A frequently asked question is; Can a portable solar panel directly charge a battery? You would then have to ask yourself what would happen if it did? Then decide what type of portable panel you would need? And then what type of battery a portable solar panel can charge? As you can see, the question raises a few other questions that also need consideration.
Can A Portable Solar Panel Directly Charge A Battery?
“The answer is yes of course it can directly charge a battery but I wouldn’t advise it. In fact DON’T DO IT !! Because if you do you can overcharge the battery causing irreversible damage. Even to the point of causing a fire or even an explosion. I know it’s all a bit dramatic but it is true. Overcharging a battery with a portable solar panel can easily happen. So to prevent this a solar controller is required between the solar panel and battery.“
This will regulate the flow of charge and stop charging when the battery is fully charged. As a recommendation when charging a smartphone with a portable solar charger ( the type a hiker would use). I would charge a power bank rather than your phone directly.
Although solar chargers have built in safeguards. They can allow your phone to discharge back into the solar panel. Using a power bank will prevent this and you can then safely charge your smartphone from the power bank.
How Does A Solar Charge Controller Protect The Battery When Charging With A Portable Solar Panel?
First things first, do not use a cheap solar controller. It might fail but still continue to charge your battery.
The signs that the battery is overcharging can be very difficult to spot. Until it has burst and started to release toxic fumes. This is particularly dangerous in an enclosed space like a recreational vehicle. Sorry about the second warning but it could save you from serious injury.
What typical protection can a solar charge controller give to a battery?
How does a solar charge controller work?
As you know the portable solar panel collects sunlight through it’s solar cells and converts it into direct current (DC). But this can generate too many volts for the battery to handle causing it to overcharge.
The solar controller reduces the number of volts. Then regulates the flow of DC current delivering it safely to the battery. Don’t worry I am not going to bore you with how it actually does it.
The controller also protects the battery from becoming completely drained. This can occur when the battery’s voltage is too low. The controller disconnects the load (electrical appliance) from the battery so as not to completely deplete it.
This is because, if the battery voltage is low and the load (electrical appliance) remains connected. It can damage the battery which can lead to it losing some of its overall capacity.
The controller also prevents battery discharge at night or when the portable solar panels are not charging. Due to clouds and adverse weather conditions. This prevents damage to your overall solar system.
What types of solar charge controllers are available?
Solar charge controllers come in two varieties; they are PWM and MPPT.
PWM stands for pulse-width modulation and MPPT stands for maximum power point tracking.
I am not going to go into the ins and outs of the benefits of each type here. But I can tell you that if you want the best efficiency that a solar controller can achieve. Choose the MPPT variety; they are more efficient than PWM controllers.
There are all sorts of different solar controllers out there but they usually range from 5A to 100A for use with portable solar panels. The amp rating is usually an indication of how many solar panel watts in an array a controller can handle.
The calculation for this is really easy: You multiply the number of battery volts by the charge controller amps. This will then equal the number of portable solar panel watts that can be input into the system.
So with a 12v battery system and a 50A charge controller as an example. The charge controller can handle 600 watts of solar panel input. (12V x 50A = 600W) The solar input doubles in a 24V battery system. (24V x 50A = 1200W)
What Type of Portable Solar Panel Do You Need To Charge A Battery?
There are 3 generally recognised types of solar panels these are;
Portable panels are usually made from either monocrystalline or polycrystalline photovoltaic (PV) cells. You can tell the difference between the panels by their colour. Monocrystalline are dark in colour, some are even black. While polycrystalline panels are blue.
Monocrystalline panels are the best to use because they are constructed from single PV cells. Whereas polycrystalline panels are made from multiple PV cells.
The monocrystalline single PV cell construction makes these types of panels the most efficient. This means they have the potential to charge the battery faster. But they are more expensive to buy.
What type of portable solar panels are available
There are 3 portable panel types: rigid, flexible and soft folding.
These are available in 2 types;
Recreational vehicle and trailer
Manufactured to be installed on a vehicle. These panels are very similar to the type you would have fitted to your residence roof. But they are much smaller and lighter.
These are usually used by campers and anybody that needs off-grid power. Because they are foldable they are easy to transport and store. They usually fold down into the size of a suitcase or briefcase.
Flexible solar panels as the name suggests means that they can be bent. They are lighter and thinner than rigid panels and are ideal for curved surface installation. Such as those found on recreational vehicles, trailers and boats.
Soft folding panels
These types of panels are constructed from polymers which makes them softer than rigid and flexible panels. Again they are easily transported and are popular with hikers, cyclists and campers.
What size portable solar panels are available?
Portables are usually measured by output in watts and the higher the wattage the faster it will charge a battery. They come in many different sizes from 5w to 300w for lots of different uses. I will outline some of the wattage vs panel use;
5 to 10 watt solar panels
Maintaining and trickle charging 12V lead-acid vehicle batteries can be done with 5w to 10w solar Panels. But make sure there is a built-in solar controller
Up to 40w portable panels
Very popular with hikers, backpackers, campers,travellers and campers. These panels are small, lightweight panels and are usually referred to as portable solar chargers. Able to charge electronic batteries like smartphones and portable power banks when out and about.
Although portable solar chargers do not have a recognised built-in solar controller. They do have a controller unit which provides various different safeguards.
Make sure the safeguards include overcharge protection. You can usually find this information in the product specifications on the manufacturers website.
50w to 300w portable panels
These sizes can charge virtually any type of battery from smartphones to recreational vehicle batteries. The foldable type is very good at charging portable power stations. Which are great for powering appliances or charging electronics on the go. You do not need a solar controller for a power station because they have one built-in.
If you are charging vehicle house batteries with a portable folding solar panel. You need to make sure that it has a built-in solar controller. If not you will need to add a controller separately.
What Type Of Battery Will A Portable Solar Panel Charge?
There are several different types of batteries that can be charged using solar. The nature of their portability makes them very versatile.
The obvious type of batteries that require charging are the deep cycle type. These are found in recreational vehicles, trailers, caravans and boats. They can even be used in a home setup to power a shed, garage or outbuilding.
Other types of portable battery are portable power stations and power banks. Portable power stations are batteries that have a built-in solar controller and inverter. Mainly used for camping and powering home appliances they are easily moved around and stored.
A power Bank is a small portable battery that fits into your pocket, pack, bag or vehicle glove compartment. Mainly used by hikers, backpackers, campers and people who frequently find themselves needing portable charging power. Their main use is to charge electronics like smartphones, laptops and tablets.
Newer battery innovations have arrived that can be charged with portable solar panels. Such as refrigerators and TV’s with built-in rechargeable batteries.
My Closing Thoughts
You might feel due to budget constraints that a solar charge controller might not be necessary. This is absolutely not the case because it is an integral part of any solar system. Think portable solar panel – solar controller – battery and you won’t have any problems when it comes to safety.
Because after all your health, life and wellbeing are far more important than a few dollars. Anybody giving you advice that a solar controller isn’t necessary between a portable solar panel and a battery. Is talking out of their hat because they are giving you advice that will cost you even more money in the long run. Take a look at my
I hope you enjoyed my post and have found it helpful. If you have any questions about directly charging a battery with portable solar panels. Or want to leave your own personal thoughts, please feel free to leave a comment below