Piper J3
Well Known Member
I don’t want to get stranded with a dead battery caused by either the battery itself or the voltage regulator going on the fritz. The Rotax 912 uses capacitance discharge (CD) ignitions vs. magnetos as used on most other aircraft engines. The consequence is that you cannot hand prop the engine if the electric starter doesn’t do its job. The CD ignitions need ~ 500 rpm to self-generate enough voltage to create spark. You’re not going to hand prop (read: backdrive) a 2.4:1 gearbox – ain’t going to happen.
So, I’ve been thinking about what to do if the Odyssey battery ever lets me down in a remote location. No problem if battery goes dead in flight – engine keeps running. But can’t restart if you shut engine off.
For total cost of $70.40 I bought the following items on eBay to put a starter package together:
The RV-12 Odyssey PC680 is rated 12 Volt / 16 Ah / 170 CCA. The 82800mAh Lithium Starter Pack with advertised 200A Starting Current is able to start up to 5L gas or 2L diesel engine. The 912ULS is 1.35L so the Starter pack should crank it just fine. I used 8 AWG silicone wire to allow the battery to sit on ground and still connect to the Odyssey airplane battery. Then I added a second set of clamps just in case a Good Samaritan would come along and provide a 12-volt power source.
When completed, I tested the starter pack by jumping a totally dead 26 HP garden tractor. Cranked fast and fired right up...
82800mAh Portable Car Jump Starter Pack
Battery Clamps w/ Fuse
Ring Terminal for 8AWG
Remove Plastic Insulation
Crimp Wire and Insert Under Copper Jaw
Finished Battery Clamp with 8AWG Extension Wire
Completed Assembly
82800mAh Lithium Battery
99% Remaining After Cranking/Starting Dead 26HP Tractor
Ready for RV-12 Baggage Compartment
So, I’ve been thinking about what to do if the Odyssey battery ever lets me down in a remote location. No problem if battery goes dead in flight – engine keeps running. But can’t restart if you shut engine off.
For total cost of $70.40 I bought the following items on eBay to put a starter package together:
- LED 82800mAh Portable Car Jump Starter Pack Booster Charger Battery Power Bank J
- 8 Gauge Silicone Wire 10 feet (2x5') 8 AWG Silicone Wire Flexible Silicone Wire
- Jumper Cable EC5 Connector Alligator Clamp Booster Battery for Car Jump Starters
The RV-12 Odyssey PC680 is rated 12 Volt / 16 Ah / 170 CCA. The 82800mAh Lithium Starter Pack with advertised 200A Starting Current is able to start up to 5L gas or 2L diesel engine. The 912ULS is 1.35L so the Starter pack should crank it just fine. I used 8 AWG silicone wire to allow the battery to sit on ground and still connect to the Odyssey airplane battery. Then I added a second set of clamps just in case a Good Samaritan would come along and provide a 12-volt power source.
When completed, I tested the starter pack by jumping a totally dead 26 HP garden tractor. Cranked fast and fired right up...
82800mAh Portable Car Jump Starter Pack
Battery Clamps w/ Fuse
Ring Terminal for 8AWG
Remove Plastic Insulation
Crimp Wire and Insert Under Copper Jaw
Finished Battery Clamp with 8AWG Extension Wire
Completed Assembly
82800mAh Lithium Battery
99% Remaining After Cranking/Starting Dead 26HP Tractor
Ready for RV-12 Baggage Compartment
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