Riding for free with solar charging!

Buying green power from the utility is an obvious choice for anyone with the extra funds who consider themselves "green" minded. I have been on CPS Energy's Windtricity program at 100% for the last 5 years. All of my monies paid for electricity is derived from the west and south Texas wind farms. I pay 20-$50 more per month for electricity but I consider that anything I can do to help promote wind power as a larger fraction of our local generation capacity the better. In San Antonio, we have two coal plants to our southeast and the prevailing wind here is from the southeast which is incredibly stupid. So all of that coal exhaust wafts over the city after being spewed from these plants. CPS Energy has put in a big solar farm near the coal plants and plans to phase out one of the coal plants in a year or two.

My electric bill is still stupid cheap at 10 or 11 cents per kWh After the Wind premium has been added in. Can you believe that? I dunno how people will conserve while electricity is 7 cents/kwh for those not opted into Windtricity.
 
pdf said:
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....
Click to expand...

I should market those. I'd make them downloadable.

36foottrash.jpg
 
thanks jim for link
I did quick ebay search, shows mppts from a bit over $30 for about 10amps.
I'm wondering does an mppt also use mosfets? It might be possible to swap mosfets and make them a bit more robust, or is only the pwm solar controllers that use mosfets for output? ( I noticed that pwm solar controllers are very cheap if going over 15amps but mppts jump way up in price once over 15amp)
 
I have a question for you. I have bought some monocrytalline cells, here is the spec.:
efficiency - 18 - 18,2%
power - 4,3W
current (Impp) - 8,1A
voltage (Umpp) - 0,53V
current (Isc) - 8,77A
voltage (Uoc) - 0,63V
I am planing on building front box cargo bike. I thought i could make a box lid and then cover it with solar cells. I dont want to charge a battery pack in a day or anything like that, but if i can get like 2km top-up be good enough. Problem is the area i can cover, say i will squeeze in 12V worth at 8.1A. Is there a way to convert it to to charge 24S LiFePo4? Another one, possible to charge while discharging? Or scrap this idea? Thanks
 
whatever said:
thanks jim for link
I did quick ebay search, shows mppts from a bit over $30 for about 10amps.
I'm wondering does an mppt also use mosfets? It might be possible to swap mosfets and make them a bit more robust, or is only the pwm solar controllers that use mosfets for output? ( I noticed that pwm solar controllers are very cheap if going over 15amps but mppts jump way up in price once over 15amp)
Click to expand...

Unfortunately, I do not know how the mppt/pwm chargers work exactly or what is inside them. I would assume that they will work fine with the stated specifications without having to modify them. If I were you, I would try to use them stock before I started fiddling with them. The 15A or greater ones have big heat sinks and so I would think their greater cost is mostly due to having guts able to handle a lot of current.
 
agniusm said:
I have a question for you. I have bought some monocrytalline cells...I am planing on building front box cargo bike. I thought i could make a box lid and then cover it with solar cells. I dont want to charge a battery pack in a day or anything like that, but if i can get like 2km top-up be good enough. Problem is the area i can cover, say i will squeeze in 12V worth at 8.1A. Is there a way to convert it to to charge 24S LiFePo4? Another one, possible to charge while discharging? Or scrap this idea? Thanks
Click to expand...

In my opinion, charging while riding will not net enough electricity to be worth the extra weight and drag. Orienting the bike to get good solar exposure will be rare and even if you did you would need a very large panel to make any dent in your immediate usage. Solar charging as far as my small mind sees it is in harvesting power from an optimally positioned solar panel throughout the day, storing it in a fixed battery and then charging off the fixed battery as you need it.

Let's say you could head directly into the sun on your morning journey and make 20w from your front mounted solar panel. You ride 20mph in one hour and your bike uses use 15wh per mile. That means that in one hour's time you used 300 watt hours but your solar panel only produced 20 watt hours in that hour. So, even if your charging was 100% efficient you would only have made 6.7% of your power to go the 20 miles. Also, getting the solar 12V into a higher voltage battery bank requires a RC style charger that might use 3w just to run the electronics. It is also not plausible to keep the panels perpendicular to the sun for any meaningful amount of time when you are moving.

I think you can charge while discharging but I'm not sure. Cars do it every day.
 
edamame said:
agniusm said:
I have a question for you. I have bought some monocrytalline cells...I am planing on building front box cargo bike. I thought i could make a box lid and then cover it with solar cells. I dont want to charge a battery pack in a day or anything like that, but if i can get like 2km top-up be good enough. Problem is the area i can cover, say i will squeeze in 12V worth at 8.1A. Is there a way to convert it to to charge 24S LiFePo4? Another one, possible to charge while discharging? Or scrap this idea? Thanks
Click to expand...

In my opinion, charging while riding will not net enough electricity to be worth the extra weight and drag. Orienting the bike to get good solar exposure will be rare and even if you did you would need a very large panel to make any dent in your immediate usage. Solar charging as far as my small mind sees it is in harvesting power from an optimally positioned solar panel throughout the day, storing it in a fixed battery and then charging off the fixed battery as you need it.

Let's say you could head directly into the sun on your morning journey and make 20w from your front mounted solar panel. You ride 20mph in one hour and your bike uses use 15wh per mile. That means that in one hour's time you used 300 watt hours but your solar panel only produced 20 watt hours in that hour. So, even if your charging was 100% efficient you would only have made 6.7% of your power to go the 20 miles. Also, getting the solar 12V into a higher voltage battery bank requires a RC style charger that might use 3w just to run the electronics. It is also not plausible to keep the panels perpendicular to the sun for any meaningful amount of time when you are moving.

I think you can charge while discharging but I'm not sure. Cars do it every day.
Click to expand...

OK, leaving charging while driving a side, say i go to work, and spend there 8 hours. So say 60W solar panel would top up my battery 480 watt hours, say 400 and that is a quarter of 72V 20Ah battery capacity on 40km range thats 10km
I wander if there is something else than rc charger for that, cause i would be charging bulk
 
[/quote]OK, leaving charging while driving a side, say i go to work, and spend there 8 hours. So say 60W solar panel would top up my battery 480 watt hours, say 400 and that is a quarter of 72V 20Ah battery capacity on 40km range thats 10km
I wonder if there is something else than rc charger for that, cause i would be charging bulk[/quote]

At your latitude the 60w solar panel would only give you maybe 40w IF you had it pointed to the sun with no shading. Eight hours of sun per day is not realistic unless you are regularly moving the panel to best capture the sun.

If your 72V battery is charged as four lower voltage batteries (4x 5S?) then maybe you could build your solar panel to trickle charge the batteries directly. -Jim
 
Nice setup man , i am using something quite similar to your setup for my needs at home.Its nice not to have to pay for a lot of staff when you are having solar.
The only tricky part is to adjust it so it can be flexible and cover up all your small loads in an apartment,office or whatever.
Like dogman said you have to be able to have the battery in full charge almost at all times.This will ensure that your expensive deep cycle battery pack will last for a lot of years.

I started small like you now i got only one factory made 80 watt panel and some others i made up myself for 1/3 of the market cost. 1 x 25 watt ,1 x 10 watt ,1 x 160 watt panels.
Close to 300 watt/hour in good sunny days.That means that i can charge my battery in like a few hours and when the sun is up i am having unlimited power for what i use.

This covers up my 3 e-bikes , laptop , living room lights , everything that is chargeable and in general all loads i need up to 1500 watt for 6 hours of use.
The cost if you make the panels is even lower.The hole project cost me 1200 euros with all panels , mmpt controller , 1500 watt inverter . 12v125ah deep cycle battery , wiring and everything.

If you want to charge up your battery when you are at work the small panel wont do it.I think its better to have one small bulk charger and charge the pack for one hour or two.

The issue to charging while riding with solar panels is that you will have to to curry extra batteries in order to do so.Lets say you are using 72V system you need 72v*1A of charge to the battery 72 watt -15% solar efficiency - 3%-17% conversion losses you might need an 100 watt panel to achieve 1A charge to your pack.If you have lets say a small 12v 40-60 watt flexible panel somehow attached to your bike plush some batteries,controller and all you can charge the amount you need but its not practical.
 
Just wondering if anyone has any info on charging up lithiums with solar via mppt without using intermediate lead acid for storage?
For example: could you have : solar panel to mppt to rccharger to lithium pack?
maybe could use small sla in parallel with mppt in case voltage drops below rc charger minimum?
also came across nice website has some links to solar bikes
http://www.avdweb.nl/solar-bike/other-solar-bikes.html
 
whatever said:
Just wondering if anyone has any info on charging up lithiums with solar via mppt without using intermediate lead acid for storage?
For example: could you have : solar panel to mppt to rccharger to lithium pack?
maybe could use small sla in parallel with mppt in case voltage drops below rc charger minimum?
also came across nice website has some links to solar bikes
http://www.avdweb.nl/solar-bike/other-solar-bikes.html
Click to expand...

Its done with lithium phosphate batteries and Lifepo4 using MPPT or PWM controller.You just need to check it out on the net.
http://www.youtube.com/watch?v=GpQcrvRoigc&feature=related check this out.
 
As an experiment I'm gonna charge an RC Lipo off of my Kyocera solar panel today. I'm gonna feed the 20V directly into my iCharger and bypass the MPPT charge controller and 12V battery.

The iCharger can take an input of 8V to 38V so I cannot imagine it not working but it will be interesting to see what effect clouds will have on the iCharger.
 
edamame said:
As an experiment I'm gonna charge an RC Lipo off of my Kyocera solar panel today. I'm gonna feed the 20V directly into my iCharger and bypass the MPPT charge controller and 12V battery.

The iCharger can take an input of 8V to 38V so I cannot imagine it not working but it will be interesting to see what effect clouds will have on the iCharger.
Click to expand...

Powering a 500watt/1000watt charger with 135 watt panel is not a good idea.Probably it will work at max 100 watt when charging if you have a nice sunny day.
 
It was fairly sunny out today, so heres a better test of direct solar bulk charging at 24S LiCo.

[youtube]fReSBxXNPKU[/youtube]
http://www.youtube.com/watch?v=fReSBxXNPKU
 
They were $100 a piece, shipped. A fairly good value. These were blemished panels that had no sticky backing applied.

I almost pulled the trigger on a 30 pack for $2,400, but they soon disappeared. $0.65/Watt delivered, for a solution that just sticks to a metal roof!
 
ZOMGVTEK said:
They were $100 a piece, shipped. A fairly good value. These were blemished panels that had no sticky backing applied.

I almost pulled the trigger on a 30 pack for $2,400, but they soon disappeared. $0.65/Watt delivered, for a solution that just sticks to a metal roof!
Click to expand...

Yea i know this kind of sticky panels last time i checked they where awful expensive but now i see prices are better.Really nice deal you got there.
 
ZOMGVTEK said:
They were $100 a piece, shipped. A fairly good value. These were blemished panels that had no sticky backing applied.

I almost pulled the trigger on a 30 pack for $2,400, but they soon disappeared. $0.65/Watt delivered, for a solution that just sticks to a metal roof!
Click to expand...

Can you direct us to a dealer? I price these at alt-e store and they are $516 for a 144 watt roll. If I can get the price down low enough, I'll swap out my roof for an aluminum standing-seam roof and go with these panels. (I'm planning a battery-backed grid-tied setup.)
 
Unisolar went bankrupt several months ago. About a month or two ago was prime time to get these panels cheap, now they're becoming hard to find unless you want to pay a bit more.

Just look around for unisolar panels, these are not normal prices, and most of the deals are long gone. eBay is a fairly good place to try and find them, but I didn't see any great deals on there in weeks.

This is a decent price on the newer 144w panels, but its a largely undesirable solder connection.
http://www.ebay.com/itm/Uni-Solar-144-watt-PVL-144-Solar-Panel-24-Volt-with-Peel-n-Stick-from-Unisolar-/221129219935?pt=LH_DefaultDomain_0&hash=item337c541f5f

You can still get 30 packs shipped to you for about $1/watt, which isn't bad considering the mounting savings over standard panels and racking. If you have a metal roof, or need a new roof, this would be a great buy even at $1/watt. Especially if you're on grid and get government incentives. A grid tie setup with these panels can have payback times <1 year if you DIY.
 
ZOMGVTEK said:
Unisolar went bankrupt several months ago. About a month or two ago was prime time to get these panels cheap, now they're becoming hard to find unless you want to pay a bit more.

You can still get 30 packs shipped to you for about $1/watt, which isn't bad considering the mounting savings over standard panels and racking. If you have a metal roof, or need a new roof, this would be a great buy even at $1/watt. Especially if you're on grid and get government incentives. A grid tie setup with these panels can have payback times <1 year if you DIY.
Click to expand...

Mounting is a fraud i mounted my panels on my broken solar heater for like 3 euros.The 30 pack is still a nice deal even with $1/watt if you imagine that the fixed not flexible panels costs approx 150$ per 80 watt.
 
@zomgvtek
had a look at your vids, what is the role of the resistors? diy mppt?
you had the panels in series to get enough voltage to charge the ebike battery?
sorry I'm a bit confused, but seemed like there was very little loss
 
whatever said:
@zomgvtek
had a look at your vids, what is the role of the resistors? diy mppt?
you had the panels in series to get enough voltage to charge the ebike battery?
sorry I'm a bit confused, but seemed like there was very little loss
Click to expand...

The resistors are just there to demonstrate the power capability of those panels, under that lighting, in parallel.

I was connecting 4 series '24V' panels right to a 24S LiPo pack, so there was rather little loss. No MPPT, but that's not that big of a deal when the panel voltage fairly closely matches the battery.
 
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