if they are still the original batteries, they maybe garbage. I bought my e300 on ebay and my batteries were crap. I think that the scooter sat a long time before I bought it. these batteries will die if left uncharged for a long time. it should be perfectly fine running 1.5m charging then running back and charging. that will not hurt the battery. you should get 200cycles, but that's about it? I got a year of hard riding out of my batteries. I rode in all seasons.
If your batteries are dying they lose capacity so they are more like 5ah batteries than 7ah...when they get tired the motor demands more draw and the breaker trips to prevent the battery from overdraining.
my guess is your breaker(or reset button) is only 15amps and you controller is 20-30amps. so if you change to a 30amp setup you won't trip on hills and such. I would browse CL for beater scooters with a little more power and building options. the e300 is great! I'm a fan of razor controllers. I've had 2 others. 1 was a 24-60v and I didn't agree with it. The other is the 40amp 48v on my electric mini bike. it's ok but it's more "soft start" razor controllers have very snappy response, but have have a wide path to full throttle. you can crawl or sky rocket or cruise.
Any way bigger wheels, more deckspace,, and gearing choices are all turn ons. If you're lucky you can find one that just needs guts and volts on the cheap.
You may also want to look into weather proofing your electronics, chain, motor housing and shaft. Last year the salt on the sidewalks rusted my MX500. use chain wax and maybe some silcone sealant ...using it in the open ends of your harnesses or hot glue!
I think there are some weather threads on here if not on the old forum for sure. I wanted to put my whole battery tray into a storage tub type deal.