125-200cc More power(electrical)needed

2016 TE 300
44-1
Lectron
Engine ice
Trail Tech digi fan set at 180f
Garmin Montana hard wired to battery
Stock headlight(rarely used)

Bike runs great, a bit of spooge, no boil overs.
Most of my riding is intermediate-expert singletrack trail.

The other day I rode Foresthill tr. 6, approx 16mi loop. We did it twice. About 90f out, tons of dust, and yes, loads of fun!

*Midway through loop 2 my battery lost enough power that the starter output was weakened, unable to start a warm bike. My bike normally starts right up, cold or hot.
**The fan, set at 180, seemed to run a lot, and would kick on for 30sec-1min after shutting bike.
***So I'm thinking the fan tried to kill the battery

Next day I check static voltage, 12.4, charge for a while, battery comes up to 13.6.
After disconnecting charger the voltage slacks off(4-5min) to about 13.3

No simple answers I'm sure.

I will check charging system soon.

Can you guys comment on possible solutions such as:

Rewound stator for more power(Trail tech, Ricky, BD)
Stronger battery, ?Lithium?
Reset fan temp, lower/higher?

thanks,
Phil