Victron BlueSolar PWM-Light: Specs for Small Solar

The Victron BlueSolar PWM controllers are Victron’s simplest and cheapest solar charge controllers. The PWM-Light 12/24V models handle small systems from 5A to 30A, with a built-in load output and a timer for lighting. They’re not MPPT controllers, so you have to match panel voltage to battery voltage. Here’s what Victron’s datasheet says.

Victron BlueSolar PWM-Light: Specs

	12/24-5	12/24-10	12/24-20	12/24-30
Rated charge current	5A	10A	20A	30A
Battery voltage	12/24V auto	12/24V auto	12/24V auto	12/24V auto
Max solar voltage	28V (12V) / 55V (24V)	same	same	same
Self-consumption	<10mA	<10mA	<10mA	<10mA

Source: Victron BlueSolar PWM-Light Charge Controllers 12/24V datasheet.

Charging: three stages, not programmable. Absorption is 14.2V/28.4V and float 13.8V/27.6V.
Load output: low-voltage disconnect at 11.2V/22.4V, with reconnect at 13.1V/26.2V (automatic) or 12.6V/25.2V (manual).
Protection: reverse polarity (fuse), output short circuit, over temperature. Overload cuts out after 60s at 130% or 5s at 160%.
IP20, -20 to +50°C, 5mm² (AWG10) terminals.

Features

Two-digit display to set the load output and timer.
Lighting control with one timer and day/night options.
Automatic 12/24V detection.

Panel Matching Matters

Victron’s datasheet says to use 36-cell panels for 12V, and 72-cell panels (or two 36-cell panels in series) for 24V. A PWM controller pulls the panel down to roughly battery voltage. Victron’s MPPT overview explains that the panel then runs below its maximum power point, so you lose some output compared with an MPPT.

The Grounding Gotcha

The PWM-Light uses common positive grounding. Most vehicles and many DC systems use a common negative, so check your wiring before connecting loads to the load output.

Settings

The charge voltages are fixed. Victron says the controller drops to float 2 hours after absorption is reached, and starts a new cycle whenever the battery falls below 13V.

Who It’s For

Standalone lighting that should switch on at dusk with the timer.
Small 12V setups: a shed light, a gate opener, a trickle-charged boat or trailer battery.
Lead-acid batteries with a single 36-cell panel.

When to Buy an MPPT Instead

Lithium batteries, since PWM-Light charging isn’t programmable.
Panels over 36 cells, or 60/72-cell “residential” panels on a 12V battery.

The SmartSolar 75/10 or 75/15 is the next step up.

For the complete spec sheet and current manual, see the Victron BlueSolar PWM page.

Worked Example: A Shed Light on a 12V Battery

A garden shed with a 10W LED light used about 4 hours each evening, a 12V 35Ah AGM battery and a single 36-cell 50W panel:

Daily load: about 40Wh, or roughly 3.3Ah at 12V (estimate).
Panel output: a 50W panel runs at close to battery voltage on a PWM controller, so expect around 2.8–3A in full sun. Over 3 peak sun hours that’s roughly 8–9Ah, comfortably above the load (estimate).
Controller: the 12/24-5 handles the panel’s current with room to spare.
Timer: set the load output to switch on at dusk and run for 4 hours.

Worked Example: A Gate Opener on 24V

A 24V gate opener with two 12V batteries in series and a 72-cell panel (or two 36-cell panels in series). The controller detects 24V automatically. If the panel’s short-circuit current is about 9A, the 12/24-10 is the right size. The load output can feed the opener’s control board, which then disconnects at 22.4V to protect the batteries.

Worked Example: Why PWM Loses Some Power

A 36-cell panel rated 100W at about 18V Vmp delivers roughly 5.5A. On a PWM controller charging a battery at 13V, the panel is pulled down to near 13V, so it delivers around 5.5A × 13V ≈ 72W in that moment (estimate). An MPPT would convert the panel’s 18V × 5.5A ≈ 100W down to battery voltage with higher current. For small systems with cheap panels, the simplicity can still be worth it; for bigger arrays, an MPPT pays off.

Setting the Load Output and Timer

The two-digit display cycles through modes. Typical options include:

Always on (with low-voltage disconnect)
Dusk to dawn
Dusk plus a set number of hours
Off

Pick dusk plus hours for lighting so the battery isn’t drained overnight. Check the manual for the exact codes on the display.

Installation Steps

Mount the controller on a wall indoors or in a sheltered box (IP20), near the battery.
Connect the battery first, so the controller detects 12V or 24V.
Connect the panel, then the load.
Remember the common positive layout: the controller switches the negative side, so don’t connect panel or load negatives to a shared chassis negative.
Set the load mode and check the display shows charging during daylight.

Protecting the Battery

The load output’s low-voltage disconnect at 11.2V (22.4V) stops loads before a lead-acid battery is deeply drained, and reconnects automatically at 13.1V (26.2V) once the panel has recharged it. For a lighting system left unattended for weeks, that protection is what keeps the battery healthy through a cloudy spell.

Choosing a Size

Panel short-circuit current	Controller
Up to 5A (about 75W on 12V)	12/24-5
Up to 10A (about 150W on 12V)	12/24-10
Up to 20A (about 300W on 12V)	12/24-20
Up to 30A (about 450W on 12V)	12/24-30

Approximate panel sizes for 36-cell panels; size from the panel’s Isc with some margin.

FAQ

Can the Victron BlueSolar PWM charge lithium?

The PWM-Light’s three-stage charge profile isn’t programmable, so it isn’t a good fit for lithium. Use a SmartSolar MPPT.

What panel works with a 12V PWM-Light?

A 36-cell panel, according to Victron.

Can I use it with a 60-cell residential panel?

Not on a 12V battery; the voltage is too high for efficient PWM charging and may exceed the 28V limit. Use an MPPT such as a SmartSolar 75/15 or 100/20.

Does it have Bluetooth?

No. The PWM-Light is set with its display and buttons only.

Can it charge AGM and gel batteries?

Yes. Its fixed 14.2V absorption and 13.8V float suit many sealed lead-acid batteries; check your battery’s recommended voltages.

Sources: Victron BlueSolar PWM-Light Charge Controllers 12/24V datasheet; BlueSolar and SmartSolar charge controller overview; product page, victronenergy.com, accessed Oct 2026.