I also made an adapter to hold an extra battery on the back rack: https://www.prusaprinters.org/prints/69891-rad-power-radcity-ebike-battery-holder-for-rack-or

I thought it would be useful if we could use our RAD eBike battery for back-up power or for camping. I designed and 3D printed a battery adapter. I also verified that you can use an MPPT solar charge controller to charge the battery. You can charge it at 120W while using the output power. Now we just have to convince RAD Power to manufacture/sell something like this as an accessory 🙂

I put the 3D print files at: https://www.prusaprinters.org/prints/70263-rad-power-ebike-battery-adapter

https://youtu.be/vP13pjChTB4

The two batteries are clearly made by different companies or are different revisions. Notice the size of the Fuse labeling, the different lock, number of case screws and case vents. The newer one that works has a serial number

Very interesting result. I just received my second RAD Power battery. This one works just hooking up the +/- ! The battery that came with my eBike doesn't. They are made by two different manufacturers or at least are marked differently. The one that works says model HL-RP-S1304. The serial number starts with DDLGRPE4814. The one that doesn't just says RP1304AA..... What does your's say? They both work in the ebike.

I got a lot of suggestions for improvements on the RAD Owners Facebook Group.

• Rotated the compartment to go along the frame
• Added more drainage holes
• Added a rubberband hole and hook
• Put some 3D foam tape in holder bottom

The harborfreight reflective strips work nice ( https://www.harborfreight.com/10-piece-reflective-tape-97562.html )
I ordered a short USB phone cable

I put the updated 3D Print model on: https://www.prusaprinters.org/prints/70154-rad-power-ebike-cell-phone-holder-for-front-rack-b and
https://www.thingiverse.com/thing:4896651

My wife wanted a way to have easy access to her cell phone while she was riding. Her Radcity Step-thru 3 has four bolt holes on the front fork. They can be used for a front rack. I designed a small box to hold her phone that uses these bolt holes. I also used the front facing surface to mount reflective tape to make her more visible at night. I mounted it on the biker's right side so it would not interfere with the cables.

I put the 3D print file at: https://www.prusaprinters.org/prints/70058-rad-power-ebike-phone-holder and at: https://www.thingiverse.com/thing:4895813

This is my first cut. I'm thinking of making a lid that flips to the side so the compartment would be waterproof. Any other suggestions for improvements?

Here is a Radcity Step-thru 3 rack spare battery holder: https://www.thingiverse.com/thing:4894232

I just carry a spare battery on the bike rack. I designed / 3D printed an adapter that mounts the battery on the rack ( https://youtu.be/5yk3gQ04PdQ ). When the first battery is low, I just switch them. No fancy cables or electronics :-)
(although if you have a place to bring a solar panel, you can be charging the spare battery while you ride: https://youtu.be/CRZOvl0v_YE )

Here is how you can solar charge your Radcity bike battery: https://youtu.be/CRZOvl0v_YE

I bought my wife a second battery for her Rad Power Radcity Step-thru 3 (2021) eBike. I needed some way to attach it to the bike. I designed and 3D printed an adapter that mounts to the rear bike rack to hold the battery. You can lock the battery to the rack. You can also use the adapter as a wall mount to hold the battery during charging

I put the 3D print file at:
https://www.prusaprinters.org/prints/69891-rad-power-radcity-ebike-battery-holder-for-rack-or

Youtube video showing design: https://youtu.be/5yk3gQ04PdQ

I wonder if my battery is a newer version? If I connect to the +/- terminals I get a voltage. As soon as I try to draw larger currents it shuts down. I also have a Bosch eBike battery. I found that to charge the Bosch I needed to provide 5V to one of the pins.
I'm wondering if it is some new sort of safety feature to prevent accidental shorting. I guess I will have to take it apart an look. I was hoping to wait until the warranty expired... did you take any pictures when you took yours apart? I suppose another test would be to just wire the +/- between the battery and the bike and see if it still works.

Anyone know what the three small pins on the battery connector are for? The two large pins are +/-.
Looks like it's a Halong 5-pin connector. I'm trying to understand the communication protocol between the battery and the controller. I assume it a serial connection?