Mastervolt AC Master Inverter With UK Socket (12V / 2500W) M28212500 28212500


Recommended Retail Price
£1,445.05 Inc. VAT

Online Price (inc. VAT)

Part Number: AQ M28212500

  • COVID 19 Disruption
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Due to the ongoing and evolving "LOCKDOWN" situation in place since early 2020, we are anticipating a small delay in processing of orders and subsequent shipping due to a reduced workforce, in both our warehouses, and those of our suppliers.

Whilst we are trying our best to continue in a business as usual, we must again close our retail showroom doors temporarily to support the Governments COVID19 Strategy. Throughout this temporary closure we will still be shipping items from our warehouses and those of our suppliers, but it may at times be subject to a small delay.

The quickest way to get an answer to any questions you may have is to email us on Alternatively should you wish to actually speak to a member of our team, please call us on 02087884587 and Choose Option 1.





The Mastervolt AC Master power inverter produces a pure sine wave AC (Alternating Current) output from a DC (Direct Current) input from your boats battery bank. Because of the pure sine wave output, it is safe and reliable and prevents damage to the equipment it is connected to. The inverter is easy to install and features built in protection against over-temperature, overload, short circuit, high or low battery voltage and reverse polarity.

The power inverter is robustly built and delivers the full output even in demanding conditions. The high frequency technology used eliminates noise typically associated with power inverters, such as buzzing or humming. It also features an automatic power saving mode, meaning a longer run time and less strain on your batteries. The 28212500 model is MasterBus compatible and can be used with remote control M70405080 for easy operation.

With the 2500 Watt model, you can use a 3 phase system, or combine up to 15 units in parallel for higher power outputs.

General specifications

Output voltage: 230/240 V - 50/60 Hz (selectable)

Output waveform: true sine

Nominal battery voltage: 12 V

Recommended battery capacity: ≥ 270 Ah

Continuous power at 25 °C / 77 °F, cos phi 1: 2500 W

Continuous power at 40 °C / 104 °F, cos phi 1: 2500 W

Peak load (3 s): < 3000 W

Peak load (< 0.2 s): < 4000 W

AC connection: hardwired with UK plug

Galvanisedanic isolation: yes

Efficiency: 88 %

Parallel configuration: yes, up to 15 units

3-Phase configuration: yes, 3 units

Display/read-out: LED indication: battery voltage, load level, status

Alarms: potential free alarm contact

Dimensions, hxwxd: 283 x 436 x 128mm (11.1 x 17.2 x 5.0 inch)

Weight: 8 kg (17.6 lb)

Compliance: CE, E-mark, RCM

Technical specifications

Technology: high frequency, input & output fully isolated

Low battery voltage, switches off at: 10.5 V

Low battery voltage, switches on at: 12.5 V

High battery voltage, switches off at: 16.5 V

High battery voltage, switches on at: 14.5 V

Input current (nominal load): 250 A

No-load power consumption (ON mode): < 3.6 A

No-load power consumption (energy saving mode): < 1.1 A

Minimal DC fuse (slow blow): 300 A

Minimal cable size: 95mm²

Harmonic distortion typical: < 5 %

Cos phi: all power factors allowed

Transfer system: integrated, automatic (inverter to grid: 8~10 ms, grid to inverter: 16~50 ms). Not for parallel & 3-phase operation (external transfer system possible)

Temperature range (ambient temp.): -20 °C to 60 °C, derating power > 40 °C (-4 °F to 140 °F)

Cooling: temperature and load controlled fan

Protection degree: IP21, horizontal wall mounting

Protections: over-temperature, overload, short circuit, high/low voltage, reverse polarity (fuse)

MasterBus compatible: yes, using a MasterBus AC Master Interface


Brand Mastervolt
Voltage 12V
Height 283mm (11.1")
Width 436mm (17.2")
Depth 128mm (5.0")
Weight 8 kg (17.6 lb)
Temperature Range Ambient Temperature: -20 °C to 60 °C, derating power > 40 °C (-4 °F to 140 °F)
Protection Rating IP21

Key Features

Pure sine wave technology protects sensitive equipment

Delivers full output at high peak power under the most demanding conditions

Automatic power-saving system for extended runtime

Compact and lightweight design, saving valuable installation time

Reliable and safe operation; protected against over-temperature, overload, short circuit, high or low battery voltage

Variable speed fan for quiet operation at low power

Convenient plug connection and also hard wired

Downloads - Click the links below

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Our Mail Order team ship chandlery, yacht parts and sailing clothing around the world. We try to use the best value couriers available, and we will endeavour to get your products to you as quickly and as cost effectively as possible. 

As with everything automatic, sometimes it might not present you with the best value price, please feel free to contact our helpful team who will endeavour to provide you with our best price for shipping to your address.

UK Standard Delivery

Please use the checkout process to get an accurate shipping quote for your cart, all of our rates are automatically calculated based upon your selections.

As with everything automatic, sometimes it might not present you with the best value price, please feel free to contact our helpful team who will endeavour to provide you with our best price for shipping to your address.

International Delivery

International Delivery is calculated based on a series of complex formulae at checkout and includes options such as UPS International. If you cannot see a rate at checkout, please contact us.

Delivery further information

The delivery charge is automatically added to your order and you will see the total amount you have to pay before you confirm the order. Unfortunately we have to charge carriage but we do attempt to keep it to a minimum where possible

All orders leaving us require a signature, and the delivery could take place any time between 8am and 6pm depending on the courier used. If you are liable to be out, please give an alternative delivery address or type instructions into the notes section as you place your order.

Standard Service; We will aim to dispatch goods within 3 working days. Delivery on the standard service is via courier, will require a signature and we aim to deliver within 5 working days. This service will only arrive on working days.

Courier delivery; The majority of our parcels will be sent via a courier, the bulk of which are with APC Streetwise. Please be aware that they advertise their delivery times as anywhere between 8am - 6pm Monday to Friday. We are not able to dictate to them a time slot. And in most cases a signature will be required.

New! For 2020 – Putney EmbankmentClick & Collect service; New for 2020 finds our first ever collection point on the Putney Embankment. Please select Pick Up at checkout to activate the service

NB; For orders to mainland Europe and Rest of World, the cost for carriage is calculated on order package weight and final destination. The price given at checkout is a guide only and an accurate postage cost will be calculated and invoiced to you if a supplement is required. If you would like to know this figure before despatch please feel free to contact us for a quote. Please be advised that if your order is sent via courier outside of the EU you may need to pay for import/custom taxes after the order has been delivered to you. This is standard procedure by the courier to ensure that your order is delivered to you as soon as possible and not delayed in customs. These charges are solely dependent on your local customs office and the courier, we have no control over these charges. We would kindly suggest contacting your local customs office for more information and advice. Additional charges for customs clearance must be borne by you; unfortunately, we have no control over these charges and cannot predict what they may be. We are unable to reimburse any costs incurred regardless of the circumstances.

ANTIFOUL & PAINT ORDERS; Please be aware that we can only send antifoul & Paint products within GB Mainland. We CANNOT send antifoul & paint outside of GB Mainland. If you have any questions regarding this please feel free to contact our Mail order department.

LIFEJACKETS & CO2 CANNISTERS; Please be aware that we cannot currently send lifejackets with CO2 cannisters included outside of GB Mainland

LIQUIDS & CHEMICALS; Please note we are unable to deliver liquids or chemicals overseas or to highlands and island addresses. We will also have to use a courier service within GB Mainland for liquids or chemicals.

SALE OF KNIVES; In accordance with UK Law (The Offensive Weapons Act 1996), we are unable to sell knives to anyone under 18 years of age. We are unable to send knives to overseas destinations. You must upload a copy of a valid identity document to your order at time of ordering or your order will be cancelled. Knives must be sent on a signature courier service. Valid forms of ID are EU Passports, EU Photocard Driving Licence, MOD Form 90 ID Card, EU Member State National Identity Card, “PASS” ID Cards.


Last Updated 2nd September 2020

Our returns policy lasts 30 days. If 30 days have gone by since your purchase, unfortunately we can’t offer you a refund or exchange.

To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging.

To complete your return, we require a receipt or proof of purchase.

Please do not send your purchase back to the manufacturer.

To read our full returns and exchanges policy, please click here.


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