I just transfered the 1 yo batteries from my dying Ryobi to the B/D CMM1000. Batteries are expensive to ship so if you can find them locally, the cost will be much less. The Interstate batteries that fit into the CMM1000 were BSL 1116. You'll need 2 of these 12v 18Ah batteries. The terminals are different than the B/D batteries, but it wasn't a problem to bend the wiring eyelets.