Van's Air Force
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SD-8 Alternator
- Thread starter szicree
- Start date
Not Enough
Steve,
The SD-8 on my -7 backs up the 40 amp alternator on an all-electric aircraft. I've played with it to find out how it performs should I ever need it. The SD-8 is 8 amps max, and it puts out very little juice at idle rpms, even well up into cruise there's little left after a few loads and IR losses nurse off it. (I wonder if it's not really a generator; it's permanent magnet and I don't know if the regulator also contains a rectifier.) The net consequence is that your starting battery is going to gradually die for lack of recharging.
The installed cost of an SD-8 is hundreds of dollars more than an alternator, it is only ounces lighter, and a more complex installation since it needs individual regulation components. Other than back-up for dual electronic ignition, I wouldn't install one. Even then, my current project is going to be dual battery rather than SD-8.
Oh, yeah. The SD-8 interferes with the sender if you use Van's tach, thus making you buy a tach cable and finding a place to hang the sender instead of simply screwing it into the back of the accessory case.
In short, a lone SD-8 makes a wimpy, expensive, clumsy source of electricity.
John Siebold
Steve,
The SD-8 on my -7 backs up the 40 amp alternator on an all-electric aircraft. I've played with it to find out how it performs should I ever need it. The SD-8 is 8 amps max, and it puts out very little juice at idle rpms, even well up into cruise there's little left after a few loads and IR losses nurse off it. (I wonder if it's not really a generator; it's permanent magnet and I don't know if the regulator also contains a rectifier.) The net consequence is that your starting battery is going to gradually die for lack of recharging.
The installed cost of an SD-8 is hundreds of dollars more than an alternator, it is only ounces lighter, and a more complex installation since it needs individual regulation components. Other than back-up for dual electronic ignition, I wouldn't install one. Even then, my current project is going to be dual battery rather than SD-8.
Oh, yeah. The SD-8 interferes with the sender if you use Van's tach, thus making you buy a tach cable and finding a place to hang the sender instead of simply screwing it into the back of the accessory case.
In short, a lone SD-8 makes a wimpy, expensive, clumsy source of electricity.
John Siebold
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Dad's RV-10
Well Known Member
How about GAMI's Supplenator?
Not sure of the price, but it's self exciting and rated at 30 amps.
Brad
Not sure of the price, but it's self exciting and rated at 30 amps.
Brad
gmcjetpilot
Well Known Member
Why not?
So a 8 amp PM alternator would work. Why not? You just can't go digital all electric panel and battery dependant Electronic ignition (EI). It has been done before with a basic VFR panel. With that said, a little fairly inexpensive 40 amp ND belt driven alternator can bolt to the front of the engine, or even a small 20 amp John Deer PM alternator. With the installed weight of a ND alternator at about 7lbs and low cost this may be more practical. You have the flywheel pulley there and nothing that needs to go in that space why not?
G
* You could drop almost 1 AMP of continuous load by replacing the battery contactor (relay) with a cool Kilovac (Tyco) relay that uses very little power to stay closed. It works on 12v and can handle 12-900V at 500amps continuous, weighs less than 1lb, is small and has magnetic latch relay. It is not like a latching relay that stays latched if power is removed, which could be bad. The current to keep the SPST relay closed is 0.13 amps. Typical "HOT" relay is almost 1 amp.
Not to disagree I know of a RV-4 with this set up and I heard no complaint. I love the idea of a simple day VFR RV. I looked into this. For bare bone VFR cruise I got about 4-6 amps, for worst case everything (Comm. transmitting, flap motor running, boost pump on) 9.1 amps max*.RV7ator said:
So a 8 amp PM alternator would work. Why not? You just can't go digital all electric panel and battery dependant Electronic ignition (EI). It has been done before with a basic VFR panel. With that said, a little fairly inexpensive 40 amp ND belt driven alternator can bolt to the front of the engine, or even a small 20 amp John Deer PM alternator. With the installed weight of a ND alternator at about 7lbs and low cost this may be more practical. You have the flywheel pulley there and nothing that needs to go in that space why not?
G
* You could drop almost 1 AMP of continuous load by replacing the battery contactor (relay) with a cool Kilovac (Tyco) relay that uses very little power to stay closed. It works on 12v and can handle 12-900V at 500amps continuous, weighs less than 1lb, is small and has magnetic latch relay. It is not like a latching relay that stays latched if power is removed, which could be bad. The current to keep the SPST relay closed is 0.13 amps. Typical "HOT" relay is almost 1 amp.
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Awesome info from everybody. Thanks a million. Now my next question is where do I get a good alternator? I suppose 30 amps should be more than enough for me. I'm still on the fence regarding the OV protection/internal/external regulator thing and would appreciate advice on this as well.
Steve Zicree
Steve Zicree
Bill Palmer
Well Known Member
SD-8 Install Picture?
Would someone please post an SD-8 install picture, or two? Specifically, I have an SD-8, and I'm planning to install it on my Lycoming angle-valve's vacuum-drive pad, but I'm wondering about the clearance with the tach drive. Will a tach drive 90-degree adapter clear the SD-8 okay, or do I need to use a tach cable to remote-mount a tach drive sensor?
Thank You,
Bill Palmer
RV-8A In-Work
Would someone please post an SD-8 install picture, or two? Specifically, I have an SD-8, and I'm planning to install it on my Lycoming angle-valve's vacuum-drive pad, but I'm wondering about the clearance with the tach drive. Will a tach drive 90-degree adapter clear the SD-8 okay, or do I need to use a tach cable to remote-mount a tach drive sensor?
Thank You,
Bill Palmer
RV-8A In-Work
Russ McCutcheon
Well Known Member
I am solely using an SD-8 on my day/night VFR -4 with no problems, at engine overhaul I replaced it with a new SD-8 and B&C said it would actually put out about 10A at an engine speed of 2450. I run KX155 nav/com, German 396, Rnav FC-10 fuel computer, intercom with one Bose ANR head set, the old one that uses power from the plane not remote battery powered, and engine gauges. I can even fly an hour or so with the nav lights on and still start the next day but I don?t think it is quite keeping up with the lights. I normally keep the plane plugged in to a battery tender but have also made many cross country flights/trips for more then a week and never had an issue maintaining the battery with ought plugging it in. This won?t work for everybody but for a basic VFR plane it does very well and is simple and clean.
Mine is on an IO-360 angle valve and as far as the tack goes mine is an Electronics International and I don?t know where it gets its signal but the tack output on the Acss case is caped and I don?t remember if it would interfere with it or not, it must be getting its signal from a mag would be my guess.
Mine is on an IO-360 angle valve and as far as the tack goes mine is an Electronics International and I don?t know where it gets its signal but the tack output on the Acss case is caped and I don?t remember if it would interfere with it or not, it must be getting its signal from a mag would be my guess.
Geico266
Well Known Member
Over load protection is important. I had an "automotive" alternator fail and charged my system with 18+ volts. Cooked my EFIS stand by battery $30, and was suspect in weakening my BMA EFIS1 mother board ($900 a month later). A friend of mine had the same "auto" alternator, cost him $2,500 in fixing a Dynon, radios & transponders when his failed full power. We both replaced ours with an alternators from Plane Power.
Take a look at Plane Power. Over load protection, lite weight, and 2 year warranty from DATE of purchase.
http://www.plane-power.com/
BTW, Van's now recommends, & sells Plane Power alternators.
Take a look at Plane Power. Over load protection, lite weight, and 2 year warranty from DATE of purchase.
http://www.plane-power.com/
BTW, Van's now recommends, & sells Plane Power alternators.
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Highflight
Well Known Member
Air UPSer said:
The Supplenator is intriguing, but the illustration at the top is a 3D Cad drawing (evidently, there is no actual product available for a real photo to be taken), plus the last update of that page was in "1-17/02".
Does that product even exist yet?... or will it ever?
I think if push came to shove, I'd vote for 8 Amps of real power (SD-8) over 30 Amps of nothing.
The SD-8 has been around a long time and has proven to be not only a reliable back up power generator, but a good stand-alone power generator for lightly equipped day/VFR aircraft.
That said, it would be nice if the Supplinator were an actual product you could put your hands on.
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Picture of SD-8 Install
Bill, you can see the SD-8 installed on my engine in the following picture post:
http://img207.imageshack.us/my.php?image=engineonstandlz5.jpg
It is the orange item installed on the accessory case (replaces the vacumn pump) next to the 90 degree oil filter adaptor.
Bill, you can see the SD-8 installed on my engine in the following picture post:
http://img207.imageshack.us/my.php?image=engineonstandlz5.jpg
It is the orange item installed on the accessory case (replaces the vacumn pump) next to the 90 degree oil filter adaptor.
mgomez
Well Known Member
Don't forget the battery charging load
I too was thinking of using the SD-8 to power my essential bus. I have installed two batteries, and plan on two alternators, two regulators, etc...in other words two separate electrical systems. I would like to be able to parallel the batteries for starting so the ess bus's battery will discharge a bit. The essential generator needs to be able to charge it. So I decided the SD-8 was a bit small, and was thinking of the SD-20. It's heavier, but the SD-8 was barely earning its way onto the airplane.
Cheers,
Martin
szicree said:
I too was thinking of using the SD-8 to power my essential bus. I have installed two batteries, and plan on two alternators, two regulators, etc...in other words two separate electrical systems. I would like to be able to parallel the batteries for starting so the ess bus's battery will discharge a bit. The essential generator needs to be able to charge it. So I decided the SD-8 was a bit small, and was thinking of the SD-20. It's heavier, but the SD-8 was barely earning its way onto the airplane.
Cheers,
Martin
Bill Palmer
Well Known Member
Pictures Help!
Thank You, Russ and Gary, for your SD-8 install pictures!
It looks like the SD-8 orange housing is a little too close to the tach drive to install a 90-degree adapter, or sender, directly to the drive. On the other hand, it looks like there's enough clearance to install a tach cable. So that's what I'll do: run a tach cable from the tach drive to a firewall-mounted sender.
Thanks Again!
Bill
Thank You, Russ and Gary, for your SD-8 install pictures!
It looks like the SD-8 orange housing is a little too close to the tach drive to install a 90-degree adapter, or sender, directly to the drive. On the other hand, it looks like there's enough clearance to install a tach cable. So that's what I'll do: run a tach cable from the tach drive to a firewall-mounted sender.
Thanks Again!
Bill
Boyd Birchler
Well Known Member
On acro planes we all used the SD8. Kept everything going, never saw any problems,but we did not have much equipment.
I had an SD8 on my Christen Eagle and it had no problem keeping up with the electrical loads of that airplane.
SL40 comm
GTX327 Xpdr
PM3000 Intercom
Garmin 196 on ships power
Fuel flow computer
No lights
SL40 comm
GTX327 Xpdr
PM3000 Intercom
Garmin 196 on ships power
Fuel flow computer
No lights
Gear Driven Alternators
Old thread, but it seems technology is moving forward. B&C now have a much wider range of beautiful gear driven alternators.
Seems like a better way to do it, although a bit more expensive.
I'll probably go this way if my current alternator fails.
Old thread, but it seems technology is moving forward. B&C now have a much wider range of beautiful gear driven alternators.
Seems like a better way to do it, although a bit more expensive.
I'll probably go this way if my current alternator fails.
Larry DeCamp
Well Known Member
Specific answers for Steve
The SD- on the top vac pad will not clear the tach cable signal generator supplied by Vans. I did not want a cable to the firewall so I built a short aluminum extension tube and drive cable to clear the SD-8.
Power demand flying is:
Battery contactor
Vans steam gauges 4
Mgl digital gauges 3
Fuel computor/ red cube 1
MGL V6 radio
Ifly 740 gps
Tip stobes 2
Always shows 14.2 volts at 2,300 RPM
The SD- on the top vac pad will not clear the tach cable signal generator supplied by Vans. I did not want a cable to the firewall so I built a short aluminum extension tube and drive cable to clear the SD-8.
Power demand flying is:
Battery contactor
Vans steam gauges 4
Mgl digital gauges 3
Fuel computor/ red cube 1
MGL V6 radio
Ifly 740 gps
Tip stobes 2
Always shows 14.2 volts at 2,300 RPM
Old thread, but it seems technology is moving forward. B&C now have a much wider range of beautiful gear driven alternators.
Seems like a better way to do it, although a bit more expensive.
I'll probably go this way if my current alternator fails.
This is what I'm running for my backup alternator on my vacuum pad, and it handles all flight loads just fine at normal flying RPM. That's dual Dynon, 430W, Lightspeed Plasma, and electric fuel pump in place of engine-driven. If I bring landing/strobe/nav lights online and pull the power below 1800 rpm then my voltage drops and the battery starts to contribute.
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gmcjetpilot
Well Known Member
I have researched this, even the larger pad mounted alternators do not make much more than 10 amps at idle. The weight savings is not that grea,t and there is a possible issue of shearing the spline drive (which can happen apparently). Also heat in the back of engine compartment might lower longevity of alternator?
Belt driven fwd alternator will make more power at all RPM's. and the extra weight of the brackets and belt is not that much. It should also be cooler up front then off the accessory pad off the back of the engine. Also the belt absorbs the power pulses of the engine. Vibration will not help an alternator but if you have good LORD mounts and balanced prop you should be OK there.
With that said a pad mounted alternator as your only source of power is an option. It will save some weight and move CG aft. If going B&C it will be expensive, plus cost of external voltage regulator. Plane Power has a pad mounted option with internal voltage regulator. Just be aware you are not going to be making much power to charge the battery and run electronic ignition, avionics and lights and iand...
Belt driven fwd alternator will make more power at all RPM's. and the extra weight of the brackets and belt is not that much. It should also be cooler up front then off the accessory pad off the back of the engine. Also the belt absorbs the power pulses of the engine. Vibration will not help an alternator but if you have good LORD mounts and balanced prop you should be OK there.
With that said a pad mounted alternator as your only source of power is an option. It will save some weight and move CG aft. If going B&C it will be expensive, plus cost of external voltage regulator. Plane Power has a pad mounted option with internal voltage regulator. Just be aware you are not going to be making much power to charge the battery and run electronic ignition, avionics and lights and iand...
