Many thanks for all your I formation... I will open an old box and have a look... I don't know about root causes other than bad design... If they had stuck with relays all would be fine... As for symptoms.. There were none... Just instantaneous failure.
My D1 30 of 2017 vintage and relatively light use has had three MDI failures... 4th box fine so far... Bypass switches installed for glowplugs and starter motor installed as backup. Online searches indicate possible cause being a back EMF from the fuel shut off solved by a simple diode across...
No worries... Energy is finite in quantity as the universe is a closed system apparently... On the other hand charging FOR things will deplete ones finite resources for sure....
I carry a 3m square of trawler quality fishing net. The inner end attaches to two mooring cleats and the outer corners to be lifted by the boom and mainsheet once the casualty is alongside and within the net who can be rolled inboard once raised to deck level.. ..as advised by a wily old skipper...
I don't carry a knife ashore. However I once bought a nice Buck penknife in the US... The shop assistant approved my choice as being a "good Christian knife"...I had to ask why so... and was told that apparently the Buck company contribute to their chosen church organisation.... I couldn't but...