charging your small electronic devices whilst dinghy cruising using portable solar panel

An update on small boat electronics

Although I did say the next blog post will be about the advice and tips I got on installing a 12v system on Arwen, I am delaying it for a week. Some people have given really interesting feedback whilst others have briefly shared their systems and it is worth writing it up and sharing it. 

All the blogs about charging electronics on a small boat are found at the end of this one.

Instead, in this blog post I want to briefly sum up my research about solar panels and charging external batteries with solar panels.

I am, if truth be known, still leaning towards not installing a 12v system in the boat and instead having a more portable range of power charging options – a couple of large capacity external power banks which could be topped up or recharged if necessary, by a separate solar panel system - a system that would cover all my varying outdoor pursuits. 

You can imagine my delight therefore, when I dug out the literature that accompanied my old PowerMonkey Traveller Extreme battery and solar panel (above). The power pack gives out 5v via a USB but also gives out 12v (at 0.8a) and I'd forgotten that - that is enough to charge my VHF radio. All I need to find is a cable to connect the two – a cable that has a 2.5mm jack plug at each end. So I will need to find an 'electrician' for that one. 

So, unbeknown to me, my one big issue has just been solved – charging the radio. 

Of course, getting the right combination of separate solar panels and external battery power bank will be critical. I’ve done quite a bit of reading on line and here is a brief summary of my findings regarding portable solar panels, just in case anyone else is thinking of going down this route.

The obvious

Firstly, look for reputable brands, read the reviews on buying and tech sites and check out in the reviews what customer service is like if the panels have had to be returned for some reason. As always high-quality descriptions of the panels with very few literary mistakes are a helpful reassurance.

 Most reviewer sites seem to agree that pocket sized panels won’t meet the needs of power-hungry tablets and phones. Where they are effective, they are then let down by poor charging times using direct sunlight to charge the device.  Larger capacity panels seem far more effective and faster charging but at the price of bulk and weight.  Generally, the higher the wattage, the faster devices will charge.

Basic electric terminology

It is really important to have an understanding of basic electric terminology and this was where I was initially struggling.  However, GearLab gave a good plumbing analogy which helped.

Voltage = water pressure

Current (amps) = flow rate

Ohms (resistance) = pipe size

Watts is a measure of electrical power (which is voltage x current)

Watts and Amps are commonly referred to in descriptions of the performance of various panels. Again, what seems clear to most reviewers is that a 4 or 5W panel is good enough to charge small phones or MP3 players but takes at least 4 – 6 hrs to charge a device.  7+W is needed to charge most modern smart phones.  If you are charging multiple devices or an Ipad – then 15+W’s is required and if you want to charge a laptop – go with a panel, battery and an inverter combination. Any AC devices will require 25+W’s panel, a battery and a DC to AC inverter.

Integrated battery and solar panel systems are becoming increasingly popular especially if you want enough power just to see you through a weekend.

Output power

Stress is clearly related to the amount of output power from your panel or battery apparently! Under-powered and charging times are frustratingly long!

Check carefully about the output from the panel or battery power bank you are thinking of buying. Manufacturers’ report total amperage output of both ports combined; they do it for max amperage of each USB port so meaning you have to add all the port amperages to get the total output. It’s a minefield so if you are comparing outputs of various panels or external batteries make sure you are comparing like with like! Some will report 2.1A max so two devices plugged in will share this. Others report 2.1A max where one port is this but the other port is only 1A. It drove me crazy trying to compare different products!

Solar panel considerations

Firstly, types of panel – CIG’s – very flexible, cheaper, lighter but not very durable – delaminate over time.  Mono-crystalline – best for small scale energy consumers – so found in most back-packing models for weekends away in the hills. They are rigid, durable and pretty efficient depending on size and wattage etc.  Poly-crystalline panels are less efficient than mono ones and seem to gain little favour from any reviewers I could find.

Think about your practical needs when deciding what panels to go for. When will you use them most, what kind of climate will you be operating in, will they need to be waterproof, how cloudy will it get on your trips, what weight are they, how long are they?

When looking at folding solar panel chargers, look carefully at the number of USB ports they have and what the amperage is of each port. If you are charging cameras which require a wall charger for example, make sure the panel has an adapter or that you can fit one. Anything requiring a 12v cigarette charging port will not work with most of the panels I looked at without some major modification and addition of regulators or inverters etc.

Built in chargers with solar panels seemed to fail to live up to reviewers’ expectations. The phrase ‘Jack of all trades – master of none’ was repeated on many tech review sites.  On the other hand, separate folding panel packs that could charge a portable power bank – seemed to be a very popular choice for extended trips. If you are looking at the integrated panel and battery system, go for ones with 2-amp ports. These devices do have an advantage in that you can leave them for hours and just periodically adjust them for best angle with sun. You plug in your device that needs charging at night. However, remember that many reviewers found them to be ‘master of none’ – the panels being too small to charge the battery in a reasonable amount of time. In some tests, some integrated units took over 40 hrs of sunlight to fully charge the battery pack.

Remember to think about ease of use. If buying a folding panel pack look for auto restart technology i.e. the panel doesn’t shut off or stop the charging of an attached device if a cloud passes overhead. Avoid anything which requires complicated set ups with excessive numbers of adapters and cables.  Think through your needs carefully and match the panel to your devices regarding watts, amperage etc.  Longer cables are an advantage as it means you can keep the device being charged in a dry bag or rucksack pocket. Waterproofness is a good thing!

Weight wise, as touched on above, the lighter the better so check the combined weight of panel and accessories, not just the panel itself. And remember weight is a compromise because lightness comes at the expense of durability in many instances.

Portability is an important consideration. Folding panel packs which have a stash pocket are good because the charging device is held securely and protected at the same time. Does it have hanging grommets? What is its total length – will it fit across your thwart, rucksack, saddle bags? Does the panel have a fold out stand so it can be propped up off the ground as well?

Finally, check what accessories you need to charge all your electronics and then check compatibility with your choice of folding solar panels.

The solar charger vs external battery dilemma

iMuto 20000mAh compact portable power bank

Most reviewers seemed to like this separate panel and external battery combination - charging the battery at home and then topping it up with the panel every so often. Most external batteries will charge a smart phone 4 or 5 times. Power banks store power, operate at any time, are less bulky, less expensive and lighter that integrated systems and are great for shorter trips away. Power hungry devices such as tablets and high-end smart phones require better quality power banks though. Reviewers teamed the power banks with a folding solar panel pack where they were going off grid for four or more days.

Value for money

One test site had a nice way of working out value for money by looking at price per watt. Divide the price of the chosen panels by their wattage. £10 – 15 per watt they considered good value. £20+ they regarded as expensive unless it came with lots of valuable accessories.

So with all this in mind - what am I looking at?

Well my requirements are fairly simple. I want to be able to charge on the go -  1 android phone, 12 GoPro batteries, 4 camera batteries, occasionally an android tablet, at various times 4 external power banks of varying capacities and of course, my VHF radio. I want a system that is multipurpose - so covers my cycling, camping, canoeing, off grid caravanning and trekking as well. The solar panel component is critical to the whole system - giving me the ability to plug phones and tablets in to it directly for charging or for it to charge up my external power banks. On short trips the panels and a small external battery pack will be the main items taken. I never take a laptop with me when I travel, just the tablet.  And that's it - simplicity, flexibility, portability and efficiency. 

So, I am investigating these three - the first two come up regularly in top ten reviews on gear and tech reviewing websites.


https://www.amazon.co.uk/BigBlue-Charger-Foldable-SunPower-Cellphones-28W/dp/B01EXWCPLC/ref=sr_1_5?crid=30FGCGFWPWC30&keywords=big+blue+28w+solar+charger&qid=1559715143&s=gateway&sprefix=big+blue+28w%2Caps%2C248&sr=8-5

OR

https://www.amazon.co.uk/RAVPower-UK-RP-PC005-Waterproof-Smartphones/dp/B01FH2HYCW/ref=sr_1_6?crid=30FGCGFWPWC30&keywords=big+blue+28w+solar+charger&qid=1559715339&s=gateway&sprefix=big+blue+28w%2Caps%2C248&sr=8-6

OR

https://www.amazon.co.uk/FLOUREON-SunPower-Foldable-Waterproof-Charging/dp/B0788PFXT2/ref=sr_1_7?crid=30FGCGFWPWC30&keywords=big+blue+28w+solar+charger&qid=1559715339&s=gateway&sprefix=big+blue+28w%2Caps%2C248&sr=8-7


As for battery power banks - still looking! And no - I haven't ruled out just going for a 12v system on Arwen instead. Somewhat torn - there are advantages and disadvantages to both approaches!


Other posts about charging electronics on small boats are found here: 

https://arwensmeanderings.blogspot.com/2019/06/electronics-in-small-open-boats.html
https://arwensmeanderings.blogspot.com/2019/06/electronics-in-small-boats-portability.html
https://arwensmeanderings.blogspot.com/2019/06/electronics-on-small-boats-portable.html
https://arwensmeanderings.blogspot.com/2019/06/small-boat-electronics-part-four.html
https://arwensmeanderings.blogspot.com/2019/06/first-impressions-of-big-blue-5v-28w.html