Polarna Custom 52v Issues - Overheating, power cutoff, and seat options

[mr brandon]

Hello,

I have two of the Polarna X-01 which have had most parts replaced.
This parts list is my primary, the other one doesn't have the YSS/sur-ron brakes:

DNM Volcano fork + rebuild F wheel on thru-axle hub
YSS shocks (335mm, could be longer)
Bafang G063 motor
KT 35A controller (sinewave w/light model, wired directly with crimp connectors, no plastic Anderson connectors)
Sur-Ron metal tube throttle wired in
12v buck converter - 2 headlights + horn
accelerometer brake light (no wiring reqd)
1/2" gel seat pad + seat cover
Drift King cranks
ODI Oury grips
Left Mirror
Sur-Ron brake caliper/lever with Warp9 levers - 203f/180r
CST Scout tires

This bike has a few issues:
1) overheats more frequently now after ~3 minutes of ~25mph riding, which is full throttle on a mild grade. I suspect the controller as the connectors aren't melted this time. Maybe the mosfets are having an issue from heat, I recently hauled an air conditioner home (+400 ft hill) on a bin velcro'd to the bars/fork, and noticed a power/heat difference after. The Anderson connects melted about 3 months ago so I cut them out and wired directly to the motor's 3 power wires. I also do Costco runs with this bike.

I'm interested in going to a higher power controller. First because of the heat issue, and I want to go to 60/72V batteries when these 52V die, which could be another 2-3 years from now. My speed is capped at 28mph but below 50v it's below 25mph on a mild grade and I can't ride with traffic. I would like to have that option. I've seen 45A controllers come with a ceramic connector block and round connects on the wires that are fastened inside. This seems way more robust than the Anderson or even going direct. But I understand that you're not supposed to use a controller with Amp output higher than the battery BMS. I don't know if trusting these cheap controllers / displays to limit amp output is a good idea. I'm also concerned about losing range going from a 52v25ah battery to a 60v19.5ah battery, for instance. Eventually I might try to cool the motor further like w/liquid per another user's post on here. I am also replacing the plastic gears inside the motor as from the feel of it they have exploded again.

Is there a cheap-ish controller than can do both 52V and 60/72V? What connectors would I be putting on the motor's cable? I'll be replacing the cable next as it's been cut down from several replacements. My current controller was ~$40 and I am on #3. I also am worried about theft.

2) The stock seat was so bad, so I replaced it, but the replacement was just as bad so I added gel and a cover velcro'd on top. It looks really bad and needs constant re-adjusting so I'm also looking for a seat. Unfortunately the bolt pattern is not that common. Super73, sur-ron, don't use this pattern. The original seller page is gone so I'd have to measure the bolt holes distances to give any more useful info. Is there a universal seat adapter or something we can use to get around this issue?

Pics for attention. And some riding clip

Thanks to the community for sharing your knowledge. Please feel free to make any suggestions or recommendations.

 

[amberwolf]

Note that when you go to higher power usage, you'll need batteries that can support that higher power. If your present batteries were made to run this bike they almost certainly can't handle anything more (and probably can barely maybe handle it's demands).

Before you buy new stuff, first determine the worst case job you need this to do for you under the worst case riding conditions, and then use the various simulators / calculators like those at ebikes.ca to find out how much power that will take. Then use that guesstimate to find motor, controller, and battery that can do that job.