How to Solar Charge an Electric Bicycle

[LockH]

...still I do so prefer a stiff tailwind to a gusty headwind.

Hehe... Have picked up scraps of sailcover cloth to fashion a small spanker sail. Sort of an assist to my assist:

By pulling sail in/letting out, should get "lift" from most winds coming from all but straight ahead.

 

[LockH]

"Scatec Solar to build solar power plants in Pakistan"
http://7thspace.com/headlines/512617/scatec_solar_to_build_solar_power_plants_in_pakistan.html

In part:

The projects, comprising three plants generating 50 MW each, is to be completed in about a year. An additional 150 MW is planned to be developed in a second stage, bringing the total investment to nearly USD 600 million. The 150 MW plants will be able to power about 150, 000 homes during peak daytime hours.

Oh oh... I feel Ebiker Lust coming on.

 

[launchpad]

Hey ddk, good to see you have still been so active both in the forum and on the trike!

My panels are currently part of a porch now, but your experience adds evidence of needing about 300W of flat-mounted panel (depends on latitude and # of sun-drenched days) My 300W panel averaged more like 75W but my latitude is 42degree north where you're what? 20 degrees south?

Yep, 27 deg South makes a big difference. With the old Eco-worth panels, we were able to generate a 140+ W in ideal conditions (stationary trike with the array tilted towards the sun). Generally we were sucking down around 100W in full sun while on the move. However the panels didn't stand up to the rough roads hence making our own is the next step. Using more efficient cells and layout I will let you know the numbers once we are up and running.

The Tandem is currently in for repairs. Apparently 10+ years and many 1000s of kms is tough on the weld on the steering cross section. Local metal fabricator to perform some reinforcing magic.

As mentioned, laminating the solar cells with a standard household laminator has proven very successfull. Interestingly the output is improved vs unlaminated cells. My reckoning is the pressure of the laminate improves the connection of the tabbing wire to the cell. 2 month timeline to be testing the new panels (perspex base).

 

[kiwiev]

Cool thread

We are on stand alone solar and no I'm not a greenie tree hugger no offence, just a realist it was going to cost $60k to get power in and transformer on a line that was doggy.

We have 7.5 kw of pannel a third is on a tracker and is great first thing for Coffee etc, we built the house on it and have been in 5 years. Batteries are lead 48 volt by 3200ah. And a 7kw inverter with 20kw surge.

I charge my Sonic EV on it and can weld all day at 250amps.

So for me charging my Giant Trance in 8 minutes it's a 72 volt 10ah pack is cool.

The thing I want to do is get 20 x 260 watt solar panels and direct charge my ev at 158 volts and 34 amps.

Does anyone know if this has been done.

Cheers Kiwi

 

[launchpad]

Great work on the Sonic 7 Kiwi. Most impressive build!

That is one serious controller you are after. I found it hard enough to find a 56V MPPT system and it can only give 8 amps. Mind you on a Trike that's 'oodles'.

We will keep an eye on your thread to see how you go. I have no idea if multiple controllers would work (series or parallel). The MPPT are brilliant though for varying light conditions.

Watch out for that cold front coming through this arvo.... It arrives up here tomorrow!

 

[kiwiev]

Thanks Launchpad

Yes the front is just starting a bit of sleet on and off but snow over night may loose the power oh that's right we are stand alone.

Maybe 3 out back controllers like you say in series may work have to ring around.

Cheers Kiwi

 

[Cowardlyduck]

What's the lowest your stand alone setup gets? I mean percentage wise, how low does your SLA bank get?

Cheers

 

[kiwiev]

Hey Blake

It's fully charged at 50.8 volts assuming no charge no load and we run it down to 50.0 volts or 80 % that's gives good cycles.

It will only produce what you use have used 36kw in a day car charging vacuuming my partner baking. We don't skimp on anything just do it while the suns out we have over 75 power points and 3 fridge s.

We did have a SOC meter but we changed to outback controller when we added more panels can charge 80 amps at around 57 volts.

Cheers Kiwi

 

[Cowardlyduck]

Wowzers, that's some impressive numbers there Conrad...if only you were hooked up to the mains with that power output...you would be making a small fortune in electricity sales back to the grid.

Cheers

 

[LockH]

"Thin film" solar looking better and better.
"U.S. Army develops new solar cells that are 1,000 times thinner than current technology"
http://inhabitat.com/u-s-army-paten...e-1000-times-thinner-than-current-technology/

At the heart of advancements in solar power technology is the drive to make solar cells smaller, lighter, and more efficient. It’s already possible to print paper-thin solar cells, but the Army’s latest patent is for solar cells just a fraction of that thickness, which is tough to imagine. A piece of paper is 100,000 nanometers thick, while the Army’s new solar cells are made from layers of silver and gold semiconductors that result in “a combined thickness of only a few hundred nanometers,” according to Dr. Michael Scalora, a research physicist at the U.S. Army Aviation and Missile Research, Development and Engineering Center (AMRDEC), who is the co-inventor of the new technology.

 

[LockH]

[youtube]eQ3daW6CDJI[/youtube]

 

[AF7JA]

I have been following this conversation with interest. I am seriously considering this panel http://www.wholesalesolar.com/1922279/solarworld/solar-panels/sw315-xl-silver-mono to provide power for a long velomobile tour (I suspect on a trailer. I think it would be too heavy over the top).

It would be used with a 36V geared hub. I have a question, what kind of a controller would I need for a 36V panel (max 45V) into a 36V Lithium Ion Battery?

Here are the specs:

PERFORMANCE UNDER STANDARD TEST CONDITIONS (STC)*
SW 310 SW315
Maximum power Pmax 310 Wp 315 Wp
Open circuit voltage Voc 45.8 V 45.9 V
Maximum power point voltage Vmpp 36.6 V 36.8 V
Short circuit current Isc 9.09 A 9.16 A
Maximum power point current Impp 8.56 A 8.63 A
Module efficiency ƞm 15.77 % 16.03 %
Measuring tolerance (Pmax) traceable to TUV Rheinland: +/-2% (TUV Power controlled) *STC: 1000W/m², 25°C, AM 1.5
PERFORMANCE AT 800 W/M2
, NOCT, AM 1.5
SW 310 SW315
Maximum power Pmax 234 Wp 237 Wp
Open circuit voltage Voc 42.3 V 42.4 V
Maximum power point voltage Vmpp 33.8 V 34.0 V
Short circuit current Isc 7.41 A 7.46 A
Maximum power point current Impp 6.92 A 6.97 A

 

[ddk]

I have been following this conversation with interest. I am seriously considering this panel http://www.wholesalesolar.com/1922279/solarworld/solar-panels/sw315-xl-silver-mono to provide power for a long velomobile tour (I suspect on a trailer. I think it would be too heavy over the top).

It would be used with a 36V geared hub. I have a question, what kind of a controller would I need for a 36V panel (max 45V) into a 36V Lithium Ion Battery?

Here are the specs:

PERFORMANCE UNDER STANDARD TEST CONDITIONS (STC)*
SW 310 SW315
Maximum power Pmax 310 Wp 315 Wp
Open circuit voltage Voc 45.8 V 45.9 V
Maximum power point voltage Vmpp 36.6 V 36.8 V
Short circuit current Isc 9.09 A 9.16 A
Maximum power point current Impp 8.56 A 8.63 A
Module efficiency ƞm 15.77 % 16.03 %
Measuring tolerance (Pmax) traceable to TUV Rheinland: +/-2% (TUV Power controlled) *STC: 1000W/m², 25°C, AM 1.5
PERFORMANCE AT 800 W/M2
, NOCT, AM 1.5
SW 310 SW315
Maximum power Pmax 234 Wp 237 Wp
Open circuit voltage Voc 42.3 V 42.4 V
Maximum power point voltage Vmpp 33.8 V 34.0 V
Short circuit current Isc 7.41 A 7.46 A
Maximum power point current Impp 6.92 A 6.97 A

Silly me...
the specs I find to be most important seem to be missing?
size?
weight?

you really want the panel to be less than 762mm wide for lots of road-reasons.
-weight. kinda important as it determines structure of trailer or roof supports and how much additional power required to push the whole load down the road, so to speak.

opinions: while I prefer cells that gives better efficiencies in shaded condition over monocrystalline silicon cells, my understanding is newer cells can have over 20% efficiency in full sun.
I've yet to find sources, however.
But I'm not actively searching, either.

 

[AF7JA]

Silly me...
the specs I find to be most important seem to be missing?
size?
weight?

you really want the panel to be less than 762mm wide for lots of road-reasons.
-weight. kinda important as it determines structure of trailer or roof supports and how much additional power required to push the whole load down the road, so to speak.

opinions: while I prefer cells that gives better efficiencies in shaded condition over monocrystalline silicon cells, my understanding is newer cells can have over 20% efficiency in full sun.
I've yet to find sources, however.
But I'm not actively searching, either.

Sorry, I feel that if this were to be a go it would need to be on a trailer with several, bright, flashers on it:

SW315 XL Silver Mono 315 W 9.16 A 36.8 VDC 49.6 lbs 78.15" × 38.98" × 1.8"
CHSM6612P-310 Silver Poly 310 W 8.68 A 35.8 VDC 51.7 lbs 77.01" × 39.13" × 1.97"

There are a few others; but, they are all over a meter wide. If you can point me at more suitable (smaller ~300W 36V) I would be interested.

 

[Modbikemax]

opinions: while I prefer cells that gives better efficiencies in shaded condition over monocrystalline silicon cells, my understanding is newer cells can have over 20% efficiency in full sun.

'Shade tolerant panels' is sales speak for 'ours is better than theirs' but the reality is the energy comes from the sun, block the sun and you block the energy. Its that simple.
The other reality is you wont buy 20% efficient cells on ebay or your favourite discount store no matter what they write on the label.
Unless you have access to surplus satellites you wont be getting 20%.

 

[LockH]

"Playa Solar 2 Achieves 3.8c/kWh, The Cheapest Nationwide"
https://www.kompulsa.com/2015/07/10/playa-solar-2-achieves-3-8ckwh-the-cheapest-nationwide/

NV Energy, a Berkshire Hathaway-owned utility company has signed a PPA to purchase electricity from the 100 MW Playa Solar 2 power plant at a stunning low rate of $0.0387/kWh! The cost of solar electricity is still decreasing. In the past, we reported on a Texan solar power plant that sold its electricity for 5.8 cents/kWh, and that was incredible news but nothing compared to this. 3.87 cents/kWh is approximately 68% cheaper than the national average electricity cost.

8)

 

[launchpad]

There are a few others; but, they are all over a meter wide. If you can point me at more suitable (smaller ~300W 36V) I would be interested.

No perfect solutions here. But avoiding glass covered one for mobile applications would have to be a must.

We started with the semi-flexible versions. A couple of players in this field. We used the following:

http://www.eco-worthy.com/catalog/w...tallinemonocrystalline-solar-panel-p-207.html

While they may be semi-flexible (shorthand for bendable, but please don't) they do not handle vibration well. However @ 1.85kg per 50W, they work ok on the tandem (we used 4 x + a couple of small ones). The cost @ $190 per 50 W (ex freight) is not cheap.

I have looked at the fully flexible, but their output (when I looked earlier this year) was low compared to their weight and size and not a suitable replacement. Looking forward to when they will be.

So in the mean time its "make our own panels" with our solar cells, tabbing wire and home laminator mounted on thin perspex. The trick with whatever system you use for mobile is a good MPPT to give you optimum charging as you move in and out of shade.

Cheers.

 

[ddk]

I used these panels. http://www.dmsolar.com/solar-module-1141.html
26.5" wide, 60 long. The length of the trike and trailer was just short of 15'

...
'Shade tolerant panels' is sales speak for 'ours is better than theirs' but the reality is the energy comes from the sun, block the sun and you block the energy. Its that simple.
The other reality is you wont buy 20% efficient cells on ebay or your favourite discount store no matter what they write on the label.
Unless you have access to surplus satellites you wont be getting 20%.

I used both thin film ansd monocrystalline panel co-currently on my motor home and am just telling about my experience. I hold no theory why, but it might be a 'total area' thing, as the thin film panels were more than twice the area as the monocrystalline panels for similar power output in full sun.
My experience: Under foggy conditions the mono panels wouldn't even kick on their MPPT, whereas the thin films would be providing about 15-50W (made me look at my old notebook lol)
Both MPPTs are Blue Sky 20 amp networked types. One is still being used today.
Don't know if they're yet available... but there's got to be better/cheaper units available now... a decade or so later.
I haven't even started looking at cell types, and I failed to finish my first panel attempt a few years ago

 

[LockH]

... and when a solar-powered ebiker stops to eat:

Looks like a Fresnel lens. Seen here:
http://inhabitat.com/wilson-solar-grill-stores-the-suns-energy-for-nighttime-fuel-free-grilling/

 

[LockH]

"Crystal Clear Solar Panels Could Turn Your iPhone Into an Energy Generator"

Not iPhones exactly. But thinking windscreen or the shell of a velomobile bike/trike.

"Downside"?

There is a big downside to this tech as it currently exists – the conversion efficiency sits at a lowly 1% – compared to as much as 25% for traditional solar panels. But the MSU researchers are aiming for more than 5% efficiency when their new panels are fully optimized.

Seen here:
http://inhabitat.com/new-crystal-clear-solar-panels-could-turn-your-iphone-into-an-energy-generator/

 

[whatever]

I was messing around with some solar cells and fibreglass, if you put a thin layer of fibreglass ( not matting) you can bend the cell quite a bit without cracking. I found out by accident, I had just put a layer of fibreglass on the backside of a cell, it bent whilst curing, without cracking.

 

[Modbikemax]

I used these panels. http://www.dmsolar.com/solar-module-1141.html
26.5" wide, 60 long. The length of the trike and trailer was just short of 15'

...
'Shade tolerant panels' is sales speak for 'ours is better than theirs' but the reality is the energy comes from the sun, block the sun and you block the energy. Its that simple.
The other reality is you wont buy 20% efficient cells on ebay or your favourite discount store no matter what they write on the label.
Unless you have access to surplus satellites you wont be getting 20%.

I used both thin film ansd monocrystalline panel concurrently on my motor home and am just telling about my experience. I hold no theory why, but it might be a 'total area' thing, as the thin film panels were more than twice the area as the monocrystalline panels for similar power output in full sun.
My experience: Under foggy conditions the mono panels wouldn't even kick on their MPPT, whereas the thin films would be providing about 15-50W (made me look at my old notebook lol)
Both MPPTs are Blue Sky 20 amp networked types. One is still being used today.
Don't know if they're yet available... but there's got to be better/cheaper units available now... a decade or so later.
I haven't even started looking at cell types, and I failed to finish my first panel attempt a few years ago

Thin film works ok in cool conditions but the out put drops significantly when things get hot, full sun.
They are great in cool climates where size is not an issue. On the the back of an ebike size IS an issue so not really practical.
The fact you need twice the area means more array frames and infrastructure to handle them which equals more cost.
A bit more power on a cloudy day is not going to make up for all the additional cost.
Thin film was supposed to be the cheap alternative to expensive solar panels but as it turns out mass production has reduced the cost so much that the benefits of thin film panels have never been realised. They are also more fragile and fail much sooner than silicon cell panels. I think they are great to power calculators and garden lights but not much else.

 

[ddk]

...
The fact you need twice the area means more array frames and infrastructure to handle them which equals more cost.
A bit more power on a cloudy day is not going to make up for all the additional cost.
Thin film was supposed to be the cheap alternative to expensive solar panels but as it turns out mass production has reduced the cost so much that the benefits of thin film panels have never been realised. They are also more fragile and fail much sooner than silicon cell panels. I think they are great to power calculators and garden lights but not much else.

yup, things change...
a decade ago the thin film panels were less expensive than the power-equivalent monocrystalline panels.
Now the mono, poly are about the same price per Watt where the thin films are more expensive (single-user stuff)

 

[LockH]

How a solar-powered ebike rider recharges their phone:
http://inhabitat.com/super-thin-foldable-solar-paper-panels-charge-a-smart-phone-in-2-5-hours/

 

[LockH]

"Paper-thin printed solar cells could provide power for 1.3 billion people"
http://inhabitat.com/paper-thin-printed-solar-cells-could-provide-power-for-1-3-billion/

Includes:

The cost of solar power has declined dramatically over the past few decades, from $40 per watt in 1977 to $0.74 per watt in 2013.