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Wouldn’t it be great to spend days hiking wild trails, the hills or go cycling in nature? Sure does, but can you really leave your phone or GPS behind? For most of us the answer is no, as there could be an emergency and we need to call for help. And with portable solar chargers for boondocking, solar panels and battery packs, we don’t have to.
Back in the day solar power was reserved for homes and RVs, but now there are portable solar panels and chargers you can literally put in your backpack. Now you can hike, boat and camp as much as you want and not worry about where to recharge your phone and other electronic gadgets. With the sun as your power source, it’s really free energy.
In this guide we’ll explain the basics of mobile solar chargers, what to look for, how it works and what you’ll need. All frequently asked questions about solar power are answered here too.
Note: mobile solar chargers and portable solar panels are used interchangeably. Chargers use batteries to power phones, but they also have solar panels. Don’t be confused. by their use.
How Do I Use Portable Solar Chargers?
Portable solar chargers are plug and play. You plug a mobile device into the port or battery and it starts charging. The most common connector ports are:
- 12V port: 12V ports are used by portable, home and RV solar panels. If this is the only port that comes with your panel, a 12V car adapter is required to charge a USB device.
- USB port: this is similar to the USB port on mobile devices and computers. Plug in your USB device to start the charge, that’s it. Look for portable solar panels with USB ports if you want to charge USB devices. A compatible USB cable is required.
- USB / 12V ports: panels advertised with multiple ports usually mean a USB port and a 12V port. This is the best option if you charge different electronic devices.
- Proprietary port: these are ports designed by the panel manufacturer. Be careful with these as there is no guarantee it will work with your device. if your solar charger has a proprietary port, make sure a 12V and/or USB port is also available.
If you are looking for a lightweight phone solar power bank we recommend the ADDTOP Solar Charger as it has large capacity and works well outdoors in different environments.
What Size Solar Panel is Best?
Size, weight and physical dimensions matter a lot. After all, we’re after portability, right? Well the answer is it depends on what you’re going to do.
- If you’re boondocking by RV or boat, it doesn’t matter. You can carry a good sized solar panel, battery and inverter without problems.
- If cycling, hiking or backpacking, it depends on how much you can carry comfortably. Your backpack may seem light now, but you might not feel the same after hiking for a few hours. Most backpackers prefer one pound panels or less, but it’s your call.
- Double check the product weight and dimensions. The given dimensions may refer to when the panels are folded or laid out. The weight might also refer to the panel only and not the accessories. If you’re not sure, contact the manufacturer.
Quality and Durability
Solar panels may be light, but they are durable and can deal with rugged terrain. You don’t want to drop the panels and be careless, but a few bumps here and there are inevitable when you backpack. High quality panels should be able to handle that without breaking.
Some panels are waterproof but don’t submerge them in water. Waterproof just means the panels will still work even if it gets rained on. But don’t make it a habit. Continuously exposing panels to rain will reduce its efficiency. Use them only as directed.
How Much Solar Power Do I Need?
If you’ll only charge a phone, any portable solar panel will do. Find a lightweight solar charger that is compatible with your phone and you’ll be all right. You’ll also want to make sure that charger lasts as long as possible when camping. Our choice is the Blavor Solar Power Bank as it provides fast charging and compatibility with various mobile devices.
Phones, tablets and other electronic devices require at least a 10 watt panel. A battery pack is recommended as other electronic devices don’t solar charge as well as mobile phones. A laptop also needs a 12V charge adapter or an inverter if it runs on AC.
For AC devices you need a solar panel, inverter and battery. The panels draw the sun’s energy, the battery stores it and the inverter converts the energy into AC current. There are all in one solar kits with the panels, battery and inverter included.
Portable Solar Panel Size Chart
Here is a chart to give you an idea. These are only guidelines, and you have to calculate how much power you need. For the meantime, here’s quick guide.
|Solar Panel Watt Power
|Appliance / Device
|8W+ 220mAh 3.6V
12V battery trickle charge
Portable game device
|Portable DVD player
Small, low watt appliances
Medium sized appliances
|200Wh+ 100aH 12V
|Battery size: 1200Wh+ 100aH 12V
Majority of AC appliances
How to Calculate Solar Power Requirements
For example, you have an 8Wh (watt hour) lithium ion battery mobile phone. If you use up the battery every day, you need a bit more than 8 hours to recharge. Solar charging isn’t perfect and there will always be some energy loss during the process.
For an 8Wh phone, you’ll need about 9.6 watt hours for a full recharge. Next you have to consider how much sunlight is available. Sunlight varies by location and season. In California you get about 10 hours plus on sunny days, but that could go down to 6 hours on cloudy days. If you’re in the Pacific Northwest you’ll hours receive fewer hours of sunlight. Use this to calculate the sun hours in your area.
Assume there are 6 hours of sunlight available. The formula is:
watt hours divided by available sunlight equals minimum solar panel output rating required.
In our example:
9.6 watt hours (required to charge phone) / 6 hours (available sunlight) = 1.6.
So you need at least a 1.6 watt rated solar panel to charge your phone. In ideal weather the solar panel generates 1.6 watts per hour.
How to Calculate AC/DC Power Requirements
For 12V DC and AC devices, you have to add the power consumption. DC device power is rated in amps, but you can convert it to watts (amps x 12 volts = watts).
To calculate AC and DC requirements:
Device power requirement (watts) x hours used daily = watt hours
Suppose you have a 60W laptop and use a couple of hours daily. That’s 120Wh.
An inverter is required for AC devices, and there will be some energy loss that needs to be accounted for. Multiply 120Wh x 1.2 = 144 Wh. using the same formula above:
144 Wh / 6 hours available sunlight = 24 watts. You need at least a 24W rated solar panel to charge a 60W laptop.
To recap here are the formulas:
|You Want to Calculate
|Daily Solar Power Requirement
|Watts consumed by appliance/device daily x 1.2 / available sunlight hours
|AC Appliances including Wasted Energy
|AC appliance watt hour x 1.2
|Everyday Amp Hours or Watt Hours Used
|Device power requirement (amp) x Hours Utilized = Ah (amp hours)
Device power requirement (watts) x Hours Utilized = Wh (watt hours)
The higher the panels’ peak voltage, the better the charging performance. As temperature goes up, voltage goes down, so a solar panel with high voltage peaks can still provide good results. In contrast, performance of low peak panels will deteriorate under hot weather.
Output Power Rating
The output power rating determines how fast – or slow – the panel charges your device. The higher the output rating the faster the charge. A low output rating means a slow charge. If two solar panels have the same wattage but different output power, the higher output rating is going to be faster.
Solar panel USB ports are 5 volts, but watt and amp rating differ. Some panels indicate amps and watts, but others list only the amps. If you don’t see the watts, multiply amps x 5 volts.
Most solar panel USB ports have a 2.5 watt output rating. 12V ports are often rated 3 watts so it’s faster. If your device is compatible with 12V, use it to get a faster charge.
Rigid vs. Flexible Solar Panels
There is a lot of debate between rigid / regular solar panels and their flexible counterparts. The bottom line is rigid panels are more energy efficient and durable. Flexible panels are lighter and can be used on uneven surfaces.
If you’re only charging a phone, a flexible solar panel is a good option. They’re more affordable and provide a lot more flexibility. They can be folded so it doesn’t take a lot of space in your backpack.
If you’re carrying several gadgets, a regular solar panel is better. They can’t be folded, but smaller ones are now available. If you don’t mind a bit more size, portable solar generators are also becoming commonplace. Remember, the higher the panel watts, the faster the charge.
Solar Panel Battery Packs
Some portable solar panels come with a battery. Instead of solar panels charging your device, the panels charge the battery and the battery charges your device. A lot of lightweight panels now include a battery and for good reasons.
If your solar panel doesn’t have a battery, the charge could halt if a cloud suddenly covers the sky or you accidentally cover the panel. Even if it’s for just a brief moment, this could freeze the charge and go back to zero.
Pros of Portable Solar Batteries
- You can charge your phone at night. Let the solar panel charge the battery and in the evening you can use the battery to charge your phone.
- Keep the battery power as reserve in case it rains.
- You have extra power to charge tablets and other devices
Cons of Portable Solar Batteries
- The battery adds extra weight.
- Solar panels with batteries cost more
While a battery does add a bit of weight, it really isn’t much. The additional cost is also minimal compared to the benefits you will get. If you really don’t want a battery, look for portable panels with an auto-resume function so it picks up at the point the charge stopped.
Types of Portable Solar Batteries
Many solar panels have an internal battery installed. You can connect one to yours or better yet just buy one. There are the most popular options:
Lithium ion: lithium ion is the most popular and for many good reasons. These are lightweight batteries with a port so you can charge a USB device. You can charge the battery with your computer’s USB port or your solar panel.
12 Volt Battery; 12 volt batteries are often used in RVs, and if you don’t mind the extra weight it’s a good option for extra power. You have two choices, AGM and wet cell. Wet cell is cheaper but needs ventilation and frequent maintenance. AGM needs no maintenance, has a long life and can be set up anywhere.
The catch? 12 volt batteries weigh anywhere from 30 to 100 lbs. If you’ve got an RV, car or boat it’s not a problem though. A few more things to keep in mind:
- 12 volt batteries need a charge controller to prevent overcharging. If your panel doesn’t come with a charge controller you have to buy one.
- AGM and wet cell are deep cycle batteries and must be recharged before the level drops to 50%. Bottom line: get a 12V with twice the power you use daily.
Regular Rechargeable Batteries: by regular we mean AA, AAA, C and D batteries. These are used for flashlights, cameras and other backpacking gear. Usually these are disposable, but rechargeable versions are now available.
Solar panels with AA/AAA chargers are available and these chargers often have USB functionality. This means you can use the device to charge your phone or other mobile device, or use the AA/AAA charger for flashlights, radios etc.
Tips for Choosing Portable Solar Chargers
Before you go hiking, here are some tips to help you get the most out of your solar panel and avoid frustration when in the boondocks.
What Type of Solar Power User are You?
Solar chargers, solar battery packs, portable solar generators etc. All of these different products can be confusing and even be frustrating. Using this guide, take a look and decide which category you fit in and what type of solar charger to use.
Backpacker / Hiker
Solar chargers, solar backpacks or portable battery packs are your best bet. Solar chargers are no bigger than a smartphone and even lighter. If you need more power there are solar battery packs available.
Solar panels can be mounted on your RV or car. Portable solar generators can power various gadgets, and you can also use portable solar chargers or battery packs. Hook up several solar panels on your RV and you can run most appliances. Plus you can also keep portable chargers at hand. There’s no limit to your options here.
Students / Professionals
Students will do fine with basic solar chargers, battery packs or solar backpacks. Note that laptops need more juice so a larger solar panel or battery pack is required. Mobile professionals can avail of flip chargers, portable panels or solar battery chargers that can be plugged in cars or planes. Solar chargers are especially important for international travelers as power outlets may not be readily available.
Homeowner / Construction Worker
You’ll need powerful solar generators or roof mounted solar panels. With these you’ll have enough power to run everything, but they’re no longer portable.
Once you have figured out which category you belong, go over the following to ensure you’ve got sufficient power and well prepared.
Check Power Requirements
- First, calculate how much power you need using any of the methods above. A lot of problems can be avoided if you know how much power you’ll require before going on a trip.
- List all the electronic gadgets you will bring.
- Add up the power and estimated usage per day.
- Use the formula given earlier to determine what solar panel is required.
- If you’re only going to carry a smartphone, any solar panel will do. But if you bring several gadgets, make allowance in your calculations. It is better to have more power available.
Charge First Before You Go
No matter how long the trip or where you’re going, fully charge your solar panel. Charge a day before your trip, not weeks before. If you charge too early you might end up using the power and not realize it. You can never tell with the weather so don’t get caught in a downpour without an empty solar panel.
Check the Weather
This might seem obvious but it needs pointing out. Without hours of sunlight you won’t be able to charge any device. Plan ahead. For a single day trek it’s not a problem. As long as it’s summer you can go out in the morning and charge your phone anytime.
If you’re in an area that gets limited sunlight, plan your trip carefully. Check the weather in the area and proceed only if conditions are ideal. If you still want to go in spite of potential cloudy skies, get a solar panel with battery so you can charge your phone regardless of weather.
How Long is Your Trip?
The duration of your trip plays a major role in deciding what type of solar charger best suits you. Some guidelines:
- Single day: a small, portable solar panel that directly charges your phone is sufficient. This assumes weather is ideal, i.e. no rain expected. Even DIY solar chargers will do.
- Two days or more (weekend trip): most would bring a battery pack, and the extra weight is worth the additional power. The battery must be fully charged and you should look for every opportunity to recharge when sunlight is available.
How Will You Travel?
How you travel determines how much sun the solar panels get and how you charge them. Here are some ideas:
- Open fields and areas: if you’re cycling, kayaking or trekking, attach the solar panels on your backpack. The panels will be exposed to the sun as you go about storing energy. This is the best example of on the go charging so when you take a break, you can charge your phone.
- Forest hiking: better keep your solar panels in your backpack as the trees will block the sun. Look for an open spot in the forest and set the panel down to charge it.
- Near water; as long as there is sunlight you can strap the solar panels on your pack. Be careful when charging to avoid getting water splashed on the solar panels. While they’re advertised as waterproof, don’t expect them to work if they are drenched.
Solar Panel Charger vs. Solar Battery Pack
We’ve covered this so we won’t go over it again, but to help you decide, here are factors you must consider before packing.
- How much power do you need?
- The more powerful the battery, the heavier. Solar chargers are lighter but offer less power.
- How many gadgets will you bring?
- Do you think one charge is enough for your trip, or do you need more?
- If you prefer solar chargers, get one with strong attachments so it doesn’t fly off during a strong wind gust.
Charge at the Right Spot
Solar charging will be faster if done the right way. Make sure the panels are not obstructed and have a clear path to the sun. Do not pass over it as that could disrupt or even stop the charge. You won’t have this problem if you’re charging from a battery though.
Your solar panels need the sun’s energy, but if it’s too hot, wait for the temperature to go down a little. Refer to your solar panel’s manual for information for ideal temperature range. If it is too hot the solar panels won’t be able to charge properly, so it needs to be in the proper range. Fortunately most of these solar panels can run in different – and even extreme – conditions. .
Once your phone is plugged in the solar panel, let it charge uninterrupted. Depending on the solar charger’s design, it may or may not be able to resume if something were to momentarily block the sun, i.e. a cloud or you walk past the charger.
There are so many portable solar panels to choose from it can be bewildering for a first timer. Here are a few salient points:
- Limit your search to a solar panel that meets your minimum power requirements.
- Check the feedback online. Buy only those with positive reviews. The more detailed the reviews the better. You can tell if the reviewer has used the product by how they discuss its features.
- If two products offer the same feature set, go with the cheaper one if the manufacturer’s products get consistent positive reviews.
- When reading user reviews, think of how their situation compares with yours. What works for them may or may not work you.
In the end you really can’t tell a product’s quality until you’ve taken it out backpacking. You should look at two aspects, the quality of the charge and the build quality. Since you’re out in the trails, the panels will be exposed to the elements and must be able to withstand them.
Frequently Asked Questions
What is the difference between a portable solar panel, solar charger and a solar battery pack?
Portable solar chargers and solar panels are the same. They are solar panels that charge your mobile device directly. Battery packs are batteries with solar panels. The panels charge the battery which power up your mobile. Solar battery packs are becoming so common however that portable solar panels can now refer to battery packs too.
How do i maintain my solar panel charger?
Solar chargers need no maintenance. You may wipe dirt from the surface, but that’s it.
How long will my solar panel charger last?
These devices last for years as the warranty will show. It also depends how you use them. Solar backpacks are durable but avoid bumping them incessantly against hard surfaces. Deep scratches are best avoided as it could disrupt energy flow.
Why is my solar charger so slow?
The most obvious reason is lack of sunlight. The more sun energy it receives, the faster the charge. It also depends on the panel and battery design. The rule of thumb is to position the solar panel so it gets maximum exposure to the sun (assuming it isn’t too hot).
What is the difference between a portable solar panel and a solar kit?
Think of a solar kit as a larger, but still portable solar panel. Most kits come with a solar panel, battery, inverter and all the required connectors. Some include a battery charge controller as well. These are more powerful than your basic solar phone charger and can be mounted on RVs.
Portable solar panels makes it possible for us to get back to nature without sacrificing the comforts of mobile technology. If you’ve always wanted to go hiking but the thought of giving up your electronics held you back, well now you can have the best of both worlds.
I am an advocate of solar power. Through portablesolarexpert.com I want to share with all of you what I have learned and cotinue to learn about renewable energy.