When a Rad Power Bikes e-bike will not power on, Rad's own Help Center gives a fixed order of checks: the battery first, then the electrical connectors, one at a time. This guide follows Rad's two articles on it and keeps Rad's steps apart from our notes.
Which battery layout does your Rad have?
Rad splits the steps by battery type (model lists are Rad's):
- External battery: RadWagon, RadRunner, RadMission, RadCity 4 and earlier, RadRover 5 and earlier, RadExpand and RadMini.
- Semi-integrated battery: Radster, RadRunner 3 Plus, RadRover 6 Plus and RadCity 5 Plus.
- Integrated battery: RadKick, which has its own article and is not covered here.
Step 1: rule out the battery
External battery. The keyport must be in the ON position. In either OFF position the bike will not power on and the battery will not show its charge. Press and hold the status button next to the battery LEDs. If none light, charge the battery. Rad says that if the battery is properly connected to the charger but will not charge, work with a local bike shop to change the fuses. If a charged battery still will not start the bike, turn the key to OFF and unlocked, remove the battery, hold MODE or POWER to drain remaining power, and inspect the battery and tray contacts. If you find dirt, damage or moisture, Rad says to contact its customer support. If not, refit the battery and try again.
Semi-integrated battery. Press and release the battery button: one light means almost empty, ten means full. If nothing lights, the battery may need charging or may be in ship mode, an off state used in transit. Batteries with ship mode carry a bright orange sticker. Holding the battery button for at least three seconds takes one out of ship mode. Next, remove the battery, drain any remaining power with the Power button, and inspect the terminals. If everything looks undamaged but damp, Rad says to let it air dry completely. If the inside of the connector is damaged or dirty, do not try to repair it or clean the contacts.
If the bike powers on but shows an error message, look that message up instead, starting with our Rad Power error codes reference.
Step 2: check the connectors, one at a time
With the battery out, unplug one connector, inspect the inside, reconnect it and try to power on before you move to the next. Photograph the connections and cable routing first. To reconnect, line up the internal notch and pins with the external arrows and press the halves together without twisting. Cut zip ties only where you need slack.
External-battery bikes (Rad's example is a RadCity 2 Step-Thru):
- Display connector. Follow the cable from the display and remote to the wiring harness. Unscrew the metal connector ends and check for debris, moisture or broken pins. Reconnect it and twist the metal ends to secure.
- Harness routing. The harness must not be twisted around the front of the bike or pinched when you turn the handlebar fully.
- Wiring harness connector. Pry off the downtube grommet with a flat head screwdriver, then check the harness where it meets the controller.
- Battery connector. This is the cable from the bottom of the battery mounting tray to the controller.
Semi-integrated bikes (Rad's example is a RadRover 6 Plus):
- Jumper cable connector, if fitted. The RadCity 5 Plus and RadRover 6 Plus can have one. If the accessory cable ends in a connector cover, there is none. If it loops back and plugs into another cable, there is.
- Rad UI display and remote connectors. If either is disconnected or damaged, the bike will not power on.
- Wiring harness connector. It sits just behind the bottom of the seat tube once you partly loosen the external cable cover bolts. Rad says its 11 pins must be clean and not bent.
- Battery connector. Remove the four bolts on the internal cable cover and the two on the battery mount cover, then lift off the mount to reach it.
On semi-integrated bikes, Rad says a connector that is damaged, dirty or wet inside may mean the part needs replacing. On external-battery bikes, Rad says that if the bike still will not power on after the battery connector check, an electrical component may be at fault and you should contact its customer support.
Our notes, not Rad's
Test after every connector: if you reseat three plugs at once and the bike comes back, you will not know which one was the cause. This guide does not say which part has failed or that any RideRow part fits a Rad. If you are weighing aftermarket parts, read which Rad Power models can use an aftermarket controller kit first. For a brand-neutral self-check, see our e-bike repair online page or the power chain checklist.
Source: Rad Power Bikes Help Center, "Troubleshoot a bike that won't turn on (bikes with external battery)" (updated October 21, 2025) and the same title for semi-integrated batteries (updated April 1, 2025), read October 26, 2026. Search those titles on Rad's support page, and check the current version.
RideRow is an independent parts retailer and is not affiliated with, endorsed by, or sponsored by Rad Power Bikes. Rad Power Bikes and model names are trademarks of their respective owners and are used here only to identify the bikes this guide covers.