I would like to have a full size secondary alternator in my all-electric Legacy. This way I won’t have to shed electrical loads if the primary alternator fails. I have been researching a pulley-driven alternator off the prop flange, and have found a few tantalizing clues.

 

The IOF240-B4 has a belt-driven alternator with a pulley that bolts to the prop flange. That pulley will fit our engines. The alternator mount brackets from the IO240 probably wouldn’t be any help because our crankcase is different. Fabricating brackets from scratch to fit my engine is a possibility.

 

The most intriguing option is the IO550P4. TCM’s accessory listing for this engine has an entry “AUX ALTERNATOR WITH FRONT MOUNT PROVISION”. Is anyone familiar with this option? I asked TCM, and they are scratching their heads as to what it means.

 

BTW, I also considered at using the rear-mounted air conditioner compressor bracket, but looks like the Legacy doesn’t have enough room between the engine and firewall for the pulleys.  

I am aware of the B&C 20amp alternator, and will keep that as a fallback if I can’t make this idea work.

 

Thanks,

Adam Molny

Legacy #151