Securing solar panel to bike while touring
 

For the first time I am taking a folding, 4 panel solar panel, on a bike tour and am looking for a way to mount it on the bike as I ride to charge an auxiliary battery. The panel has 4 brass reinforced holes for securing it onto something. The brand is Big Blue.

I’m looking for input from those of you who have experience securing solar panels to a bicycle while on tour, and how you secured the panel to the bike while riding.

I am not asking for reasons not to take it with me, but am looking for different methods of attachment a panel to the bike.

Guy I saw touring used bungie cords he had trimmed to appropriate sizes. Had it in top of a bag that was on top of the rear rack. As noted, his was stolen when he was camping in Yellowstone. They’re not cheap so stash it away.

Looks like your panel is larger than one instance I saw (a while ago)

https://cimg5.ibsrv.net/gimg/bikefor...46a50457c0.jpg

I used a 4 panel with eyelets at one end last year for 3 months on tour. I had an Ortlieb rackpack on the rear to mount it across. I used mini carabiners to attach the eyelets at one end to the buckles connecting to the rear pannier on that side (there was a nylon D ring to connect to). The other end I used some thin cord to tie into a strap and a mini carabiner tied to the cord. Another carabiner connected to the strap also, giving me another two points to connect to the D ring on that side of the panniers. I don't have any photos.

I could use the carabiners at one end to attach to the tent fly when we were camping to catch the sun better than laying it on the ground.

It worked fine when we had the sun to our backs most of the day, charging up a power bank which was housed on a pannier.

Well, what size is it?

I think the answer also depends on what else you have lashed to your bike and how/where,

Ideally, versatile mounting with multiple anchors:
- flat across the rear panniers at mid-day with high sun
- inclined upward in rear when sun at back, with body torso blocking airflow from front.
- inclined upward in front when sun in front; This is easier than it sounds, with bottom of panel on rack that moves with fork (steered), and top of panel secured to handlebars (steered). Airflow is a problem if flat, but steepled/folded panel will add stiffness and reduce drag around panel.
- panel across main and rear triangles for sun from side.

Keep in mind with the above, if biking very remote, may make sense. If camping in evenings with AC power at campsite or stopping for an hour at a public library, the charge rate into the battery bank may be MUCH faster, especially if you can wire to have multiple AC chargers feeding into a single battery bank.

I started a past tour with a solar panel but mailed it home in the second week after realizing that the same weight is better spent on two more battery banks. Those things hold a huge amount of charge, far more than what a solar panel can deliver.

Have you consider a trailer with a 200 watt panel mounted on top? roughly 31x54

Happy Feet has not posted on this forum for a couple years, here is one of his old posts on solar power:
https://www.bikeforums.net/20422005-post17.html

You're asking "how many calories in this box?" without knowing how many snickers bars or cauliflower chunks are inside!

What are the measurements of the panel unfolded and when packed?

Do you need to unfold and charge while riding?

Do you have a trailer?

What type of front/rear panniers do you have?

Are the tops of the panniers level with the top of the rack?

Are the solar panels bendable or rigid?

What are the dimensions of the bike frame triangle.

How much abuse can these panels take?

https://bigblue-tech.com/collections/solar-panel

Apologies for not including the dimensions of the solar panel. It is a 4 panel design that hinges between panels. Overall length is 23 inches and width is 11 inches.

The issue I have is the length is a hinderance. The panel itself charges the battery pack quite well, however attaching to the bike is a stumbling block because it is so long. I am using a duffle bag mounted transversely on the rear rack and plan to mount it on top of that when needed.

The panel is longer than the duffle and will have to overhang on the sides. Not sure this is an acceptable way to position it. I just may look for a smaller panel.

For those that want to know the battery is a 20k unit and the panel when angled to the sun will give it a 50% charge in just a few hours. It even works on cloudy days, just not as well.

Appears you want to deploy on the bike (not just store it safely) while riding.

Does the system have to be fully-deployed? Fold it in half on top of the duffel, will that charge half as fast?

Maybe do a test of the system in various stages of deployment?

Saddlesores, I gave that thought and am concerned with damaging the panels folded under since they will be face down on the duffle bag. Not sure if that is good for them and I really don't want to find out the hard way. The panel will charge at a reduced rate if some of the panels are blocked off.

The liter of the two 4 panel models on the site is nearly 15.5 lbs. :eek:

If you fold it so that one of the four panels is underneath it, will that damage it, and if not, will it still work?

If a panel is almost 6 inches, maybe that would be adequate to shorten it? Yes, you would be cutting out 25 percent of the power, but it still might do the trick.

In that case, it appears they also have 2- and 3-panel units.
Assume you require 4-panels for your charging needs.
Can you get two 2-panel units?
Deploy one on the bike while riding, which should fit atop your duffel.
Deploy both units, possibly connected, in camp.

Is panel in question the 200W/15lb model or the 28W/1.5lb model? https://bigblue-tech.com/products/28...-solar-charger

The 200W version is 7ft by 2 ft unfolded. The 28W version is 3ft by 1 ft unfolded. In addition to weight and power, the logistics of attaching will be different depending on size ...

Have you tried looking for a small, low wattage flat panel? Might be a better option.

I'd be inclined to slot a 23x11 piece of the pink dense styrofoam for straps, than screw the panel on top. Then you can have it secured to your center bag or rack hanging well off the back with the styrofoam doing the structural part without a weight penalty.

Maybe the OP will be kind enough to show us what he talking about. Details definitely matter.

This is a 10 watt/2 panel. Sounds like the OP's is twice the size. Panels work best, of course, in direct sun. But they can also generate in partial sun or if a portion of the panel is obscured. But there is a threshold of % of panel obstructed below which the panel shuts down and doesn't generate any power. I think if more than 30-40% is obstructed, the panel shuts down, so the idea of the OP folding their 4 panel system in half won't work. You can test this at home before hitting the road.
https://cimg8.ibsrv.net/gimg/bikefor...dcbda38de4.jpg

Johnmflores, how well does your 10w unit charge? Say you are charging a 20k battery starting at 25% and want to take it to 75%, how long does it take?

Not as good as I want it to be. I've got a 19,200 mAH battery and how fast it charges is highly dependent upon circumstances:

1. Rain or clouds = terrible
2. Pedaling towards the sun so the panel sits in my shadow = not good
3. Pedaling in the shade = not good
4. Camping in the shade = meh
5. Pedaling away from the sun but around trees that cast shade on the road = meh
6. Pedaling away from the sun in Nevada = good
7. Camping in direct sun = good

On my GAP/C&O trip it was practically useless because I was in shade most of the time. Under those conditions, I'd be lucky if I got a 20k battery from 25% to 35% after a full day of riding. Instead, I relied upon this:

https://cimg5.ibsrv.net/gimg/bikefor...93686cf6a9.jpg

I'll probably still bring the solar panel because I travel with a lot of cameras and a laptop so I need all the help I can get. And a couple of hours of sunlight at a campground may make the difference some days.

You do not know until you try it. I have a panel that I use to keep my vehicle battery up, if part of the panel from edge to edge is obstructed, it shuts down. But if obstructed in the other direction from edge to edge, it only looses partial power.

If it is a 10 watt panel and if it really does put out 10 watts when aimed perfectly at the sun on a cloudless day, your 19.2 amp hour battery pack is probably in the 60 to 70 watt hour range. Thus, perfect conditions, 6 to 7 hours.

My bike tour six years ago, my dynohub was not keeping my battery up like it should. Ended up plugging a charger into an outlet in a laundry room at a campground and found that my charger was not charging as fast is it should. At that point I started checking cables and found that I had a bum cable, half my power from the dynohub did not make it thru that cable. Changed cables, and I was self reliant for power with my dynohub for the rest of my tour.

Lesson learned, use good cables.

I also carry a meter so I can see how much power is going through my USB port, but if you don't know what the numbers mean, a good meter might not be of any help. In my case, the meter was how I discovered a bum cable was my problem, changed cables and the charger plugged into the outlet started putting twice the power into my battery pack.

That's a sunny and cool day; heat reduces a solar panel's efficiency, up to 25% by some accounts.

Cables. Cables. Cables. I try to be redundant, but mixing and matching USB-A and C and micro USB is a minor PITA. I actually have some devices that require USB-A to micro USB; they will not charge with USB-C to micro USB.

I've been contemplating a dynohub but I hear mixed reviews. The most common criticism is that it just doesn't produce a lot of power. I'm a power hog because of my cameras. On the GAP/C&O last year, with my 19.2k bank and using my laptop to charge some devices (see USB-A to micro USB, above), I was able to go about 2.5 days of filming, backing up at the end of each day, and recharging overnight before needing a wall outlet.

I think on flat ground I am getting about 2 watts out of my dynohub on average when touring. I base that assumption on an hour long exercise ride where I measured roughly 2.5 watts on average. Touring, I am slower than an exercise ride. A couple of watts is not much. And in hilly terrain, I generate much less, the downhills do not last very long and I get minimal charge on the uphills. That is one reason why I have such a big powerbank at 44 watt hours of capacity. A hilly day, I generate less power than I use and a few consecutive hilly days and the number of lights on my powerbank for charge level are getting fewer.

I am quite frugal with my power usage. A dynohub would probably be of little help to you. There are different dynohub powered USB chargers with different outputs. Even with a really high output one like the Forumslader (spell?) you would probably not have enough. I am using a Cycle2Charge V3, it has maybe 50 percent more output than the Sinewave Revolution that I used to use.

A 20 amp hour powerbank that charges fast is pretty cheap, thus you might be best off having enough powerbanks to last between opportunities to plug into an outlet somewhere.

Before I had a dynohub, on a bike tour, every time I walked into a restaurant I looked for a seat near an outlet to charge things, and that was in the era where USB chargers did not put out a lot of power. Now with high output chargers and powerbanks that will accept a fast charge, that looks like the way to go.

Because my phone might use a lot more power than my old one, I plan to carry another powerbank on future bike tours, as a backup. It is a fast charging Anker 72 watt hour powerbank.

Thanks for sharing your experiences. I'm probably going to hold off for now. My battery bank uses standard 18650 cells (like oversized AAs). I like the idea of being able to replace cells should they wear out. I may look for another, smaller bank for redundancy's sake.

Can you expand WRT your charger? I have a couple of 18650s and the Fenix X11 single-cell charger. A couple of 3500mAh cells + the X11 makes for a lightweight kit. (136g). Slow (re)charging, though