40 watt portable solar battery charger / maintainer for RV


Our new 40 Watt portable solar system functions by converting sunlight directly to electrical power to charge accessory or chassis batteries.

In stock

SKU: SLCK040-12. Category: .

Product Description

The portability of these solar battery chargers and solar generators enable them to be used in a wide range of applications.  Our portable solar powered charger is a unique design that requires no installation expertise and can be set up and operational in less than 5 minutes.  This solar system, and others like it offered by Off The Grid RV Solar, are designed specifically for those users that want to employ a source of renewable energy, in the solitude of the great outdoors, without breaking the bank.

The new SLCK040-12 40 watt portable solar battery charger is a one-panel design.  EVERYTHING is included for use.  There is nothing else to buy.  There are two ways this model can be used.  First, as a battery maintainer.  A battery maintainer is VERY VERY different than a battery charger and is the source of much confusion on the part consumers who have never purchased a solar device before.  A battery maintainer ‘MAINTAINS’ the charge in an already fully charged battery or bank of batteries.  This is because they generate only a very small amount of power.  Only about 2.3 amps to be exact.  This is PERFECT when storing your batteries for long periods of time wihout AC power being available.  If used as a battery maintainer, you simply put the solar panel in direct sun facing south, prop it up with the built-in tilt leg to about a 30 degree angle, and attach the two battery clips (red and black) to the appropriate positive and negative battery terminals of any 12V battery or battery bank.  A built in charge controller (sometimes referred to as a regulator) is included and already installed in the system.  A charge controller is a requirement in most solar system in order to prevent the battery from becomming overcharged and damaged.  As a battery maintainer, this one 40 watt system can maintain a 100% charge in just one battery or up to 6 deep cycle, RV, Marine, or automotive type batteries.  Even AGM Batteries are compatible.  Solar experts all agree that even a small solar panel used as a ‘maintainer’ will significantly extend the overall life expectancy of your expensive battery bank. Even by YEARS!


The SLCK040-12 can also be used as a battery charger in certain conditions.  However, the user must first understand and accept the limitations.  We at Off The Grid RV Solar recommend that this model ONLY be used as a battery charger where just ONE battery is being charged AND when the energy consumption of the boat, RV, Auto, ATV, or Snow Machine is very very small.  How small?  Feel free to contact us to disucuss your application further.  Our testing has shown that the operation of just 2-3 RV or Marine lights for a few hours each evening drains the battery about by the same amount the SLCK040-12 solar panel can produce the next day.  The user must then understand the many ‘parasitic’ loads inherent in the design of thier RV or Boat.  These parasitic energy drains may not be obvious but can be quite large and is where many first time solar users make mistakes.  The staff here at Off The Grid RV Solar are very familiar with RV and Marine systems and can discuss then in detail with you so the solar system can be sized correctly.
The SLCK040-12, 40 Watt portable solar battery charger employs a 3 stage, PWMtype, solar charge controller which is completely compatible with 12 Volt sealed and flooded type batteries or battery banks.  An adjustable tilt leg enables the user to adjust the angle of the panel for maximum energy absorption.  The power cable extends to 16 feet allowing the user get the solar panel in the sun even if parked in the shade. Battery clips are included with each unit allowing fast and easy set-up even without any technical experience. And finally, everything fits inside a padded storage case to safely store this solar equipment when not in use. Properly sized, these solar power maintainer/chargers can dramatically reduce or eliminate the amount of generator use normally needed to charge and maintain accessory batteries. And, they are perfect for maintaining the charge in your batteries during long periods of storage where an AC power source is not availble to run a standard battery charger.

So, give us a call or stop by to discuss one of many of our wide range of portable solar battery charging systems.  Our portable solar power systems makes use of renewable energy which is environmentally friendly, highly efficient, and now, surprisingly affordable.


The 40 watt SLCK040-12 model is ideally suited for maintaining fully charged battery banks containing one to six batteries where battery storage for long periods of time is necessary.  Battery charging for ONE battery can occur if the load (energy demand) is VERY light.   Some of the features of the 40 watt Economy unit are:


  • Built in 3 stage PWM charge controller with bulk, absorption, and float modes.
  • Produces 10-20 amp/hours per day in full sun*.
  • 2.3 amp operating current* (approx)
  • 17.2V max operating voltage
  • 14.4V peak charge voltage (temp compensated)
  • 13.8V float mode voltage
  • Compatible with Lead-acid, Gel, or AGM type batteries
  • Indicator lights confirm proper operation
  • One, adjustable, telescoping tilt leg
  • 16′ connection cord standard
  • Padded fabric storage case included as standard
  • Safety fuse
  • Battery clips for connection to battery
  • Dimensions panel:  27″x22″x1.5″, 13 lbs.
  • Dimensions of padded fabric case:  29″x24″x3″, 4 lbs.
  • Total shipping weight with cardboard box: 21lbs


(*Actual amp/hours produced and output amperage may vary depending on atmospheric conditions including: Temperature, humidity, altitude, pollution, cloud cover, fog, rain and other precipitation, dust, and dirt on the solar panels’ surface.  The figures shown are an average and can vary considerably either up or down)

Additional Information

Weight 21 lbs


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