Foil Drive MAX+ vs MAX: Is It Worth Upgrading?

The Foil Drive Assist MAX+ is more than a renamed version of the original Assist MAX. It moves Foil Drive's all-round foil assist onto the newer Gen 2.5 43.2V platform, increases available thrust and power, and introduces the FM+ smart-battery system.

For an existing MAX owner, though, that does not automatically make MAX+ the right upgrade.

The original Assist MAX is still a very capable foil-assist system. It can also be considerably lighter in its smaller-battery configurations, and if you already own several 40V batteries, chargers and accessories, there is real value tied up in the system you already have.

So the useful question is not simply, “Is MAX+ better?” It is what does MAX+ improve, and will those improvements actually change your sessions?

This guide compares the Foil Drive Assist MAX+ with the original Foil Drive Assist MAX Gen 2 and explains when we would upgrade, when we would keep the existing system and what needs replacing if you do make the move.

The quick answer

Choose MAX+ if you are buying new: it puts you straight onto Foil Drive's newer Gen 2.5 platform with more power, 35.5kg quoted maximum thrust and the FM+ battery family.
Consider upgrading from MAX if you need more: MAX+ offers a useful step up in thrust, peak power and sustained power, which can matter for heavier riders, smaller boards, smaller foils and repeated flatwater starts.
Keep your MAX if it already works: if take-offs are reliable and your current batteries cover your sessions, there is no need to replace a good system simply because a newer one exists.
Do not upgrade expecting less weight: the launch MAX+ with FM+ 650 has a quoted minimum installed weight of 6.71kg. An original MAX can start around 4.8kg with its lighter battery configuration.
Count your existing batteries: original MAX batteries and chargers do not work with MAX+. Moving platforms means factoring the battery system into the upgrade cost.

Foil Drive MAX+ vs MAX specifications

Specification	Assist MAX Gen 2	Assist MAX+ Gen 2.5
System platform	Gen 2	Gen 2.5
System voltage	40V	43.2V
Maximum quoted thrust	Up to 29kg	35.5kg
Peak power	1,854W	2,150W
Sustained power	1,455W	1,750W
Battery capacity range	332–594Wh	648Wh FM+ 650 at launch
Minimum quoted installed weight	Approx. 4.8kg with MAX Sport	6.71kg with FM+ 650
Installed length	Up to 525mm depending on battery	540mm with FM+ 650
Original MAX battery compatibility	Yes	No
FM+ 650 compatibility	No	Yes
Battery shared with Fusion	No	FM+ 650 can also run Fusion with the correct adaptor
App compatibility	Foil Drive App	Foil Drive App with Gen 2.5 smart-battery information

Those figures make the upgrade easier to understand.

Using Foil Drive's current quoted specifications, MAX+ offers roughly 22% more maximum thrust, around 16% more peak power and about 20% more sustained power than the original MAX.

That is a meaningful performance increase. It is not, however, a free increase: the 648Wh launch battery makes MAX+ heavier than a lightweight original-MAX configuration.

Also bear in mind that actual thrust depends on motor and propeller configuration. The figures above are the current manufacturer maximum system figures rather than a promise that every motor and prop combination will deliver exactly the same result.

The biggest difference: MAX+ has more usable power

If there is one reason to move from MAX to MAX+, this is it.

The original MAX remains a strong all-round foil assist, but MAX+ increases maximum thrust from a quoted 29kg to 35.5kg and sustained output from 1,455W to 1,750W.

Where might you notice that?

Getting a heavier rider moving onto foil.
Repeated flatwater take-off practice.
Getting a shorter or lower-volume board through its initial acceleration phase.
Using a smaller or faster foil that requires more speed before releasing.
Recovering after a touchdown without ending the run.
Motoring back upwind before another downwind run.
Using Foil Drive for longer periods rather than only very short take-off bursts.

If your current MAX already does all of those things comfortably for your board, foil and weight, the extra numbers may make relatively little difference to your normal session.

But if you regularly feel you are asking everything from the original MAX, MAX+ is a genuine step rather than simply a cosmetic update.

Do not overlook the weight difference

This is one of the most important details for existing MAX owners.

The original Assist MAX can achieve an installed weight of around 4.8kg with the MAX Sport battery. Foil Drive quotes a 6.71kg minimum installed weight for MAX+ with the launch FM+ 650 battery, integrated High Power motor and three-blade setup.

Those figures are not directly like-for-like battery comparisons: the FM+ 650 carries 648Wh, while the lightest original-MAX setup uses a much smaller battery. But they make an important point.

MAX+ is not automatically a weight-saving upgrade.

If you mainly surf foil, use the motor for short bursts and have deliberately built a lightweight MAX setup, keeping that system may make more sense than moving to the 650Wh MAX+ simply for the sake of having Gen 2.5.

Foil Drive has indicated that a smaller FM+ 430 battery is planned for early 2027. That could change the weight-versus-runtime equation for MAX+ later, but we would make today's decision around equipment actually available rather than a future product.

What is better about the FM+ battery system?

MAX+ launches with the Foil Drive FM+ 650 Battery.

Although it is called the 650, its rated capacity is 648Wh. It runs at 43.2V, weighs approximately 3.95kg and uses Foil Drive's newer Gen 2.5 battery technology.

The upgrade is not just the amount of energy stored.

The FM+ battery includes a newer battery-management system which can provide information such as State of Charge and battery health to the V3 Controller and Foil Drive App. Foil Drive also states that the Gen 2.5 battery platform is designed to maintain full power down to around 10% State of Charge before normal voltage sag becomes noticeable.

The FM+ design also combines the battery and nose section into a one-piece moulded unit. That simplifies the physical battery assembly and is intended to improve sealing, durability and water flow around the unit.

Foil Drive quotes an average charge time of approximately 85 minutes for the FM+ 650 with the correct 43V charger.

The downside: none of your original MAX batteries transfer

This is the part existing owners need to price properly.

MAX+ does not accept Gen 2 MAX batteries. The FM+ 650 also cannot be fitted to an original MAX.

The 43V charging system is different too, so your existing MAX charger is not the charger for the FM+ battery platform.

For somebody buying their first Foil Drive this is not a problem. For somebody who already owns a MAX High Power battery, MAX Sport battery, travel battery and perhaps a spare charger, it can materially change the economics of upgrading.

We would therefore compare the cost and usefulness of the whole collection, not simply the price difference between two electronics boxes.

MAX+ does give you a better route into the Gen 2.5 ecosystem

There is a flip side to changing battery platforms.

The FM+ 650 is not restricted to MAX+. It can also be fitted to Foil Drive Fusion using the FM+ Battery Adaptor.

That means someone building a larger Foil Drive collection can potentially use one FM+ battery family across a compact MAX+ foil-assist setup and a more powerful Fusion setup.

That could be particularly useful if one rider wants MAX+ for surf and assisted wing foiling but also wants access to Fusion for heavier-duty sessions.

It is less important if you only intend to own one Foil Drive. Shared battery compatibility is useful when you actually have another system to share it with.

What about battery runtime?

Do not compare MAX and MAX+ purely by dividing one battery's watt-hours by another.

Battery capacity tells you how much energy is stored. It does not tell you how long your complete session will last.

Foil Drive's indicative FM+ 650 testing uses an 80kg rider, 800cm² front wing and 40-litre board. Under those controlled assumptions, Foil Drive gives approximately:

FM+ 650 use	Intermediate rider	Advanced rider
E-foil-style riding	Approx. 31 minutes	Approx. 52 minutes
Surf foil use	Approx. 40–50 minutes	Approx. 55–70 minutes

The difference between those numbers explains why headline runtime claims need care.

An experienced surf foiler may use the motor for a few seconds, release the trigger and then ride or pump for a considerable distance. A progressing rider who repeatedly touches down and restarts can use far more battery during the same time on the water.

Your weight, front wing, board drag, motor height, propeller, wind, current and throttle use all affect the result.

When deciding whether MAX+ gives you “more runtime”, compare it with the specific MAX battery you currently use and the way you use your motor.

Should you upgrade if take-offs are difficult?

Possibly, but we would not order MAX+ until we understood why your current setup is struggling.

More thrust can clearly help, but difficult take-offs can also come from:

A board that is too small or sticky through the water.
A front foil that needs too much speed for the rider and conditions.
Motor height that does not suit how you are trying to take off.
Propeller choice.
A battery that is no longer delivering as expected.
Rider technique or weight distribution.
Trying to use equipment that has become too performance-orientated too quickly.

If the MAX itself is not the limiting factor, replacing the entire system can be a very expensive way to leave the original problem unchanged.

Send us your board, foil, rider weight and current Foil Drive configuration and we can work through it before recommending a complete replacement.

When MAX+ is a worthwhile upgrade

You regularly need more thrust

If you are constantly operating the original MAX near its limit, the move from 29kg to 35.5kg quoted maximum thrust is meaningful.

This is particularly relevant as rider weight rises, or when you want to combine Foil Drive with lower-volume boards and smaller, faster foils.

You want more sustained power

The difference between 1,455W and 1,750W sustained output matters when the motor is being asked to work for more than a very short acceleration burst.

Flatwater starts, longer powered sections and repeated recoveries are good examples.

You want the FM+ smart-battery platform

If the State of Charge information, newer battery management, 648Wh capacity and future Gen 2.5 battery ecosystem are useful to you, MAX+ is the route into that platform.

You expect to own Fusion as well

This is one of the stronger arguments for switching. The ability to use the FM+ 650 in MAX+ and, with the adaptor, in Fusion reduces the number of completely separate battery families you need to maintain.

You are effectively starting again anyway

If your old MAX is being sold as a complete system, or you were already planning to replace batteries and substantially change the motor setup, moving onto Gen 2.5 becomes easier to justify.

When we would keep the original Assist MAX

Your MAX already gets you onto foil reliably

If it works, it works.

A newer system does not make an original MAX stop producing 29kg of quoted maximum thrust or remove the sessions you already enjoy with it.

If you only need a few seconds of assistance before switching the motor off, the additional sustained power of MAX+ may have little practical value.

You value minimum installed weight

The lightweight end of the original MAX battery range remains attractive, particularly for surf riders and experienced foilers trying to preserve a more natural board-and-foil feel.

MAX+ with the FM+ 650 gives you more battery, but more battery means more weight.

You already have several good MAX batteries

One working MAX battery is one thing. A collection of batteries, including travel and high-power options, changes the calculation considerably.

If you have already built the system around your riding, replacing that entire battery ecosystem needs to produce a worthwhile benefit.

A targeted Gen 2 upgrade would solve the problem

The Foil Drive MAX Sport High Power 396 Battery, for example, is a 396Wh, 40V battery specifically for the original Assist MAX platform. It weighs approximately 1.85kg.

For the right existing owner, changing a battery or refining the motor and propeller setup may achieve what is needed without replacing the whole system.

This depends heavily on what you already own, so check compatibility before buying individual components.

Original MAX vs MAX+: the real-world upgrade decision

Your situation	What we would look at first
Buying your first Foil Drive	MAX+ is the logical all-round starting point if its price and weight suit your setup.
MAX works perfectly	Keep riding it. Upgrade when you can identify something you actually need to improve.
MAX struggles to get you moving	Check board, foil, motor, propeller, battery condition and rider weight before deciding.
Heavy rider / smaller foil	The extra thrust and sustained power of MAX+ become more relevant.
Surf rider prioritising minimum weight	Compare carefully. A light original-MAX configuration can still be considerably lighter than MAX+ with FM+ 650.
Own several Gen 2 batteries	Factor the value of your complete existing battery collection into the change.
Planning to buy Fusion too	MAX+'s shared FM+ battery family becomes a genuine advantage.
Need more runtime only	Compare your existing MAX battery options before assuming you need a completely different system.

What can you carry across from MAX to MAX+?

There are two things we can say very clearly:

Original MAX batteries do not work with MAX+.
The original MAX charging platform does not charge the new FM+ batteries.

For motors, removable cables, pods, controllers, mounting parts and other accessories, we would check the exact version rather than making a blanket compatibility claim.

Foil Drive has changed motor generations, propeller options and mounting arrangements over time. A photograph of the motor and connector, together with the battery, cable and system details, normally tells us far more than simply saying you own “a Gen 2 MAX”.

If you are buying a used system, this becomes even more important. Confirm what is actually included before comparing the asking price with a new MAX+ package.

How much more powerful is MAX+?

Using Foil Drive's current maximum system specifications:

MAX: 29kg maximum thrust.
MAX+: 35.5kg maximum thrust.
MAX: 1,854W peak output.
MAX+: 2,150W peak output.
MAX: 1,455W sustained output.
MAX+: 1,750W sustained output.

That works out at roughly 22% more quoted maximum thrust, 16% more peak power and 20% more sustained power.

Those are meaningful changes, but the right buying decision still depends on whether you need them.

MAX+ or Fusion if you are upgrading anyway?

There is another question worth asking before replacing a MAX.

If the reason you want to upgrade is that you are a heavier rider, want much longer powered sessions or are moving increasingly towards e-foil-style riding, it is worth comparing MAX+ with Foil Drive Fusion as well.

MAX+ is Foil Drive's Gen 2.5 all-rounder. Fusion sits above it for maximum power and runtime and can use the larger 864Wh Fusion battery as well as the FM+ 650 with the appropriate adaptor.

In other words, do not automatically progress from MAX to MAX+ simply because the names line up. Work out where your riding is going first.

Try and discuss Foil Drive at The SUP Co x Lymington

A Foil Drive upgrade can involve several thousand pounds of equipment, so this is exactly the sort of purchase where speaking to someone who understands the complete setup is useful.

At The SUP Co x Lymington we can help work through your existing board, foil, Foil Drive system and what you actually want to improve.

Selected foil-assist demo opportunities are available subject to conditions, equipment availability and rider suitability. If there is a particular MAX+, Fusion or setup you would like to see, contact us before travelling so we can confirm what is available.

Compare the complete upgrade cost

If you are moving from MAX to MAX+, budget for the complete system change rather than viewing the drive unit in isolation.

Consider:

The MAX+ system.
The FM+ 650 battery.
The correct 43V charger.
Your chosen motor and mounting arrangement.
Any additional batteries you need.
The value of your existing MAX batteries and charger.
Whether keeping your MAX complete as a second system makes more sense than splitting it for parts.

Finance options are available on qualifying orders, which can be useful when investing in a complete setup.

Availability can vary by battery, motor, mast and package configuration, so if timing matters please ask us to confirm the exact combination before ordering.

Foil Drive MAX+ vs MAX FAQs

Is Foil Drive MAX+ much more powerful than MAX?

MAX+ is a meaningful power increase. Foil Drive currently quotes 35.5kg maximum thrust for MAX+ versus up to 29kg for the original MAX. Peak output rises from 1,854W to 2,150W and sustained output from 1,455W to 1,750W.

Can I turn my original MAX into MAX+ by changing the battery?

No. MAX and MAX+ use different electrical and battery platforms. The original MAX is a 40V Gen 2 system while MAX+ uses the 43.2V Gen 2.5 architecture.

Can I use an FM+ 650 battery in my original MAX?

No. The FM+ 650 is not compatible with the original Gen 2 MAX.

Can I use my original MAX batteries in MAX+?

No. Gen 2 MAX batteries are not compatible with the MAX+ system.

Can I use my MAX charger with MAX+?

No. MAX+ uses the newer 43V charging platform. Use the correct Foil Drive charger specified for the FM+ battery.

Is MAX+ lighter than MAX?

Not in the launch FM+ 650 configuration. Foil Drive quotes a minimum installed weight of 6.71kg for MAX+ with the FM+ 650, while an original MAX can start at around 4.8kg with the smaller MAX Sport battery. The batteries are very different capacities, so compare weight and runtime together.

Is the FM+ 650 better than an original MAX battery?

It is a newer 648Wh smart battery with Gen 2.5 battery management, State of Charge information and a one-piece design, but “better” depends on the job. An experienced surf foiler may prefer the lower installed weight of a smaller original MAX battery, while another rider may value the FM+ 650's capacity and newer battery platform.

Does the FM+ Battery Adaptor let me use FM+ 650 in my MAX?

No. The adaptor allows the smaller FM+ battery to locate correctly within the longer Fusion system. It does not convert the original MAX to the Gen 2.5 battery platform.

Should I upgrade if I already own several MAX batteries?

Only if MAX+ delivers a benefit you actually need. Your existing batteries cannot transfer, so several healthy MAX batteries can represent a significant reason to keep your current system unless additional power or Gen 2.5 functionality justifies changing platform.

Will MAX+ make flatwater take-offs easier?

The additional thrust and sustained power can help, particularly for heavier riders or less efficient board-and-foil combinations. But board shape, foil choice, motor position, propeller and rider technique remain important. We recommend reviewing the complete setup rather than assuming power alone will solve the problem.

Is the FM+ 430 battery available now?

Foil Drive has indicated an early-2027 release for the smaller FM+ 430. Treat it as a planned future option and check current availability rather than basing today's purchase on it.

Can MAX+ and Fusion share batteries?

Yes. The FM+ 650 fits MAX+ directly and can be used in Fusion with the correct FM+ Battery Adaptor. The larger Fusion 860 battery remains a Fusion-only option.

Can I try MAX+ before upgrading?

Ask The SUP Co x Lymington team about current Foil Drive demo opportunities. Availability varies, so contact us before travelling and bring details of your existing board, foil and MAX setup so we can make the comparison relevant.

So, is Foil Drive MAX+ worth upgrading to?

If you are buying your first Foil Drive, MAX+ makes a very strong case as the new all-round Gen 2.5 system. You get substantially more thrust and power than the original MAX, a 648Wh smart battery and a battery platform that can also cross over into Fusion.

If you already own an Assist MAX, the answer depends on what you are trying to fix.

Upgrade if you genuinely need more thrust, more sustained power or want to move into the Gen 2.5 battery ecosystem.

Keep your MAX if it already gets you onto foil reliably, gives you enough session time and particularly if you have invested in several batteries or prioritise a lightweight installation.

The best upgrade is the one that solves an actual limitation rather than simply replacing last year's equipment.

Send The SUP Company your current Foil Drive setup, including your rider weight, board, front wing, mast, motor and battery. We can help work out whether MAX+, a targeted MAX upgrade or a move to Fusion makes the most sense.

You can also browse the Foil Drive range at The SUP Company or view the Foil Drive Assist MAX+ Gen 2.5.

Foil Drive MAX+ vs MAX | Should You Upgrade?