Back in the spring I bought a CMI 90A IR alternator. This charges my 2 GC2 batteries quite well. I rarely plug into shore power and use the Sterling ProCharge Ultra 30 charger I also purchased from @Maine Sail. I have the alternator output ran directly to the house bank with a service disconnect installed.
Several times I've checked the battery voltage after arriving at the boat and find 12.7 volts which I believe indicates a fully or near fully charged battery.
This week I've been able to sail every day. I motor about 15 minutes out and then 15 minutes back. Power consumption is GPS and auto pilot for the 3-5 hours of sailing.
On the ride back last night the alternator belt started squealing when I started the motor to come in. The tach would "turn off and on" and I could see the volt meter jumping as the alternator would load and unload. Then the tach went to zero and the volt meter only showed the battery voltage as the alt stopped charging. I backed off the throttle from 2500rpm to around 1500 rpm. The belt stopped squealing and I motored back in.
This morning I tightened the belt but the alt still wasn't charging, per the volt meter, and the tach remained at zero.
I have plenty of battery power so we went sailing anyway for the afternoon. When it was time to come back in I started the motor and still no tach or charging. After about 5 minutes I heard the motor load up and the tach came to life and the volt meter showed the alt was charging. The alt would load, then unload, a few times. Then it loaded up and stayed charging while we motored the final 10 minutes back to the dock.
We went out again to watch the sunset and motored for about an hour and the alt worked fine the entire time.
My first thought was the alt sense connection but this alternator internally senses the power at the alt output that is connected directly to the batteries. The only connections to the alternator are the output +, output - and tach sensor.
Any ideas why it stopped working for a while, even with a tight belt, then started again?
Several times I've checked the battery voltage after arriving at the boat and find 12.7 volts which I believe indicates a fully or near fully charged battery.
This week I've been able to sail every day. I motor about 15 minutes out and then 15 minutes back. Power consumption is GPS and auto pilot for the 3-5 hours of sailing.
On the ride back last night the alternator belt started squealing when I started the motor to come in. The tach would "turn off and on" and I could see the volt meter jumping as the alternator would load and unload. Then the tach went to zero and the volt meter only showed the battery voltage as the alt stopped charging. I backed off the throttle from 2500rpm to around 1500 rpm. The belt stopped squealing and I motored back in.
This morning I tightened the belt but the alt still wasn't charging, per the volt meter, and the tach remained at zero.
I have plenty of battery power so we went sailing anyway for the afternoon. When it was time to come back in I started the motor and still no tach or charging. After about 5 minutes I heard the motor load up and the tach came to life and the volt meter showed the alt was charging. The alt would load, then unload, a few times. Then it loaded up and stayed charging while we motored the final 10 minutes back to the dock.
We went out again to watch the sunset and motored for about an hour and the alt worked fine the entire time.
My first thought was the alt sense connection but this alternator internally senses the power at the alt output that is connected directly to the batteries. The only connections to the alternator are the output +, output - and tach sensor.
Any ideas why it stopped working for a while, even with a tight belt, then started again?
