Thank you for the question.
Part of the STC process is to thoroughly test and provide data (proof) that the battery is equal or better than what came with the aircraft and meets all the battery requirements needed. The reason many aircraft came with such high capacity (Ah) lead acid batteries is because you need more capacity to achieve higher cranking, not because the capacity is needed. The ETX900-TSO has the same cranking amps as the 35 Ah lead acid battery with 15.6Ah, which not only provides the 30 minutes of required energy in an alternator out situation, but typically will provide over an hour worth of energy for the equipment that you would be operating in an emergency situation. We do not have any plans to make a higher amp version at this time as it would cost more, weight more, and technically has shown not to be needed. I am always happy to talk with you if you would like to call, my number is 970.674.8884 x2, or we will be at the Oshkosh show next week in Hangar C if you are attending, you can come talk to us in person.
However, if you are a pilot that flies over ocean or rough terrain and there are no options for landing over a period of an hour, then having a higher capacity battery would be important for you and this battery may not be the best choice for you.
