Solar charge controllers and solar panels for boats and motorhomes
A solar charge controller sits between the solar panel and the on-board battery. It limits voltage and current, charges with the right profile and stops the battery from discharging through the panel at night. Here you will find MPPT and PWM solar charge controllers from Studer and Mastervolt from 25 to 80 A, plus Sunware solar panels for boats and vehicles.
In brief: The solar panel produces the power, the charge controller adapts it to the battery. An MPPT controller gets more energy out of the panel than a PWM controller because it continuously searches for the point of maximum power.
Solar charge controllers compared
| Controller | Regulation | Battery | Max. charge current | Max. PV power (12 / 24 / 48 V) | Max. PV voltage | Connectivity |
|---|
| Mastervolt SCM25 | MPPT | 12 / 24 V | 25 A | 360 / 720 Wp / – | 75 V | – |
| Mastervolt SCM40 | PWM | 12 / 24 V | 40 A | 720 / 1440 Wp / – (recommended) | n/a | – |
| Mastervolt SCM60 | MPPT | 12 / 24 / 48 V | 60 A | 900 / 1800 / 3600 Wp | 145 V | MasterBus |
| Studer VT 40 | MPPT | 12 / 24 / 48 V | 40 A | 650 / 1250 / 2500 W | 150 V (75 V at 12 V) | Studer CAN bus |
| Studer VT 65 | MPPT | 12 / 24 / 48 V | 65 A | 1000 / 2000 / 4000 W | 150 V (75 V at 12 V) | Studer CAN bus |
| Studer VT 80 | MPPT | 12 / 24 / 48 V | 80 A | 1250 / 2500 / 5000 W | 150 V (75 V at 12 V) | Studer CAN bus |
Values from the product data in the shop. For the SCM40 the manufacturer states the PV power as a recommendation and does not specify a maximum PV voltage.
How to choose the right solar charge controller
- Battery voltage: SCM25 and SCM40 work at 12 and 24 V, SCM60 and VT also at 48 V.
- Panel power: The total of your panels must not exceed the controller’s PV power at your battery voltage. Example 600 Wp at 12 V: the SCM40 (720 Wp, PWM), SCM60 (900 Wp) or VT 40 (650 W) fit, the SCM25 (360 Wp) is too small. How much panel power you need follows from your daily consumption, see Calculating battery capacity.
- Panel voltage: The open-circuit voltage of the panels connected in series must stay below the controller’s maximum PV voltage. Open-circuit voltage rises in cold weather, so plan with a margin.
- Battery type: According to the manufacturer, the SCM25 and SCM60 support lithium-ion batteries, the SCM60 additionally with lithium protection via MasterBus. The VT offers 8 predefined, fully configurable charging curves. The SCM40 is intended for AGM, gel and flooded batteries.
- System: The VT matches a Studer Xtender via the Studer CAN bus. In a Mastervolt or philippi P-Bus system the SCM60 fits; via the CMB interface it appears on the PSL and PSM3 monitors.
Studer VarioTrack (VT) – MPPT solar charge controller, 40 to 80 A
The VT solar charge controller continuously searches for the optimal voltage of the solar generator to draw the maximum available power. This operating point changes constantly with irradiation and temperature.
- Tracking efficiency and overall efficiency above 99 %
- 4-stage charging for longer battery life, 8 predefined charging curves, fully configurable
- IP 54 protection, reverse current below 1 W in night mode
- Display, programming and data logging via the RCC-02 and RCC-03 remote controls
- Ideal in an Xtender system with synchronised battery management
Mastervolt Solar ChargeMaster – SCM25, SCM40 and SCM60
The Solar ChargeMaster comes in three sizes. The SCM25 is a compact MPPT controller for smaller systems. The SCM40 is a PWM controller for simple 12 and 24 V systems with lead-acid batteries. The SCM60 is a MasterBus-capable MPPT controller for larger systems up to 48 V and 3600 Wp. All three charge with a 3-stage+ profile and have IP23 protection. philippi integrates the SCM60 into the P-Bus via the CMB interface; solar yield and battery status are then shown on the PSL or PSM3.
Sunware solar panels for deck, bimini and guardrail
- Series-20 solar panels: can be walked on and are made for fixed deck mounting, adapting to curved surfaces up to 3 cm per metre. Screwed, bonded or clipped.
- TX solar panels: foldable, waterproof and saltwater-resistant, attached with LOXX quick fasteners, for example to a bimini or sprayhood. 60 to 240 Wp.
- TX-Rail solar panels: mounted on the guardrail, the tilt can be adjusted for better yield. Monocrystalline (PERC), 60, 90 and 120 Wp.
Frequently asked questions about solar charge controllers
What is an MPPT charge controller?
An MPPT controller continuously searches for the operating point at which the solar module delivers the most power and converts the higher module voltage into charging current. Compared with simple PWM controllers, it gets more energy out of the module when irradiation varies. The Studer VT and Mastervolt SCM25 and SCM60 use MPPT, the SCM40 PWM.
What size of solar charge controller do I need?
What matters is the panel power at your battery voltage. Each controller has a limit, at 12 V for example 360 Wp for the SCM25, 650 W for the VT 40 and 900 Wp for the SCM60. The open-circuit voltage of the panels must also stay below the maximum PV voltage: 75 V (SCM25), 145 V (SCM60) and 150 V (VT).
Do the solar controllers also charge lithium batteries?
That depends on the model. According to the manufacturer, the Mastervolt SCM25 and SCM60 support lithium-ion batteries, the SCM60 additionally with a lithium protection function via MasterBus. The SCM40 is intended for AGM, gel and flooded batteries. The Studer VT solar charge controller offers eight predefined charging curves and a four-stage profile for common battery systems.
Can the solar controller be combined with the inverter?
Yes. The Studer VT solar charge controller communicates with the Xtender XTM and XTH inverter-chargers via the Studer CAN bus and is displayed and configured using the RCC-02 and RCC-03 remote controls. The MasterBus-capable Mastervolt SCM60 can be connected to the philippi P-Bus via the CMB interface and displayed on the PSL or PSM3.
Which solar modules are suitable for a boat?
The range includes three Sunware designs: the Series-20 solar modules can be walked on and are intended for fixed deck mounting, also on slightly curved surfaces. The TX solar modules are foldable and are attached with LOXX quick fasteners, for example to a bimini or sprayhood. The TX-Rail solar modules are mounted on the guardrail and can be tilted.
