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Sanyo Installs Two Solar Parking Lots for Bikes and Provides 100 Hybrid Bikes in Tokyo

Bicycle parking lot in Sakurashinmachi, Setagaya, where Sanyo’s Smart Energy System “Solar Parking Lot” is installed. Top-right shows the box containing the lithium-ion battery systems and battery chargers. Click to enlarge.

Sanyo Electric has completed installation of two Solar Parking Lots for hybrid bikes, incorporating solar panels and lithium-ion battery systems, and also provided 100 electric hybrid “eneloop bikes”, in Setagaya, Tokyo Japan. Each Solar Parking Lot holds 40 eneloop bikes. The power generated from the solar panels installed on the roof is stored to be used to recharge the electric hybrid bicycle batteries and illuminate the parking lot lights. Sanyo is using its new Standard Battery System for Power Storage announced in November 2009 in the system. (Earlier post.)

For each of the bicycle parking lots operated by the city of Setagaya at Keio Line Sakurajosui Station and Tokyu Den-en Toshi Line Sakurashinmachi Station, HIT (Heterojunction with Intrinsic Thin-layer) solar panels (approximate 46 m2, 7.56 kW) are installed on the roof to generate sufficient power to recharge the batteries of a total of 100 eneloop bike units and illuminate the LED parking lot lights.

HIT is a Sanyo-developed technology and is a hybrid model that combines a crystalline silicon substrate and an amorphous silicon thin film. It offers the current highest-class power generation level per installation area, based on energy conversion efficiency and temperature characteristics, according to Sanyo.

Eneloop bike
The eneloop bike. Click to enlarge.

Introduced by Sanyo in Japan in December 2008, the eneloop bike is a 26-inch, three-speed regenerative, pedal-assist hybrid electric bicycle. Riders can propel the eneloop bike under their own power or can engage the bike’s motor and electrical system to pedal in one of three assist modes:—standard, power-up or auto—where the front hub-based motor helps the bicycle and rider travel forward.

Sanyo also employs its Torque-sensing Power Management Controller within the regenerative electrical system of the eneloop bike. As a result, the “Synergetic Hybrid Bicycle” automatically adjusts to differences in terrain uphill/downhill slopes, applying the appropriate amount of assisted power when needed and engaging the regenerative properties of the “energy looping” (ene+loop) eneloop “Loop Charging” system when coasting or braking.

The eneloop bike uses a 25.9V, 5.7Ah Li-on battery pack (i.e., about 148 Wh) and has a range of 57 km when not using recharging while riding; 75 km when using brake recharging only; and 100 km in auto mode. Recharge time is about 3.5 hours.

The 100 eneloop bike units will be provided at three locations, including Odakyu Line Kyodo Station (which does not have a solar parking lot), in addition to Sakurajosui Station and Sakurashinmachi Station and will be used as “community bicycles” by a wide range of people residing in and outside Setagaya.

Each solar parking lot lithium-ion battery system comprises 312 18650-size cells. By combining solar panels with energy storage, the solar parking lot enables recharging the electric hybrid bicycles without any commercial power source, even at night or on a rainy day. The lithium-ion battery system also features AC power outlets that can be used to power external equipment during an emergency.

In addition, the installed system incorporates a DC charger, enabling photovoltaic energy generated and stored in DC (direct current) to be used directly and effectively without AC (alternative current) conversion.

The Solar Parking Lots are examples of Sanyo’s Smart Energy Systems (SES), which combine technologies for Energy Creation (photovoltaic system), Energy Storage (rechargeable battery), and Energy Saving (commercial equipment, etc.). The Solar Parking Lot installed in Setagaya is a small-scale SES.



I don't quite follow their mileage figures.
They specify a speed of 15 kph (say 9mph) which probably requires 100w, thus a 145 WHr battery should give 1.5 hours usage, or about 23 KM in 1.5 hours (at 15 kph). Which is not 57 Km.
Unless they are actually only using 40w - however, noone is going to use an e-bike at a speed of 15 kph - this is slower than any normal cyclist would go.

People are much more likely to go at 15 mph (24 kph) which is the limit of their electric boost power.

Also, I am not entirely sure of the benefit of solar charging - by all means put up solar panels, but just use them to offset normal power usage or feed it into the grid.

If you are in a very isolated place, it would make sense, or of the cost of laying a power cable was very high, maybe, else you would be better just making sure they are pointing south and separate the charging and the solar panels.

Unless you are doing it as a minor advertising stunt to prove how "green" you are.

[ IMHO, if you really want to be green, send the panels to the 3rd world where they can use them to generate electricity in seriously isolated places and claim an offset for your trouble. You could put a sticker on the bike park to say how good you are. ]


Excellent idea and what a clear message Sanyo is sending to the world.

If 10,000+++ firms do the same, something like 1,000,000+++ ICE vehicles could be taken off the roads-streets and reduce fuels consumption & CO2 emissions.

However, a minimum education level would be required to make sure that users return the e-bikes in conditions. Otherwise, a $1,000+ deposit may be required in many places.


Absolutely first rate thumbs up for Sanyo. They make the PV so this is a perfect match for their technology. If they were to package the whole system and direct-sell at discount - they have a winner. Especially in sunbelt nations. They might think about doing this on a larger scale for the first EVs. A business in Arizona or Southern Cal would be good place to start.

Only one question, in non sunbelt areas, like Pacific NW or Canada, with prolonged bad weather - what happens?

Will S

Great project, shows we can propel ourselves around on very little energy that can be gathered in the roof of the bikeport.

sulleny, PNW can be a challenge in the winter, though parts of Canada are rather sunny. For example, there is a subdivision near Calgary that is solar heated;

Drake's Landing


Form ove substance. - "Unless you are doing it as a minor advertising stunt to prove how "green" you are."


I have pointed to Drakes Landing as an example of what can be done for years. In Arizona you do not have dark color cars with dark interior for a good reason. Solar car ports can pay for themselves in a short time. We have gotten used to "free" parking for so long that we know no other way. Time for a change in the way we look at things.


Ah yes, I remember this and I remember thinking: 'If there is enough sun for heating why don't they use the sun for electricity too.' The District Heating System of Drake Landing had to be put into place before the houses were built because it's a complete system, so they installed the collectors on the roofs of the garages which could be built before the houses were.

What this means is that the roofs of the houses themselves are free for the installation of PV systems because PV systems are more flexible.


You do not need district heating, each house can provide its own heating, cooling and electricity. New thin film cells can be made on transparent materials that transmit the infrared to solar thermal collectors while converting the shorter wave lengths to electricity. The solar thermal energy can be stored in the soil under the house all summer long to provide heat in the winter. We have done this and can do this but we don't.

Will S

The borehole thermal storage used at Drake's Landing works well en masse, but not for individual homes. I modeled this myself, as I thought I might give it a try. However, the dissipation losses are simply too great, even with a 4x4 grid (which itself is too expensive). The 'dense pack' grid used at DL means there is roughly 50% losses at the periphery, but the center acts as the main thermal store.

For fun, try it yourself using Earth Energy Designer.


Most of the loss is lateral, if everyone had it and the neighborhood was bounded by an underground thermal wall it would be fine. But no one works together for the common good, everyone is more interested in their own situation.


"New thin film cells can be made on transparent materials that transmit the infrared to solar thermal collectors while converting the shorter wave lengths to electricity."

SJC, do you have a link for this? I am convinced there is a large business sector to come from PV film applied to various building materials.


No link but lots of research papers. It is really not all that difficult.




Thanks for the links ai_vin.

Silicon solar cells can to the same thing. There have been bifacial designs that use reflected light to convert on both sides of the cells. If the sintered layer is left off the back the cell passes IR wavelengths nicely. This has been known for decades.


I also remember seeing a concentrating solar collector system that had a beam splitter at the focal point. Visible light went one way and IR went the other, and both could be used.


Yes, you can use "cold mirrors" which are a form of selective beam splitter on concentrated solar troughs and dishes. That way you can harness photoelectric and solar thermal at the same time.

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