How to Solar Charge an Electric Bicycle

mvly said:
I think for this to be even feasible, you will need serious solar panels and some good sunlight throughout the day.

Here is my quick math:
My battery: 48V30Ah ~ 1440WattsHours ~ 1.5KWh battery (50 miles range all electric/no pedal)
Accounting for inefficiency on energy conversion of the charger I'll make it 2KWh requirement to fully charge the battery.
Assuming an average of 6 hours of full sunlight on all the panels per day throughout the year.
So to make 2KWh in 6 hours, I will need a panel that can spit out 333.33Watts.
Of course, I will not be able to get full power of the panels at its advertised power output, so I would say 400W or 500W panels in full good sunlight for 6 hours will be good enough to charge my battery.
Of course, then I will need 2 batteries since I would use one for riding and 1 charging.
Finally I will need a controller and inverter, etc to get started to charge my battery.

The panels put out DC already so why would you want to go DC->AC->DC? It'd just waste a bunch of energy for no reason. I think all you'd need is a dump controller...a 48v version of one of these I guess. :?
 
I haven't read all this thread, but have an idea:
rc chargers ( turnigy/imax/icharger etc etc etc), require a 12volt ( approx) power source ( I think some range dependent on charger from 12v up to 18v or so).....
why not use a cheap mppt on a 12volt sla ( 12-18ahr) or even a car battery, then run the chargers off this,
I dont think you could run the chargers directly off solar panel or panel mppt, the sla is more to keep voltage constant to charger, I would think that even if sla is fully charged the rc charger will be draining off excess power, maybe would be pretty efficient and safe for lithiums
and also quite cheap. IF clouds appear, will be some power stored in sla to keep charge process going.......what you guys think?
 
i see this idea suggested on first page of this thread by neptronix.......any one tried it yet?
 
John in CR has mentioned several times that he was going (or doing this). I charge my lipo off of my 12v sla marine battery all the time. All I need is a solar panel and a solar charge controller and I'd be set.
 
whatever said:
I haven't read all this thread, but have an idea:
rc chargers ( turnigy/imax/icharger etc etc etc), require a 12volt ( approx) power source ( I think some range dependent on charger from 12v up to 18v or so).....
why not use a cheap mppt on a 12volt sla ( 12-18ahr) or even a car battery, then run the chargers off this,
I dont think you could run the chargers directly off solar panel or panel mppt, the sla is more to keep voltage constant to charger, I would think that even if sla is fully charged the rc charger will be draining off excess power, maybe would be pretty efficient and safe for lithiums
and also quite cheap. IF clouds appear, will be some power stored in sla to keep charge process going.......what you guys think?


If you have a solar panel, doing anything with it but grid-tying it is ALWAYS going to be the best way to use that energy. Probably by a factor of 10x or 20x over doing anything involving a car battery (which has a limited capacity, can't be used constantly, poor charge efficiency, will involve tons of downtime with your solar panel doing nothing because the battery is full, etc etc)

If you need to draw power, use the grid, no other option is going to be as efficient. If you have the ability to generate solar power, pump the grid with every watt you can make from sunrise to sunset.
 
Luckily for me, I worked for a solar/hearth company.

I was able to take home a 160 watt solar panel which was returned under warranty.
The panel was rated at 30 volt open circuit but there was a connection issue somewhere in the panel.
So here I have a free panel which is now 15 volts and puts out 80 watts.

Next there was a raffle at work and the one item was a morning star 12 volt charge controller, and of course I won that. (I should have bought a lottery ticket)

Need a couple 12 volt batteries, and actually purchase some lithium batteries and I should be good to go.

I plan on buying batteries and setting this up in the spring, as the cold and snow is on its way (so don't hold your breath for the review)
 
Hey Whatever,
I think it is similar. I just use a 40W 12volt panel into a deep cycle SLA salvaged for cheap. 100 bucks for the panel, 20 for the charge controller, both off ebay.

My turnigy LiPo charger takes an input voltage of between 10.8 volts and 18 volts.
I have two LiPo battery packs for my Aprilia Enjoy, I just rotate them out and go.
Works ok. Cheap. No grid connect costs. Spend the extra on two large lipo packs.

240v to 12v car charger for backup in winter.
 
My wife has an Aprilia electric now too - I think I just got permission to invest in a 120W panel and a big-arse SLA!

I am often surprised when riding past bus-stops in Australia that the solar panels are still sitting on top - no one has thought to borrow them :wink: :p
 
I'm just wondering if you could use an rc charger directly with a solar panel? or via an mppt? without an sla in the circuit.
The solar panel output will be constantly changing depending on sun conditions, I dont know whether the rc chargers can deal with that, or do they
need constant voltage/current input source? Or maybe a mppt or charge regulator for solar panel might keep the voltage constant?
It would make adding solar panels to ebikes a very simple process if its possible
 
whatever said:
I'm just wondering if you could use an rc charger directly with a solar panel? or via an mppt? without an sla in the circuit.
The solar panel output will be constantly changing depending on sun conditions, I dont know whether the rc chargers can deal with that, or do they
need constant voltage/current input source? Or maybe a mppt or charge regulator for solar panel might keep the voltage constant?
It would make adding solar panels to ebikes a very simple process if its possible


The iCharger line has settings to allow it to reduce output current if input voltage falls below a certain point.

However, this application of a solar pannel would be extremely wasteful unless you had an unlimited string of ebikes that needed charging from sun-up to sun-down.

Grid-tie. Uses every drop your pannel makes all day everyday. Then you can use that grid anytime you like.
 
intended use is on a 3 wheeler so panel would be portable in that its always fixed to the vehicle.
I've read a little on rc forum where they seem to be recommending stable power supplies, just not sure if a constantly changing input from a solar cell
will possibly damage ( or at least confuse) an icharger ( or similar)
 
I am interested in this too. what about using some cells on bike to like on aptera? I mean there is regenerative braking, why not to add couple of cells to charge a pack when possible? I am talking about a cago bike with a box at the front, making a lid with few of those cells.
 
I really like this topic , but it seems most have missed the point ! Being able to charge an electric bike from solar isn't about the most efficient use of the solar panel .... It's firstly about being able to use the sun ( not everyone can grid connect their house ) , then it's about flexibility - being able to recharge when a PowerPoint isn't available - touring perhaps?

I have just bought a slab of unisolar flexible cells that i think are going to be light enough and push enough amps - if I can get a charge controller , or make something described in previous posts I think this will be a really fun way of extending my range .

It may in the end be better to buy a second lifepo4 battery, but I have a feeling that if I was touring ,I could use the sunniest parts of the day for R&R ( yes only realistic in sunny places/ seasons ) and really stretch my ebikes grid dependence
 
Hi AlSpong - I really was close to picking up a bunch of those unisolar cells off ebay a couple months back..for a cloudy day PV charger... but I think the dimensions are just too large.. you would need alot of open space for a portable 10 cell array.. however.. good luck!

Anyways, I just returned from a 700km biking trek across parts of B.C. Canada.. I carried a set of 8 custom made PV panels for charge testing.. and hybrid solar e-biking! - my panels are in the black box on the right rear.
p3pb10050441.jpg

8 panels can be wired into 2 separate arrays, I like a parallel connection for a more constant 8-10 volts @ approx. 10amps
Icharger 208B was utilized for its low voltage input..

When I wanted to charge a battery, depending on the ground condition .. I would just throw my panels down on the grass and wire them up.. done... but
the issue is - direct sun exposure.
Off angle's are going to reduce amps. so unless its middle of summer and the sun is directly overhead.. you wont be getting the PV cells maximum output...
A mppt is great but your only going to get the maximum watts that the panels can achieve at the given sun exposure or angle - aswell.. right ??

I have seen pics online of e-bikers holding a sheet of mylar/al. foil or a mirror to reflect sunlight onto the surface of a panel laying flat.. which makes sense but is not a good solution because this could create hotspots, which is why I utilize diffuse reflectors.
p4pb10143738.jpg

larger image / pic was taken Friday, September 27 2013
My panels have been packed around for several thousand km's this summer and the top sheet FEP material has become visibly marked and scratched... with some damage to 2-3 PV cells.. Without the diffuse reflectors the output of each panel is low, and not up to spec. The cells are Sunpower Bin C cells (just 18% - Bin A are 21% - Maxeon Gen 3 are 24% rated) and they were not tested or matched.. so forget about e-biking on solar power alone or charging a high capacity battery in a day...if not pointed directly towards the sun at all times... (if its not directly overhead). With this mod though, charging is alot easier to setup & maintain.. and cells that would probably be tossed in the garbage, actually outputting enough watts to ride on only sunlight... top speed so far 7-8km/h
 
I've been talking with a former landlady of mine... About a trial/demo/proof of concept thingee... In my town (Toronto, Ontario) there is a north-west to downtown former railroad path that is being developed as a walk/bike pathway... called the West Toronto Railpath... The City has a "study" on the go currently:
http://www.toronto.ca/involved/projects/westrailpath/index.htm

...and some folks have thrown up an entry on Wikipedia:
http://en.wikipedia.org/wiki/West_Toronto_Railpath

So it's only maybe 4 km long...

But I think maybe watt is missing from this "project" is something like this:
http://greenings.tv/archives/730?lang=en

Not "huge scale" like that, but just one or a few canopies that have solar panels on top... To provide shade for cyclists from the sun and rain, etc, but also to generate some PV electricity?

So first stage will be just be a "proof of concept" thingee, that could be disassembled and sold off piecemeal if the project goes "belly up"...

But, you guys like?

L
 
Sigh... Had lunch yesterday with a business lady and former landlord (lady) of mine (and the proud owner of her first ebike) that paid for my lunch (again!), to try and interest her in the solar canopy "experiment" thingee... But she insists I need a thing called a "business plan". I am more used to dealing with business folks that take action, not sit around "planning"...

So Plan B... Lessee who do I know who are rebels (other than the good folks on ES I mean...Hehe...) Hmmm... Oh! I know, multihull sailors! And just like some ebikers, they are quite used to the established community poo-poo'ing then, or trying to ban or restrict them...

Turns out, next Sunday, October 20, the Toronto Multihull Cruising Club is having their annual "haul out"... And I used to crew on the trimaran of one of their "leading lights", in the early days when the club was first starting out.

So plan now is to show up on the 20th and talk to some of the folks (club members) about whether they want to "put a lid" (cover) up maybe to cover some of their docks and/or walkways with "canvas" (or "Sunbrella" TM) plus some solar panels to generate some electricity...

To "spread the risk" on this little experiment, it occurred to me to register a not-for-profit corporation, and sell shares... And exclude any controlling interest...

Anybuddy on ES maybe that might want to buy a share or two?

Just curious...

L
 
whatever said:
intended use is on a 3 wheeler so panel would be portable in that its always fixed to the vehicle.
I've read a little on rc forum where they seem to be recommending stable power supplies, just not sure if a constantly changing input from a solar cell
will possibly damage ( or at least confuse) an icharger ( or similar)
I'm just using this quote to start off.
I've built a trike which can carry a single 150W-rated panel and I used an icharger 1010B for converting the panel's output (~21V) to to my required 41V.
Worked fine.
I also built a rack for my trailer to support a second 150W panel.
The good news is everything worked as I expected it would.
Average power output from the two panels, rated at 300W was about 1/2 that, due to the flat mounting of the panels.
The bad news is: Unless you understand what's involved and what to expect from solar panels, you will be sorely disappointed, otherwise there was no bad news except: where I live it's cool all year long and I found having a sun shade over my head all day was rather... chilling.

I now have both panels attached to my workshop where they charge up sled batteries via a 20A MPPT charger. The output of the MPPT charges 80Ah (160Ah, actually) of sled batteries that provide shop power for lights, RC chargers (I have several different types) and my hoist.
The MPPT power converter DOES add significant power to the system, over a (cheaper) PWM controller.
Panels charging a battery without a controller is a disaster, waiting for that opportune moment to strike.

I can recharge my bike battery packs day or (part of the) night via the solar charged sled batteries and during the sun shiny parts of a day the Panels are also 'powering the 12V grid' (my personal 12V power grid system) (there's an acronym there somewhere, I'm sure)
I have two sets of batteries for my trikes,where one set is always charged, or being charged while the other set is being used.
This 'fixed' solar system fits my needs to a tee.
I use grid power as a (rarely used) backup.

Note: I would gain no return monetarily by tying my little system to "the grid"
 
Hiya ddk!

So, quick question for you please? Have ya EVer seen or played with an electric slot car toy? EVer though it might be nice to take at least some of your trips hooked up to a rail, with power at least some of the time, from PV solar panels? Mounted on canopies that might keep off some of the rain and wind, and sun too?

Just curious, as always...

L
(Stuck in watt some might refer to as "the armpit of Canada" (Toronto))
 
I have 15 panels of 5 watts each. 5s3p configuration for the panels. That comes out to 110v open circuit, 0.9amps rated. I get 1.05 or so in clear sun. (I adjust my panels every hour or so to be squarely facing the sun.)

I have a diode on the line, which goes straight to my battery pack. Nothing more efficient (or dangerous) as that. I'm very good about watching my voltage and unplugging before overcharging. I only slightly overcharged twice in 9 months. Batteries are doing great.

I am going to add a step down convertor to limit the voltage to match the pack at 95% charged.

Converting to 120ac then back to 80v DC must be quite inefficient.

I just wish my yard got more sun (well, not really, then the house would get more sun and the AC would run more). I get about 80% of my ebike miles on solar power.
 
Hey ddk... BTW re electric slot cars... Our TERA Prez mentioned yesterday a "big problem" with hooking up to an (low voltage) electric rail... No passing! And I gotta admit, that is true. But hey, not much different than today, with our "bumper-to-bumper" traffic, in watt used to be termed a "rush hour" (evidently since extended to run over many hours, seems like...).
L

PS... And oh yeah, and it'd be sorta stop-and-go, with EVerybuddy pausing to stop at various "stations", to disconnect and connect... Hmmm "stop and go"? Why does that sound familiar?
 
@Lock
I'm not exactly sure what you're askining or discussingng but I'll try to shed sum lite . And provide sum hint-os to resolve your questions/concerns
*continues*
If you go to this thread you'll see how I attached solar panels to my locally-manufactured trike's "roof". I never really intended to enclose that particular trike style anymore than the solar panel roof, as the front end precludes a simple, strong mechanical way to do so.
The whole concept to using solar panels for me, was to extend the riding day for long cruises around the country. BIG battery packs provide the bulk.
-off track-
While I hugely enjoyed driving around in my motor home I knew I was missing most of the scenery because, you know, driving. On a bike or trike riding 10-15mph (15-25kph) you get to see EVERTHANG, missing almost nothing. i.e a whole different traveling experience so that was my design goal for tmy continued travels.
I'm not in a hurry to go anywhere, nor do I have to be anyplace at any set schedule, so stopping for extended periods are not an issue for me (retired-no longer a slave) so I can compromise about certain things that would otherwise be a requirement.
-back on track-
Carrying enough battery and using the panels to extend the day is what my solar panel use was about. The panels, always exposed to the sky are always generating useful power. I'm using polycrystalline panels because they provide more power under poor light conditions, than monocrystalline panels can (usually) Thin-film panels do even better in low light conditions but they're really inefficient in full sunlight, taking up to 3-4 times the space to get the same power a poly or mono panel gathers.
-ok-
the panels always delivering 'sum' power during the daylight hours. To make use of this power you need to consider that the panel(s) is always subject to different conditions delivery different amounts of power because ... vehicles change position. Expect it. This is why you need an intermediary power system* to take the power from while the solar panels add the power too.
For an intermediary system the only (at this time) successful choice is rechargeable batteries. Currently, lithium batteries are the most efficient/effective choice. (i won't dwell on 'why')
funda-mentals
solar panels are made up of cells that generate about a 3-4V voltage potential when exposed to light. These cells are then connected in series/parallel combinations, much like batteries, to make up a panel. You can purchase panels with all sorts of voltage/current constructs. How you intend to use the panels in situ should really be the only concern. (but it never is)
There is a ready-made industrial output of 12V, 24V, 48V and (115/220) systems, where sometimes, duh**, cost becomes the issue.

My concerns involve acquiring stuff that's compatible with most my other stuff.
As mentioned I live in a MotorHome where most everything runs off 12V. Owning and acquiring more 12V solar panels serves me best.
The problem with 12V power systems is the physical size of conductors needed to get power from Point A to Point B (BIG THICK WIRE) and I have 6 gauge cable between my convertors and my batteries on a 18' ( about 3 meter) run for my main service loop. There are ways to mitigate the need for long service loops, -which I also use. I have battery packs where the service is needed, reducing the need for super-thick wiring.
I also use inverters (dc/dc and dc/ac convertors) majixly change 12V into whatever I actually require for each service point.
however, there's nothing magic about (aboot) it
-All this solar/converter stuff has been around, ready for yer consumption for like, ever. Now, cheaper than ever.
I'm tired of typing.
Use a MPPT convertor to interface your panels to your intermediary system(s) because without it, a lot of the power generated by the panels gets lost in the ether.

*They're called batteries
**always
 
ddk said:
I'm not exactly sure what you're askining or discussingng
Ummm...How to solar charge an electric bicycle? (See title of this thread)

...but I'll try to shed sum lite.

Sunlight, I hope? (Hehe...)

Anywhooo... It's all very wonderful to heavy-up a vehicle with solar panels, and maybe provide some cover from the sun, rain, wind (plus electricity, of course), but seems to me a nice option if ya place yer solar PV panels on top of canvas, Sunbrella (TM), etc canopies, at least some of them, to maybe give the batts a little break (not "brake") or some partial recharge at least? "Dump" any unused "excess" into the electrical system for general consumption?

Use a MPPT convertor to interface your panels to your intermediary system(s) because without it, a lot of the power generated by the panels gets lost in the ether.
*They're called batteries
**always

OK, but use other stuff like MPPT's to shift *mirrors* mounted near the panels, to keep that sunlight focused (concentrated a bit, even) and move the light, not the panels...

OH yeah, re batteries... Places like Niagara Falls (Ontario, a sorta huge river dam with an electrical generating system) pump (store) some of that power by pumping it back up hill/up river, as I recall? Ever seen any water (energy) stored in a water tower?

But we are getting "OT" maybe... Back to jolly old King Sol (not to be confused with other king, that stinky, dirty old watts his name...)

L
 
During my experiments I proved to myself that at least 300W of panel is needed to actually power a bike (trike) during the 5 or so hours of the day (guud) sunlight is available. I used almost -0- net power from the battery packs during those hours. (climbing mountains changes everything)
The problems I see with mirrors or reflectors on a bicycle is their physical size. The better choice would be more panel
Using a tracking system on a bicycle would be likely unworkable*.

Take the panels off the bicycle and anything can be easily configured.

*for me... although I did try to devise one but it was too difficult (for me) to adjust
 
Hi ddk!

You said:
I proved to myself that at least 300W of panel is needed to actually power a bike (trike)

Hence the idea of LOTS of panels which are a shared "public utility"...

And you said:
during the 5 or so hours of the day (guud) sunlight is available.

In my burg in southern Ontario, Canada, we have 44% (the usual percentage of daylight hours with bright sunshine) meaning 2038 hours over 303 days (all are averages for the years 1971 to 2000.)

AND:
climbing mountains changes everything

Yah... But in this province we only have "baby mountains"... Watt they call a "mountain" here is maybe just an escarpment, and the highest *real* mountain stands an estimated 642 meters (2,106 ft) above mean sea level and is miles from any significant year-round habitation. Most here live in the southern end of the province, cuddled up to our southern "Great Lakes", which are only "fresh" water (well, used to be "fresh", if EVerybuddy would just stop pooping in it) and a sea-going sailor might describe as the "Great Puddles"... So the lakes and surrounding lands are sorta flat, really...

The problems I see with mirrors or reflectors on a bicycle is their physical size.

Of course! Hence the thought to "decouple" them (solar panels too)...

Take the panels off the bicycle and anything can be easily configured.

Exactamundo! Mon ami...

"solbike", in his "OP" said there are "four ways to solar charge a lithium ion battery that I know of", and to "please comment if you know of others or better ways."

He went on to list his/her "4 possibilities" (Get a standard grid connected solar system, etc; get yer own PV panel and watt some might say a "stinky" AGM batt, etc; some setup with limited range, mount some panels directly on a bike (problematic for various reasons.)

So I only wish to add a fifth scenario maybe... There had already been some talk about roads with overhead roofs, with some PV solar panels on top, eg see the idea "Power of the highway", here:
http://greenings.tv/archives/730?lang=en

Anyway... I have already mentioned in this thread some folks local to me that might like to be "guinea pigs"... to "break the mold", so to speak...

I also had the thought to form a corp for my little "experiment", and sell shares to defray/spread the risk (such as it is), but probably the good folks behind ES probably have some "fine print" here somewhere about not promoting here any "get rich" money-making schemes... Hey! I've be thinking of a way to "give back" to ES... If LOTS of folks here on ES thought this a good idea, just an experiment with maybe some canopies covered with some PV solar panels, with solar power generated maybe sold back to some local utility, with shares sold, but ES retains a controlling interest plus some small % of any net profit... Watt am I missing? No chance it might be a win for EVerybuddy here?

L
 
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