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Running mains fluorescents from inverter - Page 12

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Posted by Andrew Gabriel on June 26, 2011, 5:40 pm

It's efficient into a resistive load.
A magnetically ballasted fluorescent lamp isn't a resistive load.
Even if it has a power factor correction capacitor (and most
don't nowadays), that can only correct the inductive component
in the power factor, not the contribution from the tube, which
amounts to about half of it.

The inverter cannot recover the excess energy borrowed from it
and returned each half cycle due to the phase shift, so the load
on the inverter is much nearer to the (higher) VA rating of the
lamp than the power rating. (That's why inverters are rated in
VA and not Watts.)

Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Posted by Andy Dingley on June 25, 2011, 9:44 am
On Jun 19, 11:52pm, The Other Mike

I'd be thinking about solar (keep an eye on Maplin for bargain
clearances), recycled car batteries for low cost, then LED lighting
rather than fluoresecent.

CPC (packaged lamps) and Deal Extreme (bare components and drivers)
are both good sources

Posted by Dave Liquorice on June 25, 2011, 10:18 am
 On Sat, 25 Jun 2011 02:44:56 -0700 (PDT), Andy Dingley wrote:

Carlisle has the 3' x 1' 20W (I think) panels at 40 each ATM...

They might not have much deep cycle capacity and car batteries don't
like deep cycles anyway. However if the batteries are free... One
might need to make allowances for acid vapours - ventilation/acid
resistant enclosure.

I've not seen any "spray light every where" LED luminaires. They are
all directional to a greater or lesser extent.


Posted by Jim Wilkins on June 25, 2011, 3:40 pm

I don't know about wildlife observation labs, but I've managed several
electronics labs and machine shops which all had and needed good
uniform lighting everywhere.

If the work and personnel permit, a light low over the bench like
or under the top shelf may be enough.

I like this type:


Posted by Andy Dingley on June 25, 2011, 4:02 pm

Check mail order too. I've got one of the 100W panels that I just
clicked on by chance one day when I got a circulated text message
saying that they'd suddenly gone half price again. Shipping was too
cheap to meter.

So don't cycle them so deeply. Just use more batteries. Car batteries
are available for scrap value and half of that lot collected will
still be usable for capacity-limited low-cost energy projects like

_Appropriate_ allowance should be made, but if you avoid massive
currents and overcharging, then there's a very lot risk of the sort of
hot outgassing that throws acid vapour around. I've seen one guy break
his arm after slipping on the acid-proofed telephone exchange floor
(those big battery rooms were like swimming pools) and I've seen a
couple of "trustworthy" APC UPSes blow themselves up and spit acid
(rack-mounts UPSes are not a wise idea), but I've never yet seen a
bunch of hippies, a rack of car batteries and a wind turbine have any

LEDs aren't sold as luminaires so much, because they don't need so
much insulation, either  electrical or thermal. Many are sold as bare
sticks or even flexible tapes that you're expected to house

It's also quite easy to make your own up from bare LEDs, usually
surface mount, onto a couple of conductors. Insulated wire with knife-
scrape exposures can work for this, or you can buy magic mounting twin-
core wire that's the right spacing and pre-bared at intervals. Even
better is to series them and use a constant-current drive. Cree
SuperFluxs (400mcd @ 130) are under 40p each now by the dozen.

As it's wildlife, you might want to install a set of red lights too.
This will keep your own night vision in better shape, works better in
conjunction with NVGs, or you could simply badger watch with the
lights on.

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