How about having this little guy in the airplane at all times? Weighs less than 1 kg.
You would need the other half (which can be found quite bare)
plus a plug to go into your existing aircraft socket. Plus some 10cm of wires.
Peter wrote:
That could be done within 1kg.
That plug alone weighs from 0.7 to 1.1 kg, depending on the manufacturer.
What I would do, which may be as useful, is to make up a short converter cable to go from whatever external starting power connector you have, to the 3-pin plug I posted above. That could be done within 1kg.
The 28vdc cable I have was recovered from a military GPU that was powered by a six cylinder Ford petrol engine, when the GPU was working it would spin over a Barron engine at incredible speed and make light work of starting a RR dart.
To take the so much current the cable is huge and I guess that carrying it in my aircraft would result in a 100 mile reduction in range.
The only time I had a flat battery I hand propped the plane and continued on my way. Nowadays with a three bladed wood prop that’s not a safe option but jumper cables are usually available. I’ve never seen an owner use the ground power plug in light aircraft, and never considered carrying a cable to use it. That’s more of an maintenance shop thing IME.
Yes I do..I have a 14V system so more easy to find a suitable external power source
Until I read your initial post, I’ve never been thinking about the possibility to strand somewhere where a GPU is available but they don’t have the matching cable for it. Therefore I wouldn’t have thought of carrying a GPU cable with me.
But as most things in aviation I guess that is heavily depending on the “mission”: I can not remember when it has been the last time that I landed at an airfield without at least a local flying club. Therefore that “buying 2 automotive batteries” scenario is quite a bit outside of my personal frame of experience. People who more frequently go to more remote places obviously need to prepare differently.
I once had a hard starting piston on a remote Bahamas island and got it going with the last bit of battery. So that cable felt very good to have back then. But that was more a problem of this engine back then. So I will bring that cable to the hangar and have another few kilos payload :-)