Troubleshooting · 79Bike · Sur-Ron · Talaria
Electric motorbike battery won't charge after winter: what to do
It's the classic spring scenario: the bike spent winter in the garage and the battery refuses to charge. The good news: it isn't always a dead battery. Here's what's happening, what you can check yourself, and when to involve the workshop.
Why it happens: the BMS goes into protection
A lithium battery loses a little charge every month (self-discharge and the BMS — the battery management circuit — drawing power). Stored already low for months, it can drop below the minimum threshold monitored by the BMS, which then blocks charging to protect the cells: it's a protection, not necessarily a fault. Cold makes it worse: charging below 0 °C is not recommended anyway.
What you can check
- Temperature: leave the battery several hours at room temperature (15–25 °C) before charging.
- Charger: is the LED on? Is the socket live? If possible, test it on another compatible battery.
- Connectors: clean, dry, no corrosion or heat marks.
- Battery switch or lock: some packs must be switched on to accept a charge.
What not to do
Don't force it with another charger, a bench power supply or a "booster": recovering a deeply discharged battery requires controlled equipment and procedure, because over-discharged cells can become unstable. Never charge a battery that is swollen, deformed or getting hot: isolate it somewhere safe and contact the workshop.
Recoverable or not?
If the voltage is simply low, a controlled slow charge in the workshop often wakes the BMS up. If one or more cells have been too low for too long, the pack is irreversibly damaged and only a replacement battery will fix it. A multimeter check (pack voltage and, where accessible, cell groups) settles it in minutes.
Prevent it next year
Store the battery around 50%, dry, between 10 and 20 °C, and check its level every 4 to 8 weeks. Everything is explained in our winter storage guide.
Tools you need
- Original charger
- Multimeter (diagnosis)
- Dry, temperate room
Step-by-step procedure
- 1
Warm it up
Leave the battery several hours at room temperature before trying anything.
- 2
Test the charger
Socket, charger LED and, if possible, a test on another compatible battery.
- 3
Inspect
Clean, dry connectors; case not swollen or deformed.
- 4
Switch the pack on if needed
Activate the battery switch or lock for your model, then plug the charger in for 15 minutes.
- 5
Get a diagnosis
If nothing happens, don't force it: a workshop diagnosis will tell you whether the battery can be recovered.
Useful genuine parts
In stock, shipped in 3–10 business days.
FAQ
Is it covered by the warranty?+
A battery damaged by deep discharge from long storage is generally not covered. A manufacturing defect is, according to the warranty terms (1-year battery warranty on 79Bike bikes sold by Ride On Distribution).
How much is a new battery?+
Genuine Falcon Pro and Falcon GT batteries are available as spare parts; the current price is shown on the product page.
Can I ship a damaged battery?+
Damaged lithium batteries are subject to strict transport rules. Contact us before sending anything.
Key takeaways
Warm it up, test the charger, inspect, then get a diagnosis without forcing it. Often the battery comes back; if not, storing it at 50% will prevent the problem next year.
Need a hand?
Our workshop in Toulouse Sud (France) services 79Bike, Sur-Ron and Talaria. Send us a photo or video of the problem.
Related guides
These guides are for information only. If in doubt about a safety-critical part (brakes, steering, wheels), have a professional do the work. Always follow the manufacturer's manual.