Subject: Re: High Power traps run off batteries

From: "A.P.K.Torry" <[email-masked]>
Date: Mon, 17 Jun 1996 09:37:13 GMT

>The traps we are talking about are Skinner traps using a 125W MV lamp
>with a choke. We are NOT talking about the smaller Heath traps which
>use actinic bulbs (these are very ineffecient in Shetland).

The only way to run these lights off of batteries is to use an inverter (12 V DC
 to
240 V AC), in order to strike a 125W MV bulb you would need an initial 240V AC
 current of about 10 Amps (The choke acts like an immediate short), using an
 inverter would mean an initial 12V DC current of 200 Amps!, which will burn out
 most batteries (Not to mention the output MOSFET of the inverter)  in 5 seconds
 flat.

The RAF used to use mechanical inverters which consisted of a 12(24) V DC motor
 attached to the input shaft of a generator, this method is very much more
 ineffecient as far as battery life is concerned but produces much higher power
 output.

I agree the 8 watt heath trap tubes are just not up to it but I think you will
 find that a 5' Actinic tube produces 3-4 times more UV light than the
 equivalent Robinson trap ever can and will run off of car batteries for up to 8
 hours.
Just give the 5' a try and I think you will be surprised. I agree the

Hope this helps

Andrew T.

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From: Sam Droege <[email-masked]>
Date: Mon, 17 Jun 1996 09:23:01 MST

>We have recently applied for a grant to buy some traps and a
>generator but we have been advised that we would be better off
>buying heavy duty lorry batteries and using those instead.

Don't know how much juice your traps take, but if you use batteries
don't use lorry batteries use deep cycle lead-acid batteries (also
known as marine) or, if you can afford, them NICAD.  The deep cycle
batteries are designed to take deep discharges, truck batteries are
designed to be constantly charged by the truck engine.

While deep cycle batteries can handle draw downs better than truck,
they last a lot longer if you charge them after every night.
However, a good deep cycle battery is extremely heavy and difficult
for one person to handle, so logistics can be a problem too.

You might want to look into a solar panel rig to charge your
batteries (if you are not in the woods and if you are not drawing a
lot of current).   This would eliminate almost all of the headaches.

sam

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From: Andrew Stagg <[email-masked]>
Date: Mon, 17 Jun 1996 16:06:54 +-100

Andrew,

What do you use to convert 12V DC to 240V AC on the 5' tubes, I have a 5' set-up
 but at present it is mains only.

Andrew

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From: "A.P.K.Torry" <[email-masked]>
Date: Tue, 18 Jun 1996 09:31:23 GMT

Cirkit electronics magazine sells a kit for a 120W inverter.

RS components sell a 200W inverter.

Try some local camping/Caravanning centres.

The 5' light fitting pulls some 12A from the battery when it fires but this
 drops to a steady 5A once started, a good fully charged battery will run the
 light fro about 4 hours but most of the inverters you can buy have voltage
 dropout detectors which shut down the inverter when the battery output voltage
 drops below 10V, this means that you would still be able to start your car
 after a few hours mothing.

Hope this helps

Andrew T