Lately our 2018 Chieftain Dark Horse has had a pause while the starter is cranking, not starting unless I give ever so slight throttle when if fires (if not it stalls), and some time backfiring once. Yesterday, I rode to work and got code C1038 when starting to ride home. I just did a voltage check and the voltage dropped to 6.6XX & came back up to 12.XXX while the starter was cranking. Battery tender was plugged in all day. Battery is fully charged. I thinking it time to replace the battery even though the bike has only been in service since Oct 24, 2017 (we bought the bike used & didn't renew any warranty before it expired, so no warranty). What are your thoughts? Anything else I can check?