Controllers are named by their limits: a "100/50" accepts up to 100 V of panel voltage and charges at up to 50 A. Based on manufacturer specs and public reviews.
Sizing in three steps
- Battery voltage: 12, 24 or 48 V.
- Charge current ≈ array watts ÷ battery voltage.
- PV voltage: series string Voc at the coldest expected temperature must stay under the controller's max.
| Model | Voltage | Max PV voltage | Charge current | Connectivity |
|---|---|---|---|---|
| Victron SmartSolar MPPT 100/30 | 12/24V battery | 100 V | 30 A | Bluetooth (VictronConnect app) |
| Victron SmartSolar MPPT 100/50 | 12/24V battery | 100 V | 50 A | Bluetooth (VictronConnect app) |
"check" = not confirmed on the sources we used; verify on the manufacturer page before buying.
12V systems up to roughly 440 W of panels
Victron SmartSolar MPPT 100/30
Best for: 12V systems up to roughly 440 W of panels
| Voltage | 12/24V battery |
|---|---|
| Max PV voltage | 100 V |
| Charge current | 30 A |
| Connectivity | Bluetooth (VictronConnect app) |
Strengths
- Reference brand in off-grid and marine circles
- Bluetooth monitoring built in
Watch-outs
- No screen on the unit: app or accessory needed
Specs: manufacturer / retailer spec sheets (source 1). Prices change daily, so we do not print them.
12V systems up to roughly 700 W of panels
Victron SmartSolar MPPT 100/50
Best for: 12V systems up to roughly 700 W of panels
| Voltage | 12/24V battery |
|---|---|
| Max PV voltage | 100 V |
| Charge current | 50 A |
| Connectivity | Bluetooth (VictronConnect app) |
Strengths
- Same platform as the 100/30 with more current
- Fits a typical 12V cabin with 2 to 3 panels
Watch-outs
- 100 V PV ceiling: plan strings in parallel or 2S, check cold-weather Voc
Specs: manufacturer / retailer spec sheets (source 1). Prices change daily, so we do not print them.
Other brands (Renogy, EPEver and others) make MPPT controllers in similar sizes. Apply the same three numbers and compare the documented efficiency, temperature range, monitoring and warranty.
Transfer switches, power inlets, sub-panels and hard-wired batteries change your home's wiring. In most places this legally requires a licensed electrician and sometimes a permit and utility notification. This page explains the options so you can talk to an electrician, it is not installation instructions.
FAQ
MPPT or PWM?
MPPT controllers convert excess panel voltage into extra charging current and typically harvest more energy, especially with higher-voltage panels or cold conditions. PWM is cheaper and simpler for very small systems with panels matched to battery voltage.
How do I size the controller current?
Divide array watts by battery voltage: 600 W ÷ 12 V ≈ 50 A. Many installers allow some oversizing of the array, within the controller's documented limits.
What happens if PV voltage exceeds the controller rating?
It can permanently damage the controller. Always calculate cold-weather Voc for your series string and keep it below the controller's max PV voltage.