Please help - battery life of LED lighting strip

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gasman

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Good afternoon all. I wonder if I can seek advice from electrical wizards here?
As part of my recently completed tambour whisky cabinet, I installed a motion-sensor triggered LED lighting strip
Amazon lights
It came with a 3m strip which you could trim to length and a battery box with 4 x AA batteries
The cables and lights were very carefully cut into grooves etc so that they could not be seen - ie I can no longer get them out without doing some serious damage
My problem is that, even though I only open the doors once or twice a week, and the motion sensor means that the lights are on for about 30 seconds after closing the doors, I am only getting about 2 or 3 weeks before the batteries go flat
The battery box has a USB connector to the lighting cable - so the only solution I can think of is to buy a power source with a 5V output but I just wonder if anyone can shed any light on why the batteries last for so short a time?
Thanks
Mark
 

baldkev

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Are they definitely switching off as expected? Maybe your misses or kids in trolling you 😆

Rechargeable aa's?
 

gasman

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Yes definitely going off. No one else drinks whisky in the house ;). Kids long gone. 4 brand new Duracell batteries lasting about 10 minutes of actual lighting time
 

martin.pearson

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Take it the motion sensor is inside the cabinet & operates when the door opens, that will draw some power I am guessing but shouldn't be a lot. I tend not to use batteries with any of the LED stuff that I do now because they tend not to last for very long, when I first experimented with different set ups I found the batteries would sometimes go flat overnight even though everything was turned off & I could never figure out why. Only thing I have put batteries in for some time now are the Grandkids birthday numbers but they aren't expected to last for more than the day really lol

Nettle number 4.jpg
 
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Sporky McGuffin

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The product page says you can power it via USB. I suspect there are actually a lot of LEDs in that strip, and probably not terribly clever power management. I'd still expect a few hours of continuous high brightness from four AAs though.
 

Wildman

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the motion detector is constantly drawing current. a pressure switch or usb it is then.
 

MorrisWoodman12

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Duracell MN1500 AA cells are rated at 2850 mAhr.
Your LED lights are specified as 10W at 5V I.e. 2A or 2000mA.
Thus the batteries should last 1.4 hours ignoring the drain from the motion sensor.

Opening the door say twice a week over three weeks for, let's say, 5 minutes plus 30 seconds extra each time is 33 minutes LED usage total or 1100 mAhr.
Three weeks is about 500 hours. If the motion sensor is drawing 3mA (a not inconceivable amount) that would be a further 1500 mAhr.

Thus the total is 2600 mAhr so your batteries are dead after 3 weeks! Even if the motion sensor draws less current the battery won't last much longer.
I also note one other customer who reviewed this product on that great south American river site complained of poor battery life.
Your only recourse I think is a USB power source capable of 2A or more.
Have fun.
Martin
 

Sporky McGuffin

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Duracell MN1500 AA cells are rated at 2850 mAhr.
Your LED lights are specified as 10W at 5V I.e. 2A or 2000mA.
Thus the batteries should last 1.4 hours ignoring the drain from the motion sensor.

My suspicion is that 2850mAH is probably life to half voltage or something like that. As the LED strip needs 5V, and four AAs comes to 6v, the usable life of those batteries could be a lot shorter - once the voltage drops too far they're effectively dead, even though they might work in something less demanding.

This is the sort of thing that can be solved with a couple of pounds' worth of extra components in the controller - run the batteries in parallel (or 2x2), charge pump the voltage up to what you need, and you end up with longer usable life.
 

gasman

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Thanks so much everyone - very helpful esp the electrical sums which I always struggle with
I have already thought of the 5V supply - and actually an iPhone-type charger which is 5W/2A should work fine I think (it says the lights are 10W so that is correct as I understand it). Then I will get a long female-to-male USB cable and that should do it I think. Thanks again. Mark
 

John Brown

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I assume the motion sensor is a PIR device?
If so, then you can get these that draw as little as 50 microamps. That said, yours may use a lot more. I did a job a couple of years ago for monitoring toilet footfall, using PIR and Lora, which is how I know this...
 

Spectric

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Rather than a mains powered adaptor you could use a powerbank from the likes of Anker, more easy to conceal and they have large storage ability. I use one to power my Ublox GPS receiver when out walking. Your drain is due to the electronics in the sensor which is just waiting to sense motion, a better option would have been a micro switch or mag switch to detect door opening which would have drawn nothing.
 

pe2dave

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(Yes, another pessimistic view)
Burying the led's may look good, but low cost LED's life could be quite short?
How would the cabinet look with no lighting?
bottom line - plan for replacement with cheap led strips.
 

gasman

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Thanks both. Roy thank you great idea - I have one and will try
Dave the cabinet looks fine without the lighting - but if possible I prefer it to have it - makes it look very striking
 

MorrisWoodman12

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I have already thought of the 5V supply - and actually an iPhone-type charger which is 5W/2A should work fine I think (it says the lights are 10W so that is correct as I understand it).
Bit confusing. If it's 5V/2A rather than 5W then that should be fine. I assume it is just a W/V typo.
 

John Brown

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Rather than a mains powered adaptor you could use a powerbank from the likes of Anker, more easy to conceal and they have large storage ability. I use one to power my Ublox GPS receiver when out walking. Your drain is due to the electronics in the sensor which is just waiting to sense motion, a better option would have been a micro switch or mag switch to detect door opening which would have drawn nothing.
Be aware that some of the power banks shut off when the current falls below a certain threshold. My Anker one does.
 

gasman

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Many thanks to all who contributed
I tried the power bank idea - but it was not reliable and cut out as John Brown suggested above
So in the end I simply bought a 5m male-to-female USB lead and used an iPhone adaptor plug with a USB port and it worked perfectly. Problem solved so thanks again for all your help
Cheers
Mark
 
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