Not sure if this would work better for you or not, but you could mae a little battery pack by hooking 6 sets of AAs in serries and use as many of those as you want in parallel to give your 9v output a much longer life. 2 sets of six would double your capacity, 3 would tripple it, and so on. Additionally, if you want to use rechargeable, you could use rechargeable AAs insteaad. Amd i think you can buy per made battery holders for your 6 in series on amason.