how to connect MOtorola 30 amp alternator?

[ArtJ]

I have a rebuilt and stored 30 amp motorola alternator that has not been on the boat for a number of years.

I would like to bring in as a spare with me on a boat trip to Maine this week
in case I have trouble with the fancy stuff that I installed and need a backup.

I would appreciate it if someone could direct me to the proper way to connect
it. There is a push on terminal with short pigtail and two lug based connections at least.


Thanks very much

Art

[rigspelt]

Art, some of us have posted pictures and discussions of the Motorola wiring in archived posts. You might want to try a Search using rigspelt for example. Sorry - rushing off for a sail or I'd look them up.

[ArtJ]

I just browsed some threads.

Apparently, the yellow wire goes to the plus side of the coil,
The output terminal is obvious, and the ground connection I assume
is thru the case bolting.

The regulator terminal is occupied by the regulator already.
There is a ground terminal, but again, I am assuming that it receives this via
the bolt?

Art

[hanleyclifford]

Make sure that the "fancy stuff" does not include an external regulator unless you can and will bypass it in the event of using your spare which I believe does have internal regulation.

[ArtJ]

Hanley

Will do . By the way, in another posting you mentioned not recommending
external 3 stage smart regulators anymore. I would be interested in hearing
your thoughts on this.

Thanks

Art

[sastanley]

motorola regulator

Art, If your stock Motorola regulator gives up the ghost, I found a bolt-on replacement that allows you to adjust the output voltage.

One of the problems with the stock regulator on the 35A Motorola is its output is only about 13.8 volts...way too low by today's standards for 12v systems. Compounding that problem on my boat is a passive diode type isolator, which ate another 0.7 volts. My batteries where only getting about 13.1 - 13.2volts. I have the regulator set to send about 14.9 to the isolator, giving me ~14.2v or so at the battery posts.

Hanley, I am interested too. I bought this $45 regulator instead of an external unit from Blue Sea,etc.. to keep my installation simple for now. If I were to get a fancier, i.e., higher output alternator if/when I need one, I'd look to get fancier charging equipment too.

Here is a link to the unit. http://www.ase-supply.com/product_p/trs-m5-197a.htm

[hanleyclifford]

Shawn - I understand your concerns about voltage. But keep this in mind: selection of alternator and voltage depend on how you use the engine. If you ran all day with the voltage you indicate, you would have boiled batteries. I run my engine 10 hours at a whack and therefore I set at about 13.5 volts. As for a new alternator, know that the stock accessory drive sheave will only support about 60 amps no matter how big an alternator you buy. Look at the charging curves from the Balmar catalogue. Too bad you Cat 30 guys cannot move your alternators up front like I did. All the best, Hanley

[sastanley]

Hanley...good points and I understand that long charge intervals would kill them at that voltage. I guess what I probably need is a smart charge controller, like the $75 Blue Sea unit.

I am usually running my motor as little as possible, runs up the creek are 50-60 minutes, or out to the bay about the same.

"Fancier " would be the 55 amp unit at Moyer, or similar. I have another 35 amp Motorola alt. as a spare though, and I only have one Group 27 house & a group 24 start battery. I have converted my anchor light and 80% of my cabin lighting to LED, so I don't really need any more juice!

[Dave Neptune]

Side bar

Hanley, you seem to be one of the resident electrical gurus and I would like to ask you a question. I have thought of upgrading my charging form stock and just found a Motorola 55amp. alternator under a pile of dune buggy parts.
It is set up for an external regulator and I am looking for a recomendation for an adjustable one. I tend to motor for 5~7 hours to my mooring ~ use the batteries for a few days (no refer.) ~ start the lil beastie for safety and sail off the mooring then shut her down for the sail home. I again start her for about 15~20 minutes to motor into the slip. There she sits usually for 2 weeks and the process begins again. I do not use shore power or a battery charger unless I leave something on and kill the "House side" 2-235 AH golf cart 6 volts. Note my start battery is a deep cycle grp 27 which usually stays off line except for the run to the island.
I would like a bit more than the stock alternator provides as sometimes when staying for a week my batteries will get low and I would like to speed up the recharge process (motor to the Isthmus for dinner or drinks ) of which I seldom need or do.

Dave Neptune

[hanleyclifford]

If you have a 55 amp alternator set up for external regulation you have close to the ideal for your purposes. I think it was Jerry who posted the link to the adjustable regulator site. I would not use the multistage regulator. The multistage regulator is good for the boat that lives on a mooring, has lots of electrical demands, runs it's batteries down below 50%, and wants to recharge them in the minimum time without reaching over and turning that little screw and then remembering to turn it back after an hour of charging. I believe that the adjustable one voltage rate unit offers the best of flexibility, simplicity, and affordability.

[rigspelt]

If you ran all day with the voltage you indicate [14.2], you would have boiled batteries.

Hanley, I'm no expert, but is it not true that boat charging systems before the smart chargers and external regulators ran at 14.2-14.4 volts and apparently did not boil off batteries, or so I understand? Don't automobiles run at that voltage? Seems that many boats still run that way? I agree there is no need to run charging systems that high after an initial equalization charge, and that on cruising boats it makes sense to have a means to float them in the mid-13's, but I'm still unconvinced about the mid-14's necessarily overheating batteries in all installations.

Nevertheless, I would feel better if I could convert this API 55 amp alternator to an external regulator so I could dial the output back away from shore power. We have a smart charger for dockside charging.

[Mark S]

Rigsy,

At what voltage does your API 55 amp alternator charge through the internal regulator? I don't recall off the top of my head what my API does, so I'll make a note to do that, but I remember noting that it's less than 14 volts.

Mark

[hanleyclifford]

I would agree that 14.2 volts would probably be ok but Shawn indicated that he was setting at 14.9, losing .7 at the isolator (relying on it in effect to impose a fixed "regulation" on the system). I would not feel comfortable doing this and that is why I do not use isolators. The real question is - what voltage is actually being delivered to the batterys? Shawn indicated that his alternator was putting out 13.8 volts. I submit that would be fine if in fact it were being delivered to the batterys. In all probability he is losing voltage in the line as well as the isolator. Neil and I went around on this question of truck alternators putting out 14 volts with no apparent problem; but again, what is being delivered to the battery? Because I use maximum wiring in my system, I can deliver fairly close to alternator voltage to the batterys. When I set around 14 volts I have experienced fluid loss, and for this reason I have retreated into the mid 13 range.

[ndutton]

Neil and I went around on this question of truck alternators putting out 14 volts with no apparent problem;

To clarify, as I recall our discussion it didn't circle around a specific charging voltage but rather adjustable regulators vs. fixed ones. There's a popular belief that adjustable regulators are a better way to go, giving the operator more control.

Being old skool I'm not a member of that congregation. I figure the fixed output was determined by those much smarter than me and when countered with the suggestion of reduced battery life due to a fixed charge voltage I offered my truck charging system as an example of something that works well - - fixed regulation and many years of battery life.

Besides, I'm busy enough keeping my guests on domestic beer while keeping the imported stuff for me.

Footnote: the old skool fixed charging voltage for lead acid batteries was 13.8 volts, been that way forever before these young whippersnappers came up with all this new fangled electronic stuff. I should add that my alternator has a fixed voltage regulator and my lead acid batteries are over five years old and counting with no noticeable reduction in performance.

[rigspelt]

Rigsy, At what voltage does your API 55 amp alternator charge through the internal regulator? I don't recall off the top of my head what my API does, so I'll make a note to do that, but I remember noting that it's less than 14 volts. Mark

Mark, it should be about 14.2 V according to the specs for that model. Mine seems to be charging at 14.6, which is higher than I would like. Took it to a reliable shop, but they say it's fine, and that they cannot set it lower. We are not doing any long distance cruising, so dealing with that is still on my back burner list.