Hi,

Has anyone had experience of fitting a 100A high output alternator to
a Bukh DV24 engine to either replace or supplement the 50A standard
alternator?

The standard alternator belt isn't wide enough to support an
alternator over 80A. Adding a second alternator would seem the way to
go as this means that a split device isn't required and simplifies the
wiring.

Thanks,
Peter

"PeterS" wrote in news:1170165916.682938.227460
@j27g2000cwj.googlegroups.com:

Hi,

Has anyone had experience of fitting a 100A high output alternator to
a Bukh DV24 engine to either replace or supplement the 50A standard
alternator?

The standard alternator belt isn't wide enough to support an
alternator over 80A. Adding a second alternator would seem the way to
go as this means that a split device isn't required and simplifies the
wiring.

Thanks,
Peter



Doesn't matter if it's a 1000A alternator with 8 belts. Your batteries
will still charge about 25% of their AH capacity for about 5-8 hours to
recharge them. As long as the alternator has the capacity to drive the
loads plus 25% of the AH capacity of the house batteries (after the first
10 minutes when boaters DREAM the batteries are all charged up because
the current dropped off) the alternator is big enough. Overkill will NOT
recharge the batteries in 30 minutes, a pipe dream until the nanotube Ni-
Mh 3 minute batteries are delivered in the near future. THEN, you'll
need the 4000A alternator for 3 minutes to a 100% charge.

1920 lead-acid technology charges SLOWLY over HOURS not minutes....sorry.

80A is plenty....over 1100 watts, which would soon boil the electrolyte
and warp up the plates if the battery didn't prevent it at 14.2V.

Larry
--
Democracy is when two wolves and a sheep vote on who's for dinner.
Liberty is when the sheep has his own gun.

Larry, thanks for mentioning the nanotube battery (capacitor). I had been
out of the loop on that one. Very exciting technology. :-)


"Larry" wrote in message
...
"PeterS" wrote in news:1170165916.682938.227460
@j27g2000cwj.googlegroups.com:

Hi,

Has anyone had experience of fitting a 100A high output alternator to
a Bukh DV24 engine to either replace or supplement the 50A standard
alternator?

The standard alternator belt isn't wide enough to support an
alternator over 80A. Adding a second alternator would seem the way to
go as this means that a split device isn't required and simplifies the
wiring.

Thanks,
Peter



Doesn't matter if it's a 1000A alternator with 8 belts. Your batteries
will still charge about 25% of their AH capacity for about 5-8 hours to
recharge them. As long as the alternator has the capacity to drive the
loads plus 25% of the AH capacity of the house batteries (after the first
10 minutes when boaters DREAM the batteries are all charged up because
the current dropped off) the alternator is big enough. Overkill will NOT
recharge the batteries in 30 minutes, a pipe dream until the nanotube Ni-
Mh 3 minute batteries are delivered in the near future. THEN, you'll
need the 4000A alternator for 3 minutes to a 100% charge.

1920 lead-acid technology charges SLOWLY over HOURS not minutes....sorry.

80A is plenty....over 1100 watts, which would soon boil the electrolyte
and warp up the plates if the battery didn't prevent it at 14.2V.

Larry
--
Democracy is when two wolves and a sheep vote on who's for dinner.
Liberty is when the sheep has his own gun.

Larry wrote:

Has anyone had experience of fitting a 100A high output alternator to
a Bukh DV24 engine to either replace or supplement the 50A standard
alternator?
....

Doesn't matter if it's a 1000A alternator with 8 belts. Your batteries
will still charge about 25% of their AH capacity for about 5-8 hours to
recharge them. As long as the alternator has the capacity to drive the
loads plus 25% of the AH capacity of the house batteries (after the first
10 minutes when boaters DREAM the batteries are all charged up because
the current dropped off) the alternator is big enough. Overkill will NOT
recharge the batteries in 30 minutes, a pipe dream until the nanotube Ni-
Mh 3 minute batteries are delivered in the near future. THEN, you'll
need the 4000A alternator for 3 minutes to a 100% charge.

1920 lead-acid technology charges SLOWLY over HOURS not minutes....sorry.

80A is plenty....over 1100 watts, which would soon boil the electrolyte
and warp up the plates if the battery didn't prevent it at 14.2V.

Why are you so obsessed about this, Larry? Its gotten to the point
that you're just ranting nonsense!

The truth is that many cruisers have over 400 Amp-Hours of batteries.
My boat, for example, was designed to carry 4 6V golf carts (Trojan
T-105s), for about 450 AH as the house bank, or 520 AH if I use the
oversized T-145. A pair of 8D's will be in the same range.

I frequently charge with a 110 Amp Balmar and it puts out 105 Amps
when started, and it stays up of 90 Amps for quite some time. I
usually charge when the bank is down 200 AH, and bring it up 120 AH,
so I'm running for roughly 90 minutes. If I used a smaller
alternator, or a less aggressive regulator, that time would go up 10
or 15 minutes. While this might seem like a small thing, after
running for over 90 minutes one starts thinking the saving 15 minutes
might be worth some real money.

These aren't made up numbers; I've been doing this for about 6 weeks
every summer for the last 8 years, and with a similar but smaller
setup on my previous boat for 8 years before that. Lest you claim
that the high charge rate is cooking the batteries, there might be
some truth, but my first set of Trojans lasted 6 years, and might have
gone longer except illness prevented me from giving them proper care
one winter. Since the Trojans are cheap ($70 each) this is not a big
deal.

There's absolutely no reason why the OP shouldn't use a 100 Amp
alternator, assuming he has a large enough bank.

"Jeff" wrote in message
. ..
Larry wrote:
The truth is that many cruisers have over 400 Amp-Hours of batteries. My
boat, for example, was designed to carry 4 6V golf carts (Trojan T-105s),
for about 450 AH as the house bank, or 520 AH if I use the oversized
T-145. A pair of 8D's will be in the same range.

I frequently charge with a 110 Amp Balmar and it puts out 105 Amps when
started, and it stays up of 90 Amps for quite some time. I usually charge
when the bank is down 200 AH, and bring it up 120 AH, so I'm running for
roughly 90 minutes. If I used a smaller alternator, or a less aggressive
regulator, that time would go up 10 or 15 minutes. While this might seem
like a small thing, after running for over 90 minutes one starts thinking
the saving 15 minutes might be worth some real money.

These aren't made up numbers; I've been doing this for about 6 weeks every
summer for the last 8 years, and with a similar but smaller setup on my
previous boat for 8 years before that. Lest you claim that the high
charge rate is cooking the batteries, there might be some truth, but my
first set of Trojans lasted 6 years, and might have gone longer except
illness prevented me from giving them proper care one winter. Since the
Trojans are cheap ($70 each) this is not a big deal.

There's absolutely no reason why the OP shouldn't use a 100 Amp
alternator, assuming he has a large enough bank.

Essie has a Model 20 Universal (5416) 16hp Diesel, fitted with a 50 Amp
alternator. The biggest alternator I can put on this engine, according to my
research, is an 80 Amp. When I install my new batteries this year, I'll have
375 ah aboard, being charged by that small alternator and supplimented by my
two 35 watt solar panels. I have no illusions that I will be able to
fully-charge that bank with my onboard charging capabilities -- my aim is to
set out with as much amp-hours as I can get so that I don't draw-down my
batteries as much as I would if they were smaller. Back in the slip, the 50
Amp shorepower charger can complete the job. The 80 Amp alternator, if I fit
it, will be close to 25% of bank capacity, but not quite. The 50 Amp
alternator is only 15.5% of capacity, which will probably prompt me to go
ahead and upgrade the alternator. But that's not exactly cheap.

In Jeff writes:

Larry wrote:

Has anyone had experience of fitting a 100A high output alternator to
a Bukh DV24 engine to either replace or supplement the 50A standard
alternator?
...

Doesn't matter if it's a 1000A alternator with 8 belts. Your batteries
will still charge about 25% of their AH capacity for about 5-8 hours to
recharge them. As long as the alternator has the capacity to drive the
loads plus 25% of the AH capacity of the house batteries (after the first
10 minutes when boaters DREAM the batteries are all charged up because
the current dropped off) the alternator is big enough. Overkill will NOT
recharge the batteries in 30 minutes, a pipe dream until the nanotube Ni-
Mh 3 minute batteries are delivered in the near future. THEN, you'll
need the 4000A alternator for 3 minutes to a 100% charge.

1920 lead-acid technology charges SLOWLY over HOURS not minutes....sorry.

80A is plenty....over 1100 watts, which would soon boil the electrolyte
and warp up the plates if the battery didn't prevent it at 14.2V.

Why are you so obsessed about this, Larry? Its gotten to the point
that you're just ranting nonsense!

The truth is that many cruisers have over 400 Amp-Hours of batteries.
My boat, for example, was designed to carry 4 6V golf carts (Trojan
T-105s), for about 450 AH as the house bank, or 520 AH if I use the
oversized T-145. A pair of 8D's will be in the same range.

I frequently charge with a 110 Amp Balmar and it puts out 105 Amps
when started, and it stays up of 90 Amps for quite some time. I
usually charge when the bank is down 200 AH, and bring it up 120 AH,
so I'm running for roughly 90 minutes. If I used a smaller
alternator, or a less aggressive regulator, that time would go up 10
or 15 minutes. While this might seem like a small thing, after
running for over 90 minutes one starts thinking the saving 15 minutes
might be worth some real money.

These aren't made up numbers; I've been doing this for about 6 weeks
every summer for the last 8 years, and with a similar but smaller
setup on my previous boat for 8 years before that. Lest you claim
that the high charge rate is cooking the batteries, there might be
some truth, but my first set of Trojans lasted 6 years, and might have
gone longer except illness prevented me from giving them proper care
one winter. Since the Trojans are cheap ($70 each) this is not a big
deal.

There's absolutely no reason why the OP shouldn't use a 100 Amp
alternator, assuming he has a large enough bank.

The point is, that if you increase your chargin capasity, then you have
to increase the battery capasity. The fastest chargin happens when the
batteries are relatively empty, there are "rules of thumb" like 40 - 80,
meanin that start charging when your batteries are almost half empty and
go until they are about 80 full. If the batteries go much deeper than 40
(you might have some other limits (30 or 50) it is not good for the
batteries and to fill them up to some 95 - 100 will take enorm time.
You have to have enough batteries that you do not regularly overstep the
limits, then your 100 A Balmar will be just fine.

- Lauri Tarkkonen

Larry,

Thanks for that, but I've done my calculations...

My domestic battery bank is 315Ah. 25% is about 79A, plus running
load of say 10A gives a total required charging of around 90A. 100A
would seem a good choice as it means I don't have to run the
alternator at full speed.

Regards
Peter

Thanks, an 80A alternator is the easiest way forward for me - like you
I'll be supplementing my charging with a wind generator and solar
panels.

Lauri Tarkkonen wrote:
....

The point is, that if you increase your chargin capasity, then you have
to increase the battery capasity. The fastest chargin happens when the
batteries are relatively empty, there are "rules of thumb" like 40 - 80,
meanin that start charging when your batteries are almost half empty and
go until they are about 80 full. If the batteries go much deeper than 40
(you might have some other limits (30 or 50) it is not good for the
batteries and to fill them up to some 95 - 100 will take enorm time.
You have to have enough batteries that you do not regularly overstep the
limits, then your 100 A Balmar will be just fine.

You're right. While at anchor, I have little hope of fully charging
the bank. However, if we power somewhere for several hours, that does
bring it up close to 100%.

I try to avoid going below 50%, so that means I follow the now
traditional 50%-85% regime.

KLC Lewis wrote:
....

Essie has a Model 20 Universal (5416) 16hp Diesel, fitted with a 50 Amp
alternator. The biggest alternator I can put on this engine, according to my
research, is an 80 Amp.

What is the limitation? I would agree that with size of the bank more
than 80 might not be cost effective, but the small case alternators go
up over 100 Amps.

When I install my new batteries this year, I'll have
375 ah aboard, being charged by that small alternator and supplimented by my
two 35 watt solar panels. I have no illusions that I will be able to
fully-charge that bank with my onboard charging capabilities -- my aim is to
set out with as much amp-hours as I can get so that I don't draw-down my
batteries as much as I would if they were smaller. Back in the slip, the 50
Amp shorepower charger can complete the job. The 80 Amp alternator, if I fit
it, will be close to 25% of bank capacity, but not quite. The 50 Amp
alternator is only 15.5% of capacity, which will probably prompt me to go
ahead and upgrade the alternator. But that's not exactly cheap.