Does anyone know what an alternative would be for the Capnostream 35 internal battery? Medtronic wants $1,000.00 to send it in to replace it every two years. The part number is SF00035. Lithium-Ion Rechargeable Battery. 7.2VDC/4.464Wh/IEC 2INP5/31/36. I have checked Interstate Batteries and cannot find a match. I have done general queries on the internet and can’t find anything either.