How a simple solar panel charger saved me wasting money on new car batteries

A solar panel charger being attached to a car battery
My handy solar panel charger being attached to the car battery to keep it charged up (Image credit: Future / Amy Willis)

I have a rather old but large white Renault Master van on my driveway at the moment from all the renovation work I have been doing to my house. It is currently serving as a rather unattractive storage unit for recycled kitchen units that I intend to put into my utility room when I finally get around to building it.

Aside from the constant door knocks asking if I want to sell the van for conversion into a mobile home (this is a thing now apparently), the other nuisance is keeping the van's battery charged up in case I have to move it. And if I failed to remember to start up the van every few weeks to give it a boost — the battery not only ran flat, but it frequently would malfunction so it wouldn't even charge. This was a real pain as it meant I couldn't shift this huge van out the way for jobs such as finishing off the driveway or getting a grab lorry in to remove soil and rubble from the site until I went and purchased a new van battery. This happened at least twice, costing around £150 on a new battery each time it needed replacing.

That was until I happened upon an inexpensive bit of kit that is increasingly gaining in popularity — a solar panel battery charger.

How a solar panel charger clips to a car battery

I spent around £50 on my BURNTEC 12V 10W solar panel charger from Amazon in May this year (currently out of stock) and there are some decent solar panel chargers available to pick up easily on Amazon. This 12V POWOXI 20W solar charger  is fairly inexpensive and comes with a wall fixing bracket and safe charge box, while this ECOWORTHY 10W one is super cheap for what it is.

When the solar panel charger arrived it came in a cardboard box that looked like an oversized letter. Inside it is a pretty basic bit of kit, there is literally a solar PV panel on an aluminium weather-resident frame with two plastic-sheathed cables – a red and a black one – and plastic-sheathed clips.

The cables clicked into position and literally all that was required was to connect the clips to the positive and negative terminals of the car battery that needed charging up to keep it ticking over. With the van I simply connected it to the battery and popped the solar panel on the bonnet in the sunshine. It does state that the solar panel charger should be removed before attempting to start the vehicle.

A large white van that has been sitting on my driveway

The offending huge white van on my driveway that needs regular battery charging (Image credit: Future / Amy Willis)

The solar panel charger is easily used for other stuff too

I have a second application for the solar panel charger too, for use on a smaller car battery that I use for some electric fencing. This means I can essentially just leave the car battery powering an electric fence energiser 24/7 without having to worry if the car battery has run flat. 

With this I easily pulled back the plastic sheath on the solar panel charger's metal clips to allow both the clips for the solar panel charger and the clips for the energiser to fit on the battery terminals.

There are multiple other uses, for instance any classic cars, caravans, motorhomes, boats or anything else you need to run off a car battery in the tool shed. The far more powerful 120W Nicesolar solar panel "off-grid" charging kit seems to be a good go-to option for those with a need for a much higher demand charger — and even off-grid living in a small camper van or perhaps a make-shift holiday hut.

You can also get portable solar panel chargers with USB connection on Amazonto charge up your iPhone, ipad or computer on the go. Do bear in mind that the charging capacity may be different in smaller, more portable models.

Features on a solar panel charger to look for

Solar panel chargers aren't all made of the same solar cell material. You can get monocrystalline solar panel chargers, Amorphous solar panel chargers and Polycrystalline solar panel chargers. 

Homebuilding's expert David Hilton explains the difference well in his solar PV guide, saying: "Monocrystalline cells tend to be black in colour and are slightly more efficient (around 21%) than polycrystalline cells but are also more sensitive to heat. Polycrystalline cells tend to be blue-ish in colour and are slightly less efficient (around 19%). They can often be less expensive as the manufacturing process is less intensive."

You also need to consider if you plan to have the solar panel charger out in all weather or not. If you do intend on keeping it outside make sure the charger is made from aluminium and states that it is weatherproof. Some of the chargers are designed to only sit inside your car on the dashboard and therefore aren't a good option for outside applications.

Clearly the solar panel's power generation is going to be important if you have a higher demand than just using it to keep a car battery ticking over. You'll need to pay attention to the wattage if this is the case. Likewise make sure the suitability is for the voltage of battery you intend to use it for, for instance a 12V car battery.

Reverse discharge is worth a thought too, to make sure you aren't unintentionally draining your battery when the sun isn't shining rather than keeping it topped up. Some solar panel chargers come with a separate controller for this while others have blocker diodes built into the panel.

To save money, it's also worth making sure the solar panel charger comes with cables and alligator clips so you don't have to buy these separately.

POWOXI 20W Solar Panel 12V Solar Panel Charger Kit + 8A Controller | £59.99

POWOXI 20W Solar Panel 12V Solar Panel Charger Kit + 8A Controller | £59.99
Kit comes with bracket and safe charge box as well as Polycrystalline Silicon solar panel to trickle charge 12V batteries. Rain and wind proof but does state that it shouldn't be submerged in water. 12-month warranty

ECO-WORTHY 10W Solar Panel for 12 Volt battery Charger | £35.99

ECO-WORTHY 10W Solar Panel for 12 Volt battery Charger | £35.99
This super cheap monocrystalline solar panel charger is lower wattage but still capable of trickle charging a 12V car battery. Comes with PVC suckers to stick to a window or windscreen and a set of clips. Has built in blocking diode to prevent reverse discharge

Nicesolar 120W 12V Solar Panel Off-Grid System, Solar Panel Kit | £149.99

Nicesolar 120W 12V Solar Panel Off-Grid System, Solar Panel Kit | £149.99
This kit is a lot more powerful, claiming to generate a whopping 120W. This is ideal for a battery with a higher demand on it with claims you could use if for off-grid living (clearly not for a whole house though!) Comes with connector, controller, bracket, cables and Monocrystalline solar panel

Amy Willis

Amy spent over a decade in London editing and writing for The Daily Telegraph, MailOnline, and before moving to East Anglia where she began renovating a period property in rural Suffolk. During this time she also did some TV work at ITV Anglia and CBS as well as freelancing for Yahoo, AOL, ESPN and The Mirror. When the pandemic hit she switched to full-time building work on her renovation and spent nearly two years focusing solely on that. She's taken a hands-on DIY approach to the project, knocking down walls, restoring oak beams and laying slabs with the help of family members to save costs. She has largely focused on using natural materials, such as limestone, oak and sisal carpet, to put character back into the property that was largely removed during the eighties. The project has extended into the garden too, with the cottage's exterior completely re-landscaped with a digger and a new driveway added. She has dealt with de-listing a property as well as handling land disputes and conveyancing administration.