Water cooled, high amp 12v alternator

[Dan Kimblad]

Originally Posted by skipperpete

Hi Dan, well done. Did you use raw water for cooling or fresh? The YouTube vid didn’t work on my iPhone but I’ll try later with a desktop.

Hi Pete
Thnx. I have spent about 200 hour last winter. Built my own test bench with a 10 horsepower 3 phase engine and a frequens converter. I have used 5 x 100Ah LiFePO4 battery only for this purpose and a load of 50 x 55Watt H1 halogen bulbs.

The cooling system have its own heatechanger and bruschless pump that circulate the water only to the alternator. The heatexchanger is in line with the coolingwater to the engine.

[Dan Kimblad]

Originally Posted by Cheechako

but.... what was the battery temperature !? Most hi output alternators shut down due to battery temp, not alternator failure...

Hi Cheechako
I charge LiFePO4 battery. They will not be warm, but lead battery will be warm.
A standard alternator are build for lead normaly. When you charge LiFePO4 you will have a overheated alternator instead. Please look at this link and film.
https://www.victronenergy.com/blog/2...rging-lithium/
I have a Flir thermo camera to controll the heat. The battery doesnt make any sign of heat at all when I charge like 250Amp to a bank of 500Ah LiFePO4

[Dan Kimblad]

Originally Posted by SailingHarmonie

Just because many people here haven't heard of water-cooled alternators doesn't make them especially rare or exotic.

I have a WhisperPower DC generator with a water-cooled permanent magnet alternator that outputs 150 Amps at 24DC, 3.6 kiloWatts, way bigger than most drive engine powered alternators. The big benefit here is it can run at full rated output for as long as needed without ever overheating. It is cooled with the engine coolant, so it runs at a steady ~80C or so. It also does all of its rectifying and voltage control in an external box, although that heat load is not large. Not really any different than a similarly sized line-powered battery charger, which is basically what it is.

Permanent magnet alternators are more amenable to water-cooling. The magnets themselves don't really generate heat, they are on the moving rotor, so you can just let them spin and not worry about cooling them. You just cool the coils on the stator where the heat is coming from. A permanent magnet alternator is also MUCH more efficient at converting mechanical energy into electrical power, so there is significantly less waste heat to start with.

A field coil alternator makes a significant amount of its waste heat in the rotating field coils. Those can not be (easily) water cooled, so you still need to blow air through it to keep them from melting down, and that partially defeats the purpose of the water cooling.

Hi SailingHarmonie
Con gratulation that you have the best genset on the market. WhisperPower.
The company I am working for have the exclusive rights for that brand in Sweden.
But please, consider those yacht owners that hasn’t the space for a genset or money for it, what is the best alternative?
My concept is not directly uniquely but it’s a big different with a fan cooled alternator.
To understand everything, I build my own test facilities for alternator. It’s a 10 horsepower 3 phase 4 pole 400 volt ABB engine controlled by a Hitachi frequency inverter. Only for testing and load I bought 5 x 100Ah LiFePO4 and 50pcs H1 55 watt halogen bulbs, totally 2700 Watt as resistive load.

How much are the moving rotor consuming? Its only 4,5Amp that means 60 Watt. Those 60 watts are the only heat that the internal fan must take care of. Those 60 watts are the extra heat in the motor accommodation.
When the alternator windings are water cooled it doesn’t melt down at low speed. (Balmar need a massive air flow to keep it “cool”. That means Balmar can’t produce a lot of amp at low speed).

My alternator runs at steady temperature of 42 °C (internally heat) for several hours at 1500 rpm and charge 225 Amp. That’s 3.15 kW.
I used a Flir thermo camera to find hot spot. For example, just by adding an aluminum tube over the existing steel bar where the positive are connected on the alternator I reduced the temperature from 180 degree to 90. It was a massive resistance loss on that steel bar when 240 amp was passing throw.

Since 1989 I have work as sales engineer with al kind of small electrical motors but the last 25 year mostly only with PM motor, and I love my job. Lately I have been obsessed of alternators! Its same as motors but run it backwards.
I started up this project 2019 with a smaller water-cooled alternator. I have built the same concept in my brothers Benetau 55. Later he will have two modified alternators. Totally 6.30kW
https://www.youtube.com/shorts/MQ-vAkQmICg
How many alternators that I have destroyed, and rectifiers? They are several and some more. But by try and error I have learned so much and still learning.

[CapsizedVeteran]

Originally Posted by Dan Kimblad

Hi SailingHarmonie
Con gratulation that you have the best genset on the market. WhisperPower.
The company I am working for have the exclusive rights for that brand in Sweden.
But please, consider those yacht owners that hasn’t the space for a genset or money for it, what is the best alternative?
My concept is not directly uniquely but it’s a big different with a fan cooled alternator.
To understand everything, I build my own test facilities for alternator. It’s a 10 horsepower 3 phase 4 pole 400 volt ABB engine controlled by a Hitachi frequency inverter. Only for testing and load I bought 5 x 100Ah LiFePO4 and 50pcs H1 55 watt halogen bulbs, totally 2700 Watt as resistive load.

How much are the moving rotor consuming? Its only 4,5Amp that means 60 Watt. Those 60 watts are the only heat that the internal fan must take care of. Those 60 watts are the extra heat in the motor accommodation.
When the alternator windings are water cooled it doesn’t melt down at low speed. (Balmar need a massive air flow to keep it “cool”. That means Balmar can’t produce a lot of amp at low speed).

My alternator runs at steady temperature of 42 °C (internally heat) for several hours at 1500 rpm and charge 225 Amp. That’s 3.15 kW.
I used a Flir thermo camera to find hot spot. For example, just by adding an aluminum tube over the existing steel bar where the positive are connected on the alternator I reduced the temperature from 180 degree to 90. It was a massive resistance loss on that steel bar when 240 amp was passing throw.

Since 1989 I have work as sales engineer with al kind of small electrical motors but the last 25 year mostly only with PM motor, and I love my job. Lately I have been obsessed of alternators! Its same as motors but run it backwards.
I started up this project 2019 with a smaller water-cooled alternator. I have built the same concept in my brothers Benetau 55. Later he will have two modified alternators. Totally 6.30kW
https://www.youtube.com/shorts/MQ-vAkQmICg
How many alternators that I have destroyed, and rectifiers? They are several and some more. But by try and error I have learned so much and still learning.

Bringing back a slightly old thread to hopefully ask Dan a few questions! I'm currently adding a liquid cooled alternator to my Yanmar as well, albeit with a slightly different setup. I'm curious both what voltage regulator you are using and if the alternators you are using are brushed or brushless?

Thanks

[CapsizedVeteran]

Originally Posted by SailingHarmonie

This might, or might not, be of use in this discussion, but here it is:

Our “generator” is actually a DC generator. A diesel engine spins a permanent magnet alternator, and feeds an external controller that rectifies and controls that power. This is a 150A @24V unit, or about 3.5kW

A permanant magnet alternator is WAY more efficient than a field coil alternator at converting mechanical energy to electrical energy, so there is a lot less waste heat to start with for the same output.

Since the rotating parts are simple permanent magnets, there is no need to cool them. The cooling of the non-rotating coils is now easily done with the same cooling circuit as cools the engine. No air cooling is needed at all, so a sound shield can be designed to be really effective. The engine room does not get nearly as hot. All is good.

We have been running this system for several years, and would never go back to the old AC generator.

There are a few PM alternators, but I have never needed to do a deep dive to see if they are easily retrofitted on a drive engine.

Cool story about your PMA... Glad you're happy with it. It's definitely not related at all to the specific questions I asked Dan though.

[Dan Kimblad]

Originally Posted by CapsizedVeteran

Bringing back a slightly old thread to hopefully ask Dan a few questions! I'm currently adding a liquid cooled alternator to my Yanmar as well, albeit with a slightly different setup. I'm curious both what voltage regulator you are using and if the alternators you are using are brushed or brushless?

Thanks

Hi
Its a brushed alternator from Hitachi. You can use any kind of a smart regulator. I have beeing using a Balmar MC-618 In two weeks I will receive a Wakespeed 500 It will be interesting to test this one. I have tried a regular PWM speed controller for PM motors. That works eccelent also but then you can overcharge and make stupid things. Strongly recomend this only for a controlled testing of the setup before you connect your smart regulator.