Quick answer: Choose the volts that match your kit, pick the amp hours (Ah) for how far you like to ride, and then make sure it fits in your frame. That's really all there is to it.
The 3 numbers on every battery
It helps to think of your battery like a water tank connected to a hose:
- Volts (V) are how hard the water pushes, so more volts gives you more speed.
- Amp hours (Ah) are how big the tank is, so more Ah lets you ride further.
- Watt hours (Wh) are the total amount in the tank, which you get by multiplying volts by Ah. For example, 72V x 30Ah works out to 2,160 Wh.
Step 1: Match the volts to your kit
This is the one rule you can't skip, because a battery with the wrong volts simply won't work with your kit.
| Your kit | Battery |
|---|---|
| 250W and 500W | 48V |
| 750W to 1500W | 48V or 52V |
| 2000W | 48V, 52V or 60V |
| 3000W | 60V or 72V |
| 5000W | 72V |
Step 2: Pick how far you want to go
Here's roughly how far each battery will take you on our 3000W kit:
| Battery | About how far |
|---|---|
| 72V 20Ah | 50 to 60 km |
| 60V 25Ah | 60 to 70 km |
| 72V 25Ah | 60 to 70 km |
| 72V 30Ah | 70 to 80 km |
| 72V 40Ah | 80 to 100 km |
Riding at full throttle, climbing big hills, carrying heavy loads and running soft tyres will all use more battery, while cruising on pedal assist makes it last the longest. It's best to buy for the rides you do most often, rather than the one big ride you might only do once.
Upgrading to an 80A controller? In that case, go for the 72V 30Ah or 72V 40Ah battery, as they're built to handle the extra power.
Step 3: Check it fits
Triangle batteries sit inside the main triangle of your frame, while downtube batteries bolt on where a drink bottle would go. Downtube batteries are slimmer and suit the smaller kits.
Hardcase batteries have a hard shell and are more compact, whereas softcase batteries come in a padded bag. We use softcase for the big 30Ah and 40Ah packs, so they need a bit more room. Here are the sizes (side x top x bottom):
| Battery | Size |
|---|---|
| 48V or 52V 20Ah hardcase | 25 x 39 x 32 cm |
| 52V 30Ah softcase | 28 x 43.5 x 46.5 cm |
| 60V 25Ah hardcase | 24 x 37 x 41 cm |
| 72V 20Ah hardcase | 24 x 36.5 x 41 cm |
| 72V 25Ah hardcase | 25 x 39 x 38 cm |
| 72V 30Ah softcase | 26 x 40 x 45 cm |
Charge it safely
- Always use the charger we supply with your battery.
- Stay nearby while it charges, and avoid charging overnight or while you're out.
- Charge it on a hard floor, away from anything that could burn and out of doorways.
- Give it time to cool down after a ride before you plug it in.
- Unplug it once the light turns green, and try to recharge when it gets down to about 10 to 20%.
If your battery ever looks swollen, gets very hot, starts hissing or smells strange, stop using it straight away, move it outside and get in touch with us. If it's smoking, get everyone out and call 000.
Make it last
Keep your battery somewhere cool and dry, and if you won't be riding for a while, leave it at about half charge. Every battery comes with a charger, is rated for 1,200+ charges (up to about 5 years) and is backed by an 18-month warranty. When it's finally worn out, please take it to a battery recycling drop-off rather than putting it in the bin.
Common questions
Will a bigger Ah battery make my bike faster?
Not faster, but it will take you further. Remember that Ah gives you distance, while volts give you speed.
Can I use a 72V battery on my 2000W kit?
No, you'll always need to use the volts your kit is made for.
Not sure which battery suits you? Email sunny@ampx.com.au with your kit and how far you like to ride, and we'll point you in the right direction.