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Posted

Need one of those  lit signboards in a remote location which requires a long and dangerous piece of wire to power it as done by just about every small business in Thailand.

Id like to move to a battery powered arrangement  later perhaps even solar powered. We can bring the sign in a night to charge it and it needs to be idiot proof. 

Using LED lights i think i can keep the power consumption to under 60 watts an hour and it needs to run for a maximum of 4 hours per evening.

I can find plenty of computer UPS  but they are both too complex and not waterproof enough for my needs.    Plus im pretty sure a lot of them lie about their specifications as they go very quiet when i ask about running 60 watts for 4 hours.

Can anyone suggest anything for this.  ive looked online but cant find anything that isnt designed for running a house.  The only actual sign ive seen doing this had a car battery with wires held in by matchsticks  in the bottom which presumably they charged with a battery charger during the day.

I could probably make the electronics but i do have a history of not finishing "interesting" projects or spending a week finding a 50 cent part  and we need this fairly urgently so id like something off the shelf if possible.  Solar charged  would be great if anyone knows how to do that.

 

Oh as a PS does anyone know where the signboard "boxes" are made. If i do go DIY i need an empty box to start with. 

 

Posted

Perhaps you could take a look at emergency lightning systems. Some of the older ones, which uses 12 volt halogen lights, have quite decent batteries included. 

 

The package would include 220V charger and 12 volt battery and it's portable. 

 

60 watt for led lights consumption is quite a lot. 

Posted

This needs to be moved to the 'diy electrical forum'.

Crossey (and others) can set you right.

 

I agree, 60 watts for a LED sign is nutz.

I have a 8 watt LED bulb, compares to a 70 watt incandescent.

Posted

@oilinki good call on the emergency light idea, should be easy to adapt.

 

Otherwise 12V LEDs and a small vehicle battery would do the trick. No need for a UPS type thing, just a cheap charger to top up the battery when it's low.

 

As others note, 60W of LED is a lighthouse.

 

Posted
On 11/05/2018 at 4:38 AM, howto said:

This needs to be moved to the 'diy electrical forum'.

Crossey (and others) can set you right.

 

I agree, 60 watts for a LED sign is nutz.

I have a 8 watt LED bulb, compares to a 70 watt incandescent.

Sorry for posting incorrectly

 

Im talking about the light box type of sign. Those signs usually now  have 4 LED tubes in them . 5-10 watts each = 40 watts . They have to shine through coloured graphics on both sides and the tubes give a nice  non directional diffuse light .

I'm assuming a 12 - 220 volt inverter will take some power also so i want 60 watts per hour to be safe and to give some overhead for battery deterioration etc. I had considered the security light route but those seem to give a maximum of 4 hours at 12 watts so I'd have to uprate the battery, get 12 V diffuse lighting  and get a big box by which time it was looking both expensive and hard. 

 

As an aside the  latest super slim lightbox  signs seem to have the back light panel from a TV in them but interestingly they charge more than a price of a TV for them .

 

 

Posted

OK, let's say 60W including some for inverter inefficiency.

 

At 12V 60W is about 5A.

 

For a run period of 4 hours that's 20Ahr.

 

One should never take a lead acid battery below 50% charge, so a vehicle battery of 50-60Ahr is what you want.

 

Should be reasonably easy to find one and a cheap trickle charger to top it up during the day.

 

Posted

Thanks for the 50% tip. That I didn't know I was looking at 24ah batteries. Having read up a bit what I need is an AGM deep cycle battery.  Ordinary car batteries are not designed for regular deep discharge and gel batteries fail in heat. Even then it seems like 500 cycles or a year and a half  is the maximum you can expect. Good faq here.

 

www.solar-electric.com/learning-center/batteries-and-charging/deep-cycle-battery-faq.html

 

 

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