Mastervolt 12 Volt Lithium-Ion Battery (200Ah) M66012750 66012750



Part Number: AQ M66012750

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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 66012750 Lithium-Ion battery boasts easy installation, along with a long lifespan along and fast recharge, making it an ideal replacement for lead-acid batteries. This battery saves up to 70% in space and weight, recharges in less than an hour. They are suitable for use in unlimited parallel operation, or up to 10 units in series, making it easy to increase capacity in your electrical system.

The Lithium-Ion (LiFePO4) battery is extremely safe chemically, and features a waterproof electronics cabinet. It has been tested and certified according to UN38.3, ensuring it is safe to transport. It has an Battery Management System (BMS) but should be used in conjunction with an external safety relay. The MLI Ultra batteries are equipped with a self-learning balancing algorithm that predicts the behaviour of each individual battery cell and balances proactively, resulting in a faster and more efficient charge cycle. The self-learning system eliminates unnecessary stress on the cells, resulting in an even longer battery cycle life.

The battery is MasterBus compatible, meaning they can be connected easily to a MasterBus system where you can operate and monitor all Mastervolt devices in one panel. In addition, they can also be linked via CZone / NMEA 2000 protocols.

General specifications

Nominal battery voltage: 13.2 V

Nominal battery capacity: 200 Ah

Nominal battery energy capacity: 2750 Wh

Cycle life: 3500 cycles at 80 % DOD at 25 ⁰C, max. C3 charge and C2 discharge

Max. charge current: 200 A

Recommended charge current: ≤ 60 A

Max. continuous discharge current: 500 A

Continuous charge current: 200 A

Peak discharge current: 1800 A (10 sec.)

Battery monitoring: integrated

MasterBus communication: yes

CZone / NMEA 2000 communication: yes

Terminals: M8

Mounting position: upright (recommended) or either long side

Max. outer dimensions (incl. terminals/grip handles), lxwxh: 341 x 197 x 355mm (13.4 x 7.8 x 14.0 inch)

Product weight: 27 kg (59.5 lb)

Shipping weight: 30 kg (66.1 lb)

Compliance: CE, E-Mark / DNV-GL planned for end 2021

Technical specifications

Battery chemistry: Lithium Iron Phosphate

Protection degree: IP65 (electronics cabinet)

Parallel connection: yes, unlimited

Series connection: yes, up to 10 batteries - systems over 48 V require a separate battery box to prevent access to high voltage parts

Protections: over voltage, under voltage, over temperature

Safety relay: to be added mandatorily

Safety relay controls: integrated


Capacity 200 Ah
Style Lithium-Ion
Brand Mastervolt
Application Domestic
Capacity [Ah] C20 200 to 299
Height 355mm (14.0")
Width 197mm (7.8")
Length 341mm (13.4")
Weight 27 kg (59.5 lb)

Key Features

Extreme performance, heavy duty Lithium Ion batteries.

BMS and LiFePO4 chemistry according to highest safety standards.

Saves up to 70 % in space and weight.

More than three times the life span of traditional batteries.

Fast charging within 60 minutes.

High charge / discharge rate up to 2.5 C.

Integrated battery monitoring (Ah consumed, state of charge).

Series connection up to 10 batteries possible.

MasterBus communication with any Mastervolt battery charger.

CZone and NMEA 2000 compatible.

Waterproof electronics compartment.

Designed according to UN38.3.

CE, E-Mark certified.

DNV-GL (pending).

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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