Need torque - Manco 615 with BLDC/MY1020 72V 3000W motor

We have a big old Manco 606 two seater go kart -- Strapped a ebay BLDC/MY1020 72V 3000W motor to it, running off six 12V 22AH AGM batteries. Motor sprocket is a 11 tooth going to a live axle 60 tooth drive gear -- that's turning 18 inch tires.

So far so good -- It can drive around on pavement and haul me around (200lbs) and a few kids -- but it will torque stall on a 20-30 degree off road incline when going from a dead stop.

As such I'd like to possibly add a second motor and controller --- Any recommendations? Just strap another MY1020 72V on there? Or can I add something a bit more torquey?

If its the battery low-voltage circuit cutting power, you might only need more or bigger batteries. Does it torque stall more easily as the batteries get lower?

I can hear the motor straining the chain when it can't get up the hill, so I don't believe it's the low-voltage circuit cutting power. I assume it's just the design of the non geared motor and the heavy weight of the kart and riders.

I'm using these batteries:
https://www.amazon.com/gp/product/B00K9E8RIY?pf_rd_r=Q0PWT82M5DWHYBY87EMW&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee

Rated discharge is quite high, and the controller I'm using is 55amps -- I have a inline maxi 60A fuse.

Also, hello Iowa! Grew up there.

Found an 80 tooth drive gear at BMI -- Going to throw it on to gear ratio some additional torque

https://www.bmikarts.com/Azusa-4140-Chain-Sprocket-Full_p_3752.html

So with the 80 tooth gear, all the inclines around the yard are no problem now. We lost a bit of speed on the top end, but for around the neighborhood that's probably a good thing. . .

So 300lb Manco two seater / side by side with ~ 300 lbs of passengers all running off a 72V 3000W BLDC MY1020 motor for $100. :lol: