Readers might also like to read a more in-depth article on the subject: Installing a high powered alternator on your boat
The project is to replace the standard alternator on a Yanmar 3JH3E engine with an upgraded 100 Amp output Balmar 60-100-SR-IG alternator. The Yanmar takes a dual foot mount alternator and so we chose the Balmar 60-100-SR-IG alternator for the job. It was bought as a kit with the ARS5-H regulator and in the kit came a battery temperature sensor and an alternator temperature sensor. Also included was some mounting hardware which we ended up not using. The complete kit was the Balmar 60-YP-100-SR Alternator Kit 12 Volts 100 Amps. This engine has a 1/2" wide drive belt so getting enough traction to drive a 100 Amp alternator is not a problem
The first thing to do is to turn off the engine battery switch so that the engine cannot start while you are working on it, and then to double check that this has disconnected the alternator from the battery so that you don't short it out when removing the old alternator. Then you loosen the adjustment arm holding tension on the alternator belt. This makes the drive belt relatively easy to remove. In this case access to the back of the alternator was a bit difficult and I opted to unbolt the alternator first to make removal of the old connections easier. In this next picture you will see I have taken out the alternator mounting bolt and am temporarily removing the adjustment arm to make it easier to work.
This next shot shows the alternator has been completely removed.
Next I did a test fit to see that everything was going to work OK
The old alternator had a spacer on it that was attached with a bolt from the back and I transferred this to the new alternator. This isn't typical but it was easy to do.
At this stage I thought it would be easiest to attach all the small harness wires before mounting the alternator because access was difficult and it was easiest to get this fiddly stuff done while the alternator was out. First I clipped in the plug with the field wire (blue) and the stator wire (white) The field wire is what energizes the alternator. The stator wire provides a tachometer feed. In this case the Yanmar has its own separate tachometer sensor on the flywheel so the stator output of the alternator is not used.
The picture above shows the positive and negative wires to the regulator. The lower red wire with the fuse is the power supply to the regulator. It is connected to the B+ Terminal at the back of the alternator. The other small red wire was already in place and is the wire to the internal backup regulator. The black wire is connected to the B- Terminal. the plug you see with the brown and blue wire is normally not used. This brown connection can be energized with +12 volts to activate the backup internal regulator. Next the alternator temperature sensor is connected to the alternator and the wire is inserted into the split loom wiring harness and plugged in to the regulator.
Then with all these fiddly little wires pre-installed the alternator is put back on to the engine for the final time. The only connections that remain to be connected are the alternator output wires, both positive and negative, and the brown wire from the regulator which is that one that tell it to turn on.
I'm sorry that I wasn't able to photograph the rest of the wiring. Access was too tight and the lighting wasn't very good. I connected the battery temperature sensor to the battery and ran its wire back to the voltage regulator. I connected the brown wire of the regulator harness to the small red wire (top of the T plug) that went to the old alternator. You can figure out which is the correct wire by trial and error with a voltmeter, you want the wire that becomes +12 volts when the ignition is turned on. I used 2 awg positive and negative output wires and ran them all the way back to the house battery, with appropriate circuit protection on the positive wire. I put a rubber boot over the positive terminal at the back of the alternator so it wouldn't short out if you dropped a wrench down there. As the ARS5-H regulator was going to end up in a tight spot I left it out until I programmed it and did a test run of the completed installation. A video will follow showing the operation of the regulator:
In the video you will see that the AGM battery program was selected and because this job was done in cold weather you will see that the battery temperature was 6 Degrees C which allowed the regulator to increase the output voltage for the bulk charge quite a bit higher that the standard 14.3 Volts. You will also see that the alternator got quite hot, this is because we turned on the inverter to give it a big load to test it out. I didn't get hot enough for the temperature program to cut in and limit the output.
See also our blog post What is an alternator regulator and what does it do?
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