Batteries drained in 2-3 days despite LEDs being off?

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Raven Morpheus
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Joined: Sun Jul 31, 2016 3:47 pm

Batteries drained in 2-3 days despite LEDs being off?

Post by Raven Morpheus » Tue Sep 27, 2016 5:32 pm

Hey all

I have a 1/43 AMT X-Wing which has 4 LEDs in it, one for each engine. It was powered by one 3V CR2032 battery and had an on/off switch (which I had installed under R2D2 and used him as the button).

The battery was still working even after a few months, but I hadn't really had the LEDs lit all that often. However I have hung the model on my ceiling and cannot reach it without a small step ladder, so I can't casually reach it to turn the LEDs on/off with a switch...

So, on Saturday I decided to install a wireless LED controller, one of these, take the switch out, as it wasn't working properly under R2D2, and go from using 1 CR2032 to using 2 CR2032 batteries in a battery holder with a switch (because the LED controller requires at least 5v power).

I left the switch on the battery holder set to on, thinking I'd not drain the batteries and today I went to try out the LEDs to make sure everything was still working and I found that the batteries have drained to the point that the LED controller will no longer function.

I think that even though the LED controller puts the circuit on standby the LED controller itself is still drawing power from the batteries, it wouldn't be able to turn on/off if it didn't.

So, without using a physical switch (or by leaving one in the on state) how can I stop the LED controller from draining the batteries in 2-3 days?

I've thought about using a 9v PP3 battery, but I'm not sure how much longer one would last - I'm looking for a small battery that will last for months?

Thanks in advance for any advice on this.

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Location: Oxford UK

Post by Ant » Wed Sep 28, 2016 1:49 am

Yes, the wireless controller will be drawing some current all the time, which will drain the batteries. Coupled with that, the CR2032 cells have very little capacity and are not intended for 'always on' circuits unless the draw is down in the micro amp range.

A 9v would give you a bit longer life, but not much. The controller needs 5v and the battery supplies 9v so you have to get rid of the excess 4v with a regulator, which basically means transforming it into waste heat. That's almost half your battery.

I think you will struggle to find a solution more effective than just a switch.

Raven Morpheus
Posts: 6
Joined: Sun Jul 31, 2016 3:47 pm

Post by Raven Morpheus » Wed Sep 28, 2016 1:01 pm

Ant wrote: I think you will struggle to find a solution more effective than just a switch.
Thanks, yes I'm thinking that as well.

I've considered buying some 3.7v 14500 or 16340 2300mah rechargeable batteries (basically AA or CR123A sized), using 2 of them (they should just about fit inside the X-Wing) to give 7.4v and see how they go, at least I can recharge them rather than having to keep replacing them. But even those will probably only last a couple of days in an always on circuit.

The LED controller works on 5v to 24v so I can use any power source within that range so bleeding off excess voltage isn't a problem.

Wish I knew what the LED controller is drawing when set to standby, then I might be able to work out how long batteries should last...

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