It's possible there is a problem with your charging system, and you aren't getting enough voltage for a good spark until the engine and generator are turning at a higher speed. (mechanics.stackexchange.com)
According to the company, the utility provides enough voltage configure options to push the cards to their limits. (digitaltrends.com)
Anything beyond 50 feet between your house and your solar panel placement is going to result in a big enough voltage drop that it will need to be addressed. (thetinylife.com)