Highest Output Alternator

[JoeFish]

I'm looking for a new alternator for our motor.

In a perfect world I'd like to find one that I can push a lot of amps into our house batteries quickly, as I sail on AP a lot and that tends to suck up about 50Ah a day plus all the other normal loads from radios, instruments, etc. (I'll admit we use far less in that department than some).

An suggestions for something high output?

Original engine was 16HP and we made hull speed with that. The new motor is a 26HP triple with a max prop so we have plenty of reserve to push a big alternator.

[Jd1]

Balmer AT series, 200 amp
Problem will be pushing the power into the batteries unless you run Lithiums ...

I have done part one of my electrical upgrade which was the AT-200 with an MC 614 external regulator and a serpentine belt upgrade. This is for a Kubota/Universal m35b engine (if I recall the details correctly). I know the alternator can push out the power but my battery input is still limited. I will need to play with the regulator setup to improve that but currently I can pump about 60 amps into an approx 350 Ah flooded lead acid cell bank when I am down to about 70% capacity. That reduces quickly to around 30 amps and then tapers off from there but if I turn on the microwave which draws 90 amps then battery charging goes to about zero. In other words the alternator can pump out 90 amps or possibly more but it's difficult to tell because the system adjusts slowly to changing loads and I have not had a reason to run my microwave for longer than about a minute.
In addition you get into voltage drops (no sense line directly to battery yet, limited cable gauge) etc etc which throws things off so basically I don't expect to see more output as it sits now.
All of these figures are approximate as I have not made a big point out of finding out the exact capacity of the alternator since the eventual idea is to switch to Lithium batteries and charge at a fixed 160 A rate.

[JoeFish]

Yes, we're switching to LiFePO4 now so this is the time to get a high output alternator.

I've never really understood if an alternator's load on the engine increases if it has demand on it or not, that has me considering what the happy medium is as we can end up motoring a lot if we're on the back side of Vancouver Island.

[Jd1]

Originally Posted by JoeFish

Yes, we're switching to LiFePO4 now so this is the time to get a high output alternator.

I've never really understood if an alternator's load on the engine increases if it has demand on it or not, that has me considering what the happy medium is as we can end up motoring a lot if we're on the back side of Vancouver Island.

Yes, the alternator load on the motor is directly proportional to the amount of power it puts out. The nice thing about the external regulator is that you can adjust an awful lot of the charging parameters. Mind you, the user interface to change these parameters is about as primitive as it gets so you will want to work out a 'set and forget' happy medium.
There are parameters for 'belt manager' that adjust how much power the alternator will output (assuming that the alternator or batteries aren't overheating ... basically you de-rate the output a bit to reduce stress on the alternator and increase life) and you can install a switch for 'small engine mode' which halves your power output in case you should need the power for the boat. You can also add a switch that completely shuts off charging so 100% engine power is available to the prop when you need it.
Lots of config options and a very nice setup but pretty darn pricey!
As I mentioned, I plan on setting max output to about 160 amps which should keep temperatures in check when feeding the Lithiums. I currently have no power limiting switches installed as that only becomes an issue with batteries that can absorb all that power which are not installed yet.

[JoeFish]

$1400 seems a bit on the whacky side for an alternator that only puts out 160. Sure it has some nice features, but $1400?

Fitzall makes a USCG approved marine alternator that puts out a full 220A @ 1200rpm for $400. Can the Balmar really be so much better?

[barnakiel]

Originally Posted by JoeFish

... one that I can push a lot of amps into our house batteries quickly, ...

Mission impossible. Batteries have acceptance rate and that's that.

Most of the time, it is a regulator, not alternator, issue.

b.

[wingless]

Originally Posted by barnakiel

Mission impossible. Batteries have acceptance rate and that's that.

As shown in this reply, a flooded cell battery should be charged at C/10 rate and an AGM should be charged w/ at-least the 0.2C rate.

Most alternators / regulators only provide the specified output at operating RPM, not at idle.

[Hud3]

I switched from a 100A to a Balmar 210A alternator. Had a special bracket mount made by a local mechanic, and installed a double pulley on the engine. Also installed a duct fan to draw cool bilge air into the engine compartment over the alternator. Had a MC 514 regulator feeding the 600AH AGM house bank, and Digital Duo-charge unit to handle the engine start battery. It basically cut the charging time in half, so simply motoring in and out of anchorages went a long way toward doing the charging duty.

I had a switch installed so I could turn off the alternator if I suddenly needed full engine power for some reason. The engine was a 56 hp Yanmar, and handled the alternator load with ease. Only needed the cutoff switch once.

[Sandero]

High output alternator can't shove lots of amps into a battery system which won't accept for any number of reasons. Make sure your entire system is "balanced".

[a64pilot]

IF you could get 200 amps, better have some kind of fancy drive system.
I'd love to see someone come out with a toothed kevlar drive belt, the type you see driving the camshafts on cars, but as far as I know, it doesn't exist.

[Jd1]

Originally Posted by a64pilot

IF you could get 200 amps, better have some kind of fancy drive system.
I'd love to see someone come out with a toothed kevlar drive belt, the type you see driving the camshafts on cars, but as far as I know, it doesn't exist.

As I said earlier, I use a serpentine belt system and it works just fine!

[Dockhead]

As others have said -- there is no point in an alternator too big for your battery bank. I think about 20% to 25% ratio of nominal alternator power to nominal bank capacity should be about right. Remember, that nominal rated power is rarely achieved, only at high revs, low temperature, etc.

Remember also that there is a huge difference between "hot-rated" alternators -- designed to produce high power levels continuously -- and car-type alternators which are just made for topping up batteries and running on-board loads, not producing large amounts of power. "Hot-rated" alternators are made for school busses and emergency vehicles under brands like Prestolite and Leece-Neville. Balmar don't make their own alternators and I think Balmar-branded alternators are a waste of money.

Remember that school-bus alternators usually require double belts (or maybe a serpentine). It's important to get the the drive system right. It can be expensive since you will likely have to change the pully on the engine and have a special bracket made, but it's really worth it.

And don't forget about external regulation. You will want to use one of the various multistage external regulators.

I have 110 amps by 24v (like 220 x 12v), a Leece-Neville as originally installed on my boat. I just added an Adverc external regulator to it. It charges a 420 amp/hours x 24v domestic bank and does a very good job. There is always abundant power when the main engine is running, and we always arrive with fully charged batts even if we motored for a relatively short time. I think it really makes sense to get this right.

[ColdEH]

Originally Posted by Jd1

As I said earlier, I use a serpentine belt system and it works just fine!

I direct coupled my 325 A EchoTec alternator to the crank shaft with a love joy connector.

It runs at the generators 1800 RPM and produces around 265 amps at 12 volt at that speed.

I think it takes 9 hp to spin it. Belts on a small engine were not an option as it would probably eat the bearing at the fly wheel from the side force. I guess I could have put a load belt on the opposite side but the "love joy" was a simpler solution.

Regards

[cal40john]

Check out post #3

Originally Posted by barnakiel

Mission impossible. Batteries have acceptance rate and that's that.

Most of the time, it is a regulator, not alternator, issue.

b.

[DeepFrz]

A 160 amp alternator with the Balmar regulator should suit you well I would think. I don't think you mentioned the size of your battery bank but I would throttle back the alternator about 20% or so. Also would recommend you use the serpentine kit.

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