Cruising Without Alternator (Temporarily)

[valhalla360]

Originally Posted by Wotname

I beg to differ although I do agree that if the engine starts readily, not many amp hours are saved while the battery remains close to full charge. In the OP's instance, his start battery will discharge over time until it will struggle to turn the engine though compression fast enough to generate enough heat to fire. By starting decompressed, a near flat battery will easily start a 3GM30 (IME).

After the initial inrush current, the current draw of the starter motor rises sharply as each piston approaches TDC on the compression cycle. A discharged battery simply can not supply the necessary current to push the piston though compression. However decompressed, the starter motor requires much less current and what energy is supplied is essentially stored in the flywheel.

The current draw of a starter motor (which is always series wound) is directly proportional to the torque generated and inversely proportional to it's speed. Thus in a low torque and high application, the current is minimal. Decompression allows the starter motor to operate at lower torque and higher speed than a compressed engine.

If you are at the point the battery can't turn the motor over...yeah, it could help.

But if the battery is strong, it's a coin flip which will use more as the decompression method is typically going to require a longer run time for the stater negating the reduced current draw.

Another question for the OP: does the motor accommodate hand starting and if so, before heading out practice to see how it works.

[theway]

Originally Posted by valhalla360

...

Another question for the OP: does the motor accommodate hand starting and if so, before heading out practice to see how it works.

The short answer is no.

[NorthCoastJoe]

If you can not get yours repaired you should be able to adapt a car alternator to your Yanmar. You will have to get creative with mounts and using 1/2 inch pipe and stacks of washers as spacers to get the pivot side right. Line up the belt pulley that way. Then set up the tension arm side with whatever you can make work. I have done this on several cars and tractors.

My Pearson's Yanmar 3gm30f has a car alternator on it and if I get over to the boat in the next few days I will get you a picture of the setup and type of alternator used.

Use the decompression levers as stated earlier, once it starts on one cylinder you should be good. It might be hand crankable, a Yanmar 2gm I once owned had the hand crank provision.

[valhalla360]

Originally Posted by theway

The short answer is no.

If you aren't going to fix the alternator before heading out...the long answer may be worth while. Most small diesels can be hand started but not always easy.

Used to have a 75hp evinrude...I figured out how to hand start it...it was a bear to do but it could be done.

[Rumpi]

Heareth oh unbelievers the words of the Church of The Electron:

The Monsun Demon has cast the curse of the Green and White Corrosion of Connections over the sacred generating device in question. According to the writings of Apostole Ohm the exorcism should be as follows:

1. Thou shalt remove any impurities from all connections by wielding the power of the Sacred Bristles of Bronze and the Holy Solvent of Cleanliness.
2. Thou shalt ward off the Curse of Corrosion by the power of the High Amulet of Dielectric Grease.
3. Thou shalt not take the names of the Saints Pixii, Faraday, Kelvin and Deri in vain for fear of the Revenge of The Black Smoke.
4. Thou shall observe the ways of the Profets Volt and Ampere to the letter.

For all the above The Holy Church will reward you with the Blessing of The Free Flow of Electron.

[roland stockham]

Given that you alternator is an antique and may be very hard to find parts for I would find a standard car alternator that fits. If you take it to the shop they can normally match up the lugs and pulley. Fitting the extra lead for the external regulator is simple, while you have the cover off give the diode plate a spray with conformal coating. An 85a output is ideal for a bank of up to 400a/h and going bigger will not shorten charging times. Should be around $100US. I have always used car alternators and never had a problem. High output ones are a rip off price and for FLA,s never give a significant reduction in charge times.

[smac999]

Originally Posted by theway

Thank you....
You make some very good points here and I think this is what caused my hesitation and passiveness towards the issue initially. I still now have thoughts that after a couple hours of motoring it will come back alive. I will however promote that by checking the contacts on the alternator for corrosion, maybe loosen and clean as good as I can and tighten them up again.

So the test I did for magnetism was detach plug from regulator and connect the red to the blue with a wire. Does that sound right? I’m pretty sure it’s 12V coming from the red wire. Now, Does the black wire need to remain connected to regulator during that test? I’m guessing that might have been the problem if so.... checking now!

(I just checked keeping the black wire attached, I also tested the red wire and jumper for 12V, it’s there, and when connected to the blue, still no magnetism - I’ll give the contacts on the back of the alternator and any other connections a look in the morning.)


The readings I got are here:
—-
Measurements from the ARS-2. With engine at 1,400RPM, 1,000RPM, and only ignition on.

- 1,400RPM
RED - 13.51
BROWN - 13.32
BLUE - 13.30 and dropping

- 1,000RPM
RED - 12.92
BROWN - 12.78
BLUE - 12.89

- Ignition on only
RED - 13.01
BROWN - 12.58
BLUE - 12.89 and jumping around

Is this with everything plugged in? Or with stuff jumpered?

Sounds like Your alt is charging but is low. As it went from 13v to 13.5v. What is the voltage on the back of the alt at 1400?

Put a clamp meter on the alt pos cable with a discharged battery.

[Q Xopa]

Originally Posted by theway

The alternator is an old Balmar 9 series and based on the photos I sent to Balmar to help asses the problem, he suggested that it’s 20+ years old. More accurately he said it went out of production 20 years ago.

The story is: I left the boat for 4 months and on return it would not charge the batteries. The readings at the regulator are accurate which suggests wiring is fine, so I did the test to see if any magnetism comes from the pulley bolt/nut and got nothing. It seems like a good time to replace it.

As for the math, thanks.
What is the 3600 in the equation?

(And for the record the engine usually starts right away, definitely less than 5 seconds)

3600 = 60secs x 60mins = 1 hour.

[hamburking]

One time, not so long ago, spiders clogged the vent on my fuel tank, and the atomic 4 suddenly stopped running. Of course I didn't know about the spiders, and I began searching for the trouble...fuel, spark, air, etc. Over the next hour...I was out sailing, no wind situation, 2 kids aboard with me. I must have tried to start that A4 at least 20 times with a good long (5 seconds) crank each time. Finally, in desperation, I removed the deck filler cap to look down into the fuel tank...and presto...engine starts. For about 10 minutes, then vacuum again. But by this time I had figured it out, and manually vented the tank every 5 minutes until I go back to the dock for a proper fix (find the spiders).

The point of the story is that I cranked and cranked a huge amount. One starter battery (from canadian tire) and the crank speed never even slowed. I did leave lots of time between cranks to ensure the starter didn't overheat.

And this was about the worst thing that ever happened to me with an atomic 4 (had one on two different boats). On the other boat, the alternator died entirely. I took it up to "kingston starter and alternator" and they rebuilt it for a modest price in just a couple days. They never mentioned the age or model, just made it good as new.

[cal40john]

Originally Posted by theway

My alternator recently died and was wondering how long a starter battery can last if only used for cranking the engine? I have the Bluetop D34M. I’m curious about two situations...


2: (Actual) If the starter battery was charged some from 2 - 100watt solar panels.... I have 2 House banks fed by 2 - 100watt solar panels (one per bank). That power can also be sent to the starter battery when the starter battery switch is on. My general power needs are low and easily met with the solar, my concern is starter battery draw from each crank.


Thanks,
austin

As others have pointed out the 3GM30 doesn't have electrical loads while running (well except the tach). The solar panels charging the starter battery should be more than adequate to make up energy used to start the engine.

[mabowers]

Originally Posted by theway

. I do have the ability to turn off the starter battery completely with a switch. I’ll definitely run some test to make sure nothing is drawing from it and monitor it often.

Is there any chance that turning off that switch while the engine was running is the cause of your alternator failure in the 1st place ?

[Rumpi]

Originally Posted by theway

Thank you....
You make some very good points here and I think this is what caused my hesitation and passiveness towards the issue initially. I still now have thoughts that after a couple hours of motoring it will come back alive. I will however promote that by checking the contacts on the alternator for corrosion, maybe loosen and clean as good as I can and tighten them up again.

So the test I did for magnetism was detach plug from regulator and connect the red to the blue with a wire. Does that sound right? I’m pretty sure it’s 12V coming from the red wire. Now, Does the black wire need to remain connected to regulator during that test? I’m guessing that might have been the problem if so.... checking now!

(I just checked keeping the black wire attached, I also tested the red wire and jumper for 12V, it’s there, and when connected to the blue, still no magnetism - I’ll give the contacts on the back of the alternator and any other connections a look in the morning.)


The readings I got are here:
—-
Measurements from the ARS-2. With engine at 1,400RPM, 1,000RPM, and only ignition on.

- 1,400RPM
RED - 13.51
BROWN - 13.32
BLUE - 13.30 and dropping

- 1,000RPM
RED - 12.92
BROWN - 12.78
BLUE - 12.89

- Ignition on only
RED - 13.01
BROWN - 12.58
BLUE - 12.89 and jumping around

1. Your alternator is working somewhat, you can not have 13.5V at 1400RPM and 13V at 0 RPM othervise.
2. You have corrosion on the connections and it will not get better by simply running the engine.
3. Disconnect battery negative clean terminal and battery post. Follow the wire trough all connections to the alternator terminal cleaning every intermediate connection if present. Possible connections are starter motor, engine block, negative bus bar. Every one of this needs to have the bolts taken of, every surface (including the bolt and washers) wire brushed and sprayed with contact cleaner spray, reassembled and tighened then liberaly coated with dielectric grease (do not put the grease on first). Every auto parts store should have contact spray and dielectric grease.
4. Leaving the negative terminal disconnected repeat process for positive terminal and wires.
5. Your voltage regulator is working. Clean the connectors with spray anyway.
6. Tighten the alternator belt to spec, look for rust on the pulleys and remove if present.
7. Reconnect battery terminals, start the engine and measure voltage at battery. Report back.

[Dockhead]

Originally Posted by Rumpi

I have to point out the obvious: alternators don't die from sitting around. If it was fine 4 months ago it's fine now. Your problem is corrosion. If you did the magnetism check correctly (ignition on) and don't get any it means your field is not getting current or the alternator can not complete the circuit to ground. You say the readings at the regulator are accurate, can you describe this?

Balmar series 9 are isolated ground so first thing is to check the ground wire. Disconnect, clean, reconnect and check continuity. Ideally the wire should go to the battery negative and be of the same gauge as the positive one. Now check again for magnetism. If no magnetism present connect 12V to the field wire (jumper). If you get magnetism the alternator is ok and the problem is on the regulator side. If not then the sliprings have a bad connection.

[Fuss]

fix alternator as mentioned etc but it’s always good to have some sort of cheap backup so buy a 10ah motorbike charger and a small inverter to power it.

[Sailmonkey]

Originally Posted by Fuss

fix alternator as mentioned etc but it’s always good to have some sort of cheap backup so buy a 10ah motorbike charger and a small inverter to power it.

Are you suggesting to use the inverter to power a battery charger to charge the battery that the inverter is using to power the battery charger?