Riding for free with solar charging!

edamame

10 W
Joined
Mar 19, 2012
Messages
66
Location
San Antonio, Tx
Hey y'all,

I wanted to make a quick post for anyone wanting to run their bikes on solar power only. I built my A2B Metro a few months ago with 72V power and wanted to utilize a 135W Kyocera solar panel I had for charging my R/C batteries. The setup cost me around $1000 so it wasn't cheap but I don't use any grid power for commuting to work every day which is just over 9 miles per day. Please feel free to ask any questions. (I have since switched to a 24V garage system with a damaged but functional 235W Schott panel that given to me by my solar installer.)

Here is a shot of the whole system showing the panel on my new garage roof. I am in the process of having a 6.5kw grid tied array installed on my house roof but I wanted to run the bike off grid. As soon as the grid tied sytem is done I will move the Kyocera panel over there and try to run all of my office equipment on that panel as well. (The Kyocera panel now runs just my office equipment.) The bike uses 300wh/day and the office uses maybe 450wh/day. My office devices use the following on 12VDC:

Computer using M4-ATX power supply 25w
Dell 2340M monitor 15w (very nice quality)
Altec Lansing USB powered speakers .5w
AT&T cordless phone .9w (8vdc running with old car phone charger)
Logitech mouse charger 3w (8vdc running with old car phone charger)
Netgear N600 wireless router 6w
Nokia cell phone charger 3w while charging

I picked all equipment based on being able to run on 12vdc. I want to maximize the use of this 135w panel. This is all for my learning more about managing loads.

wholeshebang.JPG


Here is a look at the bike at the charging station. I have a Morningstar Sunsaver MPPT charge controller mounted on an aluminum plate on the left. This gets power from the solar panel. It is pretty efficient and I've seen up to 121W peak charging from my 135W panel (with an 80-100 watt average in good summer sun). In the middle on the ground is the iCharger 3010B which feeds both of my stock A2B 10S battery packs in parallel (I've recently switched to using 12AH of RC Lipos). I try to charge in the daytime when the solar resource is greatest and the charge controller can pump out the juice. Finally, I have one big 100Ah Sears Diehard deep cycle battery with two smaller UPS batteries in parallel to store the solar power. I bought this battery since it was reasonably priced and locally available.

solarchargingstation1.JPG


Here are the batteries I now use instead of the stock A2B ones:

piggies.jpg


Here's a pic of the bike next to it's big brother, our Nissan Leaf:

leafjr.JPG
 
One other thing:

Originally I had a PWM type Morningstar Sunkeeper12 charge controller that was only $70 but it could not keep the deep cycle battery sufficiently charged to cover charging for my commute. I went ahead and bought the MPPT charger for $200 and it was night and day as far as being able to keep up with my demand. Now, it's like I'm plugging into the grid when I go to charge up the bike. I wish I had paid the bigger money up front.
 
MPPT stands for Maximum Power Point Tracking. It is generally thought to be the most efficient.

http://www.morningstarcorp.com/en/products
 
Let's not confuse MPPT with optimal battery charging. Your original solar charge controller was apparently the ancient/cheap PWM (pulse-width-modulation) type which connects the panel to the battery at a varying rate, initially 100% connected till the battery is bulk charged, then dropping during plate absorption to finally a small percentage of on to maintain full charge.

That uses an FET to connect the panel to the battery and the battery charging current can never be greater than the panel current. E.g. even if the panel could supply 36 volts at 5 amps, you are still only getting 5 amps charge current into a 12 volt battery.

The modern/cheap charger uses a buck converter to trade excess voltage for extra current, so 36 volts at 5 amps can become 12 volts at 15 amps. The inductor and diode for the buck converter adds almost nothing to the cost. All the controller has to do is raise or lower the frequency of the drive until the charging current is maximized.

MPPT involves complex and proprietary algorithms that scan the load resistance to find the sweet spot for the maximum power transfer. Useful for grid-tie feeds and solar water pumping, but no need to pay for all that engineering if all you need to do is maximize charging current. Unfortunately the manufacturers have chosen to obfuscate this issue, so there seems to be no middle ground between $30 PWM controllers and $300 MPPT controllers.
 
dak664,

My MPPT charge controller only cost $200 and is far superior to the PWM charger that it replaced. The MPPT charger outputs way more watt hours per day than the PWM charger did.
 
Definitely cool stuff, but it's probably more practical to just grid tie the solar and charge right off the grid at any time. You will best utilize the solar energy, have no battery to degrade and add additional cost, only downside is its useless when the grid is out.

Plus, electricity is quite cheap for a bike, especially if you're running short ranges at pedal bike speeds. You probably use 200-300wh/day to charge those 9 miles up I presume. That's about $0.04, even at a high $0.15/kWh. All the components in the solar setup have finite lifespan, and degrade over time, some more rapidly than others. The storage battery is likely the highest expense in terms of $/charge, since lead generally won't last past about 5 years. The solar panel might make it 20-40 years before it fails or the output is very low, the inverter is a real wildcard.

I'm not bashing this, just bringing up that its not quite free. It's very likely its substantially more expensive to charge off solar this way, than it would be to just plug into the wall. Initial costs are high, and it will not last forever.

That said, I'd definitely invest in a 5-10kW solar system, and buy a Model S if I had anywhere to put the panels. It almost makes sense, finically, after all those tax cuts and kickbacks. Mostly, its just cool.
 
Edamame keep charging your ebike on your system. I do. It's nice to say it's solar charged.

But next start looking for vampire loads in your house and see if you can put them on your system. I have (2) 125W Kyrocera panels, the Morningstar mppt, (4) golf cart batteries plus a 300W Morningstar pure sign inverter. On this I charge my ebike and plus power the following items:

dsl modem
wireless router
3 iphone chargers
1 laptop
doorbell transformer
irrigation timeclock
visio (ipad like) device
wife's e-reader
garage door operator

Basically anything near the garage or just inside the house. I run this stuff 24/7. It's called an RV solar system (or a poor mans solar system). I can honestly say I have cut my electric bill in half. I started my system in 2007 and so everything is completely paid for by the savings. I say go for it.

Now if I can figure out how to put my Zero motorcycle on this system. :twisted:
 
Looks to me like you have it about perfect. Got a big enough panel to fill a battery in one day, that's the thing most people don't get at first. They think a 10 watt panel for 6 hours will put significant power into thier bike. I tend to say an 80w panel is about the minimum.

Sure, grid tie it if you have 1000w of panel, but below that it gets a bit pricy for what you'd get out of it. Not that your large panel is cheap, but the bragging is priceless. Lots cheaper than adding an inverter, a building permit, an electrician, and a grid tie panel box with disconnect etc.
 
Thanks Dogman. Yeah, I bought the biggest panel that was shippable by common carrier so I wouldn't have that bottleneck of enough charging capacity. Now Kyocera only make the 140W in the same size and it's cheaper than what I paid last summer. The panel can probably provide enough juice for about 300wh of riding per day after charging losses if I had to guess.

edcastrovalley,

I have all of my wall warts on power strips and they get shut down when not in use. I have a 12vdc power supply for my computer and a 12v HP monitor so I could run my computer on dc if I had to but it is pretty inconvenient to get the 12vdc to where my computer is so I keep it on grid power. I am having a 6.5kwh grid tied solar array put on the patio roof next month and have enough main roof for a smaller one next year to cover all of my electrical usage including the Leaf's. We use a bit of electricity being in San Antonio. I plan on selling this joint and getting a smaller place within the next five years. At least I'll leave it with enough generation capacity to meet a reasonably frugal family's demand.
 
ZOMGVTEK,

You are correct in your assessment that charging the bike from the grid is the cheaper way to go BUT I already had the solar panel and batteries prior to owning the bike for my R/C charging so all I had to do is buy the iCharger 3010B and MPPT charge controller to complete my setup for the bike. The up front costs are not free at all and are likely to degrade with time but I can ride a lot of miles without burning anything which, to me at least, means a lot. My thread title is provocative fer sure and was meant to attract those of the same mind who, damn the financials, just want to do something off-grid like I did. Charging from stored solar energy has a huge psychological benefit and I've made a few right moves so I have the extra cash to do it. I figure my hobbies need to make green sense. The solar charging is as much my hobby as the bicycle is and maybe a little bit more.

ZOMGVTEK said:
Definitely cool stuff, but it's probably more practical to just grid tie the solar and charge right off the grid at any time. You will best utilize the solar energy, have no battery to degrade and add additional cost, only downside is its useless when the grid is out.

Plus, electricity is quite cheap for a bike, especially if you're running short ranges at pedal bike speeds. You probably use 200-300wh/day to charge those 9 miles up I presume. That's about $0.04, even at a high $0.15/kWh. All the components in the solar setup have finite lifespan, and degrade over time, some more rapidly than others. The storage battery is likely the highest expense in terms of $/charge, since lead generally won't last past about 5 years. The solar panel might make it 20-40 years before it fails or the output is very low, the inverter is a real wildcard.

I'm not bashing this, just bringing up that its not quite free. It's very likely its substantially more expensive to charge off solar this way, than it would be to just plug into the wall. Initial costs are high, and it will not last forever.

That said, I'd definitely invest in a 5-10kW solar system, and buy a Model S if I had anywhere to put the panels. It almost makes sense, finically, after all those tax cuts and kickbacks. Mostly, its just cool.
 
Way to go Edamame, that's what I like - a real (grid tied) system.

In fact, I checked into getting a system a couple months ago but the contractor I talked to wanted to lease me a system and use the "solar savings" to make the lease payments. My small RV system screwed that up. We downloaded my electric usage from my power company and there wasn't much to work with. My last couple of bills were $65 and out of that $15 was for natural gas and about $15 for taxes which left him little for the electric. He ended trying to recruit me to get my neighbors to lease systems from him. :lol: I guess that's where they make their money, from leasing systems. He didn't want to talk about selling a system.

I should install my own system. It's the permit process I need to learn about. I understand it eats up a sizeable portion of labor hours for solar contractors here in California.
 
Edcastrovalley,

I wish my electrical usage was so low. I am working on the big draws one by one. I changed my pool pump for a permanent magnet DC type from Speck in Germany and cut my wattage from 1830 watts to about 132 watts, a huge saving (Speck EcoM3). My pool cleaner went from using a pump driving a Polaris that drew 1460W to an electric powered robotic cleaner that uses 120W and cleans the pool much better (Hayward Tigershark).

Electricity is cheap here at $0.07 to as little as $0.10 per kwh with my elected wind power premium added in so adding solar doesn't make sense to most people here. I am doing it for educational purposes and a need to make this house make more sense. I hope to publicize my results so that others might do the same. I also have two kids and want them to see what it means to pay the full cost of what you use.

An added benefit is that solar at the net zero level will also boost my property value or at least might make my house easier to sell.

If I had a modest electricity usage I would also go solar without question.
 
The fingers said:
Two would make a nice solar trailer for "endless" range. 8)

Or any way of taking solar panels(seen some that are rollable) with you so parked or otherwise ebike could constantly be in a charging mode...(?)
 
tying your charging to the grid means you have to get the permit, and you have to do the push ups, the inspector will find some other fault with your wiring so by the end you will be out $2k for trying to hook up to the grid.

do your own thing, stay away from the inspectors.
 
If he's in California the inspectors will find him. They lay awake at night dreading the possibility that somewhere, SOMEONE isn't suffering.

Tying to the grid means you can use your electricity the way you do now. My mother is in the country with a LOT of panels and batteries, still there's the propane generator running on a normal day.

But instead of the Sears DieHard, (I have two in my truck, nothing against them) better bet for energy storage is Sulfur Sodium, the battery of the between now and the future, at least. Said to have a 3,600 cycle life.

http://www.electricitystorage.org/technology/storage_technologies/batteries/soidum_sulfur_batteries/

tumblr_lxo6fxkcwu1qabdv7o2_250.jpg
 
Nice, thanks for sharing your setup!

I have a solar charging setup for my e-bike too. Slightly smaller system than yours but good enough for me so far, maybe an upgrade in future.
~70W Peak of Solar Panels
Cheap PWM Charger Controller from ebay (considering an upgrade to a decent MPPT after reading your post)
Trojan 12V 76Ah AGM Deep Cycle
iCharger 3010B
300W inverter for running AC appliances (rarely used)

I use the setup to charge my 6s lipos for my e-bike, and smaller 3s lipos for my RC planes. Also use the power everyday for running 12V LED strips room lighting and charging my phone.

I must have invested more than $500 on my system, even with the high cost of electricity in Singapore at $0.30/KWh (~US$0.23), I don't expect to break even on the initial investment. Government subsidies/rebates are very low here and only apply to large grid-tied systems and requires inspection/certification/etc... I'm still happy though, just doing my part to go green and run my e-bike for "free"! :D
 
can anyone recommend an mppt that is fairly efficient but a lowish price?
I have no knowledge on them but am in the process of puting some solar cells into a panel, so mppt is next step down the track.
 
http://genasun.com/

I use one of the GV-10 now with my office solar system. I very highly recommend them for maximum harvest! They are American made, too!
 
Another option for people who have it is to buy "green power" blocks from the utilities. The only downside is that you have to purchase an electron sorter to make sure the green ones go to the bike....

But seriously, I was working on a student project where we started to install solar panels for charging a small electric car, but when we looked at the economics compared to "green power" blocks, it did not make any sense. A 150 kW-hr block is $4 a month. My bike uses about 17 watt-hr/mile and I travel about 14 miles a commuting day. That is about 61 kW-hr a year. For about $50 a year I can get all the green power I could possibly use for commuting with a lot left over. It is hard to beat that.

I'm sure everyone knows what "green power" is from the utilities. While there is something to be said for the off-grid approach, if you are already on-grid, it is hard to argue with the economy of scale of utility-based green power.

So that is an easy way to be able to claim your ride is CO2 neutral. Just a thought.
 
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