Alternator Cooling

[goboatingnow]

The actual diodes can be any suitably rated rectifier types , either regular or avalanche , since the distance between these and the coils will be short ( < 1m ) the wire can be rated accordingly. Big diodes are available from any major electronics components company.

Diodes are incorporated into the alternator body for several reasons but mostly cost.

It’s a task but not a particularly difficult one if you know what you are doing

[Sam Woodbridge]

Sailing Harry, I didn’t read every post in this thread. But I was facing a similar problem months ago. I had a hitachi alternator that over heated. I too was focused on cooling fans or something to keep the heat down. Until I started asking around on the forums. I fixed my problem by going to a Balmar alternator. In my reasoning I’ve felt most alternators are designed to charge a battery, but not several as in a huge house bank, starter, bow thruster ext.

Good luck I know your frustration

Sam

[jt11791]

Asking the squirrel in your 1GM10 to also charge your lithium bank is likely to bring PETA to your doorstep.

[sailingharry]

Simply being lithium doesn't automatically make insane charging currents. On his 27' boat, he's likely to have well under 200Ah of battery -- so even on lithium, he'll be happy to see 50A of charging. The battery won't take more than maybe 75A even if he could generate it.

[Sternwake]

As for ducting, here is the search terms you want:

Aluminum Carburetor Preheater Hose

DELTA fan model AFB0612DH-9C45

NIDEC fan model V80E12BGA7-07-T35A1

these high 60 and 80 mm fans move surprising amounts of air, at an almost a ridiculous velocity.

I intend to force feed the backs of my Vehicular alternators with the 80mm Nidec, splitting its the flow into two 1&3/4" hoses, perhaps activated with a 140f snap switch.

E bay links seem pretty temporary, but I have two of these:

https://www.ebay.com/itm/11457906377...gAAOSw0dVf2q2X

Gotta be careful stretching them to their 36" length, as they come compacted to about 14"

The Nidec fan, I remove the impeller, and seal the sides of the circuit board with Amazing goop, and lift the sticker where the wires enter the hub and seal that area too.
If untreated the solder connections at circuit board at hub will grow green and rot off.

[PaulCrawhorn]

Originally Posted by pcmm

conventional wisdom is it takes 1hp per 25amps to generate.

3 - 3.5HP per kW with IRL German gensets

but varies a lot, some claim 2-3

[PaulCrawhorn]

Originally Posted by sailingharry

Simply being lithium doesn't automatically make insane charging currents. On his 27' boat, he's likely to have well under 200Ah of battery -- so even on lithium, he'll be happy to see 50A of charging. The battery won't take more than maybe 75A even if he could generate it.

No, only with a drop-in with current limiting circuitry.

3C and higher is a normal draw from raw cells, quality low-resistance prismatics

A DCDC charger or current-limiting VR is nearly always required.

[DougR]

[QUOTE=sailingharry;3565549]Interesting thought you bring up about engine air flow. The 4JH2E is about 120 Cubic Inch. At 3000RPM, that's about 200CFM -- or about what the biggest Jabsco blower can do.


The 4JH2E is a four stroke engine, so any given cylinder pulls air into the engine only every other revolution. The air flow into the engine in a naturally aspirated engine is displacement x rpm/2. So the air flow at 3000 rpm is about 100CFM.


I might suggest that you source a magnehelic gauge or a water column tube and a simple remote thermometer and measure the actual depression in the engine room at full load RPM and the air temp in the vicinity of the alternator (and the air cleaner as well). These are the basic tools of a marine engine applications engineer and can tell volumes about the ventilation system design on your vessel. It could be eye opening.....

[Thumbs Up]

Ducting routed to deliver fresh air behind each alternator is all you should need. No need to force feed it. As long as the engine room is fairly tight. All about how you direct that air. Anyone try liquid cooling?

[SOLAR SUPPORT]

I installed two thermostats on my Mitzi 115A Alternator which has an internal regulator. Both operate at the same temperatures around 70°C. The normally closed ends of the thermostat work as a switch connected to the pair of wires coming from the rotor warning brush of the alternator. When the alternator temperature rises by 70°C, the alternator cuts off its charge. In this way, the alternator temporarily interrupts charging and cools itself in a short time thanks to its own internal fan.

The second thermostat is normally open. When the alternator temperature rises above 70°C, it activates the high speed two-stage powerful fan placed on the alternator. This fan draws 4A current, @12. 5V, so the power of the fan is 50 Watts. While the internal fan of the alternator is cooling, this fan is also activated and allows the alternator to continue charging in a shorter time.

Fan video link:

https://youtube.com/shorts/0T6lpEUAv50

Alternator rotor excitement modification details can be found under this thread :

https://www.cruisersforum.com/forums...es-259773.html

[rgleason]

Possibly recirculate or pull fresh air down along the hull or upper keel to cool it down, if you are not in the tropics. Perhaps draw cooler keel air up into the engine if not laden with salt.

[hjohnson]

Originally Posted by sailingharry

Simply being lithium doesn't automatically make insane charging currents. On his 27' boat, he's likely to have well under 200Ah of battery -- so even on lithium, he'll be happy to see 50A of charging. The battery won't take more than maybe 75A even if he could generate it.

I’ll actually have 460Ahr of LiFePO4.

But that said, the alternator is going to be controlled by a Wakespeed WS500, so I can derate the alternator as required. My use case is primarily long weekend getaways, with the occasional 7 to 8 day trip.

The plan is to Leave the dock with a fully charged battery, and supplement with the engine as a range extender. I don’t expect the engine to bring the battery back up to full charge except on very long motor runs (say motoring up/down Jervis Inlet).

[sailingharry]

Wow. I'm impressed! On our 43' that we cruise for months with minimal to no shore power, we have 800Ah of AGM, useful around 400. That runs the fridge, freezer, TV each night, Mr. Coffee every morning, diesel heater, and all the other loads. But the engine isn't a "range extender" -- it's a mission critical electric source! LOL. But at the cost of LFP, especially if you can DIY with prismatic cells, it's tempting to go high - and in your use, the returns are significant.

[kapnd]

Originally Posted by SOLAR SUPPORT

I installed two thermostats on my Mitzi 115A Alternator which has an internal regulator. Both operate at the same temperatures around 70°C. The normally closed ends of the thermostat work as a switch connected to the pair of wires coming from the rotor warning brush of the alternator. When the alternator temperature rises by 70°C, the alternator cuts off its charge. In this way, the alternator temporarily interrupts charging and cools itself in a short time thanks to its own internal fan.

The second thermostat is normally open. When the alternator temperature rises above 70°C, it activates the high speed two-stage powerful fan placed on the alternator. This fan draws 4A current, @12. 5V, so the power of the fan is 50 Watts. While the internal fan of the alternator is cooling, this fan is also activated and allows the alternator to continue charging in a shorter time.

Fan video link:

https://youtube.com/shorts/0T6lpEUAv50

Alternator rotor excitement modification details can be found under this thread :

https://www.cruisersforum.com/forums...es-259773.html

This is a very insightful solution!
All the other suggestions for air cooling are actually heating the air that the engine breathes, further degrading its already taxed capabilities.

[hjohnson]

Originally Posted by PaulCrawhorn

No, only with a drop-in with current limiting circuitry.

3C and higher is a normal draw from raw cells, quality low-resistance prismatics

A DCDC charger or current-limiting VR is nearly always required.

Yeah, that's why I've purchased a WS500 regulator to control the alternator. I can dial the power out of the alternator to pretty much whatever I like. Run it hotter when possible, dial it back when I need the power on the prop.