The Victron SmartSolar MPPT 100/50 and 150/45 come in the same size case and both have Bluetooth built in. It is easy to assume the 150/45 is the bigger controller. On a 12V RV battery it is not: it charges at 45 A, while the 100/50 charges at 50 A. The 150 buys you a higher solar input voltage, not more charging. This guide shows when that extra voltage is worth having, and when the 100/50 (or its little brother, the 100/30) is the better buy.
What the two numbers mean
Every Victron MPPT name has two numbers. The first is the highest open-circuit voltage (Voc) the solar array may ever reach. The second is the most current the controller will push into the battery. So the SmartSolar MPPT 100/50 accepts up to 100 V from the panels and charges at up to 50 A. The SmartSolar MPPT 150/45 accepts up to 150 V and charges at up to 45 A.
The charge current is what decides how much panel the controller can actually use. Victron lists a "nominal PV power" for each model and battery voltage. Connect more panel than that and, in Victron's words, the controller "will limit input power". The extra panel is not wasted on a cloudy day, but on a sunny one the controller caps its output at its rated current.
The four mid-size controllers side by side
| Model | Max PV voltage | Charge current | Most panel it will use at 12 V | At 24 V | Battery voltages |
|---|---|---|---|---|---|
| SmartSolar 100/30 | 100 V | 30 A | 440 W | 880 W | 12/24 V |
| SmartSolar 150/35 | 150 V | 35 A | 500 W | 1,000 W | 12/24/48 V |
| SmartSolar 150/45 | 150 V | 45 A | 650 W | 1,300 W | 12/24/48 V |
| SmartSolar 100/50 | 100 V | 50 A | 700 W | 1,400 W | 12/24 V |
All figures are from Victron's datasheets. The 100/30 and 100/50 share one datasheet and one case (130 x 186 x 70 mm, 1.3 kg). The 150/35 and 150/45 share another, in a case of the same size at 1.25 kg. All four take cable up to 16 mm² (AWG 6) on the power terminals.
Read down the 12 V column. The 100/50 uses more panel than the 150/45, and the 150/35 only edges past the 100/30. If your panels are wired in parallel, the 100-volt models give you more charging for your money.
When the 150-volt models earn their place
Panels wired in series add their voltages together. Series wiring lets you run a thinner cable from the roof, because the same power flows at a lower current. It is also how you use residential-size panels, which have a higher Voc than the small "12 V" panels sold for RVs. The catch is that the string voltage must stay under the controller's limit on the coldest morning of the year.
Victron's manuals give a simple panel count. A 100 V controller takes at most 144 cells in series, which is four 36-cell "12 V" panels. A 150 V controller takes up to 216 cells: six such panels, or three 72-cell "24 V" panels. Victron also points out that Voc rises as the temperature drops below 25°C. For cold climates, its rule of thumb is to keep an extra 10% safety margin.
Here is the check, using an example panel whose label shows a Voc of 24 V. Use the Voc from your own panel's label.
- Three in series: 3 x 24 V = 72 V, plus 10% = 79.2 V. That fits under a 100/50's 100 V limit.
- Four in series: 4 x 24 V = 96 V, plus 10% = 105.6 V. That is too high for a 100 V controller but fine on a 150/45. Victron gives 150 V as the absolute maximum in the coldest conditions and 145 V as the start-up and operating maximum.
There is a second voltage rule. The panel voltage must be at least 5 V above the battery voltage before the controller starts charging. That rarely matters at 12 V, but it is one reason a single small panel cannot charge a 48 V bank. Of the four controllers here, only the 150-volt models work with 48 V batteries.
So pick a 150/35 or 150/45 if any of these apply: your string voltage (with the margin) lands above 100 V, you want to wire four or more small panels in series, you are using residential-size panels in series, or your battery bank is 48 V.
Sizing by charge amps, not by model number
For a 12V battery, divide the array's watts by about 14.4 V (a typical absorption voltage) to estimate the charging amps. Then compare the result with the second number in the model name.
- 300 W of panel: 300 ÷ 14.4 = about 21 A. A 100/30 has room to spare. A 100/20 (20 A, 290 W nominal at 12 V) would be right at its limit.
- 400 W: about 28 A. A 100/30 (440 W nominal) still fits.
- 600 W: about 42 A. Either a 150/45 (650 W) or a 100/50 (700 W) will do.
- 800 W: about 56 A. That is more than any of the four can use at 12 V. See the next section.
Not sure what your rig needs in the first place? Our RV solar and battery calculator starts from your loads and sizes the panel, battery and controller together.
More than 700 W of panel on a 12V RV
At 12 V, the 100/50 is the largest controller in this group. Past about 700 W you have two choices:
- One bigger controller. The SmartSolar MPPT 150/70 VE.Can charges at 70 A and uses up to 1,000 W of panel at 12 V (2,000 W at 24 V).
- Two controllers on one battery. Victron's overview says multiple chargers can be used in parallel. Give each one its own part of the array. For larger systems, Victron recommends the VE.Can models, which daisy-chain with an RJ45 cable.
Before adding panel to an existing controller, check one more limit: the maximum PV short-circuit current. It is 35 A on the 100/30, 60 A on the 100/50, 40 A on the 150/35 and 50 A on the 150/45. Victron warns that an array with a higher short-circuit current may damage the controller. That is why "over-panelling" has a ceiling even though the controller limits its own output. Our answer on how much you can overpanel a 100/50 works through it.
Fusing and wiring each one
Victron's manuals require a fuse on the battery cable, with a minimum and a maximum rating for each model:
| Model | Battery fuse, minimum | Battery fuse, maximum |
|---|---|---|
| 100/30 | 35 A | 40 A |
| 100/50 | 55 A | 70 A |
| 150/35 | 40 A | 45 A |
| 150/45 | 50 A | 63 A |
For cable sizes and fuse types, see our Victron DC cable and fuse sizing guide. On the solar side, Victron says to provide a way to disconnect the PV conductors from the rest of the system.
Quick picks
- Up to about 400 W, 12 V, panels in parallel: SmartSolar 100/30.
- 400 to 700 W, 12 V, parallel or short series strings: SmartSolar 100/50.
- Series strings above 100 V (with the cold margin), or a 48 V bank: SmartSolar 150/35 or 150/45.
- One or two small panels: the SmartSolar 75/10 to 100/20 range (145 W to 290 W nominal at 12 V).
- Over 700 W at 12 V: a 150/70 VE.Can, or two controllers.
Want the panels, controller, fuse and SmartShunt picked for you? Our Victron solar charging kits pair 200 W, 400 W and 600 W arrays with a 100/20, 100/30 or 100/50 and load every part into your cart in one click.
Prefer to add Bluetooth later? The BlueSolar MPPT versions have no Bluetooth, and Victron says a VE.Direct Bluetooth Smart dongle can be added. Browse every controller in our Victron Energy range. Found it cheaper? We'll beat it.
FAQ
Is the 150/45 better than the 100/50?
Only if you need the higher input voltage. At 12 V the 100/50 charges at 50 A and uses up to 700 W, against 45 A and 650 W for the 150/45.
Can I connect 800 W to a 100/50?
The controller will limit its output to its rated 50 A, so on a 12V battery it will use about 700 W of the array. Keep the array's short-circuit current at or below 60 A and the Voc under 100 V on the coldest day.
Do I need a 150-volt controller for a 24V system?
No. The 100/30 and 100/50 work at 24 V, and their nominal panel power doubles to 880 W and 1,400 W. The 150 is only needed for 48 V or for higher-voltage strings.
Do I need a battery sensor?
No, it is optional. Victron says a Smart Battery Sense or a BMV-712 can send battery voltage and temperature to SmartSolar controllers over Bluetooth.