Batteries. They're not the sexiest topic in foiling. But choose the wrong one and you'll be sitting on the beach watching your mates fly past while you wait for a recharge. Choose the right one and you'll wonder how you ever foiled without it.
Here's the thing about Foil Drive batteries — they're not all just "big" and "small." Each one is engineered for a specific type of rider, a specific style of riding, and a specific kind of session. Understanding the differences doesn't require an engineering degree. It just requires a few good analogies and someone willing to be straight with you.
That's what this is.
First, the Basics: What Does Battery Capacity Actually Mean?
Battery capacity is measured in watt-hours (Wh). Think of it like the fuel tank in a car. A bigger tank means you can drive further before you need to stop. A smaller tank means the car is lighter and more nimble — but you'll be pulling over sooner.
Watt-hours tell you how much total energy is stored. But here's where it gets interesting: it's not just about how much energy you have, it's about how fast you can release it. That's where voltage, amp-hours, and discharge rates come in — and that's what separates a battery that just runs your motor from one that unlocks Maximum Boost Mode.
Let's walk through the Foil Drive MAX battery lineup from smallest to biggest.
The MAX Sport Battery — The Pocket Rocket
332.64Wh | 1.5kg
Think of the Sport Battery like a high-performance motorbike engine. It's not the biggest, but it's light, responsive, and punchy. Less weight means less swing mass on the nose of your board, which translates directly into how the board feels when you're pumping, turning, or trying to unweight the front foot mid-glide.
For surfers and downwinders who care deeply about how their board responds — where every pump counts and every turn needs to feel alive — the Sport Battery is the choice. You're trading raw runtime for feel.
Best for: Experienced surfers, lighter riders, short sharp sessions, anyone who hates a heavy nose.
The MAX Travel Battery — The Goldilocks
356.6Wh | 1.7kg
The Travel Battery sits between the Sport and the Sport High Power — a bit more capacity than the Sport, in the same compact form factor. Originally designed as a second battery for travel (think: fits in your carry-on alongside your main battery), it's become a popular choice for riders who want more runtime than the Sport without stepping up to a heavier pack.
It's not trying to be the most powerful or the longest-running. It's trying to be the most convenient — and it does that job very well.
Best for: Travelling riders, those who want a compact second battery, anyone who flies to their sessions.
The MAX Sport High Power 396 Battery — The New Sweet Spot
396Wh | 1.85kg
This is the newest addition to the lineup and, frankly, one of the most interesting batteries Foil Drive has released. It's essentially a Sport battery that's been to the gym.
Here's the analogy: imagine a sports car that's had its engine upgraded but kept the same lightweight body. Same compact dimensions as the Sport and Travel, but 20% more runtime than the original Sport — and crucially, it still keeps that light, nimble feel that surf and downwind riders love.
At 1.85kg, it's only marginally heavier than the Travel Battery, but it stores significantly more energy. For riders who've been frustrated by the Sport Battery running out mid-session, or who've wanted a bit more range without committing to the weight of the MAX High Power — this is your battery.
It supports Boost Mode but does not unlock Maximum Boost (that's reserved for the High Power Battery paired with the High Power Motor). Think of it as getting 90% of the performance at 70% of the weight.
Best for: Surfers and downwinders wanting more runtime without sacrificing feel. The upgrade path from the Sport Battery. Anyone who finds the MAX High Power overkill.
The MAX High Power Battery — The Full Send
594Wh | 2.8kg
Now we're talking. If the Sport Battery is a motorbike engine, the High Power Battery is a V8. It holds 594 watt-hours — over 50% more capacity than the Sport High Power 396 — and it's the only battery in the MAX lineup that unlocks Maximum Boost Mode at 128% throttle when paired with the High Power V2 Motor.
What does that actually feel like? Imagine you're climbing a steep hill and someone gives you a push — not a gentle nudge, but a real shove that has you scrambling to keep up. That extra 28% of throttle is a genuine, noticeable surge of power. It delivers 18 seconds of maximum boost, which in foiling terms is an eternity. It's the difference between catching a wave and owning a wave.
The runtime figures back this up. Paired with the High Power Motor, riders report up to 40–45% more runtime than the standard Power Battery. For long downwind runs, extended wing sessions, or anyone who needs to cover serious water, this is the only battery worth considering.
Yes, it weighs 2.8kg. Yes, you'll notice it on the nose of the board. But for the power and range it delivers, most riders consider that a fair trade.
Best for: Maximum range, Maximum Boost Mode, e-foil-adjacent performance, heavier riders, long sessions, downwinders going deep, anyone who wants everything the Assist MAX can do.
Side-by-Side: The Numbers
| Battery | Capacity | Weight | Boost Mode | Best For |
|---|---|---|---|---|
| MAX Sport | 332.64 Wh | 1.5kg | Standard | Feel, lightness, short sessions |
| MAX Travel | 356.6 Wh | 1.7kg | Standard | Travel, compact second battery |
| MAX Sport High Power 396 | 396 Wh | 1.85kg | Standard | More runtime, still light |
| MAX High Power | 594 Wh | 2.8kg | Maximum Boost (128%) | Everything. Full power. |
The Charging Question
Runtime is only half the equation. The other half is how quickly you can get back on the water between sessions.
All MAX batteries are compatible with both the Foil Drive 40V Standard Charger and the 40V Fast Charger (8A). If you're running the High Power Battery — with its larger 594Wh capacity — the Fast Charger becomes even more valuable. A standard charge on a big battery can feel like waiting for a kettle to boil in slow motion. The Fast Charger is the difference between a coffee break and a full lunch stop.
If you're serious about back-to-back sessions, budget for the Fast Charger alongside your battery. It's one of the best-value accessories in the Foil Drive ecosystem.
So, Which One Should You Buy?
Here's the honest version:
Get the MAX Sport if you're an experienced foiler, you prioritise the feel of your board above all else, and your sessions rarely run longer than 45 minutes.
Get the MAX Travel if you need a compact second battery or you travel frequently and want something that fits in carry-on luggage alongside your main pack.
Get the MAX Sport High Power 396 if you've been running the Sport Battery and find yourself running out of juice before the session is done, or if you want the sweet spot between feel and runtime without going to the full-size High Power pack.
Get the MAX High Power if you want maximum everything — maximum runtime, maximum boost, maximum performance. If you're doing long downwinders, heavy-use assist sessions, or you simply want the best the Assist MAX system has to offer, this is the one.
And if you want to run two batteries? The most popular combination we see is a MAX High Power as the main battery and a MAX Sport High Power 396 as the backup — giving you a full power session followed by a lighter, more nimble second session on the same day.
Come Talk to Us
We ride this stuff. We sell this stuff. And we've helped a lot of people figure out exactly which battery suits their riding, their board, and their budget.
If you're not sure, come into Stonker Boardsports in Torquay and we'll sort you out. Or browse the full Foil Drive battery range online — every option ships from us here on the Surf Coast.
Because life's too short for the wrong battery :)
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