Hey Lawrence I hand built a panel for my boat 5 years ago when panels were 3X expensive over the cells. Although my panel still works well I wouldn't do it again as prices have fallen so sharply the last few years. As Cor mentioned your max panel voltage should be higher than the cell pack so it can still charge your batts on cloudy days. I used 36 solar cells which gives about 18v max for my simple 12 volt setup. Soldering 36 cells together was tedious as they are oh-so-fragile, I didn't have feelings in the tips of my fingers for weeks! :-) For the panel enclosure I used a plastic from sign making materials, a sheet of plexiglass, lexan and pressure treat treated wood. The first year of use it leaked but after doing the plexiglass to lexan seal over with a better sealant it hasn't leaked since. The light weight flexible panels that are on the market today look great and would be much lighter than anything that could be built. Good luck on your project, solar vehicles are feasible, my boat hasn't touched a plug in over 5 years!
Cheers Dan http://www.evalbum.com/3432 On Sun, Apr 16, 2017 at 8:39 PM, Cor van de Water via EV <firstname.lastname@example.org> wrote: > Hi Lawrence, > I hear your enthusiasm about building your own solar panel > And I have bought loose solar cells in the past also, but it is > exceedingly difficult > To make a *reliable* panel with loose cells, especially the first time > around. > If you do not mind to get your panel become flakey after a while and > re-doing > A new panel once a year or so then by all means, go ahead. It certainly > is a good way > To get respect for the workmanship of solar panel makers. > Don't forget that you will need some form of encapsulating cover for the > cells > As well as some backing (sticky) foil to avoid the cells are shifting > around. > Official panels always get an encapsulation of poured clear potting > material. > Old panels did not always use the best quality material and thus it > turned hazy, > Reducing power. You can buy the potting material in small quantities, > but my > Calculations show that for standard panels, DIY is cost prohibitive > compared to > Buying professionally made panels, in other words: only if you need a > special > Version of panel (shape or other characteristic forcing you to deviate > from standard) > Then it might make sense at greater cost to make your own. > > Then the application: please be aware that while solar cells spec that > they deliver > Approx. 0.55V per cell, that is peak voltage at room temp. > If you want the cells to deliver max *power* output while actually > sitting in the hot sun > (voltage goes down with increasing temp) then you should count on closer > to 0.4V per cell > So a 100 cell panel will have an MPP (Max Power Point) of about 40V > That is why you see a standard 12V panel with 36 Cells, because then the > MPP will be > Above the voltage at which a 12V lead acid battery charges (approx. 14V) > > Typically you size the panel to have its MPP voltage at or slightly > above the max battery > Voltage to make charging efficient. If there is a large difference in > voltage (panel much higher than the > Battery, then you can use a simple buck converter with an MPPT control > circuit to step it down and > Increase the charging current. > Obviously you can also use a Boost converter to step up, but if the > voltages cross over then you have a bit more of a design issue. > So the simplest is to design the panel slightly higher than the battery > voltage, even without electronics your charging will work > And a simple disconnecting circuit when the battery is full. > Hope this gives some ideas, > Cor. > > -----Original Message----- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Chris Tromley > via EV > Sent: Sunday, April 16, 2017 2:18 PM > To: Lawrence Rhodes; Electric Vehicle Discussion List > Subject: Re: [EVDL] Solar trike project. > > Lawrence, > > Go to LunaCycle.com and look at the Bafang BBS02 mid drive. These are > far more versatile than a hub motor because you can use the trike's > gearing, making real-life hills MUCH easier. The BBS01 is officially a > 750W system, but LunaCycle hotrods it (reliably) to like 1300W. Not > sure what the BBS02 tops out at - it's officially a 1000W system. > > It's possible hub motors get better peak efficiency, but mid drive > e-bikes have shown their superiority in real world use. > > LunaCycle also makes battery packs with various 18650 cells with > built-in BMS. Spend some time on their site. > > Chris > > On Sun, Apr 16, 2017 at 3:59 PM, Lawrence Rhodes via EV > <email@example.com> > wrote: > > > Hello all, > > As some of you might know I have been obsessed with solar vehicles for > > > a few years. After the success of Team Einhoven for many years I > > have a project which is 1/4 the size of their machine and for me a > > good place to start economically while doable physically. I have > > found a source of solar cells on ebay(might not be the best quality > > but I didn't look long. I can always change the supplier) 100 cells > > will give me a 355w panel at 50 to 60 volts. 1/4 the power of Stella > > Lux. I could run a 48v system. Maybe a little more. 7 to 8 Leaf > > cells would give me 3.5 to 4kw system. 50.2 to 57 volt system. The > > panel would be roughly equivalent to the pack in voltage making the > > charging semi simple. I have no experience charging lithium or in > > building a 3 foot by 6 foot solar panel but aside from this the main > > challenge will be encapsulating not only the solar cells but the trike > > > to get very good coefficient of drag. My speed will also be less. I > > want to top out at 30mph level ground under power. This vehicle will > > be a moped under California law maxing out at 2000 watts motive power. > > > I already bought the trike for 600 dollars. The cells will cost less > > than 250 dollars including shipping. The Leaf cells of which I need 8 > > > are negotiable. Then the electric conversion kit for the Terra trike. > > > Charger and BMS. If I have done my math I may get my 30mph top speed > > on level ground just using the solar panels. But I'd be happy with 25 > > > mph. I need an efficient 2000 watt drive train. I'm leaning toward a > > hub motor. I need good BMS and charger and maybe an inverter or some > > way of putting power to the batteries without burning them up if I go > > old school bad boy. Thanks for any advice. Lawrence > > Rhodeshttps://s-media-cache- > > ak0.pinimg.com/originals/5b/8f/f8/5b8ff8d7102813a71db79d470e7e52a9.jpg > > Utah Trikes - Jim's Fargo > > > > > > | > > | > > | > > | | | > > > > | > > > > | > > | > > | | > > Utah Trikes - Jim's Fargo > > All-weather trike | | > > > > | > > > > | > > > > https://www.pinterest.com/pin/22447698114328862/ > > -------------- next part -------------- An HTML attachment was > > scrubbed... > > URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/ > > attachments/20170416/1eeb95a9/attachment.htm> > > _______________________________________________ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag > > > racing at NEDRA (http://groups.yahoo.com/ > > group/NEDRA) > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20170416/2bec > 79eb/attachment.htm> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag > racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/ > group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... 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