After close no-start situation with a cold temp start at an airport away from home base, I'm also planning to add emergency jump capability. I have a Nocco jump pack and they sell an extension cable that you can attached to the battery that can also be used to connect their battery charger/maintainer. It's an 8ga cable and only 18 inches but I think it will be long enough to reach out through the oil filler door in case I needed to use it with the pack.
Years ago, a DA42 was jumpstarted due to a dead battery and took off shortly after. The battery hadn't had a chance to recharge enough and when they retracted the gear, the electric motor drew enough current to pull the system voltage so low that the ECUs went offline. Result was a dual engine failure after takeoff and crash. They redesigned the system after that, but one reason why some planes have minimum battery charge levels.
Years ago, a DA42 was jumpstarted due to a dead battery and took off shortly after. The battery hadn't had a chance to recharge enough and when they retracted the gear, the electric motor drew enough current to pull the system voltage so low that the ECUs went offline. Result was a dual engine failure after takeoff and crash. They redesigned the system after that, but one reason why some planes have minimum battery charge levels.
I'm going to run a jump start receptacle about 4-5 feet from my battery on the firewall, would 6AWG be enough to carry the starter AMPS? I can do it in 4AWG but I'd like to make it as light as possible.
Many Thanks
I have an Anderson connector and 6AWG, but my run is only 8 inches, and the ground is #4. It is accessible via the oil door on my -7.
It has limited usage and if the engine is hard to start and battery completely dead it would only be used after several minutes of charging.
I consider it helping a weak battery to get a good spin, not for extended cranking, maybe 100A for 15 sec.
Actual usage is certainly problematic, and extreme caution advised.
Bill you wouldn't happen to have any pictures of your setup would you? Any motive/rational for wire size?
I have really been thinking about this mod a lot lately. Mainly to avoid a pissed off wife when my plane can't start multiple hours drive from home.
Sorry, the only photos found were mock ups for location and no final. I have been moving to a different hangar the last 2 weeks, I'll get you a picture on my next visit, it should be soon, more organization to be done .
Regarding wire, I figured that the use at high amps will be rare, and that it should be helping a weak, not dead battery. #6 is good for ~100 amps at ~100C so I "decided" it should be adequate for the rare case. If worried, then some charging prior to crank would be in order.