RadMini 4 Controller upgrade review

[Altema]

Thank you so much for the review and updates. I have a mini I plan on upgrading as well but Im nervous about the 35 amp wire being too short on the controller and having to solder the wires together to make an extension? So you didnt have to do that to the 25 amp controller?

No extensions were used for the 25 amp controller, but I did have to run the cable in front of the controller to help it reach. You can see it in the two photos below.
The 35 amp version has the same length cable for the display, but the controller itself is longer, so it may need an extension. I'll test that out later today and let you know if the 35 amp controller can be installed without an extension. Right now I have the 35 amp zip-tied on top of the 25 amp, so both are on the bike in piggyback fashion for testing.

[Altema]

The 35 amp controller is in! Well, partially, anyways. Kyle from Bolton was right; both controllers use the same trapezoidal waveform. However, the 35 amp controller is two stage: It starts off in a low power mode, then switches to a high power mode. I don't know if the switch to high power mode is based on RPM or power demand, but I'll find out later today. After doing bench tests, I took it for a ride, and you can feel the high power mode engage like a turbo kicking in. It's a hoot, and although it's not any quieter, the absurd power kind of makes you forget about it.

I'll have more info later, but here are some initial impressions of the 35 amp controller.
1. The larger controller will fit in the stock location on the RadMini 4.
2. The noise levels are quieter in low power mode, slightly louder at full throttle.
3. PAS levels are higher, even with setting C14 set to "01", so you will need to adjust yourself. PAS 3 is over 400 watts.
4. The 35 and 25 amp controller both surge at top speed. 19mph, 20mph, 19mph, 20mph... you get the picture.
5. The two stage power output is a good thing, as starting off at full power would flip you on your back.
6. The 35 amp controller output is 1600 watts observed.

[Altema]

Loulou718 - I installed the 35 amp controller, and the cable to the display is a bit short, but I was able to make it work. I'm going to ask Electro Bike World and Bolton if they have a 3 or 4 inch extension. Attached is a photo of the temporary work around.

[Loulou718]

Loulou718 - I installed the 35 amp controller, and the cable to the display is a bit short, but I was able to make it work. I'm going to ask Electro Bike World and Bolton if they have a 3 or 4 inch extension. Attached is a photo of the temporary work around.

That is awesome news thank you for all the updates!! Im gonna go ahead and order the upgrades in early Dec, cant wait to take on this project.

[Altema]

I took my first "long" ride today with the 35 amp controller. 15 miles on wet trails, and I went out of my way to climb one of the steepest hills around. PAS level 2 is my new best friend, as PAS 3 is just too much power now (over 400 watts). I don't feel like dialing back the overall power, but I did adjust the PAS group control to the lowest level (C14=1). Oddly, battery range is better than the 25 amp controller, and seems on par with the stock setup. This morning's ride, with lots of full throttle, some cruise control, and the uphill stress test on throttle only, still left me with the battery at 55%. That should mean 30 to 45 miles of range.

[Altema]

Update: I've confirmed the 35 amp controller is a more efficient than the 25 amp one, but still not as efficient as the Rad controller.
From my own experience with mixed use and multiple charge cycles...

With Single battery
Stock Rad: 30 to 40 miles
35 amp upgrade: 25 to 30 miles
25 amp upgrade: 20 to 25 miles

With Dual battery
Stock Rad: 60 to 80 miles
35 amp upgrade: 50 to 65 miles
25 amp upgrade: 40 to 55 miles

The experience a low battery is the same with both upgrade controllers, but very different from the Rad controller.
The stock Rad controller gradually decreases power output in a very linear fashion. After that last bar is blinking it will slow to a crawl, but keep going quite a while.
The upgrade controllers also decrease power, but it's not as noticeable until the end. It will still accelerate somewhat strongly, but when you do, the voltage drops below the cut off threshold and the motor will turn off. You can pedal for a minute and the motor will start working again, but the only way to keep it working is to avoid the throttle and use a lower PAS level. I'd say the Rad power management is much more predictable.
 

[Altema]

Just as little update on the status. With winter now being on the scene here, I've decide to leave the upgrade in place. The 25 amp version was not worth the range loss and noise, and if that was all I had I'd probably be sticking to the original controller all the time. However, the 35 amp version is more efficient than the 25, and the extra power makes the noise more tolerable. The other factor is there are fewer other people sharing the bike paths, and with more time being spend on desolate routes, I'm using the cruise control more. We shall se when summer rolls around, and more people are enjoying the peace and quiet. But for now, the extra power comes in handy slogging through mud and snow.

PS: I've added this comment to the original post as well, in case someone reads it and thinks the controller upgrade is a waste of time. It isn't, but there are still situations where I prefer the stock controller.

[anotherviktor]

Just as little update on the status. With winter now being on the scene here, I've decide to leave the upgrade in place. The 25 amp version was not worth the range loss and noise, and if that was all I had I'd probably be sticking to the original controller all the time. However, the 35 amp version is more efficient than the 25, and the extra power makes the noise more tolerable. The other factor is there are fewer other people sharing the bike paths, and with more time being spend on desolate routes, I'm using the cruise control more. We shall se when summer rolls around, and more people are enjoying the peace and quiet. But for now, the extra power comes in handy slogging through mud and snow.

PS: I've added this comment to the original post as well, in case someone reads it and thinks the controller upgrade is a waste of time. It isn't, but there are still situations where I prefer the stock controller.

The whole thread with your updates is quite interesting! I'm wondering, what is the amp max current in the US stock controller? I've been considering the idea of buying a stock US controller from someone to upgrade my RR+ EU - The "limited" 250W setup is decent but I need just a bit more power for some hills, thinking that the 35A controller would be an overkill.

[Altema]

The stock Rad controller is around 17.2 amps for the US version. There is a 25 amp version available from Electro Bike World, but I believe there is a store in the UK that sells it as well. I don't recommend it though, as it is not very efficient and will shorten your battery range quite a bit.

[Altema]

Something had bothered me from the start about the upgrade, so I took the main cable from the controller to the display, and cut it!
No, it was not self-inflicted vandalism. This specific cable has been too short from day one, and had to be routed in front of the controller, then suspended in cable tie loops to make up for the shortness. I used the cable from my unused 25 amp controller, cut it long, and spliced it onto the 35 amp controller to make it several inches longer. This enabled me to finally route it along the back of the controller, and through the proper frame loops to the front display. The photos show the short cable routing, then the splice in progress, the splice completed, and finally the cable routed properly. It should be noted that the cable never gave me any trouble, but I knew it was not optimal, and it prevented me from using a skid plate.

There are ten wires in this cable, and neither Bolton nor Electro Bike World had extensions. I cut five wires short and five long, then cut the other side to match, and this prevents all the splices from bunching up in the same spot. I used shrink wrap tubing on the main housing, and smaller shrink tubing on the individual splices. Each splice was checked to make sure there were no cold joints, then the tubing slid over and heated, then the main tube was slid into position and heated. The shrink tubing is tight, but RTV sealant will be used for extra protection against moisture. Note that in the picture of the individual splices, the shrink tubing is not yet complete. Everything was plugged back in and the batteries re-connected, and all worked perfectly.

Now the cable is in it's proper place and protected, there is no longer tension on the front cable group, and I can also install the skid plate that's been siting on the floor!

[FortunatelyTheMilk]

Nice work! This isn't your first rodeo, it's very near!

[RideIdaho]

Outstanding.  Thank you so much for all of this info.  Can you try to explain the difference in loudness from the 35 upgrade to stock.  I know that is kind of hard, but that is my biggest hang up.

[Altema]

Outstanding.  Thank you so much for all of this info.  Can you try to explain the difference in loudness from the 35 upgrade to stock.  I know that is kind of hard, but that is my biggest hang up.

At full speed, the volume is about the same, just different in nature. The big difference is at low power. For example, when in pedal assist level 2 and going about 10mph, the tires are the loudest noise. With the upgrade controller, the hum of motor is the loudest noise. It's annoying to some people, and I got used to it after a month or so, but still wish I had the more refined Rad controller for those quiet rides by the lake or through the woods.

[reggy]

By the way, I did a deep dive on some of the more useful settings, and thought I'd document them.

The C14 setting is not mentioned most of the time, but it adjusts the pedal assist levels. The settings are 1, 2, and 3, with each level increasing the power of the PAS levels. 2 is default, but I changed mine to 1 to get the PAS closer to how I usually ride.

Setting C5 changes the maximum power sent to the motor, but the manual did not mention the special functions of settings 02, 01, and 00. Those last three deliver full power, but with a curve that builds up to full power. This curve is based on time, not speed, so if you are already going 10 mph, it still takes the same amount of time to get to full power. This is useful if you don't want to get hit suddenly with full power, like when carrying a passenger or cargo.

C5 (Controller Maximum Current Adjustment Mode, 00 - 10)

  C5=10: 1200 watts, 1170 watts observed
  C5=09: 1176 watts, 1070 watts observed
  C5=08: 1128 watts, 1010 watts observed
  C5=07: 1056 watts, 960 watts observed
  C5=06: 960 watts, 930 watts observed
  C5=05: 840 watts, 880 watts observed
  C5=04: 696 watts, 770 watts observed
  C5=03: 528 watts, 570 watts observed
  C5=02: 1150 watts observed, soft start
  C5=01: 1150 watts observed, softer start
  C5=00: 1150 watts observed, softest start

Thanks for sharing very helpful. I have a canadian radmini4 with has a 500 watt motor. I've set C5=04. Any danger to motor when supplying more than 500 watts? How much power can these 500 watt motors handle consistently without burning out?

[Altema]

By the way, I did a deep dive on some of the more useful settings, and thought I'd document them.

The C14 setting is not mentioned most of the time, but it adjusts the pedal assist levels. The settings are 1, 2, and 3, with each level increasing the power of the PAS levels. 2 is default, but I changed mine to 1 to get the PAS closer to how I usually ride.

Setting C5 changes the maximum power sent to the motor, but the manual did not mention the special functions of settings 02, 01, and 00. Those last three deliver full power, but with a curve that builds up to full power. This curve is based on time, not speed, so if you are already going 10 mph, it still takes the same amount of time to get to full power. This is useful if you don't want to get hit suddenly with full power, like when carrying a passenger or cargo.

C5 (Controller Maximum Current Adjustment Mode, 00 - 10)

  C5=10: 1200 watts, 1170 watts observed
  C5=09: 1176 watts, 1070 watts observed
  C5=08: 1128 watts, 1010 watts observed
  C5=07: 1056 watts, 960 watts observed
  C5=06: 960 watts, 930 watts observed
  C5=05: 840 watts, 880 watts observed
  C5=04: 696 watts, 770 watts observed
  C5=03: 528 watts, 570 watts observed
  C5=02: 1150 watts observed, soft start
  C5=01: 1150 watts observed, softer start
  C5=00: 1150 watts observed, softest start

Thanks for sharing very helpful. I have a canadian radmini4 with has a 500 watt motor. I've set C5=04. Any danger to motor when supplying more than 500 watts? How much power can these 500 watt motors handle consistently without burning out?

I don't know if the Canadian motor is physically the same as the US motor, but the peak rating of Bafang motors is usually double the nominal rating, so you should be safe with the C5=04 setting. The "nominal" rating of a motor in most cases is simply the maximum power level that it can maintain at 100% duty cycle and never overheat. Putting more power into the motor will cause the heat to build up, but it does not become a problem unless the motor is held at that elevated power level for long periods.