Alternator choices

[evm1024]

Originally Posted by Jasmynonblue

I have a 4-236 and run a second 80 amp from a small shaft that is bolted to the front pulley. The 2 alternators are then controlled by a control box which charges the house bank first then it charges all the batteries. The 2 80 amp deliver 130 amps usually. If you go to big amp alternators you'll need big Serpentine belts as v belts won't hack the HP. I also run my watermaker from that front shaft as well.

I ended up putting a serpentine kit on my Perkins 4.236. Rather than buying a kit I ended up buying parts from SW Diesel. The cost for the K6 pulleys ended up being around $400 rather than the $1000 for a kit.

With 700 AH of LiFePO4 I have never been able to get close to a 0.25C (175 Amp) charge rate let alone the spec sheet max of 3C (2100 amps).

I expect to limit my charging rate to 0.2C or so. This would be running the alternator at 70% of its rated 200 amps.

http://www.cruisersforum.com/forums/...ys-162564.html

[a64pilot]

Originally Posted by joezzz

My conversation with Balmar,based solely on recharging of batteris indicated a larger alternator doesn't mean faster charging.
Why? As they told me, each series battery can only absorb a fixed amount of charging amps. So larger is not better. If your battery can only handle lets say 45 amps/hr. A 75 amp alternator will not charge it faster.

I believe Balmar, surprised a little in they are not trying to upsell you on more than you need.
An alternator is a lot like engine size, yes I could put s small block Chevy on my boat, but 40 HP easily get it to hull speed, no real use for more.
However I want a large alternator myself as Im an AGM bank, but also I have a large inverter and can run my Watermaker off of it, with the alternator providing the power.

Just me, but I am not so sure a “large” alternator runs all that much cooler than a “smaller” one. They are the same physical size and about the same mass and have the same cooling systems, only way I can see to get more power without more heat is by increasing efficiency. I can see that they may be a little more efficient, but twice as efficient so that you can double power output by the heat generated the same? I don’t think so.
I think they are built from components that can take a little more heat, and may be a little more efficient, but they can’t make all that much more power continuously I believe.
I’d love to see testing, but I have a gut feeling that about 100 amps is all that you can get out of a small frame alternator, continuously, due to heat.
So is that 200 amp alternator worth all that much more than a 150 or a 125? I don’t have that answer. I’d have to know what the continuous output for each is, and that isn’t published I don’t think.

[john61ct]

The large-frame alts are qualitatively different.

They run **much** cooler, and will deliver 70-85% of max rated output all day long. Some 100%.

They are installed in ambulances and firetrucks, relied upon for life-critical missions.

The case and built-in mechanical cooling design are nothing like the units designed for normal automotive use.

Assuming your engine has the horses, and installed properly with a good external regulator like MC-614 and good serpentine setup at the right ratios, you basically have the equivalent of a generator on board, just DC only output, buy the inverter separately.

[Maine Sail]

Originally Posted by john61ct

The large-frame alts are qualitatively different.

They run **much** cooler, and will deliver 70-85% of max rated output all day long. Some 100%.

They are installed in ambulances and firetrucks, relied upon for life-critical missions.

The case and built-in mechanical cooling design are nothing like the units designed for normal automotive use.

Assuming your engine has the horses, and installed properly with a good external regulator like MC-614 and good serpentine setup at the right ratios, you basically have the equivalent of a generator on board, just DC only output, buy the inverter separately.

The 200A J-180mount we build here, the CMI-ED200-ER, is actually designed to run hotter than most small frame alts can run. It can run at 240-260 +/- degrees as opposed to about 205-230. We use a high temp Kester solder, about $100.00 per pound, to ensure nothing is coming unglued when punishing this alt.. We then have the stators & rotors wound for good low end performance, using better quality wire, and I've not yet been able to cook one in testing.



Course if you can't fit a large frame alt you can always externally rectify a small frame and run it at max or darn near max all day long. I'm currently running a heavily modified CS130D/Grasser with external rectification and belt manger set to OFF... Highest recorded alt temp this season is just 213F....

Next winter I may build a mount for the CMI-ED-200ER and charge at close to .5C....

[a64pilot]

Maine Sail.
Your running a heavily modified Mark Grasser 130 amp alternator.
Why may I ask didn’t you start with a much higher amp alternator?

[Dockhead]

Originally Posted by Maine Sail

The 200A J-180mount we build here, the CMI-ED200-ER, is actually designed to run hotter than most small frame alts can run. It can run at 240-260 +/- degrees as opposed to about 205-230. We use a high temp Kester solder, about $100.00 per pound, to ensure nothing is coming unglued when punishing this alt.. We then have the stators & rotors wound for good low end performance, using better quality wire, and I've not yet been able to cook one in testing.



Course if you can't fit a large frame alt you can always externally rectify a small frame and run it at max or darn near max all day long. I'm currently running a heavily modified CS130D/Grasser with external rectification and belt manger set to OFF... Highest recorded alt temp this season is just 213F....

Next winter I may build a mount for the CMI-ED-200ER and charge at close to .5C....

The amount of heat which can be transferred by a given cooling system is a linear function of delta-T -- so the hotter the alternator can run safely, the more heat it can dissipate.

I think what MS is doing here is the only way to get a lot of power out of a small frame alternator, short of water cooling or some kind of forced air cooling.

Of course a large frame alternator is a far better solution for those who have space to fit it. I have replaced my Leece Neville 8SC alternator with a new one so that I could have a spare. The new one is a little different model as the old one has been discontinued. It cranks out 100 amps (at 27 volts, so more than 2.5kW) without breaking a sweat. The case of this one, for some reason, never exceeds about 55C -- much cooler than the old one.

The only problem I have is the drive system -- twin v-belts, which have to be adjusted frequently if I'm regularly driving the alternator at full power. If I neglect this, they blow up. Some kind of cogged belt or serpentine would make a lot of sense for this kind of application.

[a64pilot]

I believe the main thing was he had Mark remove the diodes (rectifier) thereby removing a large portion of the heat.
Me, having a lead acid bank, I’ll live with 80 amps, but 80 isn’t a small number.
The other alternator, the one that can run at such a high heat, is I think a large frame isn’t it?
I believe his experiments are geared towards LFP banks that can absorb huge amounts of power.

[a64pilot]

Also just from a quick look at the web site linked, it appears he may be driving the alternator at a higher ratio, turning up the RPM where it can make more power and Cool itself better.
I’m under the impression that we underdrive our alternators, that they could turn faster without harm and would work better at higher RPM, but we are sort of constrained by stock ratios, a lot of work to change those by much. I’d like a smaller serpentine pulley for mine as an think it could be without slippage but that is a guess.

He has me salivating over that alternator, That is a great price, wonder how hard it would be to get on a 4JHE? I’d be able to run my Watermaker and charge batteries with it. Cut way down on my generator run time.
$600 for real power? Yeah, I think I’m going to do some measuring.

[Dockhead]

Originally Posted by a64pilot

Also just from a quick look at the web site linked, it appears he may be driving the alternator at a higher ratio, turning up the RPM where it can make more power and Cool itself better.
I’m under the impression that we underdrive our alternators, that they could turn faster without harm and would work better at higher RPM, but we are sort of constrained by stock ratios, a lot of work to change those by much. I’d like a smaller serpentine pulley for mine as an think it could be without slippage but that is a guess.

He has me salivating over that alternator, That is a great price, wonder how hard it would be to get on a 4JHE? I’d be able to run my Watermaker and charge batteries with it. Cut way down on my generator run time.
$600 for real power? Yeah, I think I’m going to do some measuring.

Well, I have the same basic engine (4JH3 HTE) and there is a bracket mount on the right side of the engine for a second alternator. Yanmar make a pulley which will drive a second alternator. If you have enough room in your engine compartment (and I don't think it takes much), you could mount a second alternator, a large case one, and then you'd really be cooking with gas.

[john61ct]

Or with a microwave and induction stove if you feel like it 8-)

[Dockhead]

Originally Posted by john61ct

Or with a microwave and induction stove if you feel like it 8-)

ha ha

And convection oven

My next boat . . .


And I actually do run my induction hob and microwave off my alternator via the Victron inverter -- with ease. Even the washer/dryer . ..

[evm1024]

I ended up buying a Delco-Remy 28Si (pn 8600313) for a pretty good price. $365 for an OEM Delco.

This is a 200 amp internally regulated large frame alt on a j-180 mount.

If I were to do it again I would have bought MaineSails 28Si based unit for about $200 more. Sadly I had my order in before I became aware of his option.

Why pay the $200 more? His unit comes with the conversion to external regulation already done, Some (unknown to me which) upgraded parts and of course and perhaps most important the quality we come to expect from all that he does (his good work as it is).

But be that as it may be I have my alternator and have a few tasks to do. Likely I'll start another thread on the conversion to external regulation and fitting it on my Perkins 4.236 (which has a serpentine belt already).

I spent a little bit of time getting to know the alt. It appears that the internal regulator is a P type which is good as that it means that one of the brushes is already grounded. It also has a "relay" output which looks like it is a connection to the stator for a tach.

So on first inspection it should be dumb easy to make it external regulation.

My plan is to get a aftermarket internal regulator ( the horder in me wants to keep the oem delco regulator).

I'll gut the internals of the regulator and wire the positive brush to one of the connections on the regulator "frame" and make sure that the tach output is still connected.

There are 3 connection posts on my model alt which are integrated into the regulator assembly.

Then it will be on to the mount....

Here are 2 photos. One with is next to a 100 amp Hehr alternator which is more or less a Balmar 90 series (just a "normal" size alt).

The other is the back of the 28Si with the cover removed.

On second thought I might just cut a piece of G10 board and put some studs on it for the terminals.

[evm1024]

I realized that I did not close up this thread very well so here goes.

The 28Si was converted to external regulation, installed on my Perkins 4.236 and is running with a Balmar MC-612 regulator.

With no special programming to the regulator I saw 175 amps or so into a nearly full 700 ah LiFePO4 house bank.

The regulator was programmed to run closer to 120 amps and the alt was at 130 degrees F after 30 minutes at 120+ amps.

The conversion to external regulation is documented here:

http://www.cruisersforum.com/forums/...on-204361.html

[kenbo]

I know it would be a PITA to create but I'd love to see a temp vs. amp output for this alternator all the way up to maximum. 130 degrees vs 120 amps is excellent.

[Cowpoos]

What alternators have people found aftermarket in the Hitachi style mount alternators that are good bang for the buck?