Victron Energy's SmartSolar MPPT charge controllers are the most popular solar charge controllers in UK van conversions. They are not the cheapest option, but they are the most reliable, best-supported, and most feature-rich choice for a 12V campervan solar system.
This review covers everything you need to know: how MPPT works, which SmartSolar model to buy, real-world UK performance, Bluetooth app functionality, and how it compares to cheaper alternatives.
What an MPPT Controller Does
A solar panel outputs a voltage higher than 12V (typically 18–22V for a 12V panel). An MPPT (Maximum Power Point Tracking) controller converts that higher voltage to the correct charging voltage for your battery while maximising the current drawn from the panel.
MPPT is significantly more efficient than the cheaper PWM (Pulse Width Modulation) method. In UK conditions — cool temperatures, frequent cloud cover, low winter sun — MPPT captures 20–30% more energy than PWM. For a 200W solar array, that is an extra 40–60Wh per day in winter, which is enough to run a 12V fridge for 3–4 extra hours.
Victron's MPPT algorithm is among the best in the industry. Their proprietary algorithm tracks the panel's maximum power point as it shifts with temperature, cloud cover, and sun angle, adjusting every few seconds. In independent testing, Victron MPPT controllers consistently outperform equivalent Renogy and EPEver units by 2–5% in real-world conditions.
SmartSolar Range Overview
Victron offers the SmartSolar line in several current ratings. For campervans, the relevant models:
| Model | Max Solar Input (12V system) | Max PV Voltage | Max Current | Integrated Bluetooth | UK Price |
|---|---|---|---|---|---|
| SmartSolar 75/15 | 220W | 75V | 15A | Yes | £65–£85 |
| SmartSolar 100/20 | 290W | 100V | 20A | Yes | £90–£120 |
| SmartSolar 100/30 | 440W | 100V | 30A | Yes | £120–£150 |
| SmartSolar 150/35 | 500W | 150V | 35A | Yes | £150–£190 |
| SmartSolar 150/45 | 650W | 150V | 45A | Yes | £190–£240 |
| SmartSolar 150/70 | 1,000W | 150V | 70A | Yes | £290–£350 |
(The first number is the maximum PV input voltage. The second number is the maximum charge current.)
For a typical UK van conversion:
- 200W solar array → SmartSolar 75/15 or 100/20
- 300W–400W solar array → SmartSolar 100/30
- 400W–600W solar array → SmartSolar 150/35 or 150/45
- 600W+ solar array → SmartSolar 150/70 or two controllers in parallel
The 100/20 is the sweet spot for most builds. It handles up to 290W on 12V, which covers a standard 200W–280W panel setup. The extra voltage headroom (100V max) means you can wire panels in series for reduced cable loss without exceeding the controller's input limit.
Bluetooth Monitoring
The SmartSolar controllers include built-in Bluetooth. The VictronConnect app (free, iOS and Android) connects to the controller and displays:
- Solar array power output (watts) in real time
- Battery voltage and state of charge
- Charging current (amps)
- Daily and historical energy production
- Battery temperature (if using a Victron Smart Battery Sense or BMV-712)
- Charging algorithm status (bulk, absorption, float)
The app also lets you change the charging profile (lead-acid, AGM, gel, LiFePO4) and set custom voltage parameters. For LiFePO4 batteries, you typically set the absorption voltage to 14.2–14.4V and the float voltage to 13.5–13.8V.
VictronConnect logs data for up to 30 days. You can export the history to a CSV file for spreadsheeting your solar production across the year — useful for sizing your array.
Installation
The SmartSolar controllers are straightforward to install. The wiring diagram:
Solar Panel (+) → Solar Controller (PV +)
Solar Panel (-) → Solar Controller (PV -)
Solar Controller (BAT +) → Fuse (10A per 100W of panel) → Leisure Battery (+)
Solar Controller (BAT -) → Leisure Battery (-) or chassis ground
Key installation points:
- Mount the controller vertically, with the ventilation fins running vertically. The controller generates heat when charging at full current. In a confined van cupboard, it can overheat and throttle the output. Allow 10cm clearance above and below.
- The cable from the controller to the battery should be as short as possible. Voltage drop in the charge cable reduces charging efficiency. Use 6mm² cable for runs under 3m, 10mm² for longer runs.
- Install a fuse on the positive battery cable within 30cm of the battery terminal. The fuse protects the cable, not the controller. Size it to 1.25× the controller's rated current (e.g., 25A for a 20A controller).
- If your solar panels are more than 10m from the controller, wire them in series (higher voltage, lower current) to reduce cable loss. The SmartSolar 100/20 accepts up to 100V input, enough for two 12V panels in series (around 36–44V).
Real-World UK Performance
| Season | Average Daily Production | Peak Hourly Production | Notes |
|---|---|---|---|
| June (sunny) | 1,100–1,400Wh | 240W | Clear sky, panel south-facing, angled 30° |
| June (overcast) | 300–500Wh | 120W | High cloud, diffuse light still generates |
| September | 600–900Wh | 200W | Mixed sun and cloud, good overall |
| December (clear) | 150–250Wh | 180W | Short day (7 hours of usable light) |
| December (overcast) | 30–80Wh | 40W | Typical UK winter — 280W panel produces 50W |
The controller's efficiency tracked consistently at 97–99% in the VictronConnect logs. The 100/20's maximum output on a 12V system is 290W (20A × 14.5V), which we hit on clear summer days. The controller throttled the panel output rather than clipping, producing a clean, flat charging curve.
The most useful feature in UK winter: the SmartSolar's low-light performance. The controller starts charging at very low panel voltages (around 5V panel output). On December days with heavy cloud, the controller produced 5–10W when cheaper MPPT controllers (tested side by side with a Renogy Rover and EPEver Tracer) stayed in standby mode. Over a week, this was the difference between 350Wh and 220Wh from the same panel.
Comparison with Alternatives
| Factor | Victron SmartSolar | Renogy Rover | EPEver Tracer |
|---|---|---|---|
| UK Price (equivalent 20A model) | £90–£120 | £60–£80 | £40–£60 |
| Bluetooth | Built-in (VictronConnect) | Optional BT module (£25) | Optional (cheaper, less reliable) |
| Efficiency (lab) | 98–99% | 95–97% | 95–97% |
| Low-light performance | Excellent | Good | Average |
| Charging profiles | 8 presets + custom | 4 presets | 4 presets |
| Temperature compensation | Built-in | Built-in | Built-in |
| Warranty | 5 years | 2 years | 2 years |
| UK support | Victron UK (distributor network) | Online-only | Online-only |
| Cable connectors | Screw terminals (secure) | Spring clamps (fiddly) | Screw terminals |
The Victron costs 50–100% more than the alternatives. The difference is in the software, the low-light performance, the build quality (Victron controllers are potted — the circuit board is encased in resin, making them vibration-proof and water-resistant), and the UK support network. If you have a fault with a Victron controller in the UK, you can take it to a distributor and get a replacement the same day.
For a budget build where every pound counts, a Renogy Rover is adequate. For a long-term build where reliability and data matter, the Victron premium is worth it.
Common Installation Mistakes
Undersized solar cable. Using 2.5mm² or 4mm² cable between the panels and controller causes voltage drop that the controller cannot compensate for fully. At 15A charging current over 10m of 4mm² cable, the voltage drop is about 1.2V. The controller loses 30–50W of potential charging power. Use 6mm² minimum.
Over-panelling the controller. You can exceed the controller's current rating with more panel wattage as long as you stay under the max PV voltage. For example, a 100/20 controller on a 12V system can accept up to 290W nominal, but you can install 400W of panels if they are wired in series (higher voltage, lower current). On a clear day, the controller limits the output to 20A — you lose some peak production but gain significant output in cloudy conditions when the panels are below their rating.
Mounting in a sealed box. The controller needs airflow. Mount it in an open space or a ventilated compartment. Overheating causes the controller to reduce output (thermal throttling).
Related Reading
- Best Split Charge Relays (VSR) for UK Van Conversions
- AGM vs Lithium Batteries: UK Cost Comparison
- UK Solar Yield Calculator
- Series vs Parallel Wiring for Solar Panels
