One stop for solar charging ebike info?

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kiltedcelt   10 W

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One stop for solar charging ebike info?

Post by kiltedcelt » Apr 20 2020 2:07pm

I've been reading through page after page of threads on here mentioning solar recharging of ebike batteries but I'm finding little in the way of a more simplistic breakdown of what is currently known about the best panels to use and what sorts of components to use to make charging an ebike battery via solar panels a viable thing. I'm embarking on creating a tadpole cargo trike, and one thing I want to incorporate is a the ability to have an awning with solar panels just like many of the 'cycles you'd see on something like The Sun Trip. Sun Trip - that's another thing. I've looked at numerous threads regarding that as well, but again I'm finding it difficult to parse just how these 'cycles are set up for solar charging. The goal of something like Sun Trip and my intention is to have the ability to recharge the power source for an ebike without needing to rely on mains power to recharge. Are these 'cycles set up with a battery that powers the bike while riding and a second battery that is storing current generated by the panels while riding? Are they then simply swapping batteries as need, or does the battery connected to the charger then somehow recharge the main battery at stops? I'm planning right now on only working with what I have which is a BBSHD mid-drive and a 14sp 28.3 amp hour 52v battery. The battery voltage is another thing I'm perplexed about. I'm seeing plenty of info about 24/36/48v battery recharging, but nothing about 52v batteries, or at least not where I've been looking. So, is there some central site or thread where someone has collated all of this information? Created sort of a primer on how these systems should be set up, that sort of thing? I'm willing to buy or build another battery when it comes time to begin assembling the solar recharging system, as well as the other components. I realize that hub motors might be better in some regards due to having the option of regen, but that's not on the table right now. I'm also trying to make this 'cycle be more versatile so I want the ability to switch out the 26x3.0 wheels I'll be using with 26x4.0 for snow or more serious rough-road stuff. That obviously rules out hub motors as well, unless I get into things like mounting a hub motor in the frame somehow. Anyway, my budget isn't going to allow any other motor other than the BBSHD right now. Anyway, mainly just posting to see if anyone can help me narrow down my search criteria or if anyone knows of a site or collection of information where someone has put this all together along with the most recent information regarding the latest panels and battery voltages higher than 48v (ie. 52v).

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MadRhino   100 GW

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Re: One stop for solar charging ebike info?

Post by MadRhino » Apr 20 2020 2:43pm

It is not easy to find well structured info regarding solar ebikes, because it doesn’t fit the requirements of many ebike riders. Nevertheless, many on ES have experience with solar charging. You don’t need an extra battery for this purpose, for the one on your bike can be charged with solar panels and, if required, batteries can be charged and discharged at the same time.

Search first for solar charging, in ‘ebike technical’ section of the forum.
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kiltedcelt   10 W

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Re: One stop for solar charging ebike info?

Post by kiltedcelt » Apr 20 2020 3:12pm

Madrhino - thanks for the info. I'll do some more searching specifically with the criteria you mentioned. A few videos I'd watched about solar charging on 'cycles that were being ridden seemed to be engineered the way you're describing - a battery is in place, but the rider is getting a far greater amount of mileage than would be possible on the watt hours capacity of the battery alone. This is exactly the sort of information/designs I'm looking for. My ideal situation would be using just battery power for shorter trips around the city - say 60-80 miles round trip or less, although right now most of my round trips are seldom more than about 50 miles. However, getting far enough out of the city (I live in Chicago), means I need to be prepared to rack up more than 50 or 60 miles if I *really* want to get to a pretty rural area. Being able to dramatically extend that range without needing to stop to recharge is exactly what I'm looking for. Assuming I'm able to ride when it's sunny that means I can get some serious range, and demonstrating the practicality of a vehicle like this is going to be one of the main missions involved in the construction and testing.

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Re: One stop for solar charging ebike info?

Post by john61ct » Apr 20 2020 8:21pm

Solar is a very large amount of equipment relative to the very slow trickle of energy input.

As in, charge all day to get an hour of riding. Or have a chase van driving so your crew can set it up in advance.

And that is only when it's sunny!

Better to adapt to J1772 and be able to charge relatively quickly from EV charge stations.

Still heavy & bulky, but not as bad as solar.

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Re: One stop for solar charging ebike info?

Post by ZeroEm » Apr 20 2020 8:44pm

I have most of my miles have come from solar charging. Here's the catch, I have two batteries and keep one solar charging at home then swap. My equipment will never pay for it self but it makes me feel good.

No solar on my trike itself, just not worth it. I have a bike trailer that I can pull if the need of another battery but can easily go 150 miles with one.

If you are on a budget put all your money into your battery for distance and peddle a lot. Unless you just want to clam that you have solar on your bike/trike. It maybe worth it if you are going on a trip and stop a lot at camp sites.
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Re: One stop for solar charging ebike info?

Post by amberwolf » Apr 21 2020 12:13am

I suspect this thread
viewtopic.php?f=6&t=94721
will have more of the specific information you're looking for than most of the others.

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Re: One stop for solar charging ebike info?

Post by kentsbike » Apr 21 2020 9:56am

All my ebike miles for the past year have come from solar power. I don't claim that this system is very efficient, fancy, or high-tech, but it works for me. Details at:

https://kentsbike.blogspot.com/2019/04/ ... eddy.html
and

http://kentsbike.blogspot.com/2020/02/m ... life.html

Kent Peterson
Eugene, OR USA

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Re: One stop for solar charging ebike info?

Post by john61ct » Apr 21 2020 10:20am

Neither of those links work from here.

I don't think OP cares so much about the principle of being Green, not looking for gear that stays at home.

But under the impression that solar can give unlimited range while out and about.

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Re: One stop for solar charging ebike info?

Post by dogman dan » Apr 21 2020 10:58am

One thing for sure, you want the thin, very lightweight, semi flexible panels They rock, and are worth the higher price. That higher price not all that bad these days either.

I put two small 40w panels on my rv at first, then got a big 100w panel. They work great, really easy to install anywhere you want them. The only thing that would be great is if they put out 60v instead of 18v. 18v is a "12v" panel btw, compatible with the low priced charge controllers that put out 13-14v for lead batteries.

The rub with doing this for a bike, is of course, the lack of 13s charge controllers. I believe you can series connect panels to get to a 50-60v output. I was going to do a solar trailer, but ended up doing an RV :roll: . Not exactly eco, but I just couldn't do the tent camping at my age.

But my plan for the solar trailer was pretty simple, 4 small 50w 12v panels in series, then use a DC DC converter to step it down to 12s voltage. The panels would put out up to 72v in full sun, and less in shade. But the converter would supply a steady 50v. No BMS, so it was going to be a very primitive setup. low wattage, 50 or 60w of 50v would be the output.

What would be ideal, is two of the 100w 12v panels, connected to a charge controller that outputs for a standard bms equipped `13s bike battery. you'd have about 50w of 54.6v. Its not much, but it would extend range, and charge a battery full in one day stationary.

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Re: One stop for solar charging ebike info?

Post by john61ct » Apr 21 2020 12:54pm

There are MPPT boost controllers for 48V, that's standard stuff.

Would be surprised if higher voltages aren't out there by now.

Just using DCDC conversion will not efficiently capture as much power, and of course you need automatic charge termination, HVC will do for that.

The so-called flexible "semi flex" panels do not last long compared to proper framed ones, supposed to be installed so they do not flex after installation.

Really need an air gap below for cooling, otherwise lose efficiency and break sooner.

The folding "blanket" type can last a long time, but usually designed just for USB output, and need a **whole lot** of them to get the kind of wattage output an ebike pack needs.

A 10' x 10' array would IMO be a minimum starting point to get an ebike pack recharged in an afternoon.

Anything designed to charge while riding is barely going to be at all useful, might add 10% range.

For practical purposes, a gasoline motor really is the solution.

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Re: One stop for solar charging ebike info?

Post by dogman dan » Apr 22 2020 7:25am

Interesting info about the flexy panel. I had not heard about that. Nevertheless, they sure are easy to mount where you want them, change your mind, remount different. But mainly, light.

In my case, I put the 100w panel on the cover over the front window shield on the trailer. So its not air gapped, but mounted to a thin sheet of fiberglass that can cool from the back. It will have to do. The smaller panels I mounted on a piece cut from an old plastic table top. No gap, but at least not sitting on black tar roof.

I did know you can't bend those panels all the time, so you do want to support them somehow. Maybe mount them on something corrugated for support and cooling? For my solar trailer idea, they were to be mounted to the coroplast top of the trailer. So they would flex a tiny bit when riding, but still basically be supported.

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Re: One stop for solar charging ebike info?

Post by john61ct » Apr 22 2020 2:33pm

A rigid (non flexing) backing of aluminum sheeting is ideal.

There are water cooling kits that produce hot water for showers off the back.

The point of the flexibility is to allow mounting to (gently) curved surfaces.

On yachts some brands advertise to mount on a deck or cabin roof and tough enough for people to walk on. Turns out, not so much, but they made a lot of profits for a few years 8-)

Many rigid panels guaranteed for 10 or more, flex maybe average 2-3 years before issues arise.

Not sold at all in jurisdictions with strong consumer protection regimes. Where they've gone to the folding blanket style instead.


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Re: One stop for solar charging ebike info?

Post by kiltedcelt » Apr 22 2020 7:13pm

Amberwolf has the gist of what I'm looking for. There were some pretty promising things in the links provided, especially the guy with the recumbent with the solar trailer (The Grin Tech video). That video pretty much shows that a decent sized solar array can provide charge to top up a battery, extending range while you ride the bike. Of course the bikes used on the Sun Trip also bear this out but so far I've seen precious little information on how those 'cycles are set up. One thing that is very intriguing from the research is those Li-Go batteries that Grin makes. The modular nature of them and their size makes them a likely alternative type of battery configuration for someone like me - ie. not interested in fabricating my own batteries. The other thing touched on in the replies was Kent's post (and links), about home solar recharging. As I live in an apartment I have no way to recharge batteries via solar, but that is ultimately what I hope to be able to do once we own, or at least rent an actual house with a yard. I'm intrigued by all of this and the solar angle will definitely be a mentally stimulating challenge beyond the technical challenge of building the actual trike.

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Re: One stop for solar charging ebike info?

Post by dogman dan » Apr 23 2020 7:04am

Once you have the house, put what you can afford on the roof, then just plug in to the house.

It will be interesting to see how long my flexy panels last. I can see how they could fail fast on a boat, with folks walking on em. I will not be installing them flat on the roof. So maybe I get some life compared to that.

Still the lightest panel you can carry around, and relatively affordable for a low watt setup. The size of my 40w panels could be carried in a stack on a bike, then set up to charge when stopped. Hard to carry a very big setup, which is what made me think of a bike trailer 30 inches wide, and 8 feet long. Made it out of an old ladder, and thin sheets of plywood or coroplast.

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Re: One stop for solar charging ebike info?

Post by AF7JA » Apr 23 2020 10:02am

When I built my solar touring trike I planned on a road speed of 13mph. That came very close to what I really experienced.

I question those who say you don't need a large battery. There are a lot of stretches of road that have a lot of tree cover. I also needed to have the ability to dip into the battery on steep grades.

I am in the process of rebuilding the whole setup, the panels will be on a trailer this time.

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Re: One stop for solar charging ebike info?

Post by parajared » Apr 23 2020 11:56am

I set up a camping trailer for hauling all my stuff that way I can keep my e-bike uniform/clean when I'm not camping. For day trips I think it better to simply haul around more battery with you but I much prefer charging at the camp site on multi-day trips over trying to find an open outlet at a park or something.

I made mine so all the battery is on the trailer, that way that I can detach the trailer and roll it out into the sun.

I gained a lot of my inspiration watching the "Suntrip" guys.
https://www.thesuntrip.com/presentation ... tation-en/

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dogman dan   100 GW

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Re: One stop for solar charging ebike info?

Post by dogman dan » Apr 24 2020 6:32am

Its been awhile, any signs your flexy panels are wearing out fast? I'll be quite happy if mine last 10 years and still put out 75% of original.

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Re: One stop for solar charging ebike info?

Post by MadRhino » Apr 24 2020 10:40am

dogman dan wrote:
Apr 24 2020 6:32am
Its been awhile, any signs your flexy panels are wearing out fast? I'll be quite happy if mine last 10 years and still put out 75% of original.
Forget about flex solar panels. It is time to think photovoltaic paint. Might not last 10 years, but much cheaper than panels, and you can change the color once on a while. :D
https://solaractionalliance.org/solar-paint/

Image
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MadRhino   100 GW

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Re: One stop for solar charging ebike info?

Post by MadRhino » Apr 24 2020 10:47am

Solar canvas too, if you prefer a solution that can be rolled compact to travel. Make a solar shelter for you and your bike, that you can carry in a small trailer. Expansive though, but available with various surface qualities, even artistic design...
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Re: One stop for solar charging ebike info?

Post by john61ct » Apr 24 2020 1:18pm

would be nice.

Rigid framed panels designed for house / solar farm projects

from a big name maker with a 20-year warranty

Really is the best way to go, can find for well under 70¢ a watt locally if you're lucky.

Otherwise the folding type, protected in a well built case, put out pack up every time PITA but last better than the big flat semi-flex ones.

Look for Voc > 40V, efficiency > 20%, and figure 300-350Wh per day per 100W in ideal conditions with good MPPT controllers.

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Re: One stop for solar charging ebike info?

Post by markz » Apr 24 2020 6:52pm

Solar ebike charging for mobile charging while riding seems to be too much cost, too much work, too bulky (size wise) if it were not for a learning experience, wanting new experiences, or a stepping stone to move into RV/Travel Trailers and Home/Cabin Solar, or other interests, solar boating.

If you are having a one stop shop for charging, at your workplace or at home then the cost benefit of "going green" would come at a high cost compared to just using an outlet, hopefully you dont mind paying for it upfront, then plugging into the wall would suffice for me. I see somewhen mention $0.70 a Wh

Otherwise if its just that you want to try it out and see, or you want to do it has a hobby and going to move bigger and larger like RV/Travel Trailer then I can see the intrigue. I just dont see charging ebike battery with solar for a base station at home/work.

--------------

Is a small generator out of the question for mobile use, like if you wanted to charge while camping, or if you are going on a long distance ride and unsure about outlets, then a small 30-40lb 500W generator would come in handy if you are using a trailer which is the only way to rock that setup. If your riding single track, there are single wheeled trailers
https://cdn.instructables.com/FSF/E8IZ/ ... .LARGE.jpg
rather then child trailer
https://article.images.consumerreports. ... Hero-08-16

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Re: One stop for solar charging ebike info?

Post by john61ct » Apr 24 2020 11:14pm

70¢ per watt is a ballpark, many pay much more some get deals much cheaper.

That is a once-off capital investment, per production capacity.

The Wh produced in effect become free over time so long as the panel does not need replacing.

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Re: One stop for solar charging ebike info?

Post by dogman dan » Apr 25 2020 7:40am

For sure, the way to go if its stationary, on your house, or a charging station. I believe that type panel is now a lot thinner, and lighter, than was once the case. The rigid panels used to weigh a ton. Weight was the primary reason I chose flexy. When I bought the first ones, I was camping in a van a lot, and was putting them out when I needed to run a TV. I needed a small, very light, easy to carry around panel. 40w flexy was ideal. I'd just get it out, and flip it on the roof of the van.

My rv, which is basically a hole in the ground I throw money into, it's not about cost, but convenience of mounting it here today, somewhere else tomorrow. I would never advise somebody to spend $500 on flexy panels. But for my rv, or solar charge while riding a bike, its pretty clear the trade off on lifespan/vs ease of moving them around here or there makes a difference. Less than $200 I can afford to waste it somewhat in exchange for convenience. If it lasts 5 years, that's about when I may no longer be able to leave town. I'll have to stay near my doctors as I get older.

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Re: One stop for solar charging ebike info?

Post by ZeroEm » Apr 25 2020 8:13am

It has been ten years that I did a lot of Van camping. Had an inverter to watch TV and computer and some lights. Gas was around 5 US dollars a gallon in South Carolina. Solar panels would have been better than running the van to charge the battery.

Was running my E-trike on solar only but now my buck charger has quit charging after 6 months of use. Have mixed feelings on replacing it. I figure $10 a month charger for 20 cents of power.
Have three panels connected in series for 54 volts bucking up to 80 volts for full charge (80%).
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Re: One stop for solar charging ebike info?

Post by monster » Apr 26 2020 9:08am

I had success with using boost converters to charge from solar.
Got it from ebay.
It had adjustable output voltage which acted like a voltage cutoff.
The input current could be set too and that was good for optimizing panel power.
Intermittent cloud cover was a killer tho.
The variable resistor for setting the current could be changed for a light dependent resistor maybe?
That could work as a ghetto MPPT thing?

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