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Battery powered led bar/batten


Owen Radmore

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As most led lights run off an internal power supply, then they could also be run off an external battery.

 

most have an 24v supply internal,

 

some have a 12v supply internal, these would be easiest.

 

 

Or ones with external power supply would also be easy.

 

But almost any could be so, with a little work !

 

A suitable socket and a switch is all thats required.

 

Easy as !

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Mate of mine built 10 Battery powered LED Uplights by removing the 12V Switchmode powersupply and instead installing an external battery pack, which already had all the re-charging circuitry built into it. I am fairly sure he chopped and changed a few other things as well, but I don't quite see how this could be that difficult?

 

ADJ Have got the Mega Go Bar, or something to that effect as a relatively cheap battery powered Bar light.

 

Or if you go direct to China I am sure you should be bale to find something, and even get Wireless DMX!

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Mate of mine built 10 Battery powered LED Uplights by removing the 12V Switchmode powersupply and instead installing an external battery pack, which already had all the re-charging circuitry built into it. I am fairly sure he chopped and changed a few other things as well, but I don't quite see how this could be that difficult?

This would only work if the LED units actively limited the current to the LEDs. If the unit is assuming the voltage is almost precisely 12 volts (which it would be with a switched mode PSU) and is just using resistors to limit the current, then using a car battery might kill the LEDs as cars batteries are about 13.2 volts when fully charged.

 

It would be much, much easier just to use a small inverter, rather than trying to chop the electronics. You will be losing a little bit of efficiency by converting up to 230VAC, and then back down to 12VDC but its still easier than modifying your units.

 

Just had a thought though: has anyone tried connecting a battery to the mains input of a switch-mode powered LED unit? Obviously it won't work with a transformer based PSU, but I think the electric bike crowd just hook normal mains powered switch-mode PSUs to their 72 VDC battery packs in order to get the 12 volts they need for headlights, indicators, etc.

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As most led lights run off an internal power supply, then they could also be run off an external battery.

...

But almost any could be so, with a little work !

 

I've got some 36 x 3W LED PARs where the control circuitry directly modulates the PWM of the 3-channel SMPSU to control the LED brightness. You'll not be converting that type of arrangement in a hurry.

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Have a look at Astera. The AL6 sounds like the job. Nice unit and wireless options are good.

http://www.astera-led.com/en/wireless-lamps/lamps/al6-wireless-wall-washer.html

 

 

Modify is always an option, but you're going to need to know what you're doing. And by the time you've added a battery and new control electronics in Brian's example you might not be making any saving with no warrenty or support available.

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It would be much, much easier just to use a small inverter, rather than trying to chop the electronics. You will be losing a little bit of efficiency by converting up to 230VAC, and then back down to 12VDC but its still easier than modifying your units.

 

Another approach is to build a high voltage battery pack and feed the ever-so-common SMPS off that DC supply.

 

To keep the problem in proportion, 'tis probably easier to target 110VAC kit. 110VAC is about 155VDC, which is 17 9V batteries in series. Made of PP3s of at least 500mAH, thats 155 * 0.5 = 70W at a 20 hour rate. Given one can seriously overload batteries for short periods of time, and by picking the peak voltage as a start point accepting that the voltage will drop significantly under (over-)load, thats quite a lot of LED output, and it'll work with pretty much all out-of-the-box LED stuff that uses a SMPS.

 

Warning: 155V off batteries is well enough to kill; treat as mains. Fuse required. Make sure the battery pack can't get shorted part way through and cause an unfused short, as a fire is possible.

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70W at a 20 hour rate
Given one can seriously overload batteries for short periods of time,........thats quite a lot of LED output

Ummmm... no it isn't, and no you can't. That 70W over 20 hours means 70W spread over 20 hours, not 70W FOR 20 hours. So thats about 3.5W per hour for 20 hours. If you put a bigger load on that battery, the total amount of energy you'll be able to use will go down. You wouldn't, for example, be able to get 70W for 1 hour. This is due to the chemistry of the battery and something known as Peukerts law, which states that the greater the load on a battery, the less total energy you will actually get out of it.

 

Connecting 17 off the shelf 9V batteries in series is asking for trouble. They won't have all exactly the same charge in them, nor will they all be able to deliver exactly the same amount of energy. This will lead to some batteries becoming discharged faster than others, which could be quite dangerous. A long time ago while I was at school, someone in my class noticed that you could plug two 9V PP3 batteries together. They started to get very hot, and they were pulled apart before anything else happened. I hate to think what would happen to a block of 17 of them connected together.

 

Honestly, the problem of using batteries to power mains equipment is something that has been solved a long time ago. Use one car battery as big as you can find, and use a mains inverter. This is much better than chopping up the wiring in your fixtures, and bodging some half-assed power supply out of tiny batteries.

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The use of a relatively high voltage battery to power mains voltage equipment is entirely doable, though great care is required.

 

I dont think that the use of 9 volt transistor batteries is viable except for very small loads.

 

12 batteries each 12 volt and 7AH could be a better bet, these can be obtained for as little as £10 each. Although in theory series operation is undesireable due to the potential for differing capacities and states of charge, in practice it works fine. Care should be taken that all batteries are of the same make and initial state of charge.

 

Proper fuse protection is vital, and such voltages should be treated with the same respect as the mains.

RS sell cheap 48 volt battery chargers, therefore only 3 battery chargers would be needed, not 12.

 

 

a 144 volt battery of 7AH could supply 2 amps or nearly 300 watts for a couple of hours.

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At PLASA, Clay Paky had a product called the GlowUp Strip 100 which was a 1M batten type battery powered LED fixture, with a 14 to 70deg beam angle. I can't find it on their site other than in the news section though, I'm guessing it hasn't been released yet? But would be worth speaking to Ambersphere.

 

Chris

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therefore only 3 battery chargers would be needed, not 12.

Or if you wanted to make this more pointlessly complicated than it already is, you could just create a switching system which would connect your batteries together into three parallel 48V blocks and then just use one 48V charger. At least your batteries would be getting charged to the same voltage. Still not a good idea, unless you regularly charge each 12V battery individually with the same charger in order to balance the voltage across all batteries. Charging them in series only is a bad idea. If you do nothing else, you should regularly measure each battery with a good quality multi-meter to ensure all batteries have EXACTLY the same voltage.

 

Or, and I'm fairly certain I've said this before, you could just use one car battery and an inverter......

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