Alternator tension device

[Boat]

Hi all, just got the alternator tension spring kit from Moyer. I have a question as to what belt to use. i have the high output alternator also from moyer. I have the longer mounting arm as well. do i use the new arm that comes with the kit? what size belt works best? i have two new 26" will that be to long for the tensioning spring to work properly?

[ndutton]

As far as I know here is nothing special about the curved adjustment arm included with the tensioner other than it's clean and smooth allowing the alternator to move smoothly on the tensioner. A rusty, chewed up or otherwise deteriorated arm would not be good.

[Boat]

Thanks, i like shiny new parts but if i dont have to change it i would rather not i have to pull the motor this winter anyway to replace the fuel tank so will change it then. the high output alternator is a bit much. i keep smoking belts. i did just see the larger pully for the accessory drive, is that difficult to change while the drive is on the motor?

[JOHN COOKSON]

i keep smoking belts. i did just see the larger pully for the accessory drive, is that difficult to change while the drive is on the motor?

Check the pulley alignment. This can be done with a dowel or other straight edge that fits into the groves similar to how the belt fits into the groves.
Not sure this is true but lateral force on the pulley can shorten bearing life?

ex TRUE GRIT

[joe_db]

Thanks, i like shiny new parts but if i dont have to change it i would rather not i have to pull the motor this winter anyway to replace the fuel tank so will change it then. the high output alternator is a bit much. i keep smoking belts. i did just see the larger pully for the accessory drive, is that difficult to change while the drive is on the motor?

Tightness* and alignment has been mentioned, the other possibility is plain old overload. My regulator has a smooth start feature where it slowly ramps up to lesson sudden belt loads. I also have a load limit setting to dial in the max percentage of full field to reduce belt load if needed.
What kind of alternator do you have and how many amps are you getting out of it?

* a loose belt will slip and heat the pulley, which will eventually damage the alternator

[Boat]

thanks all. got it all hooked up. i did find that my mounting arm was on the wrong side of the attachment down on the bottom. i did have a bit of misalignment in the setup. all good now and we will see how long it goes. i think i have a bit to much alternator for my setup. its the 100 amp rig from moyer. maybe the 55 amp one is better suited.

[sastanley]

I think you'll find the arm in the correct spot may help with the belt issues. Don't forget to follow up!!

[joe_db]

thanks all. got it all hooked up. i did find that my mounting arm was on the wrong side of the attachment down on the bottom. i did have a bit of misalignment in the setup. all good now and we will see how long it goes. i think i have a bit to much alternator for my setup. its the 100 amp rig from moyer. maybe the 55 amp one is better suited.

You need an ammeter. I will be very surprised if you get more than 50 amps out of your setup.

[JOHN COOKSON]

i did find that my mounting arm was on the wrong side of the attachment down on the bottom. i did have a bit of misalignment in the setup..

Been down this road. This is really easy to do. As mentioned, I'm sure having the pulleys in correct alignment will help the belt issue.

ex TRUE GRIT

[ndutton]

What determines the load on the engine, pulleys and belt from alternator load is the battery State of Charge (SOC), not the size of the alternator alone. A 35A alternator delivering 35 amps will impart the same load as a 105A alternator delivering the same 35 amps. The difference is the 105A alt will be cruising along easily at a third of its rating while the 35A alt will be straining at maximum.

I run a 105A alt and monitor its output via a digital Gauss loop ammeter. I don't make a habit of running my batteries down and charge them in banks. The greatest amperage I've ever seen is around 50A (~1500 engine RPM=2600 alt RPM approx.) as Joe mentioned and that rate was short lived as the battery SOC came up with a corresponding drop in charge rate.