E-bike battery connectors and mounts
A replacement battery has to match three things: voltage, the mount or case it slides into, and the connectors on both the discharge and charge side. The voltage is on the label; this page covers the other two.
Connectors
Discharge and charge connectors
| Connector | Side | Rating | Looks like | Used on | Note |
|---|---|---|---|---|---|
| XT60 | Discharge | 60A | Yellow 2-pin, keyed | Most generic downtube packs, conversion kits | Rated 60A continuous; melts if pins are loose |
| XT90 / XT90-S | Discharge | 90A | Yellow 2-pin, larger; -S has anti-spark resistor | High-power packs 52V+, 72V | Use the -S version to stop the spark on connect |
| Anderson Powerpole (PP45) | Discharge | 45A | Red and black modular housings | Older kits, rack packs, some Rad models | Genderless; polarity is set by housing orientation |
| Anderson SB50 | Discharge | 50A | Grey or red one-piece | Scooters, mobility devices | |
| Baseplate pins (4-pin) | Discharge | 20–30A | Spring pins on a slide-in mount | Hailong, Reention, Polly downtube cases | Pin count and spacing differ by case brand |
| Baseplate pins (5-pin) | Discharge + comms | 30A | Adds a signal pin | Hailong G80, some Reention | Not interchangeable with 4-pin |
| Higo / Julet 2-pin | Discharge | 20–30A | Round waterproof, yellow or black | Integrated frame batteries on DTC brands | Many pin layouts; match the keying |
| DC 5.5×2.1 or 2.5 mm barrel | Charge | 3A | Round barrel, often with a locking collar | Most 36V and 48V packs | 2.1 vs 2.5 mm center pin are not interchangeable |
| 3-pin XLR | Charge | 5A | Microphone-style plug | Rad Power, Juiced, many Hailong packs | Check which pins carry + and -; brands differ |
| GX16 3-pin | Charge | 5A | Threaded round aviation plug | Bafang kits, EM3ev, Luna | GX16-2, -3 and -4 exist |
| RCA | Charge | 3A | Audio-style plug | Older and budget packs | Easy to short; retire if loose |
| Rosenberger magnetic | Charge | 4–6A | Magnetic snap-on | Bosch, Specialized, Giant integrated packs | Proprietary pinouts per brand |
Mounts and cases
Battery mounts and case types
| Mount / case | Position | Connector | Cell layouts | Capacity | Note |
|---|---|---|---|---|---|
| Hailong (G56 / HL-1) | Downtube | 4-pin, 5-pin on G80 | 10S–14S, up to 20 Ah | Up to 1,000 Wh | Most common aftermarket case; several generations are not cross-compatible |
| Hailong Max / G70 | Downtube | 5-pin | 13S–14S, up to 25 Ah | Up to 1,300 Wh | Wider case |
| Shark / King Shark | Downtube | 4-pin | 13S4P–14S5P | Up to 1,260 Wh | Similar footprint to Hailong but different baseplate |
| Dolphin | Downtube | 4-pin | 13S4P | 500–700 Wh | Rounded case; Gotrax and many 2018–2021 bikes |
| Reention Dorado / Eel | Downtube or semi-integrated | Reention plug | 13S–14S | Up to 1,000 Wh | Several Reention plug types; match the one on the frame |
| Polly DP-5 / DP-6 | Downtube | 4-pin | 13S4P–14S5P | Up to 1,000 Wh | DP-5 and DP-6 differ in length |
| Jumbo Shark / Tiger Shark | Downtube | 5-pin | 14S6P–20S4P | Up to 1,500 Wh | Large frame-mounted performance packs |
| Rear rack | Rack | Rack plate pins or Anderson | 10S–13S | 300–700 Wh | Rack must match the battery slide |
| Seat-tube bottle | Bottle cage | Barrel or Anderson | 10S–13S | 250–500 Wh | Small and swappable |
| Frame-integrated (OEM) | Inside downtube | Brand plug (Rad, Lectric, Aventon, Super73) | 13S–14S | 500–1,000 Wh | Only the OEM or a rebuilt original fits |
| Bosch PowerTube / PowerPack | Integrated or frame | Bosch | 10S | 400–800 Wh | Smart System and Classic+ generations are not interchangeable |
| Shimano BT-E80xx / BT-E60xx | Integrated or downtube | Shimano | 10S | 418–630 Wh | See the Shimano compatibility chart for mount and charger pairs |
Fit checklist
Before buying a replacement
| Check | Rule |
|---|---|
| Voltage | Same nominal voltage (or 52V on a 48V bike only if the controller is rated for it) |
| Case and baseplate | Same case family and generation; measure length, width and the gap between mounting holes |
| Discharge connector | Same connector, or a known adapter; 4-pin and 5-pin baseplates do not interchange |
| Charge port | Match pin type and polarity, or budget for a new charger |
| BMS current | Continuous rating at or above the controller peak amps |
| Certification | UL 2271 if you live in NYC or California, or in an apartment building that requires it |
Frequently asked questions
Can I put an XT90 battery on an XT60 bike?
Yes with a short XT90-to-XT60 adapter lead. The bike will still be limited by the XT60 rating of about 60A.
Will any Hailong battery fit my Hailong mount?
Not always. Hailong has several case generations (G56, G70, G80, Max) with different lengths and baseplate pins. Match the case code and pin count.
What charger plug does my battery use?
Look at the charge port: a round barrel, a 3-pin XLR, a threaded GX16 or a magnetic Rosenberger. The plug type and the full-charge voltage both have to match.