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Hi. Have seen a narrowboat with a 3kw. pure sinewave inverter. Was told this would be sufficient to run a washer/dryer, is this true, or would I need a generator, and whats a travel pack? Many thanks.

Asked by: Anthony Burnell  | 5.53am, Wednesday 30 June

WW says:

A 3KW pure sinewave inverter should be sufficient to run most domestic ashing machines without incident. However, as most washing machines use around 1 to 1.5KWh (1 to 1.5 "units") of energy, this equates to around 80 to 120 amp hours of battery capacity required (so around 2 or 3 110Ah batteries worth of capacity)- so unless the engine is running, your battery banks can be seriously depleted.
This means you would need a decent charging system to back up the inverter, such as a reasonable alternator, and, preferably, an external alternator controller, to ensure that the batteries are charged as quickly as possible.
This brings use to a "power pack". This is an alternator, usually a 230V one, mounted on the propulsion engine, that delivers a constant source of mains power, the actual amount depending on the engine speed. A principle type if the Electrolux (Dometic) Travelpower unit- with sophisticated controller, to ensure constant voltage regulation. They tend to be 3, 5 or 7KW in size, although they take quite a large amount of power from the engine, and, at low speeds, might not generate enough current. However, other manufacturers, such as Beta Marine, offer alternative ideas which can be looked at.
Generators, of the cheaper kind, do not produce a stable enough waveform (or frequency) for modern washing machines controls to operate. More expensive inverter-based generators (like Honda portable ones) will produce a stable supply, but need to be quite big to operate a washer- at least 2500W, preferably 3500W.
Hope that helps!

Mark Langley  | 10.27AM, Wednesday 30 June

Readers say:

Not my question but a helpful answer - thanks

Michael Tait  | 5.29PM, Monday 16 November

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