Switching existing alternator to smart regulator

[Chris Campbell]

I had a chance last year to get a Xantrex external "smart" regulator at a good price, so I did, and am now starting to look into mounting it - and am having some fairly considerable confusion!

To begin with, the external regulator is for a P-type alternator (I think they all are, this one is for sure), and I don't know whether mine is N or P. I suspect N, since a) Murphy likes his chuckle, and b) it's a 51 amp alternator that came with internal regulation, and I gather most of the small, internally regulated alternators are N-type. Both Don Casey and Nigel Calder are very helpful on figuring out which type you have - just check the resistance between the field and the ground. Next issue: which is the field? It's not labeled, and with the cover off of the regulator, it's anything but clear.

Assuming that it's an N-type, I've read that it's possible to convert your N-type to P-type, and that it's wise to have someone who knows what they're doing do it for you. Of course that doesn't seem like fun, and I wouldn't learn anything - but it might be the smart thing, dunno.

Which brings me to another, better thought. Buy a new alternator, a P-type, and hook it up to the external regulator, and keep the old Motorola as a backup! The trouble with that plan is the cash outlay - the boat budget is virtually nil this year, so plumping for a 70amp Balmar is out of the question.

The final option is to keep charging with my current regulator for now and do something about this another year - possible, but it bothers me to be charging so inefficiently...

So here's my questions: 1) Does anyone know anything that might help me figure out how to wire my existing Motorola 51amp (model number unknown - illegible - it might be BEM2017KA, but about all I'm sure of is the EM2017) up to external regulation? 2) Does anybody think that's a bad idea, and I should buy another alternator? 3) Assuming 'yes' to #2, are there alternators around that are easily connected to P-type regulation that aren't through the roof in price?

By the way, I have an 8D house battery (221 amp/hour), and fairly basic loads (lights, instruments, autopilot - not much else), so my charging needs aren't huge - but having a battery which never gets much above 75% seems like a bad idea to me.

Thanks for any and all opinions!

Chris

[Dan H]

Chris,
I'm afraid I don't have the answer, but the guy at Hi Tech Starters and Alternators do. This guy knows everything about them.
He repaired my very obsolete alternator. It only took him 4 hrs.
269-944-4050 Ask for Steve.
They are located in Benton Township, close to Benton Harbor, Michigan.
These guys repair alternators and starters. They don't just sell you new stuff, they actually take it apart and fix them. Rare these days.
Just an option if you don't get the answer some other way.
Dan

[Maine Sail]

I wrote this about converting a Universal M-25 with a Motorola 51 to a new Leece Neville 90 amp.. The info in the article will show you the conversion plate you need..

http://www.pbase.com/mainecruising/cata ... alternator

[Shoalcove]

Hi Chris,
There is an Alternator shop on Kempt rd. (I believe it is called Rands) that may be able to help. I would give them a call. I bought a starter there and they seemed OK. If they can't fix it, they may know who can.
Best regards,
David

[Chris Campbell]

Yes, Rands electric fixed my starter last year, and did a splendid job. I'll try them, as well as Diesel Electric over in Burnside. I think what may happen is that this year I'll stick with the original setup and save the smart regulator for another year when I can afford a good alternator to match it with, then I'll have a good one and my old one as a backup. This year's electrical addition was a good battery and a solar panel - I suspect that will be enough of an improvement to make the old alternator's charging habits less of a nuisance. We'll see!

Thanks for your responses!

Cheers,

Chris