Best solar chargers for car batteries 2024
Which solar charger will keep your car’s battery in top health during the dark winter months?
The approaching winter means that anyone lucky enough to have a ‘fun’ car for the warmer months will be thinking about tucking it up in storage until spring. Many others will find that the colder weather will kill weaker car batteries in little-used cars.
In an ideal world you’d keep your battery topped up with a charger plugged into a mains supply, but that’s not an option if your garage is off grid or you park on the street.
Which is where a solar maintainer could come in handy. These are not designed to charge a flat battery but should help with the natural discharging and power used by alarms, dash cams and clocks. So which of these six solutions is the one to keep your car battery topped up?
How we tested
We tested the effectiveness of the panels by attaching them to multimeters and measuring the output in natural sunlight, both when sunny and with overcast skies. We also checked the conditioners would not overcharge a battery or take power out of it in darkness.
Points were also given for panels that were easy to use inside a car or offered weather protection if designed to be operated outside the vehicle, such as on a garage roof or wall. Other features such as USB ports and a choice of power connectors were also rewarded.
Finally, we looked at the overall value, using the best prices that we could find online.
Reviews
Here’s how our selection of solar panels for car batteries compare.
PV Logic 8W Fold Up Solar Battery Maintainer
- Rating: 5 stars
- Output: 8W
- Price: Around £45
- Connections: Clips, socket plug
- Website: halfords.com
It might not be the most powerful or cheapest in this test, but the PV Logic is the best designed and easiest-to-use maintainer we tried.
For a start, it had an output that put some supposedly more powerful panels in the shade too. It’s supplied with a choice of clips or a 12V lighter socket and a long 3m cable, which plugs into the twin solar panels. When not in use, these fold into a tiny 230 x 198mm canvas package that will easily fit in a glovebox or seat pocket.
Photonic Universe 10W Solar Trickle Charging Kit
- Rating: 4.5 stars
- Output: 10W
- Price: Around £50
- Connections: Clips
- Website: photonicuniverse.com
If you are looking for a panel that’s a little more permanent, then the rugged Photonic offering is a capable option.
Designed to survive outside, it comes with a 5m-long cable – making it perfect for placing on the roof of a garage and feeding into a car inside. A USB socket means that it can also be used to charge a tracker or other device while you’re off camping, too.
The quoted output of 10W seems pessimistic to us, because the Photonic Universe exceeded some 20W rivals in overcast conditions.
Topsolar Power Panel
- Rating: 4 stars
- Output: 20W
- Price: Around £30
- Connections: Clips, hard wire
- Website: amazon.co.uk
Topsolar’s sharp edges and awkward control unit mean that it isn’t something you’d want on your dashboard, but it would work well on a garage roof or campervan.
The control unit springs to life when connected to a battery and shows the state of charge. It also offers different modes, including a USB charger.
However, the cable to the control unit is short, and this panel’s output was lower than that of its Photonic rival, despite Topsolar claiming the unit has twice the capacity. It still looks good value, though.
Ring RSP1000 Solar Charger
- Rating: 3.5 stars
- Output: 10W
- Price: Around £31
- Connections: Clips, socket plug
- Website: ringautomotive.com
The RSP1000 looks reasonable value and is supplied with both a 12V socket and battery clips. It’s claimed to be weatherproof, so can be left outside too. In our tests it produced close to the claimed maximum output.
But it’s short on extra features, with no LED indicators, suction pads for attaching to a window, or padded corners to protect delicate interior trim.
OptiMate Solar Duo 20W
- Rating: 3 stars
- Output: 20W
- Price: Around £165
- Connections: Clips, hard wire
- Website: optimate.co.uk
Unlike the other panels here, the OptiMate incorporates an electronic monitor that claims it can revive flat batteries and keep them at the perfect charge.
With an output of 20W, it was certainly able to lift the level on some half-flat cells we tried, rather than just maintaining a charge. This goes some way to justifying the eye-watering cost.
Halfords 20W Solar Maintainer
- Rating: 3 stars
- Output: 20W
- Price: Around £42
- Connections: Clips, socket
- Website: halfords.com
The 20W is the biggest of the Halfords range and is meant to be kept outside the car rather than put on the dashboard when you park. The 3m cable will limit where you can place it, though. There’s no doubting its power – it peaked at over 20W in direct sun, but with no electronic control, it could be too much for some batteries.
Verdict
None of these panels is going to make much difference if you have a duff battery or electrical fault, but they will help if you are getting a gradual power drain from electronics. The PV Logic is easy to use and store and performed well at a reasonable price. For use outside the car, the Photonic Universe 10W would be our choice, with the Topsolar panel close behind.
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