Solar power, any tinkerers out there?

[Haku]

Last weekend I got a weatherproof 30 watt polycrystalline solar panel, it's 25 years old and looks like it was made last week. I've been quite busy so haven't had much time in the day (when, obviously, it produces power) to fully test it's power capability, though it didn't have any trouble powering a pocket tv by using a 5v switching regulator.

So taking this forum's designation quite literally as "A place to recharge your batteries", are there any solar power tinkerers out there with a few words of wisdom about utilising this panel?

My intentions are for it to charge a 12 lead acid battery of some sort, for which I can then use to recharge things like this Asus Eee laptop I'm typing on as well as my mp3/mobile/pmp devices.

 

[keithhazel]

if you had one of them extended rear racks you could have a few of them to charge your battery so you could ride continuosly during daylight

 

[flecc]

The intermediate lead acid is probably important.

A to B used large solar panels to charge their Lafree NiMh batteries for quite a while, but the slow charging gradually produced large disparities in the individual cell's charges and voltages, something that never happens on those high quality batteries with correctly specified chargers.

The conclusion at the time was that intermediate lead acids which could then be used to charge the second battery at more normal speeds was the solution.
.

 

[Haku]

I'm not intending to charge my bike battery with this panel because it's just not big enough really, I'm guessing I'd need a roof full of solar panels and a bank of batteries - especially in the winter time. Also I wouldn't charge my bike battery directly from solar because I don't think lithium-polymer (or rather lithium-ion - still haven't got my freakin' polymer battery back!) likes being trickle charged, the charger for the li-pol battery gets almost burning hot & smells a bit when it's charging so it's got to be pumping a fair few amps into the battery.


Why I'm asking is that from the little web research I've been doing on solar power, it looks like for a one-panel setup all I need is the panel, a solar power regulator controller and a lead acid battery - unless I've missed some deeply important ingredient in the mix?

 

[john]

Yes, that's all you need for charging. If the regulator is sophisticated it may also have a cutoff to prevent the the battery being discharged too deeply.

Alternatively you can make your own regulator as I have done. Just using a LM317T voltage regulator and 2 resistors, plus a diode to prevent discharge through the panel. These cost pennies.

 

[Haku]

Great stuff, so the basic end of solar power is as simple as it sounds. A tech friend just gave me an old sealed lead acid 12v 7A battery from out of a UPS, don't really care if it's near it's end of life as I just need something to get the ball rolling and then upgrade to a higher capacity one if I find the setup becomes useful, picking this thing up makes me so glad I went for a lithium battery on my bike as it's 1/3 the size and heavier than the li-pol.

Now to order a solar regulator, won't go for the cheapest because I don't want any problems with overcharging or discharging. I've found a very neat little lead acid battery charge level circuit using 10 LEDs: Battery Monitor for 12V

 

[Ian]

I somehow missed this thread but a thread detailing my last years efforts at solar charging is here.

http://www.pedelecs.co.uk/forum/electric-bicycles/492-solar-charger.html

Unfortunately something went horribly wrong with last years summer and so the equipment had little use and remains largely untested in its intended roll.

 

[Haku]

Interesting thread, hope you manage to get to use it this year. "They" keep going on about global warming, well how come we still have really bad weather in the UK?

I just won a solar controller unit which is capable of handling 5x the power my panel is supposed to output in full sunlight, so that should arrive in a few days and then I can hook it up to the 7A battery I have here.
Testing what I could of the panel in this non-sunshine weather I got it to charge up 4x AA's & power 4x bright white LEDs at the same time, using a stepdown regulator & diode to stop the batteries draining into the regulator, but without any real sunshine the lights stayed on for about an hour or so after the panel stopped producing any usable power. For once I am actually looking forward to summer (I must be mad).

Told a friend I got this panel and he's interested in seeing it and told me about Damien Hurst's soon-to-be solar setup, I fairly regularly cycle past the (currently empty shell of a) building in Dudbridge, Stroud which he's going to be doing his new "art" in, from the news pieces I've seen online he's spending £1.5m on a 310kilowatt setup, he'll have 2% of the UK's total solar power.

 

[Grandad]

So taking this forum's designation quite literally as "A place to recharge your batteries", are there any solar power tinkerers out there .

Mad fellow tinkerer reporting in.

I have a solar panel mounted on the back of my pergola at the bottom of the garden. I have connected it to a stack of 12V cup heaters in the pond. (Made from an avocado bath.)

The heater warms the water and the tadpoles love to congregate around the coils.

This year I am adding a battery to drive a bilge pump. To avoid running the battery down I will feed the power to the pump through this voltage cutout gadget. The pump will be used to pump water from the adjacent stream to some sort of waterfall/fountain. (Not yet designed.)

It's great being retired!

 

[keithhazel]

It's great being retired![/QUOTE]


even better when you are as bright as you obviously are, im way off retirement but will have to educate myself a lot to be able to do the clever things retired folk do..

 

[Haku]

The heater warms the water and the tadpoles love to congregate around the coils.

Ok, you're going to have to post a picture of this!

My Morningstart SHS-10 solar charge controller arrived lunchtime, quickly hooked it up to the almost completely discharged 7A battery and stuck the panel outside, the battery voltage was initially 7.7v and is about 11.3v now, it appears to trickle charge the battery even when the sun isn't out due to boost charging circutry.

The charge controller has solar input, battery connection and voltage output, if the battery voltage drops below 11.5v it cuts the output connection until it then rises back up to 12.6v. I think I'll give it a few days solar charging before I hook something other than the multimeter to the output, see if the battery can get up to proper running voltage as I don't know how good it is having been sat in an UPS for an unknown time.


On the subject of water pumps, a friend of mine is interested in a solar powered water pump setup for a tree shaped fountain sculpture thing he'll be getting built, the pump won't directly push the water up the tree (and then out of the branches, the whole thing made of copper tubing) but push it from the pond below up to an elevated reservoir that will under gravity push the water up the tree.

 

[Footie]

I’ve had a solar-powered 12V 1.5W battery trickle charger rigged up in my campervan for the last three months. It’s managed to keep the battery up enough to start the van, which is better then when I didn’t have it last year and the battery went flat
I've been so impressed with it I just ordered a 4.8W solar battery charger from Maplin. It's an amorphous solar panel, which means it charges even in cloudy and overcast weather.

Maplin > 4.8W Solar Battery Charger

I suppose (in theory) I could now charge my ebike battery up via an inverter running from the battery being charged by the solar charger – where’s that catalogue on bike racks ….
.

 

[Haku]

I'm gonna need a bigger battery.

If the panel I have truly is putting out 2Ah at 14v in direct sunlight then it'll charge my little 7Ah battery in about 4 hours, and from the small amount of testing I've been able to do it appears that a day of sunshine (even in wintertime) charges the battery to nearly full because yesterday I left it charging and didn't drain the battery at all and this morning reading the voltage it's hovvering at 14.25v, roughly the regulation point of the solar controller, meaning it's fully charged and now it's just keeping it topped up.
Standard car batteries are around 50Ah but don't handle deep cycle too well, so not a very ideal solution for solar, a 100Ah deep cycle sealed lead acid will cost as much as my panel! and I haven't even got the thing permanently mounted to the roof yet...


I tried to find out which of the main three photovoltaic cells (monocrystalline, polycrystalline, amorphous) generally available are the best in low light (cloudy) conditions but couldn't find any hard figures from someone who's tested all three side-by-side, however I did find some figures on their efficiency:
Monocrystalline: 14% to 17%
Polycrystalline: 13% to 15%
Amorphous: 5% to 7%

 

[Grandad]

Heath Robinson lives on.

I got my system on test today. Bright sunshine so ideal for experimenting.

13.3V across battery after 3 hours pumping. The water flow is slowing down a bit, maybe a bit of a blockage is developing.

 

[tgame]

Hey that is really great!! Lucky lucky tadpoles.

 

[Merv]

Interesting thread, hope you manage to get to use it this year. "They" keep going on about global warming, well how come we still have really bad weather in the UK?

I just won a solar controller unit which is capable of handling 5x the power my panel is supposed to output in full sunlight, so that should arrive in a few days and then I can hook it up to the 7A battery I have here.
Testing what I could of the panel in this non-sunshine weather I got it to charge up 4x AA's & power 4x bright white LEDs at the same time, using a stepdown regulator & diode to stop the batteries draining into the regulator, but without any real sunshine the lights stayed on for about an hour or so after the panel stopped producing any usable power. For once I am actually looking forward to summer (I must be mad).

Told a friend I got this panel and he's interested in seeing it and told me about Damien Hurst's soon-to-be solar setup, I fairly regularly cycle past the (currently empty shell of a) building in Dudbridge, Stroud which he's going to be doing his new "art" in, from the news pieces I've seen online he's spending £1.5m on a 310kilowatt setup, he'll have 2% of the UK's total solar power.

You have the best idea _ charge a lead acid battery and use that to charge / power other devices, only remember to include fuses of course!! from time to time Maplins have 12 volt solar panels intended to trickle charge car batteries and at just under £30.00 I woudn't normally bother, however occasionally they sell them for £9.99 which is a good price for experimenters. I use them to supplement an automatic irrigation and ventilation system i designed in my wifes greenhouse. It's just long sunny days we need!! cheers Merv.

 

[Footie]

I found this site the other day when I was looking for information about solar panels for my campervan. It may be of use to someone who's thinking about a solar powered ebike. Not UK based, unfortunatly.

Solar bike panels

solarebike
.

 

[Grandad]

Well, I made a box for the battery and components and hung it on the pergola.

I then noticed that there was unused space behind the solar panel.

After a little ponder I decided to make a Little Owl box to fill the space. 'Twill be interesting to see if it gets used.

What do you hide behind your panels?​

 

[Haku]

Any evidence of owls (or any other bird) taking up residence yet?


Last night I placed an order for 72 3"x6" solar cells + connecting wire (totalling around £190) to make my own panel, each sell outputs just under 2 watts so I'll either make a single panel of up to around 140 watts or two 70 watt panels.

The biggest problem I got on making the panel is what with, do I try and buy an old window (or glass door?) or do I make my own frame from aluminium & greenhouse glass (or something as cheap), and what about the backing... things I'll have to somehow work out. Should be interesting, and hopefully I'll be able to make a panel for 1/2 the price of a commercially bought panel.

 

[Footie]

Where did you get your solar cells from?

Did you get new or cheap blemished cells?

This site has one way to build a panel - interesting reading

How I built an electricity producing Solar Panel
.