Foil Drive FM+ 650 Battery

The Foil Drive FM+ 650 Battery is the 648Wh pack built for Foil Drive's Gen 2.5 generation. It is the first Foil Drive battery designed to cross platforms: it is the standard battery for the Assist MAX+ Gen 2.5 , and with the $99 FM+ Battery Adaptor it drops straight into a Foil Drive Fusion.

For a MAX+ rider it is simply the battery — the largest capacity the system takes, and enough for a full surf session. For a Fusion rider it is something more interesting, and that is what most of this page is about.

The FM+ 650 as a sportier battery for the Foil Drive Fusion Foil Drive's MAX line has always had tiers — Sport, Travel, High Power — so riders could trade runtime for weight. The Fusion has never had that choice. It ships with the Fusion 860, a 860Wh pack that is superb for long sessions and heavy for everything else.

Add the FM+ Battery Adaptor and the FM+ 650 becomes the Fusion's sport option: roughly half the weight for three quarters of the capacity , at $500 less.

Fusion 860 FM+ 650 + adaptor Capacity 860Wh 648Wh (75%) Battery weight 7.55 kg / 16.6 lb 3.95 kg / 8.7 lb Charge time ~120 minutes ~85 minutes Price $1,849 $1,349 + $99 adaptor Also runs on a MAX+ No Yes That is 7.9 lb off the nose of the board , sitting right over the foil's centre of lift. On a Fusion the difference is immediate: the board swings faster, pumps easier, and turns tighter. It is the same trade every foiler already understands — less fuel, more feel.

Which one should you ride?

Fusion 860 — long downwinders, all-day sessions, eFoiling under power, heavier riders, anyone who would rather not think about charge level. FM+ 650 — surf, waves, pumping, lighter riders, smaller gear, travel, and anyone who owns both a Fusion and a MAX+ and wants one battery instead of two. Plenty of riders end up owning both and picking by the forecast. If you already run a MAX+ and are adding a Fusion, the FM+ 650 is the obvious first battery — it works on both.

Not sure which suits how you ride? Call the shop at (321) 252-5483 .

Gen 2.5 battery technology The FM+ 650 runs Foil Drive's Gen 2.5 cell technology, which performs deeper into the discharge cycle. Full power delivery holds down to roughly 10% before you notice the sag every battery eventually gives you — so more of the stated capacity is usable rather than held in reserve.

An intelligent Bluetooth BMS reports accurate state of charge to the V3 controller and to the Foil Drive app, where each battery can be named and its health tracked over time. Internal thermal management keeps the temperature stable so thrust stays consistent from full to empty.

The one-piece moulded design combines battery and nose cone into a single sealed unit — no separate nose cone needed, better water flow, and the weight balanced over the foil's centre of lift.

Runtime Foil Drive's own figures, based on an 80 kg rider, 800cm² wing, 5'0 40L board:

Use Intermediate Advanced eFoiling (flat water, ~70% throttle) ~31 min ~52 min Surf (3ft swell, under 5kts wind) ~40–50 min ~55–70 min Runtime varies a great deal with rider weight, gear sizing, conditions and how much you rely on the motor. The intermediate figures assume frequent touchdowns and restarts; the advanced figures assume clean riding and linking waves by pumping. Treat these as an indicative guide, not a promise.

FM+ 650 tech specs Spec Value Rated capacity 648Wh Amp hours 15Ah Nominal voltage 43.2V Max voltage 50.4V Weight 3.95 kg / 8.70 lb Battery dimensions 460 × 125 × 55 mm / 18.1 × 4.9 × 2.2 in Installed on a MAX+ 540 × 125 × 55 mm Installed on a Fusion 658 × 125 × 55 mm Nose cone Not required — integrated Battery type Lithium-ion Charge time ~85 minutes on the 43V charger Water rating IP69 Certifications UN38.3, CE, FCC, WEEE, RoHS, PSE, IP68, IP69 In the box FM+ 650 battery and carry case Charging and storage The FM+ 650 charges on the 43V charger supplied with your Fusion or MAX+ system — about 85 minutes from flat. It also has a Storage Mode , which caps the charge so the pack can sit through the off-season without degrading. Foil Drive recommends storing between 30% and 60% state of charge . Proper care is what decides how many seasons a lithium pack gives you; the battery and charger manuals are worth ten minutes of your time.

Compatibility System FM+ 650 Foil Drive Assist MAX+ (Gen 2.5) Yes — direct fit Foil Drive Fusion Yes — requires the FM+ Battery Adaptor Foil Drive Battery Caddy Yes — requires the FM+ Battery Adaptor 43V Standard Charger Yes Gen 2 Assist MAX (previous generation) No — not compatible Foil Drive FM+ 650 Battery FAQ Can I use the FM+ 650 battery on a Foil Drive Fusion?

Yes. The FM+ 650 fits the Fusion with the FM+ Battery Adaptor, a $99 part. It is the only way to run a lighter, smaller battery on a Fusion, and it is why riders who own both a Fusion and a MAX+ can share one battery between the two systems.

Is the FM+ 650 a sport battery for the Fusion?

In effect, yes — though Foil Drive does not sell it under that name. The Fusion's standard pack is the 860Wh Fusion 860 at 16.6 lb. The FM+ 650 gives you 648Wh at 8.7 lb, so it fills the same role a Sport battery does in the MAX line: less runtime, considerably less weight, sharper handling.

What is the difference between the Fusion 860 and the FM+ 650?

The Fusion 860 holds 860Wh, weighs 7.55 kg (16.6 lb), charges in about 120 minutes and costs $1,849. The FM+ 650 holds 648Wh, weighs 3.95 kg (8.7 lb), charges in about 85 minutes and costs $1,349 plus a $99 adaptor. The 860 is the endurance choice; the 650 is the light, lively one that also fits a MAX+.

How long does the FM+ 650 battery last?

Foil Drive rates it at roughly 40–70 minutes of surf riding and 31–52 minutes of eFoiling, depending on ability. An advanced rider linking waves and pumping between them will get considerably more out of a charge than a rider relying on the motor throughout.

How long does the FM+ 650 take to charge?

About 85 minutes on the 43V charger that comes with your Fusion or MAX+ system.

Will the FM+ 650 fit my older Assist MAX?

No. Gen 2 Assist MAX batteries and the FM+ series are not interchangeable. The FM+ 650 fits the Gen 2.5 MAX+ and the Fusion only.

Do I need a nose cone with it?

No. The nose cone is moulded into the battery as one sealed unit, which is part of why it handles well and seals to IP69.

Does it come with a case?

Yes — the FM+ 650 ships with its carry case.

Do you have the FM+ 650 in stock?

Yes. We stock it at our Cocoa Beach, Florida shop at 110 Dixie Lane, and ship nationwide.

Buying Foil Drive batteries in Florida Good Breeze is in Cocoa Beach on Florida's Space Coast, and we carry the Foil Drive range in depth — units, batteries, motors, adaptors and spares. If you are weighing a Fusion 860 against an FM+ 650, or working out whether one battery can cover both your systems, call the shop at (321) 252-5483 . Questions on sizing or setup? Call the shop.

See the rest of the range in foil assist units and eFoils , or browse all eFoil and foil assist gear .