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Old 22-11-2017, 07:01   #31
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Re: Water cooled, high amp 12v alternator

Is a water cooled alternator that runs at 180 to 190 F much better than a hot rated truck or school bus alternator? Delco rates their line of HD truck alternators at 225 F. Seems like a solution looking for a problem.

I used to have problems with the front brake rotors on my truck until I ran a 3" hose from the grill to the brake caliper/rotor...problem solved. Sailorboy suggested the same here. Just get the outside air forced to the back of the alternator should help a lot. Also, if your really making big amps get the bridge rectifier out of the alternator and mount it on an aluminum plate. That will remove more than half of the waste heat from the alternator. Go to the Wind Blue website and read about remote rectifiers. WAI/Transpo sells 210A, non-avalanche diode rectifiers for under $30. Run them in parallel and you're good to go.
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Old 22-11-2017, 07:02   #32
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Re: Water cooled, high amp 12v alternator

I don't say that a Honda generator is a bad solution in general, but it's not the best solution either:

-you have take it out every time you need it and put it back into storage after that to make sure it won't get stolen. This also means it will take up space in a storage locker.

-you have to be careful with CO poisoning, when running the generator needs a place where it can vent its exhaust gasses.

-if you have a 2stroke-outboard, you need a third sort of fuel for the generator.

-a 1000$ Honda generator won't charge at 60-70A by itself. It will only power a charger and one with this output current is additional $$$.

-60A is not much, even our stock 110A Vetus/Mitsubishi will put out more.

-a portable generator can't be run when underway, except for maybe very light winds.

-a high-output alternator will charge with high output whenever the engine is running meaning nearly full batteries even if the engine has just been running for half an hour when approaching an anchorage.

-a separate generator means another internal combustion engine and therefore storage for another set of spare parts and also regular services like oil changes.
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Old 22-11-2017, 07:14   #33
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Re: Water cooled, high amp 12v alternator

I don't disagree with your points in regards to a Honda2000i but I do disagree with this:

-a high-output alternator will charge with high output whenever the engine is running meaning nearly full batteries even if the engine has just been running for half an hour when approaching an anchorage.

Not true unless you have LiFePO4 batteries.
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Old 22-11-2017, 08:24   #34
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Re: Water cooled, high amp 12v alternator

Quote:
Originally Posted by txg View Post
Even if this thread is 5 years old, alternator heat problems are still a big problem as can be seen in several threads on this topic.

Still noone that tried using a water-cooled alternator on a boat? They are expensive, but i just found out that they can be bought used quite cheap, 14V 150-200Amps for about 150.
Yeah, but realistically, you can only pound a high charge into batteries for a short time. The batteries are the limiting factor.
I bet a finned aluminum alternator housing with a ducted fan wold cool really well and be simpler than a water cooled alternator.
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Old 22-11-2017, 08:35   #35
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Re: Water cooled, high amp 12v alternator

Quote:
Originally Posted by kenbo View Post
-a high-output alternator will charge with high output whenever the engine is running meaning nearly full batteries even if the engine has just been running for half an hour when approaching an anchorage.

Not true unless you have LiFePO4 batteries.
I get your point, but this depends on what you define as "nearly full", on the SOC when beginning to charge and the type of batteries used. We have a rather small 220Ah bank, but they are AGM and can take a lot of current. When we have run the engine approaching an anchorage, batteries are at least at about 75-80% most of the time. Okay, this doesn't mean full but there is a decent charge.

Quote:
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Yeah, but realistically, you can only pound a high charge into batteries for a short time. The batteries are the limiting factor.
I bet a finned aluminum alternator housing with a ducted fan wold cool really well and be simpler than a water cooled alternator.
Even if the batteries can't take all of the current it is nice to have a high-output alternator. E.g. we have an electric cooking plate running through an inverter that pulls around 130A. With a bigger alternator that can deliver 150A+ continuously, it would be possible to cook while charging the batteries at the same time.

We do cool our alternator with an external fan and while that does help a lot, watercooling would be much better.
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Old 22-11-2017, 10:41   #36
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Re: Water cooled, high amp 12v alternator

Watercooling system would be fine but IMO only worth doing if professionally designed and installed from the beginning to run off the engine cooling system.

You need to first test **that alt** for the ability to put out your desired Amp loads within target rpms for long periods of time. Most automotive can't do over 60-80A, really need large-frame truck style for higher.

For retrofitting, use forced air cooling.

Serpentine belt for sure, dual vee bare minimum for under 150A.

Single belts can't comfortably carry the torque of actually **producing** 80-100A for extended periods. The max alt rating is irrelevant.
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Old 22-11-2017, 10:45   #37
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Re: Water cooled, high amp 12v alternator

Relevant thread WHAT IS A GOOD GENERATOR ??
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Old 22-11-2017, 10:49   #38
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Re: Water cooled, high amp 12v alternator

On AGM higher acceptance rates.

Only relevant for a few minutes at low SoC. Still need 5-8 hours to get to 100% Full, essential for bank longevity.

Need solar to carry on, finish the long tail after your morning dino juice run.

http://www.sailnet.com/forums/showthread.php?t=241409
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Old 22-11-2017, 10:57   #39
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Water cooled, high amp 12v alternator

Water cooling an alternator should not be a real concern, it has been done, and it works. A whole lot less heat to remove from an alternator than say an intercooler, yet they are water cooled with few problems.
However if your concerned with salt water you could use a fresh water / antifreeze mix and remote mount a transmission cooler and blow air over that.
Many things are possible, however they start to become what I call a science project, sort of like the thread on a DC generator.
Of course its possible to build your own DC generator, just like its possible to build your own watermaker for instance. If you enjoy tinkering and have nothing else the Boat needs, go for it.
However Id bet even if you consider your time worthless, your still going to spend more $$ than just buying a Commercial solution that already has the bugs worked out. However I admit there is satisfaction is setting back and thinking I built that. Must be why people home build boats, otherwise I believe they are insane
Now if your really cruising and dont have an automobile to run around constantly scrounging parts and access to a decent shop, its really going to be more difficult than you may think.
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