At a minimum I'd suggest a GPU plug to jumper adapter, and ability to connect sufficiently sized 12 volts in series if weight is such an issue.
Had an issue on a cold morning at an airfield in Botswana in a 407 WI a dicky battery where we had to jury rig jumper cables (to a 24v battery from an islander kindly provided by the BDF)
Next trip like that definitely taking a portable GPU.