ePropulsion frequently asked questions

Electric marine motors - Frequently Asked Questions

Discover the answers to your questions on electric propulsion for boating.

Electric power is used by a whole host of boats and vessels – from small tenders up to passenger ferries.

Different types of motor suits different boats. ePropulsion has electric solutions from portable outboard motors, long range and more powerful outboards able to power boats up to 5 tonnes, and inboard POD drive electric motors for day sailers up to 50’ ocean going cruising boats.

Yes they are. There is often confusion between electric power measured in kWh (kilo watt) and traditional engines measured in HP (horse power). Due to the immediate torque produced by electric motors from 0 rpm and upwards, the kWh as a measure does not really compare with the HP measure used for internal combustion engines. The kWh is a measure of input power, and HP is a measure of output power. Compared to an electric engine with a direct drive, the action of engine (gearings, propeller shaft etc) considerably erodes the power efficiency of oil based fuel and the actual power output at the propellor. For example, 15kW electric power provides the same torque as a 40hp Yanmar diesel engine. For the time being, this is how the market is comparing it, and how the ePropulsion engines broadly equate:
ePropulsion motors:Similar to:
Spirit 1.0 Plus outboard 1kWh motor3.5 hp outboard motor
POD Drive or Navy 3.0 Evo 3kWh motor6 hp motor
POD Drive or Navy 6.0 Evo 6kWh9.9 hp motor or outboard
Increased power for inboard propulsion can be achieve by fitting twin POD drives.

The distance you can go is determined by the size of and number of batteries you have.

Your speed affects your motoring range. Lower speeds use less energy and motoring permanently at full throttle will use most power.

Your range is also influenced by sea state, currents and windage, as with all boating under power, plus your ability to regenerate battery charge whilst underway.

For cruising sailboats your engine is an auxiliary source power, for either when there is no wind, the wind is from the wrong angle or for the start and end of a voyage – leaving your berth or anchorage.

Range examples:

24’ sailboat – set up with 3kWh motor + 9kWh battery (1 x E Series 175)
5 knots = 30 miles, 6 hours
7 knots = 21 miles, 3 hours

30’ sailboat – set up with 6kWh motor + 18kWh battery (2 x E Series 175)
5 knots = 50 miles, 10 hours
7 knots = 21 miles, 3 hours
The ePropulsion motors can be used with up to 16 x 9kWh batteries with give 144  hours of motoring at full power, on the most popular model the Spirit 1.0 Plus outboard motor.

Batteries can be recharged at any level of charge without any damaging effects happening to the cells.

All batteries option can be charged with solar or hybrid generated power whilst they are simultaneously in use and discharging power.

Batteries are available with a range of charging options, including 240V chargers that plug into mains power, either at home or on a marina berth standard power supply.

Batteries can also be recharged by:

  • solar power supply – such as a fixed or portable solar panel
  • other onboard power sources – such as a generator powered by wind, diesel, petrol or hydrogen
  • using the hydro-regeneration capability on sailing boats, where at over 4 knots of boat speed the propeller automatically recharges the batteries

 Rather like filling your engine with fuel, or recharging your car, it’s about planning ahead for the voyage you are undertaking. It’s un-seamanlike to set off with insufficient fuel or water on board for any voyage and this is no different for electric power.

Just the same as you might call into a port or marina for fuel, water and provisions, you’ll call in for recharging.

Set up for your planned voyages by having:

  • Sufficient batteries on board for the trip you have in mind – eg a cross channel under motor
  • Combine battery power with regeneration options on board – such as hydro generation whilst sailing, solar or wind power supplies
  • Hybrid sources – such as a generator (diesel or hydrogen) or portable brief case sized generator for a specific trip, on board as a back-up power supply

Plug into a 16 amp normal mains power supply at a marina and recharge overnight. More marinas, such as MDL, are increasingly providing dedicated 32 and 64 amp fast charging facilities for their berth holders and visitors.


All ePropulsion batteries are fully recyclable. They are either repurposed for another job or reconditioned for continued use.

After Lithium has been used in a battery cathode, it can be used again and again. Oil and it’s bi-products such as sulphur cannot be reused.

Are the raw materials being mined for battery use harmful for the environment?

No mining is particularly good for the environment, be it tin, copper, coal or oil. However, mankind has been mining and drilling for 1000s of years, in particular most recently for oil to power cars, make plastics and other non-recyclable bi-products for use in the developed world.

There have been numerous disasters for the oceans and environment caused by the mis-handling of oil or accidents at oil rigs.

There have been no incidents of lithium accidentally contaminating the oceans due to mining or shipping incidents.

Installing an electric motor reduces running costs and maintenance, especially when using renewable recharging supplies, such as solar or hydro generation. In addition to be being kinder to the environment, and not requiring fuel, oil, new parts or servicing, it will release considerable space on board which can be used for other purposes. See our comparison chart:  
Example boat type:New Diesel engine ePropulsion POD Drive
21’ sailing boatYanmar 1 Saildrive £5799POD Drive 3.0 Evo + 1 x E80 battery & controls
Same with E175 battery £6450
Rapier 550 Catamaran
12 ton
2 x Yanmar saildrive
£20,156 – motors only
2 x POD 6.0 Evo – 36kWh (4 x E175 battery) and controls
Additional extrasCoolant systems
Fuel tanks
Exhaust systems
Solar panel
Generator (portable or fixed)
Wind generator
Running costs:
Fuel costsMarine diesel £1.04 / litre0.15p / kW
MaintenanceAnnual servicing and repairsNone
WinterisingAnnually None
Spare partsPer service / repairNone – unless needed due to accidental damage
See our comparison chart:
Outboard motors:Mercury 4 strokeePropulsion Spirit 1.0 Plus
Additional extrasPetrol – each trip
Fuel cans
Optional: Solar charger £90
Running costs:
Fuel costs (@ Cowes Harbour)Petrol £1.54 / litre0.15p / kWh
Sunshine £0.00
MaintenanceAnnual service ~ £200
Repairs – as required
WinterisingAnnually ~ £125None
Spare partsPer service / repair None

All retail sales are through our growing network of experienced UK dealers. Please find your nearest dealer here.

All trade customers, including boat builders and dealers, please contact us directly. 

We keep all our dealers updated when their orders are expected to arrive. Please contact your dealer for information relating to your order.

With the effect of the pandemic and Brexit there are issues with product supply and shipping affecting many sectors including the marine leisure industry. We are all doing our best endeavours to overcome these, so please be patient. We will supply each dealer with their orders just as soon as they arrive.