R

rnewcomb7797

Member
Was planning on the PowerPlane Flysafe backup alternator but appears they are having production issues. Guess I'll be going with a B&C standby but haven't got a clue which specific model to get. Any suggestions greatly appreciated.
 
B&C

I would get the one referenced by Carl. My -14 if fully electrically dependent and uses 17 amps or less in cruise. That alternator will easily produce 30 amps in cruise.
 
1. Call B&C and discuss it with them. You won?t regret it.
2. I put one on my plane. As stated before, it will carry the entire load.
 
I wrote a KitPlanes article recently about this. Been installing a lot of B&C standby alternators ever since (although that was not my intent). You can?t go wrong with B&C.

Vic
 
Yes, I installed this alternator and it has performed very well. These spline driven alternators seem to be more RPM dependent, so at idle RPM I get a low voltage alarm on Bus 2 on my EFIS. Just be prepared for that.

Looking at past data, at 1000 rpm drawing 9 amps at startup I show 12.8v on my backup bus that was showing 12.6v with the alternator off. Anytime over 1400 rpm I'm showing >14v. After landing at 1000 rpm I show 13.2v until shutdown.

I turn on the master and backup batteries as soon as I get in the airplane, so the backup battery is drawing 9a until after startup. This can be as long as 5 minutes, getting seat belts on etc. So I attribute the lower voltage at startup to the alternator holding the load but not able to recharge the battery until I start flying. Then it quickly recharges the back up battery.
 
They are rpm dependent, but not *more* rpm dependent. The vac pad output simply turns too slow for the alternator to generate everything it's capable of. Look at the smaller, 8A B&C permanent magnet alternator. That alternator is actually a 20A alternator, when turned at its design rpm. The larger model is almost certainly a 60A model (might even be higher; I haven't looked closely at it). Both models are overdriven at least 2-1, often even ~3-1 to crank speed in their native environments. The low shaft rpm is the reason a 20A alternator only produces 8A at typical Lyc cruise rpm, mounted on the vac pad.

If the vac pad output is driven at 1-1.3, then anything near idle will have the alt turning <1500 rpm, and at cruise, ~3100 rpm. In its original design element, it would be turning >2000 rpm at design idle, and at normal engine operating rpm, it would be >5k rpm.

Not unlike a piston engine, alternator output is rpm dependent.
 
B&C Spline drive Alternator

rnewcomb7797 said:
Was planning on the PowerPlane Flysafe backup alternator but appears they are having production issues. Guess I'll be going with a B&C standby but haven't got a clue which specific model to get. Any suggestions greatly appreciated.
Click to expand...

If you are using the VPX electrical system then you will need the LR3C B&C regulator otherwise use the SB1B model, I’m surprised that this wasn’t asked.
HTH,
Jake
 
It tightens the space around the filter a bit but it?s still rather easy to extract and replace the oil filter without having to move anything. (IO-540)
 
iamtheari said:
How hard is it to change the oil filter with an alternator hanging off the vacuum pump pad?
Click to expand...

Not a problem. The alternator is not really in the way. I remove the filter from the left side and access is no worse than if the alternator wasn't there.
 
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