My 2007 Sportsman 500 EFI has developed a starting problem. Began as a failure to spin the starter with an old battery. Can hear the fuel pump charge, then the click of the starter solenoid when the key is turned more. Would start a couple of times then not. Let it sit for a day or two and the same would be true.

Did start with the recoil starter.

Replaced the battery which tested bad with a lithium ion unit and it started immediately. Now is doing that again. Battery voltage was 13.24. Is climbing very slowly with the correct battery tender.

What should the charging voltage be?

Is it likely that the starter assembly is the culprit?

Thanks,

Mike