THE WORLD'S FIRST MOBILE SOL AR POWERED CINEMA

LINKS

POWER

Eight large solar panels convert sunlight into electricity. The electricity is stored in batteries. The electricity in the batteries is used to run projectors, amplifiers and lighting into the night The next day, the solar panels convert more sunlight into electricity to recharge the batteries. Eight hours of bright sunshine in the day will produce enough electricity to run the cinema for at least eight hours at night. Fully charged batteries give us enough back- up power to run the cinema for at least ten hours in the event of bad weather. Our tent can be fully blacked out for daytime movie shows.

AUDIO VISUAL

A number of video players are linked through a video mixer which is connected to a video projector. DV cameras are used for filming and a laptop PC for editing. Audio sources are fed through a mixing desk and amplified to a pair of high quality speakers. We use specially developed software called vjamm to manipulate video and audio live in real time. This is useful for jingles, titles, slick links and live video jamming.

HOW DOES IT WORK? We can bring you a movie show anywhere; In a field, on a beach, up a mountain, anywhere! We do not need to plug in to the mains supply or use a noisy generator. The Groovy Movie Picture House seems to use a baffling combination of Solar technology and Audio Visual equipment. But it is really quite simple. This section attempts to explain how the solar cinema ticks.

Taking a film on the road is a great way of getting it seen, judging
reactions and raising awareness without the compromises of broadcast
TV. It also makes the viewing experience far more interesting and
interactive. More than just wallpaper for couch potatos.
Our cinema is run entirely on solar electricity. We use an NEC lt380
video projector .We have used a number of different projectors over
the years, and this is definitely the best. It is very bright - 3000
lumens, but very economical on power - 250ish watts. It uses an LCD
system, which I prefer to DLP in terms of picture quality (more
expensive, but avoids the weird "rainbow Effect" which can be quite
off putting for some viewers) This projector costs about £1500. There
are many cheaper projectors out there which do a decent job. I
recommend NEC as a manufacturer though. I know many happy NEC owners.
They are very reliable, and have proper warantees, proper after sales
service, and will loan you a projector if yours needs fixing. NEC
projectors start at about £500. Beware of the temptation to buy cheap
projectors from unknown manufacturers, Ebay bargains and second hand
machines. Replacement bulbs cost a fortune for any projector. I have
never had one blow - they are quite strong and last for about 2000
hours, but on second hand projectors it is hard to tell hoe long they
have been used for - unless you buy from an honest friend.
For a screen we use a 10ft by 8ft "fastfold" screen, which packs down
small, but unfolds quickly to form a rigid freestanding frame to
stretch the screen on to. These are great, but cost 700+ new. Well
worth it if you can justify the expense.
For audio we use a couple of 12v car booster amplifiers running two
Turbosound full range PA speakers (about 600w) and it sounds very
nice. We used whatever speakers we could lay our hands on before, and
it sounded pretty awful, especially on less than perfect recordings.
With the decent quality Turbosounds, everything sounds much more
pleasant and forgiving.
To power this lot we use two battery banks - one for the amplifiers,
and one for everything else. At first we tried just one battery bank,
but discovered that when we cranked up the volume, big peaks in the
audio from loud bass pulses, caused the battery voltage to drop
momentarily, which in turn made the DVD players switch off. Not ideal.
The audio battery bank consists of 4 x 80A/h batteries, wired in
parallel to give 320A/h of 12 volts. Amplifiers are quite economical
with electric, and don't use much unless you really let rip. Just one
80A/h battery will last for a number of hours running sounds.
For everything else we use 8 x 110A/h batteries run in a 24 volt
configuration. We used to run at 12 volts but found 24 volts to be a
bit more efficient. It doesn't really matter though - depend on the
voltage of your panels and inverter. From this big battery bank we run
a 1200 watt inverter to step up from 24v (or 12v) to 220 volts AC. If
you are just running a projector, DVD player and a couple of lights
you will probably get away with a 500w inverter. Very important to us
a Pure Sine Wave inverter. Modified sine wave inverters are very
cheap, but I have blown up three mixer power supplies by using them
(makes transformers get hot) and you risk weird interference with
fussy video and audio equipment. Don't cut corners with the inverter.
A good one will be rock solid and you will never have to worry about it.
We use one made by Victron - very reliable, and can be plugged into
the mains to turn it into a chunky battery charger for emergency
charging. 1200 watts is nice because it can power angle grinders,
compressors and all sorts of useful things to have on the road. For
cheaper sine wave inverters, check out RS.
To Charge the batteries we use 4 x 200watt 24 volt panels made by
Kyosera. We upgraded to these last year, and they really do the job.
These allow us to run for an average of ten hours a day at a festival,
and if we run our batteries right down, they are usually charged back
up by the following weekend. (panels mounted flat on roof of truck for
constant charging and security. We tilt them up at gigs so the public
can see them, but it makes little difference to power generated in the
summer months. Mounted on the roof is safest, as you don't have to
move them about much. In ten years I have only broken one, and that was
because I had mounted it badly and it started to flap about when
driving up the motorway - I learned the hard way to use enough bolts,
and have had no disasters since. ) We have another 2 x 75 watt 12
volt panels made by Solarex to charge the 12 volt battery bank for the
audio. You will probably get away with less panels and batteries if you are
running basic equipment for say, a couple of screenings a day. You
need to add up the power ratings for all equipment you will be using
(watts) divide this by the voltage of your batteries (probably 12
volts) This gives you the figure for the electrical current needed
(amps) Times this by the number of hours you want to run (A/h or
Amp/hours) then halve this figure to give a realistic amp hour rating
for your battery bank. Battery A/h ratings are always very optimistic
- you can only use about half of the rated amp hours safely without
frying your batteries.
We use batteries made by Elecsol - very good quality, can be cycled
lots of times before they die, have 5 year guarantee, and are less
heavy than many makes. Before these we used recycled Batteries from UPS
backup systems. This is a bit hit and miss, and you end up with quite a
few dead ones, but saves you lots of money, and makes use of batteries
that would otherwise be on the scrapheap.
Now you know how many batteries you need to run for a certain length
of time, or how long you can run on a certain number of batteries. Now
start adding solar panels. Each panel will increase the length of time
it takes to flatten your battery bank. At the end of the day you could just run a simple system with a couple of batteries, and an inverter to run a DVD player and projector
for three or four hours, Then start adding to this when you can afford it.
When we started we had four batteries, two 75w panels and a 400w
inverter. It stretched the definition of solar powered a bit, but it
worked as long as we didn't try to run for too long. Of course we got
over excited and killed a few sets of batteries by over flattening
them (never use batteries below 11 volts, or 10.5 in an emergency)but
it got us off the ground.
Now we have enough to power lots of fancy toys like video mixers, hard
drive media players, laptops and LED parcan lighting. These are all
just icing on the cake though. The most important part is screening
interesting, inventive independent films.