Differences in Small Case Alternator Efficiencies

[GordMay]

This white paper might inform the discussion.

“Improving Alternator Efficiency Measurably Reduces Fuel Costs” ~ by Mike Bradfield, MSME, Remy, Inc.
➥ http://www.delcoremy.com/documents/h...ite-paper.aspx

[john61ct]

Yes 6HP is a lot, especially in an emergency situation when you need every watt going to the prop.

A switch at the helm killing the alt load is pretty standard, not hard to implement.

Originally Posted by a64pilot

The idea that you getting 200 amps or 2800 Watts out of a device you can hold in your hand is pretty much a fantasy.

My comment about the 200A+ "dream" clearly stated that these were not ordinary alts you could "hold in your hand"

an entirely different class of alternators, few have room for

the 14 kW one I'm dreaming of, weighs over 50kg, and that's not counting the remote-mounted VR.

And full output would demand well over 30HP, and a 1500Ah bank to safely absorb it.

[newhaul]

Originally Posted by john61ct

Yes 6HP is a lot, especially in an emergency situation when you need every watt going to the prop.

A switch at the helm killing the alt load is pretty standard, not hard to implement.




My comment about the 200A+ "dream" clearly stated that these were not ordinary alts you could "hold in your hand"

the 14 kW one I'm dreaming of, weighs over 50kg, and that's not counting the remote-mounted VR.

And full output would demand well over 30HP, and a 1500Ah bank to safely absorb it.

that is out and out ridiculous 14kw that is a generator head not an alternator to mount on a sailboat engine .
Get serious . 1500ah Lfp bank you are not going to need more than a 500 amp 24 volt truck alternator.
You really need to learn what you are posting about and the feasibility or it.

[rgleason]

Thanks Gord May, what is our use like Line Tractor, City Tractor, or School bus?


Newhaul, if your use of alt is occasional, 50a x 1.5 = 75a would be a very good improvement, if you intend to use it a lot, you could go up one notch and still not have to change the belt due to the smaller capacity batts and perhaps using belt manager, but it would be more efficient. However keep an eye on the low rpm output and pulley ratios, in each case, if that makes a difference to you.

Originally Posted by GordMay

This white paper might inform the discussion.

“Improving Alternator Efficiency Measurably Reduces Fuel Costs” ~ by Mike Bradfield, MSME, Remy, Inc.
➥ http://www.delcoremy.com/documents/h...ite-paper.aspx

[john61ct]

Originally Posted by newhaul

that is out and out ridiculous 14kw that is a generator head not an alternator to mount on a sailboat engine .

Get serious . 1500ah Lfp bank you are not going to need more than a 500 amp 24 volt truck alternator.

Yes exactly, 28V charging times 500A is 14kW.

[newhaul]

Originally Posted by john61ct

Yes exactly, 28V charging times 500A is 14kW.

what alternator ? The only I know of is the niehoff c803d
(Most common for 24v systems usually top out in the 300 amp range
Most common is like the Delco heavy duty brushless at 275 amps and 19kg weight.
It is also available as a 420 amp 12 volt. )
https://www.google.com/url?sa=t&sour...PiqdkeEXleCasW Pdf of specs

and the big question is what imaginary engine in what imaginary boat?
Or is this just another of your theoretical work ups?

[newhaul]

Originally Posted by rgleason

Thanks Gord May, what is our use like Line Tractor, City Tractor, or School bus?


Newhaul, if your use of alt is occasional, 50a x 1.5 = 75a would be a very good improvement, if you intend to use it a lot, you could go up one notch and still not have to change the belt due to the smaller capacity batts and perhaps using belt manager, but it would be more efficient. However keep an eye on the low rpm output and pulley ratios, in each case, if that makes a difference to you.

That's what I was thinking and the use would be minimal just when the solar is insufficient for several days in a row

[rgleason]

I have not read all the posts on 28V charging times 500A is 14kW.

The only I know of is the niehoff c803d
(Most common for 24v systems usually top out in the 300 amp range

but if you take 500A x 1.5 = 750a, maybe two very big alternators? How about just a generator because it would be much more efficient?

[newhaul]

Originally Posted by rgleason

I have not read all the posts on 28V charging times 500A is 14kW.



but if you take 500A x 1.5 = 750a, maybe two very big alternators? How about just a generator because it would be much more efficient?

that was my thinking as well why not a dc generator they are available much bigger than 500 amp as well but still in a small package . Why reinvent the wheel
https://polarpower.com/marine-dc-generators/#tab-id-5
There are several others out there as well.
Seems like we have had this conversation before .
http://www.cruisersforum.com/forums/...-go-65703.html

[tanglewood]

Originally Posted by a64pilot

You need to realize that 6HP is a huge number.
My 44 HP Yanmar, pretty much the generic average cruising boat motor makes about 20 HP at about 1800 RPM, throw a 6 HP load on top of that and you have increased the load on the engine by 1/3rd, which pretty severely overloads it.
My 3500 W Diesel generator makes only 7 HP as an example.

The idea that you getting 200 amps or 2800 Watts out of a device you can hold in your hand is pretty much a fantasy. It’s doable if you could liquid cool it or maybe liquid cool it and remote mount the diodes, but as is with just the two little fans? It’s not likely.

Actually, looking at a random Yanmar 44hp power output curve, at 1800 RPM the engine has gobs more power available than is being demanded by the prop, and wouldn't be anywhere close to overloaded by adding 6 hp. The only time that extra 6hp demand would push it into overload would be if you were also at max prop load, i.e. full throttle. But if you back off 200 rpm, there is now plenty of headroom for the 6hp alternator load.


And 200A @ 24V, or about 5kw is commonly available in a J180 or pad mount alternator. My boat has two of them. No liquid cooling required, though they do throw off a good bit of heat.


Now I acknowledge that these won't fit on your typical Yanmar sail engine, but they do exist in abundance and are regularly used on 150hp and up engines, and lots of boat have power in that range.

[tanglewood]

Originally Posted by newhaul

that was my thinking as well why not a dc generator they are available much bigger than 500 amp as well but still in a small package . Why reinvent the wheel
https://polarpower.com/marine-dc-generators/#tab-id-5
There are several others out there as well.
Seems like we have had this conversation before .
http://www.cruisersforum.com/forums/...-go-65703.html

Or just an off-the-shelf AC generator powering a charger or two. The key to efficiency in a generator/alternator is to get the voltage up and the current down.

[Q Xopa]

Originally Posted by newhaul

what alternator ? The only I know of is the niehoff c803d
(Most common for 24v systems usually top out in the 300 amp range
Most common is like the Delco heavy duty brushless at 275 amps and 19kg weight.
It is also available as a 420 amp 12 volt. )
https://www.google.com/url?sa=t&sour...PiqdkeEXleCasW Pdf of specs

and the big question is what imaginary engine in what imaginary boat?
Or is this just another of your theoretical work ups?

I have a Niehoff N1603, which is 28A/450A + 14V/50A. They do also make a 28V/575A version in the same case.

I haven't tried, and I guess if youre determined anything could be possible, to hang it off the side of my main 4JH4-TE.

It would take a bit of a belt drive setup, (maybe toothed), with possible crank side load issues.

I have mine coupled directly to the back of my 2YM15 as a stand alone generator.

[Pete7]

Whilst we are discussing alternators, does the air flow from the front 'fan' end to the rear or does it pull air? I have the ordinary square type of fan, just wonder how efficient it actually is at moving air through the alternator.

Pete

[rgleason]

Then there is the small matter of how to tune the prop pitch, because with the 6hp load the engine will be overloaded when in forward gear, which is not good.

Now you need a prop pitch adjuster from the cockpit. This gets more and more expensive.

[rgleason]

Some of the newer Balmar alternators pull air from both ends and discharge towards the middle. I think this design is getting more prevalent.