Solar Charging Systems For Motorhomes, Caravan, Horseboxes, Race-Trucks
Wiltshire, East Somerset (inc. Bath & NE Somerset), North Dorset and South Gloucestershire

Do solar panels actually work?
Does your leisure vehicle need a solar panel?

solar pannels blue sky

Yes, solar panels do work and very well indeed. Direct exposure to the sun is best, of course. But even when the weather isn’t so good, daylight hours will see you getting some kind of charge. And because they actually work a little too well, a solar panel controller/regulator is required to create a solar charging kit for (usually) 12v Leisure batteries as fitted to motorhomes, caravans, race-trucks and horse lorries.

Being largely a fit-and-forget item (other than an occasional clean) there are no on-going costs to solar panel charging kits and indeed can save you money and are of course, a very environmentally friendly source of free power.

Most leisure vehicle owners rightly see solar charging kits as a method of staying off-grid for longer periods. Being active once light levels are sufficient in the morning until they drop too low in the evening, a surprising amount of power can be put back into leisure batteries ready for them to support the habitation load at night.

leisure battery

There are however, less promoted benefits to having a solar charging fit on your leisure vehicle. Batteries both leisure and cranking (engine start) types do not like being idle for too long, nor left in a discharged state. It is for good reason that battery suppliers/manufacturers always recommend batteries are recharged every 4-6 weeks. Put simply this is to avoid a naturally occurring phenomena known as Sulphation of the plates When sulphation occurs, the battery starts to become less effective and can too easily become useless.

Storage Yard

By having a solar charging kit installed and providing the leisure vehicle is parked outside, the system will continually keep the battery or batteries charged up. Being charged and exercised by the solar charging kit, the sulphation process will be kept at bay, thus quietly looking after your battery (or batteries) in your absence, avoiding premature failure and the associated cost of early battery replacement. This is particularly important for leisure vehicles in general where battery use tends to be less regular, often with long inactive periods in storage.

Motor Mover

Caravans can bring their own issues, in that they often have a motor-mover system fitted for good reasons. An illustrative scenario is that the caravan is towed home or to the storage yard. It is unhitched from the towing vehicle and manoeuvred into its parking place by using the motor-mover, thus partially discharging the leisure battery. After such use the battery should be immediately recharged either via the caravans built-in charger (if mains power is available) or removed for on-bench charging. All too often the battery is left in a discharged state and sulphation begins. By having a solar charging kit installed, the battery is slowly brought up to full charge and is ready for the next use thus reducing the risk of sulphation.

sigma alarm system

Conversely, whilst motorhomes, horse lorries and race-trucks do not have the same issues as caravans, they bring other battery discharge issues. All leisure (and indeed starting) batteries will naturally slowly discharge and a solar charging kit deals with that issue. The bigger problem is that starter batteries also slowly discharge naturally but in addition they often have to permanently power in- cab radios to maintain settings and the anti-theft codes. Others have to power alarm and/or tracker systems. All of which will quite quickly drain a starter battery of vehicles in irregular use and this is a particular issue for vehicles in storage. Insurance policies often call for security devices to be active. After the battery becomes flat, alarm systems and trackers no longer operate and may make any insurance policy null and void.

wiring schematic

Solar charging kits can be configured to charge a single leisure battery, more than one leisure battery connected together for load-sharing (extra capacity), or indeed to charge both the leisure battery (or batteries) and the cranking battery. This is simply achieved using single output regulator/controllers, twin output versions and/or utilising a small current battery-to-battery charger.

sargent ec325

Some leisure vehicle distribution systems have a built-in regulator/controller within the system. In these cases a separate regulator/controller is not usually necessary, depending on the application.

Leisure Vehicle Solar Panel Services

Solar Fault Diagnosis & Repair

fluke 117 meter

If you are unfortunate to suspect any problems with an existing solar installation, The Leisure Vehicle Artisan offers a full diagnosis and rectification service at your Home, at your storage yard or on site.

New Solar Panel installations

The Leisure Vehicle Artisan has teamed up with two of the most respected solar equipment suppliers in the UK to bring you the customer a wide choice of quality equipment to suit most budgets and installation types. Both 12v and 24v systems are catered for; including those leisure vehicles running a 12v habitation system over a 24v base vehicle system (some horse lorries and race-trucks for instance).

New systems are designed; procured, fitted and commissioned using kit chosen for the best value/performance ratio for your particular need. A system will be made up from the main items listed below:

80w solar panel

Rigid solar panels are crystalline and come in two types – mono-crystalline and poly-crystalline. Mono-crystalline panels are the most effective out of all types of solar panel, with each module formed from a single silicon crystal. However, while they are the most efficient solar panels, they are also smaller and slightly more expensive watt-for-watt, but come in a wide variety of sizes and power outputs. Most of the crystalline panels you will come across will be mono-crystalline and made from a large number of small crystals and as they are smaller and lighter. The difference in efficiency means that you will need a larger poly-crystalline panel to generate the amount of energy you need. For these reasons, poly-crystalline panels are seldom fitted. Being rigid, mono-crystalline panels come with an aluminium frame to protect against damage by twisting, bending etc. and are quite robust, especially once fitted and far better suited for leisure vehicle applications.

120w solar panel kit

A solar panel kit is often the most cost-effective way of purchasing all the items required. It usually consists of the solar panel (of the size/power required), panel mounts, roof gland, sealer/adhesive, specialist MC4 connectors, cable, regulator/controller and securing screws. In short everything required.

As well as getting the right panel to suit your needs, the right regulator/controller is equally important. Its main task is to ensure the batteries don’t get overcharged, and to tell you when charging is taking place, respective voltage levels etc. A little appreciated function is to stop the solar panel discharging connected batteries in low light levels or darkness.


PWM Regulators (Pulse Width Modulation) are the most effective means to achieve constant voltage battery charging by switching the solar system controller's internal power devices. When in PWM regulation, the current from the solar array tapers according to the battery's condition and recharging needs. PWM Regulators come as single and twin output versions. Twin output versions are used to charge the leisure battery (or batteries) as the priority and when fully charged, switch to charge the starter battery (if connected). Remote monitor displays are also available with some models.


MPPT Regulator/controllers are justifiably more expensive. Maximum Power Point Tracking (MPPT) is electronic tracking - usually digital. The charge controller looks at the output of the panel(s) and compares it to the battery voltage. It then figures out what is the best power that the panel can put out to charge the battery. It takes this and converts it to best voltage to get maximum current (Amps) into the battery. (Remember, it is Amps into the battery that counts). Most modern MPPT's are around 93-97% efficient in the conversion. You typically get a 20 to 45% power gain in winter and 10-15% in summer compared to PWM types. The actual gain can vary widely depending on weather, temperature, battery state of charge, and other factors. MPPT Regulators are usually (but not exclusively) single output types, but with the addition of a small battery-to-battery charger, a starter battery can also be charged, giving the best of both worlds. Remote monitor displays are also available with some models.


Low-current Battery-to Battery chargers are designed to automatically divert charging current from the leisure battery with a constant source of energy from a solar charging kit regulator to the ‘target’ starter battery. In a solar charging system, these chargers allow an easy conversion from a single battery solar charging kit to a dual battery charging kit, without the need to upgrade the single battery solar charge regulator/controller to a dual battery model. This is perfect for systems with a high solar input, where a capable dual battery solar charge regulator/controller is expensive or difficult to procure. These chargers also stop reverse-flow from the starter battery to depleted leisure batteries.

Contact The Leisure Vehicle Artisan to discuss your requirements and to have a bespoke solar charging system designed around your specific leisure vehicle.

The Leisure Vehicle Artisan
Reassuringly Professional