07 rev not starting with dead battery

So I have a 07 summit x with 09 motor, I have had it for about 3 years and I have never ran it with a battery. It's always been stubborn getting it started when the engine is warmed up, usually 4 hard pulls. My father in law told me that the battery might play a role in the spark and to try it, so I took the battery from my bike, which was dead but I charged it before I put in and the sled fired up with the pull start a lot easier when it was warm. Anyways, I took it out today and after about a half hour I shut it off and ate for about 20 minutes, went to get going again and I have it a good 25 pills and it wouldn't turn over, i have heard some people say it will and some say it won't start with a dead battery so I pulled the positive off and it again fired up after about 4 pulls. Anyone ever dealt with anything similar, after researching on here it sounds like it's most likely a relay that charges the battery so I'm gonna try that and replace the battery, but I'm just curious if anyone has experienced anything similar or if their sled starts easier with a charged battery.
Thanks in advance