Real cool alternator

[Damen af Kungsholmen]

I started this project two years ago and tested it last season. I replaced the original alternator of 85 A to one of 155 A but water-cooled, its used in a French car. One alternative are a water-cooled alternator for Bugatti, Audi of 190 A. The standard alternator could not come up to 85 A and it became extremely hot when I charge my Li-Fe battery. That’s a common problem when you replace from lead battery to Li-Fe.

Two problem come up. The power source to the internal brushless water pump stop working. Bad electrical connection. The alternator become hot (65 °C 150°F) and reduced the charging to 15 Amps. Good to know. The multiribb belt was squeaking when charging 195 Amp in the beginning when everything is cool. My wife was literally irritated. Solution was a new bracket and a stretching screw.

Normally are the temperature on my alternator equal as the seawater plus 0,5 °C Delta t are 0,5 °C The engine compartment will remain cool. The efficiency on a alternator are about 50%. (I have measured it up in a test rig) that means heating element of 2500 Watt has to disappear somewhere.



The water pump for the engine are now source by its own belt. Too involved the water pump to the transmission with the alternator are a bad solution. Huge radial forces will appear on the bearing for the water pump. Have the Yanmar engineers designed for that extra radial forces? I am not sure.

I had 3 years ago a tuned alternator with new pulleys and multiribb belt from a US alternator tuning company. Na, I didn’t like that solution at al. The belt was an industrial standard you will never find simply as spare and in limited lengths. The belt passed over the water pump with radial forces. Everything become hot. Heat Is a disaster for lifetime. Why do they cremate people? Its end of life!

Al parts I have used are automotive standard. Volvo, Audi, BMW, Renault alternative Bugatti/Audi manufactured by Bosch, Valeo, Hella. The brackets I made by myself. I have a reduction of 3,15:1 the alternator charge up to 198 Amp idling in the beginning, when everything is “warm” then It charge only 140 Amp, still when motor are idling at 850 rpm. Al the current are charging my Li-Fe bank from Victron of totally 540 Ah. The starter and bow battery Optima 75 Ah each I charge throw two smart DC/DC charger sourced from the Li-Fe bank. Notice, the cooling liquid for the alternator are its own system and are NOT involved to the cooling system for the engine. The engines cooling system are too hot to use and will reduce the charging Amp drastically. I use a heat exchanger, well-known brand, sea water/water. Used for marine transmision like ZF.

A sneak peek how it looks like when it’s running.



I made the same solution to my brother’s Beneteau 55 last year. It works excellent. However, on his motor I did not replace the original alternator. I added up the water-cooled alternator. He got 400 Ah and 1.000 Ah Li-Fe. Totally 1.400 Ah only for household. Then he have several Optima 75Ah for thrusters. He charge them true 6 Victron 230VAC charger one each/battery sourced by the inverter. To extend lifetime of the battery when you have 24 volt system charge by using 2x12 volt to reduce skew charging, otherwise one battery will be killed.

Looking forward for another season with a lot of Amp hour.

[Charlie-Bravo]

And there was I feeling smug that my little solar panel was keeping the fridge and beer cool ! I can only dream of running a toaster and a coffee machine.

I am impressed with your good work.

CB

[Damen af Kungsholmen]

Thank you CB

Many hours of brainstorming. Got some help from my 10-year-older brother who likes new solutions that drive development forward. We discussed assembling a genset. My employer has the agency for genset in Sweden, the right price was possible. We saw no benefits with another engine humming at 3,000 rpm that requires service and maintenance.

The new alternator cut down on the charging current when it got hot in the electronics. Picked out the alternator last winter and put a fan that forced the cooling on the integrated charge regulator. Got just over 30 Amp extra in charge this year. It is very important to have a large dimension on the cable from the alternator and also from engine to the batteries. My alternator are connected with 85 mm² cable and the earth cable also. It is not so interesting to see how much power we consume. If necessary, I start the engine idling for a while. When my wife is going to buy a new household appliance, she wonders if the inverter will be able to handle the effect. The inverter is 1600 W.

The latest appliance is a baking machine. Waking up to freshly, baked bread in the boat is quality of life. Unfortunately, I am not allowed to buy a Jura coffee machine for her. May I settle for a Nespresso capsule of coffee and an electric egg cooker for the freshly baked bread. Mother-in-law demands toast the times she accompanies. Of course, we have a toaster on board. But the absolute best was when I installed the dishwasher last year. Getting rid of all the dishes at once is wonderful. Have shown it before in the forum.

If I have new projects underway? My wife tells me that I have to calm down with new projects so I do not tell here everything what is going on in my head!

Picture showing my brother design of brackets in acrylic to investigate if it will fit. Alternator with a fan. It was no fan incorporated in the alternator.

:-Dan

[Damen af Kungsholmen]

Hi all Jeanneau friends

While my "Damen" (Lady in Swedish) is standing secuerly on land I have to do something so to calm down my abstinence untill she are back to sea. I have build a test bench for alternators! I am obsest of alternators! Dont ask me how many alternator I got and how many I have burned, but they are several. I prommised my older brother to equiped his Benneteau 55 with two alternators and charging about 400A at idling and running at 1200 rpm like 500A. He have 1400Ah LiFePO4 to charge.

I have replaced the original diodes in the alternator from 50A to 70A. Last time at New Year eve I reached 307,5Amp but I think I was magneticing the rotor! Strange noice was coming out from the alternator.

When we are charging LiFePO4 batteries we need a special regulator. The original regulator are for leadacid accumulators. Later on I will come back how we have solved this topic. As you could se on the picture are the alternotor freezing cool 25C compared with tuned alternator that used to be 140C
I am trying to keep the smoke inside the alternator and not to leak out.
Untill now I am saticfied. 








 

[mario421]

Very impressive installations.

Before to go to a water-cooled alternator, did you test some external regulators like Mastervolt Alpha Pro III or BALMAR MC-614 or equivalent, which take care of the temperature of the alternator?
I am sure these external regulators are not as efficient as a water cooled alternator, but they represent a much easier solution if indeed they increase the output of the alternator.
JM

[loredo]

I can partially answer your question.  I just dumped the Alpha Pro III in favor of a Wakespeed 500.  Never been able to get the Mastervolt to do what I needed.  Once I installed the WS I got 70 Amps at idle whereas with the Mastervolt never more than 15-ish.

My advice would be, anything but the Mastervolt. YMMV...

 

[Damen af Kungsholmen]

Hi Mario421 and Loredo



They are several simpler ways to get more amp out from your alternator, but you will reach a maximum level. I have something that has far higher performance and cooler that can run for hour on full performance.

I have not tested those external regulators you mentioned. I want to have something better and can handle my type of alternator. It’s extremely simple to regulate the output from the alternator. I have done several tests. The thing whit standard alternators are that they will be overheated at low rpm when you charge higher amp. The internal fan is not cooling down enough. You can see how the smoke is leaking out. And when the smoke has come out then the alternator doesn’t work anymore.

Another effect is that the tension belt doesn’t like to run at low rpm. A standard V-belt will slip and fail in a short time at low rpm. The cooling effect are tens of times better with cold water then air. That’s why I can charge close to 200Amp when idling. When idling is not the peak point efficiency for the alternator. Charging 200Amp and 13,5 volt means a heating element of at least 2700 Watt you must cool down. Its less the 50% efficiency on an alternator. This lost heat you must bring out in an extremely small and well isolated compartment. Heating element for a sauna are typically 5-7,5kW. Look on my IR camera you can see that the alternator is dark blue.

Those brand that has tuned alternators with external regulators. What I have understand are they lowering the output when they got to hot to save the smoke inside the alternator so it will not leak out and not work anymore (what I have seen on YouTube) but I can be wrong.

My goal is to charge even faster then the last four season. But al reader. LiFePO4 accumulators are I only talking about to charge. Something that was int the past doesn’t interest me at all to charge. Lead you could have in the keel, not for absorbing energy.

[loredo]

Damen,

the Wakespeed regulator does indeed monitor the alternator temperature.  I've set mine to reduce charging @ 80 C.  Thus far, I've not yet seen kick it in. Sure it's winter and cold which of course helps with the temperatures in the engine bay.  My alternator is a Mastervolt 75A @ 24V.  I will see how things evolve once summer comes.

I'm charging LFP too but a bit more than yours (1680AH @ 24V).  For my cruising style, I think I've got enough power from the alternator.  Another reason I've chosen to not go any further with charging sources is that the single cell voltage does spread a lot under very strong charging levels. Then the BMS has to kick in which leads to another level of complication.  Something you might consider too?

Loredo

[Damen af Kungsholmen]

Hi

All on this forum have an ocean around our loving yacht. Why then cool down our alternator by hot air?

I build a testbench this winter to get answer of many question that appears when you charge closer to 300Amp. I got answer of mostly any question and of course all doubts.

The testbench consist of a 10 horse power 3phase 4 pole engine and a frequency inverter.

I find out that Balmar and Wakespeed can do the job to regulate my alternator. I have tested the Balmar MC-618 (I got 3 of them to test different solution also the twin alternator regulator). The load was 400Ah LiFePO battery and fifty H3 55Watt bulb as load of 2700Watt.

Charging 270 Amp the alternator reaches a temp below 40C and the rectifier 50C.

Slipping on the belt? No

The tuning company for alternator has a solution where you still have the same angel of wrapping around the pulley on the alternator as original. It will create a heavily radial load on alternator and water pump. I have increased that angel by more than 50% on the alternator. Water pump are close to zero radial load by a separate fanbelt.

I have also tested to boost the alternator. Give more than 14 volts for magnetizing the rotor winding when idling. No problem with enough wrapping around the pulley. I have also tested different ratio on the pulley.

I have been looking for hot spot by using a Flir camera. That was interesting. Just by adding a small aluminum tube on the alternator on a critical part and lowered the temp from 170C to 80C on that part. Also, it’s easy to see if the belt got stressed.

How many rectifiers I have blown up? Many and some more.

The pictures are showing the concept but not everything. Some minor but important part is missing. Those part will be water cut this week. When everything is mounted, I will come back.

From the alternator comes 3 cables that are 25 square mm each to the rectifier. Of course, will the rectifier be water cooled as on my testbench. I have also tested to “cool down” the alternator by using hot water from the tap in the garage until all hot water run out in the water boiler.

Alternative is to have a gen set that could full filled many dreams. That’s not mine 😊

[Damen af Kungsholmen]

At this level the motor was to week for testing!

[Trevor]

What a great write up about a wonderful topic posted by Damen af Kungsholmen.

Many thanks. While away cruising I was too obsessed with my alternator performance. I only had AGM batteries but wondered why I couldnt get my alternator to charge at higher current. I made a small box which allowed me to change the excitation current of the alternator. It was simply a couple of parts consisting of a potentiometer and a high current transistor that could simply control that current. I experimented and came to the conclusion the internal resistance of the AGM bank simply reduced the charging current no matter what I did.

I changed to Lithium and swapped out the alternator to a 120 Ah Balmar 6 series, and the MC614 external regulator. It worked ok but no charge at idle. I then changed the alternator pulley (supplied by Balmar) to a smaller one to increase the alternator revs at idle. It improved thangs a little but not enough. I then replaced the belt with a serpentine belt and that is a wonderful kit. I still dont have much charge at idle but if I lift the revs to about 1200rpm things improve immediately. I can charge when cold at about 95 amps. The overtemperature protection is a simple temperature sensor on the alternator body which reduces alternator current to 50% if the temperature goes over 100 degress C. I must say that the support given by Balmar has been very impressive during my experiments.

Water cooling certainly presents a great way to get serious about higher charging currents. I have 400 Ah of Lithium and 654 watts of solar and that allows us to live on the boat if we wish without being too concerned about power. We have a 1800 watt inverter and do run a microwave sometimes but the solar is the best thing we have ever done regarding being able forget about power consumption.

Many thanks for sharing the water cooling method of getting more out of alternators and I am so impressed with the very professional modifications to the original configuration.

Regards,

Trevor

[Damen af Kungsholmen]

Thnx Trevor

[rene460]

Thanks Dan and Trevor and all the other contributors for such an interesting and informative thread.  It has been informative reading from the start.

 We are often told about the advantages of weight and capacity of Lithium batteries and the need for special charging systems but the issues involved in charging them from the engine alternator is not often discussed in such detail.  

I must admit to finding alternators a bit of a black art even for lead acid batteries, and it is refreshing to have some of it described by experts in such an interesting way.

Mind you, I think I will still have to wait for a plug and play solution.

Can I ask what happens on a longer trip when the batteries become fully charged?  Do the regulators just scale back the output some how?  

rene460

[Trevor]

Hello rene,

Sometimes electricity follows a simliar analogy to water flow. Let's start with water tanks and move onto lithium batteries. Stick with me here.

Lets say for our method of thinking that water pressure equates to voltage. A water tank that has lots of water in it exerts a lot of pressure on the tap at the bottom of the tank (high voltage).
Let's say that water flow, the amount of water flowing out of the tap is analogis to electrical current.
Let's say that the amount the tap is turned off is analogis to electrical resistance.

If the tap is wide open the resistance is small and the water flow is very high (high current). If the tap is turned off a little, the resistance is high and the water flow is reduced (lower current). If the tap is turned off the resistance is extremely high (no water flow - no current).

1. Imagine I have two water tanks joined at the bottom of the tanks by a thin hose. The tank to the left has lots of water in it (High pressure - high voltage) and the tank to the right has not much water in it (low pressure - low voltage).

2. Water flows through the thin hose from the full tank to the empty tank. Eventually the level of the water equalises so the same level of water is on both tanks. I could say current flows from the full tank to the empty tank until they have the same voltage. When they are equal no current flows.

3. Now we can increase the size of the hose joining the two tanks. If the hose has a larger diameter the water flow (current) is larger and the two tanks equalise faster. The same result occurs but it happens much faster.

Now lets not talk about water tanks but talk about charging devices (solar regulator, alternator, mains battery charger, etc) and let the charging device take the place of the left tank.

Let's also talk about a battery taking the place of the right tank.

When the battery (right tank) has the same voltage as the charger (left tank) no current flows. If the charger has 14.1 volts, and the battery is 14.1 volts, no current flows.

Now lets talk about batteries.

If we compare AGM or Lead Wet Acid batteries to Lithiums, they have the equivalent of a thin hose (or a tap half turned off) internally meaning the time taken to charge no matter how big the charger is longer than lithium. In electrical terms we could say "AGM batteries have a higher internal resistance" than lithium.

Lithium have the equivalent of a very large hose (or tap fully open) meaning they can charge very quickly if the charger can supply the current. We can say the "Lithium batteries have a very low internal resistance".

In all cases when the battery voltage is the same as the charger voltage, no current flows.

Ok, so why all of the complexity of external regulators for alternators etc. Well batteries need to treated in general with some respect to provide optimum life. Some chargers have what is known as "three stage charging". Some are more complex but let's just examine the three stages of three stage chargers.

1. Bulk stage....put as much current into the battery as possible ( or as recommended) until the voltage reaches a certain level.
2 Absorption stage...maintain that voltage level for a certain period of time and eventually the current will back off to very little. (when battery is full and its terminal voltage equals the charger voltage)
3. Float stage.....reduce voltage of power supply and let the battery terminal voltage sit at a slightly reduced voltage long term.

The external regulators control the excitation current in the alternator using programmable software to allow these charging stages to be provided to the precious house batteries to give them optimum life. They may also sense a temperature probe on the alternator body to reduce the excitation current in the alternator if the alternator overheats (remember lithiums have low internal resistance and may keep the alternator running flat out (maximum current) for an extended time and this may cause the alternator to cook).

I hope this answers some questions about battery charging. Please relate it back to water flow if that helps. It is an almost prefect analogy and I know this stuff can sound complex but the water analogy can bring it back to simple common sense thinking.

Trevor

[rene460]

Hi Trevor, thanks so much for taking the time to post such a detailed and helpful explanation.  You have filled in many gaps for me, and joined the dots where I had not understood some of the connections.

I presume the conventional alternator normally supplied with the engine achieves adequate regulation for lead acid batteries utilising the internal resistance of the battery and alternator speed.

Rene460

[Damen af Kungsholmen]

Thnx Trevor for a simple and correct description about different stage of charging.

LiFePO4 are so much easier to charge compared to lead.

I have been using Balmar new regulator MC-618 that can take care of all different types of battery, by program it correctly and you can also adjust al the parameters if needed.

Below I will share a document of my test of the performance from an alternator. The internal regulator is removed. The rectifier diodes are removed. They can’t handle the current during a longer test. A bigger external rectifier bridge that are water cooled can handle the current I am applying.

Then the interesting thing are, how many amp is the alternator producing.

It depends on two things. The rpm and the voltage that you supply to the rotor windings (also the load, but I will not show this now, too many facts and thinking in 3 dimensional). As load I have used 3x100Ah cheaper LiFePO4 from Amazon and 50 pcs of 55 watt H1 bulb total 2700 Watt.

I have done this test by applying different voltage to the rotor windings and fix rpm.

As you could see if I apply 13 volt at 750 rpm (have in mind that the ratio between the motor and the alternator are 2,22:1 ( 1 rpm on the motor will be 2,22 rpm on the alternator)) then I got 137Amp by idling. 900 rpm I got 192 Amp.

I think this is a dream for many sailor?

Temperature are not 95C like other alternators, its more 30C.

Please enjoy hundreds of hour by different performance test during this winter.



Note, i have used a adjustable power supply for this test

[Damen af Kungsholmen]

Hi all Jeanneau friends around the world 😊


Last weekend I spent in Stockholms archipelago for the first time with my new alternator.

I had some minor fault (done by myself) but now its up and running. The Balmar MC-618 works excellent together with my alternator concept. The result Is better than I expected it would be. The regulator is programmed for a soft start so no field to the alternator will be applied the first 60 seconds. At idling and no load, the engine run 750 rpm. When the regulator starts to regulate it’s a ramp up to 105 Amp and my engine (Yanmar 4JH5E) go down to 680 rpm because of the load. Rice it up to 878 rpm I got 177 Amp and at 1369 rpm 224 Amp. By 986 rpm it charges 200 Amp. When propulsion for over an hour at 1370 rpm and charging 225 Amps the alternator temperature reach about 38 °C 104 °F and the rectifier 42 °C 108 °F

I forgot the Flir thermography camera to check hot spot. But it will come a next time soon.

Everything seems to be a verry well balanced system with no heat or stress on any parts.

This week I will install the same system in my brothers Benneteau 55 but he will have two alternators. I will come back with the result after this installation.



Its very simple to reduce the charging if I need more propulsion power in narrow water. Simply by short the temp sensor the regulator reduces the field to 50%, or if I don’t want to download by idling that much.



:-Dan

[Trevor]

That is very impressive. Thanks for sharing all of that. It is great to see some well implemented engineering improvements as in this era of lithium batteries that can actually accept that level
of charge current until they are full. Brilliant.

[Damen af Kungsholmen]

Last night I started upp my "iron sail" and toke a video.

I think this is what many want to charge when you have LiFePO4 battery bank.
The temp is about 36C after a while inside the alternator.
Also video after installation in my brothers boat.

Lack of time but I will replace his 125A aircooled alternator later.
Enjoy

[didouan]

Hi Damen (or anyone else in the know?!)

Top job with your alternator.

I'm half way through installing a Valeo 155amp water cooled alternator.

Do you know if and how much more performance you get cooling at sea temperature rather than engine temperature?!

Thank you!