This Victron SmartSolar MPPT 75/15 & 100/20 review covers Victron’s two most popular small charge controllers. They suit one or two panels on a van, shed, boat or trailer. The 75/15 handles up to 75V of panel open-circuit voltage and 15A of charge current. The 100/20 handles 100V and 20A. Both have Bluetooth built in and a load output that the larger SmartSolar models lack.
Victron SmartSolar MPPT 75/15 & 100/20 Review: Specs
| Spec | 75/15 | 100/20 |
|---|---|---|
| Max PV open-circuit voltage | 75V | 100V |
| Rated charge current | 15A | 20A |
| Nominal PV power, 12V | 220W | 290W |
| Nominal PV power, 24V | 440W | 580W |
| Max PV short-circuit current | 15A | 20A |
| Load output | 15A | 20A (1A at 48V, relay interface) |
| Battery voltage | 12/24V auto | 12/24/48V auto (48V version) |
| Peak efficiency | 98% | 98% |
| Weight | 0.5kg | 0.65kg |
| Nominal PV, 48V | n/a | 1,160W |
| Self-consumption, load off | 10mA at 12V | 10mA at 12V |
| Terminals | 6mm² / AWG10 | 6mm² / AWG10 |
Source: Victron SmartSolar MPPT 75/10, 75/15, 100/15, 100/20 datasheet. The 100/20 figures are for the 100/20-48V model.
What We Like
- Load output with low-voltage disconnect. Small DC loads such as lights or a fridge can run from the controller’s load terminals. It cuts them off at a preset voltage (11.1V or 11.8V on 12V, selectable) to protect the battery.
- Battery Life algorithm. For lead-acid batteries that rarely reach full charge, it raises the disconnect level day by day until the battery gets a near-full recharge about once a week.
- Bluetooth and VE.Direct. Set up and monitor with VictronConnect, or wire it to a Cerbo GX for VRM. Victron says it stores 46 days of history.
- Low self-consumption. The datasheet lists about 10mA with the load output off on 12V.
What to Watch
- Small terminals. They take up to 6mm² (AWG10) cable, which is fine at 15 to 20A but leaves no room to grow.
- Short-circuit limit. Victron warns that an array with a higher short-circuit current than the rating can damage the controller. Check your panel’s Isc, especially with two panels in parallel.
- Start-up voltage. PV voltage must exceed battery voltage plus 5V before charging starts.
Which One to Buy
Choose the 75/15 for a single 100W to 200W 12V panel, or panels wired in parallel. Choose the 100/20 if you want two panels in series, a 24V or 48V battery, or up to about 290W on 12V. Anything larger belongs on a 100/30 or bigger.
Manual Settings That Matter
- Lithium. Victron’s MPPT manual lists LiFePO4 defaults of 14.2V absorption for 2 hours and 13.2V float on 12V. Check your battery maker’s numbers.
- Lead-acid defaults. The default charge is 14.4V absorption and 13.8V float on 12V, and both are adjustable.
- Battery voltage. It auto-selects 12V or 24V, but set it manually in VictronConnect so it can’t guess wrong.
Setup and Troubleshooting Tips
- Won’t start charging. The manual says charging starts when the PV voltage is 5V above the battery and continues while it stays 1V above. A single 12V-nominal panel in low light may not get there.
- Lower watts than expected. Output is capped at the rated current. Victron’s own example is a 75/15 on 12V, which gives 15A x 12V = 180W into the battery.
- Error 38/39 or 80–88 (PV input shutdown). Update the firmware and check the battery voltage setting. Also check whether another charger is set to a higher voltage. For Error 38, disconnect the panels, then the battery, wait 3 minutes, and reconnect the battery first.
- Battery not charging with loads on. Charging only happens when PV power exceeds the DC load.
- Overheating terminals. Torque the connections and stay within AWG10.
Worked Example: Which Voltage Limit You Need
Add 10–15% to the panel label Voc to estimate a cold morning.
| Array | Nominal Voc | Cold estimate | 75/15 | 100/20 |
|---|---|---|---|---|
| Two 22V Voc panels in series | 44V | about 51V | Fits | Fits |
| Three 22V Voc panels in series | 66V | about 76V | Too high | Fits |
| One 37V Voc residential panel | 37V | about 43V | Fits | Fits |
| Two 37V Voc panels in series | 74V | about 85V | Too high | Fits |
On current, 15A at about 14.4V is roughly 215W, which matches the 220W nominal rating at 12V. The 100/20’s 20A works out to about 290W.
Worked examples are arithmetic estimates from the published ratings above, not test results. Real numbers depend on temperature, cable runs, battery state and load.
Victron lists every SmartSolar MPPT 75/15 & 100/20 variant, with datasheets, on its official product page.
FAQ
Does the 75/15 work with lithium batteries?
Yes. The charge voltages are adjustable in VictronConnect, and the controller will reconnect to a lithium battery whose BMS has shut it off.
Can I connect more panel watts than the rating?
The controller limits input power if more PV is connected. Stay under the voltage and short-circuit current limits.
Does it need a temperature sensor?
It has an internal sensor. A Smart Battery Sense or BMV-712 can share battery temperature and voltage over Bluetooth.
Can I put 400W on a 75/15?
The datasheet says that if more PV power is connected, the controller limits the input power. Keep the open-circuit voltage under 75V in the coldest conditions.
75/15 or 100/20?
Get the 100/20 if you need a 48V battery, panels in series above 75V, or more current.
Does the load output switch off at low voltage?
Yes. The load output disconnects at a low battery voltage you can set in VictronConnect, protecting the battery from deep discharge.
Sources: Victron SmartSolar MPPT 75/10, 75/15, 100/15, 100/20 datasheet and product page (victronenergy.com); Our Black Cat Cottage, “How to install a Victron SmartSolar MPPT 75/15 charge controller”.
Sources: Victron SmartSolar MPPT 75/10–100/20 datasheet and MPPT solar charger manual (victronenergy.com, accessed Oct 2026).
Related: SunSwift 60A MPPT Solar Charge Controller Review, BougeRV Arch Pro 200W Flexible Solar Panel Review, LiTime 12V 50Ah LiFePO4 Battery Review, plus the Victron Energy Guide