Water cooled, high amp 12v alternator

[CeesH]

I want to fit a 200 amp additional alternator to charge a 800 ah bank. The small engine room gets already very hot and i expect that after a short time the alternator regulator temp. control will bring down the current.

Searching the net i found out that Mercedes, Audi, BMW and other use water cooled alternators on their high-end models. They are rated for 150 to 200 A.

Has somebody experience using them on a marine engine?

PS. Pictures are from a Landrover 150A water cooled alternator.

CeesH

[belizesailor]

Interesting -- never even seen such a beast on a boat.

[daddle]

You'll want to check with the engine manufacturer if the front main bearing can stand up to the side load induced by the greater horsepower load of that alternator. Or use a toothed belt. Or who knows? It can be a problem.

[capn_billl]

WOW, good find!

If you're worried about the side load, put on two, one on each side. I'll have to look into one of those, the one on the right looks kinda bronze-ish?

[CeesH]

Originally Posted by capn_billl

WOW, good find!

If you're worried about the side load, put on two, one on each side. I'll have to look into one of those, the one on the right looks kinda bronze-ish?

The left one has a fixed pulley, the right one has an electro-magnetic pulley.

You cannot use these animals to replace the existing alternator, this will destroy the bearings of the water-pump. I want to attach one alternator and the pump of the watermaker as shown on the pic. I have a similar creepy engine room.

[Kettlewell]

What kind of cooling system will you have for the alternator coolant? You will need some special belts, or maybe a serpentine system to drive it. That seems like a lot of added complication.

[CeesH]

The Watermaker and the high Amp alternator will run at the same time, both controlled with an electro-magnetic pulley. This to put enough load on the engine. This gives the possibility to take the alternator cooling water through a restrictor from the watermaker boost pump.

CeesH

[Cheechako]

Wow... been waiting for someone to make one of these for years! Thought about winding copper pipe around one once, but decided it was too messy.

[Kettlewell]

This gives the possibility to take the alternator cooling water through a restrictor from the watermaker boost pump.

Isn't that going to be seawater? I doubt the cooling jacket on that alternator will be up to handling saltwater corrosion.

[guyfromiowa]

This is something that I know about from first-hand experience. A few things to consider are that 1; you should expect to use a multi-rib belt. The 'serpentine' belt can transfer more power than a v-belt at the same belt tension. Less slippage and less side loading. 2; many modern alternator systems use an alternator decoupler to smooth out the pulses and reduce vibration, (and attendant damage). This links to a short video from Youtube.com that demonstrates the vibration reduction from usage of the decoupler.

Solid Pulley vs OAP vs OAD - YouTube

Yes, you will have to re-engineer the belt drive system to use a liquid-cooled alternator, but once the parts are sourced the rest should fall into place. These alternators are not 'direction sensitive', spin them either way, no cooling fan. And the coolant will have to be antifreeze/water mix, no raw water, so the water pump and cooling system on the engine will have to carry that load as well.

Guy

[guyfromiowa]

The 'decoupler' is also known as an OAD, (overrunning alternator drive), it is used instead of a solid pulley. Automotive manufacturers have been using these things in increasing numbers for the last ten years or so. OAD systems make it possible to use lighter bracketry because of the lower vibration forces. In turn, that allows less weight and better fuel efficiency. Vibration actually can consume power from the engine, but THAT is a whole 'nother discussion.

Guy

[sailorboy1]

interesting, but wouldn't putting some blowers in the engine room be less trouble?

[Ian R]

Steyr IFG (integrated flywheel generator ) are water cooled, 4 kW output, 14,28,110 or 220 volt and only about $9,000 au (generator only )
Ian

[capn_billl]

Originally Posted by CeesH

The left one has a fixed pulley, the right one has an electro-magnetic pulley.

You cannot use these animals to replace the existing alternator, this will destroy the bearings of the water-pump. I want to attach one alternator and the pump of the watermaker as shown on the pic. I have a similar creepy engine room.

Is it really THAT bad, I calculate 5 HP max. 200amps * 12volts / 745watts per HP.

There are other loads that are in excess of 5HP on belt pulleys.

[bluetriguy]

I have a land rover with the alternator on it. The tubes are stainless but to try and use saltwater would be nuts.
I agree with capn_bill - try the obvious first install larger vents in the engine space - perhaps use a forced air type (assuming this is a diesel install ). Try taking the temperature of the space after running the engine for an hour - get a sense for what the 'real' temp is. Humans complain about heat long before engines do. What seems hot may not be. My landrover sits in the sun in Arizona all day and even the passenger compartment goes above egg frying temps in the summer - yet the water cooling on the alternator actually only cuts in if I run the engine while sitting still for over an hour. The temp in the landrover compartment is +210F (measured).
Of course that's a DRY heat... (that's an arizona joke) :-@