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Running mains fluorescents from inverter

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Posted by The Other Mike on June 19, 2011, 10:52 pm
Currently got a remote observation site (wildlife) with no grid fed
power nor any prospect of it.

Half the site has a few modified 4ft T5's (36W) retrofitted with 12v
IOTA Ballasts (2D12-1-32) fed from a lead acid battery charged by a
solar panel.   The other half of the site has 5ft T5's with magnetic
ballasts fed by a Honda EU20i generator which despite being a quiet
suitcase model and loads of additional soundproofing is still way too
noisy.  Near silent operation is essential.  Hauling fuel is also a
PITA as its a long way from the road.

So I need a way of powering the 5ft T5's (58W) from a low voltage DC
supply.  IOTA only make ballasts up to 40W and they need a circa 50v
supply, realistically I need to keep to 12v to keep the solar array
price down.

So thoughts turned to an inverter fed from an uprated solar array and

A cheap modified sine wave inverter (circa 500W capacity) on a 100Ah
brand new battery fails to even kick even one 5ft tube into life.  The
manufacturer says these inverters are not compatible with fluorescent
tubes but doesn't elaborate any further.

Does anyone have any ideas on how to get these lights working off

A change of ballast to an electronic type? (all indications are this
could won't work?)

Moving to a pure sine wave inverter (extremely expensive) ?

A different inverter supplier rather than 'one hung lo china inc' ?'

A ballast supplier that offers 12v ballasts that will drive a 58W

A homebrew 12V fluorescent inverter, running at high frequency that
will drive 5ft tubes and costs not a lot?  :)


Posted by Gazz on June 19, 2011, 11:23 pm

prolly cheapest and easiest to change the 5 foot fittings to 4 footers with
the 12 volt ballasts you know work.

you'll need a pure sine wave inverter to run a ferromagnetic ballast, bit of
a waste of money just to run a few lights, if you wanted to run laser
printers, charge electric toothbrushes etc at the site, then it may be

Posted by vaughn on June 20, 2011, 12:56 am

But what about swapping to a newer electronic ballast?  I would expect them to
have a pulse-mode input which should even work off a cheap square wave inverter.
(But I haven't tried)  Besides, they are more efficient.

Anyhow, thanks to this thread, I now know how to find 12 volt ballasts without
breaking the bank.


Posted by Andrew Gabriel on June 20, 2011, 11:05 am

They also have power factor correction inputs (usually achieving 0.95 - 0.98)
and these might not like square wave. Many nowadays are rated 50-60Hz or DC,
and the DC voltage can be lower than mains in many cases, 180V is not
uncommon, and I have one here which says 160V.

One thing you do have to be careful about when running off batteries is not
to allow the ballasts to run below their minimum rated voltages, as that
causes excessive current in the transformer primary, and quick burnout.
Some of the better ones include protection circuitry to switch-off below
the min rated voltage.

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

Posted by The Other Mike on June 20, 2011, 11:30 am
 On Mon, 20 Jun 2011 11:05:56 +0000 (UTC), andrew@cucumber.demon.co.uk
(Andrew Gabriel) wrote:



So presumably I could rectify and smooth and regulate the near sine
wave inverter output of circa 340v pp within the lamp housing and feed
an electronic ballast with say 200v?  

Any indication of suitable makes and models?


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