Schultz
wrote:

And don't forget cooling. A 200A alternator is going to generate a lot
of heat and will need to be cooled. You just can't throw it into an
enclosed engine space and expect it to crank out 200A without burning
up. You need to have a 3 stage controller with a thermocouple on the
alternator and you need to pipe air into the engine space.

Good points. In the end you may find that a generator coupled to an
inverter/charger has a lot to recommend it.


Maybe this is what we need......(c;
http://www.fleetsource.com/Alternator_p/4900j.htm

Will a 4 cyl 4-154 Perkins turn it and the prop simultaneously, or will we
have to wait for the batteries to come up before coming out of neutral on
the tranny??

Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.

On Fri, 27 Jul 2007 19:20:54 +0000, Larry wrote:

Maybe this is what we need......(c;
http://www.fleetsource.com/Alternator_p/4900j.htm

Will a 4 cyl 4-154 Perkins turn it and the prop simultaneously, or will we
have to wait for the batteries to come up before coming out of neutral on
the tranny??

It will use 3 to 4 hp under load. That should not be a problem if the
Perkins is running OK and you use dual belts.

That's the right unit assuming you can get a mount fabricated and the
Perkins has dual drive sheaves. Nothing less is going to get that
bank of L-16s charged in a reasonable length of time.

In article ,
Wayne.B wrote:

On Fri, 27 Jul 2007 19:20:54 +0000, Larry wrote:

Maybe this is what we need......(c;
http://www.fleetsource.com/Alternator_p/4900j.htm

Will a 4 cyl 4-154 Perkins turn it and the prop simultaneously, or will we
have to wait for the batteries to come up before coming out of neutral on
the tranny??

It will use 3 to 4 hp under load. That should not be a problem if the
Perkins is running OK and you use dual belts.

That's the right unit assuming you can get a mount fabricated and the
Perkins has dual drive sheaves. Nothing less is going to get that
bank of L-16s charged in a reasonable length of time.

Actually a single GearTooth Belt and GearTooth Sheaves can transfer
up to 8 HP with ease.....

Bruce in alaska
--
add a 2 before @

On Sat, 28 Jul 2007 20:02:33 GMT, Bruce in Alaska
wrote:

Actually a single GearTooth Belt and GearTooth Sheaves can transfer
up to 8 HP with ease.....

Probably so but most of us do not have gear tooth sheaves.

Bruce in Alaska wrote:
In article ,
Wayne.B wrote:


On Fri, 27 Jul 2007 19:20:54 +0000, Larry wrote:


Maybe this is what we need......(c;
http://www.fleetsource.com/Alternator_p/4900j.htm

Will a 4 cyl 4-154 Perkins turn it and the prop simultaneously, or will we
have to wait for the batteries to come up before coming out of neutral on
the tranny??

It will use 3 to 4 hp under load. That should not be a problem if the
Perkins is running OK and you use dual belts.

That's the right unit assuming you can get a mount fabricated and the
Perkins has dual drive sheaves. Nothing less is going to get that
bank of L-16s charged in a reasonable length of time.


Actually a single GearTooth Belt and GearTooth Sheaves can transfer
up to 8 HP with ease.....

Bruce in alaska

You can do 24 HP with an 8 rib micro vee.

But if you have vee belts, it doesn't matter....

--
“TANSTAAFL”

__________________________________________________ __________________________

"A prudent man foresees the difficulties ahead and prepares for them;
The simpleton goes blindly on and suffers the consequences." - Proverbs 22:3
__________________________________________________ __________________________

Wayne.B wrote in
:

reasonable length of time

= 5 hours from 40% down....(c;

Larry

On Sat, 28 Jul 2007 22:37:14 +0000, Larry wrote:

reasonable length of time

= 5 hours from 40% down....(c;

Larry

That's too long for practical usage. Let's run the numbers:

Trojan L16s are approximately 400 AH, 2 in parallel, 800 AH.

Max recharge rate in bulk charge mode at 25% = 200 amps, 150 if you're
conservative and temperature limited.

AH to be replaced at 40% down up to 80% of full charge = 160 AH (going
above 80% takes too long so must of us settle for that or slightly
higher)

Time to achieve 80% is approx 1 hour, 90% about 2 hours, and that's
good enough. My batteries have been lasting 3+ years with that kind
of usage and I'm OK with it given the amount of time I spend onboard,
and the amount of geneator time the inverter saves me.

Wayne.B wrote in
:

On Sat, 28 Jul 2007 22:37:14 +0000, Larry wrote:

reasonable length of time

= 5 hours from 40% down....(c;

Larry

That's too long for practical usage. Let's run the numbers:

Trojan L16s are approximately 400 AH, 2 in parallel, 800 AH.

Max recharge rate in bulk charge mode at 25% = 200 amps, 150 if you're
conservative and temperature limited.

AH to be replaced at 40% down up to 80% of full charge = 160 AH (going
above 80% takes too long so must of us settle for that or slightly
higher)

Time to achieve 80% is approx 1 hour, 90% about 2 hours, and that's
good enough. My batteries have been lasting 3+ years with that kind
of usage and I'm OK with it given the amount of time I spend onboard,
and the amount of geneator time the inverter saves me.


That'll work.....It's fine.....

I just don't want to be aboard any boat with 120A applied to these
batteries, sealed away in a really tight box where there is ZERO cooling,
effectively, for hours on end. I'd hate to be the one they blame when
the plates warp and touch each other, resulting in an acid steam
explosion.

Have you ever seen one? Even the stainless flatware sealed away in a
drawer far away from the batteries was just eaten alive...pitted by acid
fumes. All the clothes in the cabinets way up in the V-berth were acid
eaten, too! Everything aboard had to be tossed...anything fuming
sulfuric acid gas could eat. I certainly wouldn't want to be stranded
aboard in some hermit's cove on the hook when it happened! BOOM! The
one I saw was caused by a big battery charger at the dock whos electronic
controller malfunctioned leaving the 40A beast on full current way past
time to shut down, which it couldn't do. I wondered how high the voltage
got at 40A when she blew!

Larry
--