Author Topic: Portable lighting - need suggestions (please)  (Read 1677 times)

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joematt

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Portable lighting - need suggestions (please)
« on: October 15, 2004, 03:10:02 PM »
I desire a natural spectrum bulb and I am considering 12 volt halogen of about 35 watts.  My hope is to connect them directly to the battery without an inverter.  They would be used like "under-cabinet" lights.  We sell pottery at craft fairs so we can recharge the battery overnight, just want to carry around as little as possible weight in the batteries.  Might need to run as many as (8) 35 watt bulbs.

Thanks in advance.
« Last Edit: October 15, 2004, 03:10:02 PM by (unknown) »

Opera House

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Re: Portable lighting - need suggestions (please)
« Reply #1 on: October 16, 2004, 06:44:02 PM »
By my calculations that is 23A or 138 amp hours.  If you go to SAMS or Walmart, they have 105AH deep cycle batteries that are rated at 180 reserve minutes.  As you draw higher amps, the effective amp hours are reduced.  Reserve minutes is calculated at about 25A so each battery is rated for about 3 hours.  You will absolutely need two of these batteries  This particular battery is not that large, but all deep cycle batteries are much heavier than standard batteries.  You will need a good 8-12 hours to recharge them and take two chargers probably.  Do not use standard car batteries because you will be going into a very deep discharge.
« Last Edit: October 16, 2004, 06:44:02 PM by Opera House »

tawa

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Re: Portable lighting - need suggestions (please)
« Reply #2 on: October 21, 2004, 01:46:50 PM »
What about getting a 12v automotive battery, and some automotive light bulbs and sockets? Wire those up with a switch, and some type of mounting base for the lights. (I just posted an article about how I have a desklamp that uses automotive light bulbs.)

« Last Edit: October 21, 2004, 01:46:50 PM by tawa »

nickbish

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Re: Portable lighting - need suggestions (please)
« Reply #3 on: October 23, 2004, 12:52:11 PM »
There are some pretty good 4 foot fluorescent tubes around that are relatively cheap and can produce light of virtually any color you might want from daylight thru orange to warm pink, search the web under "color temperature" for more info. How natural the light looks is covered by the CRI (color rendition index) of the tube, those with the highest CRI are 4 to 5 times more than cheap ones but we are talking about $12 versus $3.


In the U.S. the tubes are rated at 32 watts and to drive them get a thin-lite fitment or ballast (e.g. from Wind & Sun (model #153)) I have been bashing these real hard to see if I dare put them in a school in up river Gambia (Africa). So far they have tolerated all the abuse I have thrown at them, they are silent and pulse the tube at about 20khz so have no noticeable flicker after they have been on a for a few minutes.


They draw about 2.1 amps at 12.4 volts but tolerate a lot of variation. My experience is with using 36 watt tubes which seems to be all you can get in Europe (anyone in Europe know a source of 32 watt or 28 watt 4 foot tubes?). These only seem to put out about 2000 lumens when driven from a 12 volt battery but for 10' x 10' this is still quite a lot of light.


If you want to discharge your batteries no more than 20% in 6 hours (as recommended by this site) you need about a 60 AH (amp hour) battery. You do not say if your booth will be in use everyday, just at weekends or for occasional events. Either way I would be inclined to start by using an auto battery. If you really want to go bright just multiply up by the number of lights.

« Last Edit: October 23, 2004, 12:52:11 PM by nickbish »