how to connect MOtorola 30 amp alternator?

[hanleyclifford]

Neil - I'm afraid that there are still some flies in your old "skool" ointment. First of all it is by no means certain that those who fixed the old charge rates were any smarter than you. Secondly, the old skool did not have to deal with the enormously complex electrical systems of today's cruising sailboats. Lastly, you have not addressed the matter of voltage losses from the alternator to the batterys which might be quite significant even in your old skool truck. BTW, a classy boat like the Catalina 30 should feature only the finest imported beer.

[ArtJ]

a friend of mine worked at APC American Power Conversion.
They manufacture battery back up systems for everything from
PC's to Large central computing systems.

Battery technologies used include wet lead acid , Glass matt and Gel types.

Each type has a special charging algorithm consisting of at least 3 stages.

One of which is float. I am not a battery expert, but they know what they
are doing with the smart regulators

One caviat was that if the batteries are not kept fully charged, they
deterioriate.
SO will our marine deep cycle batteries.

[hanleyclifford]

Art - All batteries will deteriorate in time but the one kept fully charged (without overcharging) will last the longest of all. Of course the batteries must be used for their purpose, and hence discharged; the first prize is therefore to discharge them as little as possible which then means having as many as possible to spread the load. It is also a fact that different types of batteries have different charging preferences. The "smart regulators", so-called, are really just devices for changing charge rates and setting charge periods, usually programable by the boat operator. Sometimes they have a "preset" program but I think they are still only as "smart" as the operator.

[ArtJ]

One other thought comes to mind, again, I am not a battery expert.

If a battery is allowed to remain discharged for a period of time
sulfation occurs (please don't ask me the chemistry). They can
sometimes be recovered by application of overvoltage higher than normal over
a specific algorithm, but it can be risky or dangerous to apply higher
than normal charge voltage. So it is best to not let the battery be left
in a discharged, or even partially discharged state for long.
Letting them get below 50 % is definitely not recommended by mfrs

Just an aside I happened to remember

[ndutton]

. . . . the old skool did not have to deal with the enormously complex electrical systems of today's cruising sailboats.

Huh??
Enormously complex??

What am I missing? Dealing with a variety of electrical systems daily, it's my opinion that it doesn't get much simpler than 12VDC, maybe a flashlight.

Anyway, that's my story and I'm stickin' to it . . .

[ArtJ]

In case anyone is interested

here is a link to a basic battery tutorial I just found. This is only one of many
including some more technical.

http://www.batterystuff.com/tutorial_battery.html

[hanleyclifford]

Huh??
Enormously complex??

What am I missing? Dealing with a variety of electrical systems daily, it's my opinion that it doesn't get much simpler than 12VDC, maybe a flashlight.

Anyway, that's my story and I'm stickin' to it . . .

Actually it does get simpler and I now know that I am an even older neanderthal than you - my boat formerly had gimballed kerosene lamps! Best Regards, Hanley

[roadnsky]

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-
I've got the AGI 55Amp and just did some voltage measurements yesterday as I continue to chase my hot Facet pump (another thread, another time)
Here's what the Alt is putting out on my vessel...

ALT: 14.28
BATTERY: 14.26

YMMV...

[roadnsky]

...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.

Here's the site for reference...

http://sterling-power-usa.com/advancedregulators.aspx

[hanleyclifford]

Jerry - Your low voltage loss between alternator and battery is most impressive. Can you tell us what sizes you use for the wire coming off the alternator (+ and -). Also what is your minimum size back to the battery? Thanks, Hanley

[roadnsky]

Jerry - Your low voltage loss between alternator and battery is most impressive. Can you tell us what sizes you use for the wire coming off the alternator (+ and -). Also what is your minimum size back to the battery? Thanks, Hanley

Doing this from memory...
8AWG from the Alt to the Starter post.
8AWG from the Starter to the Isolator Switch.
4AWG from the Isolator to the Batteries

Short runs all of them.

EDIT: I looked at the wiring and the Starter to Isolator/Battery Bank is actually a 4AWG wire. (Not 8AWG)

[ndutton]

Voltage drop is a function of wire cross sectional area (in terms of resistance per unit length), wire length and current.

As the current increases, so does the voltage drop. Without excessive length, as long as the current doesn't exceed the wire gauge's rated ampacity the voltage drop is usually insignificant. Beyond the rated ampacity however, things start to get serious.

Depending on where Jerry's regulator senses battery voltage, the regulator may make up the difference.

The 8 gauge wire from the starter to the isloator switch caught my attention, not so much for charging but for starting. I've never measured it but does anyone know the normal amperage the starter draws? My former Perkins diesel starter could draw some serious amps, like in the neighborhood of 200 - 250 as I recall, maybe more. My battery cables were 4/0 just to address the starting loads.

Disclaimer: I'm not suggesting the A4 starter is anywhere near the Perkins in terms of starting loads.

[sastanley]

you guys don't want to know what I am running (it was the biggest piece of wire I had on the boat when I eliminated the ammeter run to the cockpit in the middle of cruising.)

I think mine is 10 or 12 gauge..the run is short now though, about 24" from alternator to isolator, and then 4 awg from isolator to batteries..probably 12" & 16" runs respectively.

This setup is not permanent...it is only the beginning. I still have a random 14 gauge wire running thru the bilge that must be connected to ground on the house battery to make any of my 12 v systems work. I am guessing the "real" ground failed long ago.

[rigspelt]

The 8 gauge wire from the starter to the isloator switch caught my attention, not so much for charging but for starting. I've never measured it but does anyone know the normal amperage the starter draws? My former Perkins diesel starter could draw some serious amps, like in the neighborhood of 200 - 250 as I recall, maybe more. My battery cables were 4/0 just to address the starting loads. Disclaimer: I'm not suggesting the A4 starter is anywhere near the Perkins in terms of starting loads.

Not being an expert, I went through this decision-point for months before I settled on 4 AWG for start battery to starter (same as original on the boat for 34 years it seems), and 8 AWG for alternator output to starter solenoid B post (a foot; much shorter and larger than the old original #10 wire that had run from the alternator all the way aft to an ammeter in the cockpit ignition panel and ran both engine and house loads with #10 wires running forward again -- I scrapped those long runs in my refit). After digging up what I could, I got the impression that A4 starter draws are considerably less than 200A, perhaps less than 150A and normally maybe in the 135A range -- very easy to start. The concern is too small and overheating the wire, but I got the impression that too large can also be problematic for starter wires. Over normal short duration starter use (seconds), I thought that cable size could handle the draw in our situation, but of course a wrench left across the terminals for a prolonged period would be a different matter...

[ndutton]

Not being an expert, I went through this decision-point for months before I settled on 4 AWG for start battery to starter (same as original on the boat for 34 years it seems), and 8 AWG for alternator output to starter solenoid B post

Agreed. It seems the common wire size for our battery to starter circuit is #4. Jerry has some #8 wire in there that caught my attention. Regarding the alternator output wire, the standard alternator output is 35A max. and the common upgrade is 55A. #8 wire is capable of handling these maximums for prolonged periods and who ever sees their alternator operate at the max output anyway?

There are a few who have installed an alternator with a maximum capacity that seems beyond reason, yours truly being one of them. Replacement of the alternator output wire to a larger gauge is necessary in these upgrades. My original output wire for the Motorola 35A was #10. With my Delco 100A alternator the output wire is now #4.