The shutdowns would likely be from the controller reaching its heat limit, it’s stored inside the compartment near the cranks with no air flow. The 35 amp controller would resolve that it has many more mosfets to handle heat buildup. The frame on the Aventure isn’t the best for a controller or battery upgrade but can still be done just less options.
Controller:
I would consider two options since the rear wheel is too close to the seat tube to mount the controller between. If you don’t mind the looks you could mount the controller on the other side of the seat tube in the triangle for max airflow, otherwise you could have it look cleaner in a rear rack bag. There’s a bit more chance of it overheating but I have builds like that with almost no issues. One thing to note is that I believe your motor has the L1019 motor cable connector and the controller has Z916’s. They sell small adapters for this where you buy the controller.
Battery:
The triangle frame is too small for a battery since the top tube dips down to accomadate more riders. On bikes like the Aventure with fully integrated batteries I prefer to mount a Hailong battery on the downtube, but yours is cutting it close and the bottle mounts look too low. If that won’t work one in a rear rack bag would be best.
Parellel battery device:
These are small and I would first open the controller compartment it will likely fit in there if you’re not using that controller, otherwise you could have it in the rear bag as well. These devices are great they not only double your range they also give you an extra 5%-15% distance since it’s cutting the amp draw in half the batteries aren’t breathing as hard and they will last longer.
KT 35 Amp Controller/LCD8H Display/L1019-Z916 Adapter/Maybe Throttle
(Verify your current throttle pins for the new controller yours is likely a yellow three pin, these need black 6 pin)
electrobikeworld.com
Parellel Battery Balancer
Affordable:
Specifications: 1.Dual battery converter MAX 72V 40AH*2 2.WIRE 80mm include XT60 end 3.Size 51mm*40mm*12mm Black
eunorau-ebike.com
High Quality:
Add a second battery to your electric bike today! NOT COMPATIBLE WITH REGEN! Blend any 2 batteries using even different voltages and chemistries Compatible with 72V and Under XT60 Connector: 30 Amp Rating/ 35Amp Rating Experimental (must allow adequate air flow around device)
www.sparkcycleworks.com
Battery
Either Hailong or blue square battery in rear rack bag
USA after-sale Service center This Item ships from United States , Can ship to most US States , don't ship to Hawaii , Alaska . Free tax , no custom value , and fast shipping with US Fedex .
www.uppbattery.com