I remember that powering the stargate requires a lot of energy. Is it really possible to "jump start" the gate using an old car (as in Stargate Origins season 1 episode 3)?
closed as primarily opinion-based by Helbent IV, Buzz, Ward - Reinstate Monica, Valorum, Edlothiad Jul 21 '18 at 8:05
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While it is never explicitly stated stargates are constantly absorbing ambient energy from their surroundings. A staff blast, for example, hitting the gate would increase its charge level, a gate would always be slightly cold to the touch because it absorbs heat etc.
When you actually want to dial a gate in an emergency situation (without a DHD) you have to provide direct current to the gate so the ring unlocks and you can turn it (possibly a safety feature).
We see this several times in the SG-1 season 1 episode "The Torment of Tantalus", season 2 episode "Prisoners" and season 2 episode "1969" in which they actually use car, well truck batteries to provide the unlocking charge to the gate.