New alternator for boat diesel - what make should I look for?

[Lloyd]

Most alternators are going to operating most efficiently at about 2500 alternator rpm and about 50-60% loaded. This doesn't mean that the engine is going to operating most efficiently, especially if its a large engine/small alt..

On a sail boat we typically see 9 to 20 hp auxiliaries. This make a perfect solution, with no gen required. Size the alt and battery bank to 2-3 days load, make sure you consider Peukert, and bat temps. If your bats are cold they won't have near the voltage of warm bats, nor the amp hr availability. In the NW fall to spring period I find it's not uncommon for the bat temps to be low 50's to low 60's. This really effects voltage and amp hr., so you need to size the bank to the loads at temp.

With a small sailboat auxiliary, it can be both a generator and drive motor. Setup with a Balmar MC controller when at anchor you can run a large alternator that closely matches the available engine HP. Like a dc generator, then when you need to motor, setup a toggle switch and just flip it into small engine mode. You need to be mindful of the power take off requirements of the engine drive pulley/crank loads, and make sure you have an proper sized drive belt.

Lloyd

The engine is a 35 Hp unit, cruise RPM is between 2000 and 2300 RPM, engine pulley is 4 1/8 " diameter, Alternator pulley is 2 7/8" diameter so we are looking good there. The downside is the tiny 3/8" belt. Yes the batteries will be cold, probably in the 50-60 degree range you mentioned. Without major surgery, there is no room for additional batteries so I am stuck with 4 golf cart 6 volt units.
I actually have plenty power to operate the alternator when cruising but I like the idea of 'down shifting' (presumably via the temperature probe wire on the Balmer 614 regulator).
Are there good aftermarket sources for the bigger pulleys required or would they best be ordered through Westerbeke or Kubota ?

Here's a pdf for your engine http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&ved=0CE0QFjAF&url=http%3A%2F%2Fwww.westerbeke.com%2FproductBrochures%2Fw107.pdf&ei=ocF2UqOeMcSYiAK_wYCIBQ&usg=AFQjCNGuOWfA6H1ih6AjjQs-vSL5AeONtg&bvm=bv.55819444,d.cGE it makes 20 hp at 2000 rpm, probably a little less in the real world. 

Options
One or two extra Vee pulleys.
5", 6" or 7" diameter.
Adjustable flezible mounts.
Extra 40. 60. or 100 ampere alternator
mounted.
40 ampere alternator mounted in place
of standard generator.

That would be the way to go, the the existing alt and mount a new 2nd alt with proper belts. We know that it can at least drive a 100 amp alt on the power take off, I'm sure it can handle the "triple nickel" at rated 160 it needs about 4.8 hp.

lloyd

[Jens]

My engine is a Kubota/Universal/Westerbeke M35B and is quite different.
A second alternator would be a preferred setup for redundancy but I am not sure if an appropriate mounting arrangement is available for the Kubota engine.

[Jens]

After resting for 12 hours, the voltage of my 2 4D batteries in parallel was 12.8V. The specific gravity readings are as follows:

Battery 1: 1.285, 1.285, 1.275, 1.275, 1.275, 1.285
Battery 2: 1.280, 1.275, 1.270, 1.275, 1.250, 1.220

Both batteries were new July 27, 2010

I am in the process of equalizing now to see if Battery 2 Cell 6 can be 'fixed'.

[Lloyd]

After resting for 12 hours, the voltage of my 2 4D batteries in parallel was 12.8V. The specific gravity readings are as follows:

Battery 1: 1.285, 1.285, 1.275, 1.275, 1.275, 1.285
Battery 2: 1.280, 1.275, 1.270, 1.275, 1.250, 1.220

Both batteries were new July 27, 2010

I am in the process of equalizing now to see if Battery 2 Cell 6 can be 'fixed'.

Jens,

Make sure you equalize each bat separately, Not In Parallel.

When you said Westerbeke 4107, I just assumed it was the Perkins. Kubotas, and Yanmars don't like much side loading the crank. If you mount a second alternator opposite side it will help. Denso also makes a 100 & 130 amp hairpin alt. That would be my choice for your setup.

Lloyd

[Jens]

Jens,

Make sure you equalize each bat separately, Not In Parallel.

When you said Westerbeke 4107, I just assumed it was the Perkins. Kubotas, and Yanmars don't like much side loading the crank. If you mount a second alternator opposite side it will help. Denso also makes a 100 & 130 amp hairpin alt. That would be my choice for your setup.

Lloyd

Thanks Lloyd! I had all three batteries hooked up in parallel (the two house batteries and a small start battery). I don't recall ever seeing anything about separating the batteries but will do so tomorrow. I only had time for about an hour of equalizing today. Tomorrow I should be able to do a full 4 hour cycle though (my charger switches back to normal charge mode after 4 hours).
Question .... the charger has 3 outputs for three batteries. Could I equalize all batteries at the same time if I hook up a separate output to each positive terminal of each battery and keep a common negative ? The charger is a ProNautic 1250.
I am confused re the Westerbeke bit - I mentioned that the alternator is a Westerbeke 41017 (note the extra '1' in the number).
Based on the engine being a Kubota M35B, could you clarify for me what your suggestion is for a replacement alternator keeping in mind that the current unit is a very tight fit. Have you seen any mounting kits to mount a second alternator on this engine? Mounting does not seem to be straight forward for a second alternator. What would be your suggestion re the belt - would you leave the 3/8 belt (and all the pulleys) for the original alternator and would you run a second belt for the second (new) alternator ? .... or would you replace the current alternator and replace all pulleys for a larger belt ?

Thanks!

[Cornelius]

Correct me if i'm wrong, but isn't 30A charging close to ideal to your 320Ah bank? (C/10)

I think a good external regulator with an external temperature compensation (since your batteries are around 50-60F) would do your batteries good.

[Jens]

Correct me if i'm wrong, but isn't 30A charging close to ideal to your 320Ah bank? (C/10)

I think a good external regulator with an external temperature compensation (since your batteries are around 50-60F) would do your batteries good.

<sheepish look> Good point! Yes, you are correct .... but it just takes too long to bring the charge up at that rate and also the charge rate falls back fairly quickly from 30A (although I have never timed or graphed the charge rate vs time curve). The other aspect to my desire for a higher charge rate is my thought of moving to Lithium technology within a few years.

How much damage would a 60 A rate cause for a 320 AH bank? I would gladly accept a somewhat reduced battery life if I could cut engine run time in half.

[Lloyd]

Jens,

Make sure you equalize each bat separately, Not In Parallel.

When you said Westerbeke 4107, I just assumed it was the Perkins. Kubotas, and Yanmars don't like much side loading the crank. If you mount a second alternator opposite side it will help. Denso also makes a 100 & 130 amp hairpin alt. That would be my choice for your setup.

Lloyd

Thanks Lloyd! I had all three batteries hooked up in parallel (the two house batteries and a small start battery). I don't recall ever seeing anything about separating the batteries but will do so tomorrow. I only had time for about an hour of equalizing today. Tomorrow I should be able to do a full 4 hour cycle though (my charger switches back to normal charge mode after 4 hours).
Question .... the charger has 3 outputs for three batteries. Could I equalize all batteries at the same time if I hook up a separate output to each positive terminal of each battery and keep a common negative ? The charger is a ProNautic 1250.

Yes each bat must be measured by it's own resting voltage, in parallel the weaker bats will cause current to flow between the big and little sisters.

No a 3 terminal charger charges at the rate of the Primary#1 bat/terminal, it would require separate sense leads and separate logic, Xantrex had such a charger but it only lasted about 1 year in the market place, and couldn't do separate equalize.

It appears that bat 1-4d doesn't need an equalize, but bat2-4d has a large discrepancy between the last 2 cells, and I didn't see note of bat 3.

I am suspect of any resting voltage and SPG readings if all 3 bats were in parallel. SO to be accurate you must start over one bat at a time. This means fully charge, let rest for 24 hrs, bleed of any surface charge, then take a resting Voltage/SPG.

I am confused re the Westerbeke bit - I mentioned that the alternator is a Westerbeke 41017 (note the extra '1' in the number).

Yea, it was my error, I saw Wester....4107 and not 41017.

Based on the engine being a Kubota M35B, could you clarify for me what your suggestion is for a replacement alternator keeping in mind that the current unit is a very tight fit. Have you seen any mounting kits to mount a second alternator on this engine? Mounting does not seem to be straight forward for a second alternator. What would be your suggestion re the belt - would you leave the 3/8 belt (and all the pulleys) for the original alternator and would you run a second belt for the second (new) alternator ? .... or would you replace the current alternator and replace all pulleys for a larger belt ?

Thanks!

Yep, I am saying add a second alt, there is a factory add on pulley that bolts to the 3-bolt on the original pulley. There is also a factory bracket to mount the 2nd alt. But I think that is a non issue for someone with welding skills to fabricate there own. A 1/2 belt will drive the Denso 100-130 amp alt, because it's so much more efficient do to the hair pin stator design. And with the Balmar Controller you can dial it in with the belt manager, if it make dust.

Lloyd

[Lloyd]

Correct me if i'm wrong, but isn't 30A charging close to ideal to your 320Ah bank? (C/10)

I think a good external regulator with an external temperature compensation (since your batteries are around 50-60F) would do your batteries good.

No

A healthy well built FLA, can take 25-30% of C/20 in charge rate especially if cold.

For a charger working as a charger/power supply I speck 40-50% depending on house loads. A good three step chrarger that is temp compensated can never over charge a good battery. The terminal voltage controls the amperage by the voltage control.

But an undersized charger could under charge bats, while acting as charger/power supply for house loads and charging at the same time.

A battery can only accept as much current as it internal resistance allows, with a smart 3-stage/temp compensated it must drop current to maintain voltage control.

Lloyd

[Cornelius]

My meager experience with car/engine alternators are that the charging curve are all wrong. They usually are full(ish) throttle until the batteries hit around 14.2-14.4V, then they cut the voltage abruptly to 13.4-13.6V instead of keeping the voltage and dropping the amp - therefore, the batteries takes ages to top up.
A good 3-stage external controller would do better i think. Also, at 50-60F, the charging voltage should be higher. (14.6-14.7V?)

I fully support your decision to move to Lithium batteries. I've already swapped my 110Ah LA battery in my caravan with a 55Ah LiFePO⁴ battery, which has integrated bms, so i can charge the battery with whatever i have around; a standard LA charger, alternator, or even direct from a solar panel, since the bms cut the charging to the cells when full. And since one can discharge these batteries over 90%, i have no loss in practical capacity. It also support charging at C/1.

[Jens]

I fully support your decision to move to Lithium batteries. I've already swapped my 110Ah LA battery in my caravan with a 55Ah LiFePO⁴ battery, which has integrated bms, so i can charge the battery with whatever i have around

Not to cause thread drift but what is the make of the batteries you use ?

[Jens]

Yes each bat must be measured by it's own resting voltage, in parallel the weaker bats will cause current to flow between the big and little sisters.

No a 3 terminal charger charges at the rate of the Primary#1 bat/terminal, it would require separate sense leads and separate logic, Xantrex had such a charger but it only lasted about 1 year in the market place, and couldn't do separate equalize.

It appears that bat 1-4d doesn't need an equalize, but bat2-4d has a large discrepancy between the last 2 cells, and I didn't see note of bat 3.

I am suspect of any resting voltage and SPG readings if all 3 bats were in parallel. SO to be accurate you must start over one bat at a time. This means fully charge, let rest for 24 hrs, bleed of any surface charge, then take a resting Voltage/SPG.

Ok, I will start from scratch <sigh>

Yep, I am saying add a second alt, there is a factory add on pulley that bolts to the 3-bolt on the original pulley. There is also a factory bracket to mount the 2nd alt. But I think that is a non issue for someone with welding skills to fabricate there own. A 1/2 belt will drive the Denso 100-130 amp alt, because it's so much more efficient do to the hair pin stator design. And with the Balmar Controller you can dial it in with the belt manager, if it make dust.

Lloyd

The problem with my welding skills is that they require a lot of trial and error type of fitting procedures Not a good thing when the boat is one place and the shop another. I would gladly pay for a commercial 'bolt it on' kind of an upgrade. I will talk to my local Kubota dealer to see if he can fix me up with the bracket and pulley.

Thanks again !

Oh, also thanks for confirming that a higher charge rate is viable!

[Cornelius]

I fully support your decision to move to Lithium batteries. I've already swapped my 110Ah LA battery in my caravan with a 55Ah LiFePO⁴ battery, which has integrated bms, so i can charge the battery with whatever i have around

Not to cause thread drift but what is the make of the batteries you use ?

Not easy to say, since there's no makers name and it's probably made in China. But i bought it here in Norway... The supplier i bought it from, have mainly cells from Chinese manufacturer "Heter"

(I also have a smaller battery from the same supplier; a 12V, 30Ah, used as an all-round battery, because of it's weight - 4.4kg, and 24pc 3.3V, 10Ah cells in series-parallel to make 36V, 20Ah for my E-bike, also from Heter...)

[Jens]

It sure takes a long time to equalize multiple batteries, especially if you don't trust the system to run unattended.
I have now done one 4 hour cycle on the good house battery and it measures very even across all cells. I have done two equalize cycles on the other house battery and will test specific gravity tomorrow (after 12 hours of resting). I can't wait to see how that one weak cell is coming along. Equalizing current seemed very low at less than an amp for most of the equalization time (at 15.8V!).

I have contacted Electromaax to see if they make a serpentine pulley set for the M35B engine and they seem to have enough requests to make it worthwhile to produce a kit. Should be interesting to see what pricing is like ....

I have not been able to locate a pre-made kit for a second alternator bracket so I guess I will have to see what I can cobble up myself (and if it is feasible at all). A second alternator is definitively the preferred way to go.

[Jens]

Good news, the house battery with the bad cell came up just fine!
I must say I am surprised at how good a shape the batteries appear to be in. I was under the impression the house bank was well down in terms of life.

On the down side, I looked at possible mounting options for a second alternator but it doesn't look like anything would fit in the allowed space (short of modifying the engine cover). It looks like increasing the capacity of the existing alternator and installing serpentine pulleys will be the way to go.

Edit: to clarify, the mounting bracket doesn't seem to be the big issue but rather the space required for the second alternator is the issue.