Vans RV7 Build Diary - GAPilot

Fitting a B&C SD-8 Backup Alternator.

I have a glass cockpit and my inspector suggested I may like to fit a backup alternator.

I decide to fit the B&C Model SD-8 alternator. It is a spline-driven 14V alternator that fits to the vacuum pump drive pad. I have to say I have been rather disappointed with the 'system'. Some of this disapointment is the way it has been marketed. A popular website that advocates keeping your electrical system simply praises this 'system,' however, I have found the 'system' of a dynamo, regulator, over volt circuit, capacitor and relay etc has all the potential for problems. Especially with all the connections and joints etc.

The accessory drive I am informed rotates at 1.5 times the engine speed. See below for the output:
Engine RPM - Alt RPM - Current
2000rpm - 3000rpm - 6.8amps
2300rpm - 3450rpm - 4.3amps

The B&C SD-8 Alternator 'system'. SD-8, regulator, overvolt sensor, capacitor, relay and warning lamp.

The vacuume pump drive pad - on my Superior IO-360.

Here the SD-8 is fitted.

Another gripe - it would have been handy to know that the orange/red part of the alternator spins around!!

The regulator unit, this needs to be mounted to aid cooling. See the technical documentation for temp and voltage/amps range etc. I chose this position to enable the part to be removed easly - in case it needs replacing.


Home Page Construction Index Build Diary 2004 Build Diary 2005 Build Diary 2006 Tools Required to build Wings on about to roll out of the hanger for first engine start. Roberts RV6, we stop for fuel on the way to the RV fly-in at Colmar. The way to fit split pins properly - Aviation Standards!! First Test flight of G-OVII my RV7 carried out by Bob Cole at Thruxton on 18th November 2006. Here I am having just completed the first engine run.	Fitting a B&C SD-8 Backup Alternator. I have a glass cockpit and my inspector suggested I may like to fit a backup alternator. I decide to fit the B&C Model SD-8 alternator. It is a spline-driven 14V alternator that fits to the vacuum pump drive pad. I have to say I have been rather disappointed with the 'system'. Some of this disapointment is the way it has been marketed. A popular website that advocates keeping your electrical system simply praises this 'system,' however, I have found the 'system' of a dynamo, regulator, over volt circuit, capacitor and relay etc has all the potential for problems. Especially with all the connections and joints etc. The accessory drive I am informed rotates at 1.5 times the engine speed. See below for the output: Engine RPM - Alt RPM - Current 2000rpm - 3000rpm - 6.8amps 2300rpm - 3450rpm - 4.3amps The B&C SD-8 Alternator 'system'. SD-8, regulator, overvolt sensor, capacitor, relay and warning lamp. The vacuume pump drive pad - on my Superior IO-360. Here the SD-8 is fitted. Another gripe - it would have been handy to know that the orange/red part of the alternator spins around!! The regulator unit, this needs to be mounted to aid cooling. See the technical documentation for temp and voltage/amps range etc. I chose this position to enable the part to be removed easly - in case it needs replacing.
	I have fitted the capacitor on the other side of the panel brace to the regulator. Fitted with a nutplate to aid removal. The overvolt sensor and relay. The relay is mounted on the rear of the instrument subpanel. The screws are on the front of the subpanel so they are easier to remove. I made the bracket to hold the relay in place - using nutplates and bracket to make it easier to maintain.