Mastervolt Solar ChargeMaster Charge Controller color

The Mastervolt ChargeMaster SCM series are robust, PWM‑based solar charge controllers designed specifically for marine and mobile power systems. Built to handle high ambient temperatures, water spray, and common‑negative grounding, they offer reliable, efficient battery charging from your solar panels in both 12V and 24V systems.

Ideal for yachts, motorboats, campervans and off‑grid setups, the SCM range supports a wide range of battery types — including AGM, Gel, Flooded and Lithium‑Ion — making it a versatile choice for modern electrical systems.

Available in 20A and 40A versions.

Key Features

• PWM charging technology for dependable, efficient solar regulation
• Auto‑selecting 12V / 24V battery voltage
• Compatible with 36‑cell (12V) and 72‑cell (24V) solar panels
• Works with AGM, Gel, Flooded & Lithium‑Ion batteries
• Marine‑ready: IP23 protection, high‑temperature tolerance, water‑spray resistant
• Common negative grounding for easy integration into existing systems
• Backlit LCD display showing PV power, load power, battery voltage, charge current, warnings and state of charge
• Optional battery temperature sensor (Mastervolt 41500500)
• Passive cooling for silent, maintenance‑free operation

Performance & Capacity

• Nominal charge current: 20A or 40A
• Max PV current (Impp): 20A / 40A
• Recommended PV power:
  • 12V systems: 360 Wp (20A) / 720 Wp (40A)
  • 24V systems: 720 Wp (20A) / 1440 Wp (40A)
• Night consumption: < 7 mA

Protection & Safety

Built‑in protection against:

• Over‑temperature
• Overload
• High/low battery voltage
• High/low PV voltage
• Short circuit
• Reverse polarity
• High‑voltage transients

Physical Details

• Dimensions: 98 × 189 × 53 mm
• Weight: 0.5 kg
• Operating temperature: –20°C to +50°C (power derates above 40°C)
• Max cable size: 16 mm²
• Humidity tolerance: 95% non‑condensing

Force 4 P/No: 120132-20A (Mastervolt P/No: 131822000)  -  20A

Download Mastervolt Solar ChargeMaster Charge Controller User Manual here.

Force 4 P/No: 120132-40A (Mastervolt P/No: 131824000)  - 40A

Download Mastervolt Solar ChargeMaster Charge Controller User Manual here.

Royal Mail Service Update: Please be aware when choosing Royal Mail as your preferred delivery method, your delivery time may be impacted by ongoing strikes and may take up to 20 working days. If your order is time critical we suggest choosing a courier or Next Day Service

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

International Orders: Due to delays we have had to suspend our international delivery options. 

UK Standard Delivery

• UK Mainland 0 - 2Kg (small jiffy) £3.95 Royal Mail Service. Despatch within 3- 5 working days, delivery in 7-10 working days for orders under £100.00. This is an estimated delivery window from our chosen courier.
• UK Mainland 0 - 30KG £5.95 Courier service with signature. Despatch within 3- 5 working days, delivery in 7-10 working days. This is an estimated delivery window from our chosen courier.
• UK Mainland 0 - 30KG OVER 1.2m LENGTH £15.95 Courier service with signature. Despatch within 3- 5 working days, delivery in 7-10 working days. This is an estimated delivery window from our chosen courier.
• UK Mainland 30KG+ Price on request
• UK Mainland Next Day 0 - 30KG £9.95 Courier service with signature, orders must be placed before midday. This is an estimated delivery window from our chosen courier.
• UK Mainland Next Day 0 - 30KG OVER 1.2m length £19.95 Courier service with signature, orders must be placed before midday. This is an estimated delivery window from our chosen courier.
• UK Mainland Saturday 0 - 30KG £19.95 Courier service with signature, orders must be placed before Friday. This is an estimated delivery window from our chosen courier.
• Northern Ireland, Highlands & Islands 0 - 2KG (small jiffy) £3.95 Royal Mail Service. Despatch within 3- 5 working days, delivery in 7-10 working days for orders under £100.00. This is an estimated delivery window from our chosen courier.
• Northern Ireland, Highlands & Islands 1 - 30KG £10.95-£14.95 Courier service with signature. Despatch within 3- 5 working days, delivery in 7-10 working days
• Northern Ireland, Highlands & Islands 1 - 30KG OVER 1.2m length  from £24.95 Courier service with signature. Despatch within 3- 5 working days, delivery in 7-10 working days
• Northern Ireland, Highlands & Islands 30KG+ Price on request
• Channel Islands 0 - 2KG (small jiffy) £5.95 Royal Mail Service Despatch within 3- 5 working days, delivery in 7-10 working days for orders under £50.00
• Channel Islands 1 - 30KG £19.95 Courier service with signature. Despatch within 3- 5 working days, delivery in 7-10 working days
• Channel Islands 30KG+ Price on request

UK Exceptional Delivery

• UK Mainland; Antifoul & paints £5.95
• UK Mainland; Inflatable dinghy £10.00
• UK Mainland; Liferafts £17.50
• UK Mainland; Flares £49.95
• Northern Ireland, Highlands & Islands; Antifoul & paints £9.95
• Northern Ireland, Highlands & Islands; Inflatable dinghy price on request
• Northern Ireland, Highlands & Islands; Liferafts price on request
• Northern Ireland, Highlands & Islands; Flares not available to ship at this time
• Channel Islands; Antifoul & paints £13.50
• Channel Islands; Inflatable dinghy price on request Channel Islands; Flares not available to ship at this time

Ship to Store service; You can now order from our website for collection from one of our 9 Force 4 locations. Simply select “Ship to Store” at checkout and your goods will be ready for collection within 5 working days. This service is free however may exclude some hazardous or special order goods.

For further delivery information click here.

Standard Returns

If you are not entirely happy with your purchase, we will exchange or refund your goods in full, provided that the items are returned within 14 days of receipt.*

Please check the condition of goods on arrival - we are unable to accept goods damaged during shipping after 14 days.

Returned goods must be packaged securely, with all original packaging undamaged and in a saleable condition i.e. shoe boxes must be in the same condition as when received.

Goods must be unused and security seals intact.*

If you would like to return goods because they were ordered incorrectly or if clothing does not fit, return postage will be at your expense. If you would like us to replace the goods with another size or colour, we will charge carriage on the replacement.

Please be aware that some navigational and safety products may be dated, and as such a full refund may in some cases not be possible. If you are purchasing dated navigational charts we suggest you contact us for more information.

Faulty Goods

If you receive your goods and believe them to be faulty, please contact us straight away with a brief description of the problem. If we require you to return the product for a replacement, we will send you a pre-paid Royal Mail label for delivery back to us. Unfortuantely we cannot send the courier back to collect the items.

Returning goods to Force 4 is easy!

1. Please contact us by ringing 0345 1300 710 or email on [email protected]. This way we'll be able to determine whether you would like to return the product for a refund or whether you'd like to exchange the product. We are unable to process the return of faulty goods that we're not expecting.
2. We'll then give you a returns number. This returns number will need to be clearly marked on the outside of your parcel so it can be identified on arrival. Please note, failure to mark a returns reference number on the outside of your parcel may result in a delay in processing your return.
3. Don't forget your proof of postage, just in case!
4. Once we receive the item we'll be able to proceed with a refund or an exchange.

*this excludes faulty goods with manufacturers defects. If goods are found to be faulty during use, after the returns period, please just give us a ring on 0345 1300 710 and we'll be happy to help.

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