Thread: Basic safe lighting and dehumidifying project

So here's the rough plan. In part posting to inspire others, but also hoping someone with more sparky knowledge than I will catch any problems with it before I put it all together

The plan is to wire a safe for light and reduce humidity. Would leave a 12v incandescent bulb running 24/7 in the bottom to raise the box internal temp to reduce humidity/tools rusting, and have the LED lighting kick on when the door is opened so I don't have to wear a head torch to see what's going on in there.

Have a roll of 12v LED strip lighting (3528 SMD LED, 4.8W/m) and am thinking of setting it up using a 12V 6A (72W) laptop power supply to power a small 12 volt (<33W) incandescent bulb (keep humidity in the toolbox down) and a bunch of LED strips (5m total (24W), with 14x 0.25m strips and 2x 0.75m strips wired in parallel) behind a micro switch or PIR to turn the lights on when the door opens and off when it's closed.

My thinking so far:

1) Power supply is 12V 6A = 72W. At 80% use to keep the power supply from overheating and dieing that's 57.6W

2) LED Strip lights are 4.8W/m x 5m = 24W

3) 57.6W - 24W = 33.6W maximum available for the incandescent bulb.


- Happy to change design, but still need to achieve the same end goals, preferably without spending a ton of money.
- I do want to make sure that I'm not overloading my power supply and it's safe to leave running 24/7.

Any input, comments, or modifications?

Hmm,
DampRid Refillable Moisture Absorber 300g White Crystals
https://www.mitre10.co.nz/shop/dampr...stals/p/325507 $6.91

Blazing LED Timer Jumbo COB Light Bar
https://www.mitre10.co.nz/shop/blazi...t-bar/p/321919 $13.16

Job done unless you have some serious damp going on.

Originally Posted by Mr Browning

Hmm,
DampRid Refillable Moisture Absorber 300g White Crystals
https://www.mitre10.co.nz/shop/dampr...stals/p/325507 $6.91

Blazing LED Timer Jumbo COB Light Bar
https://www.mitre10.co.nz/shop/blazi...t-bar/p/321919 $13.16

Job done unless you have some serious damp going on.

The light bar is a good idea - if I weren't going for a powered dehumidifier I'd go towards battery, but figured since I'm running power for that might as well run the lights on the same system. Plus I already have all the components

I dislike the desiccant crystals. Had a desiccant pack swell, overflow its container and rust the heck out of the shelf and a tool next to it, which really put me off them. Plus once they've absorbed all they can absorb they stop working until you dry them out - if I'm busy I won't be checking it, so want something that's more active and reliable. There's an argument to be made whether a light bulb is more reliable, but that's a different issue I suppose.

The light bars are little gems. Magnetic as well, so still it to the roof inside the safe and they provide more than enough light to do the job.

I only use the crystals in the safe in the garage which is not powered, but have the safe on the north wall which also makes a difference, I also throw a old blanket over the safe, not only does it assist with keeping it a bit dryer, if anyone snooping looks through a window, it isnt obvious to see.

Youre so lucky to have power available.

Cracking day today in Canty!

Cheers

Rather than generating heat, in my last one I set up a bathroom extraction fan and an inlet vent at the other end. I then put this on timer to run for about a couple hours during the hottest and coldest parts of the day. Getting airflow and stopping the temp differential solved my condensation issues and fan run at much lower wattages than the power (I think the 5 inch one I used was about 15 to 20 watts, but I cannot remember.

Originally Posted by mimms2

Depends if laptop psu is regulated or not. If it is, it will push full current, which may smoke your bulb.
If not, voltage will be higher and the load will determine the output, up to max. And LED like very stable current. I MAY have an LED driver in my big ol' box of electrical shit.

I would be inclined to run a switchmode batery charger to a VRLA (outside safe - will offgas corrosive shit) and use the battery as voltage/current buffer.

Not sure what PIR options avail for dc, so pantry switch could be the go.

Five meters of LED?? You'll get a tan just deciding which gun to pick.

Try one of those garden solar sensor lights. I chucked one in the garage and put the solar panel in a window. Like these, https://www.bunnings.co.nz/arlec-330...light_p0181802

Brilliant in the garage....

Originally Posted by mimms2

Depends if laptop psu is regulated or not. If it is, it will push full current, which may smoke your bulb.
If not, voltage will be higher and the load will determine the output, up to max. And LED like very stable current. I MAY have an LED driver in my big ol' box of electrical shit.

I would be inclined to run a switchmode batery charger to a VRLA (outside safe - will offgas corrosive shit) and use the battery as voltage/current buffer.

Not sure what PIR options avail for dc, so pantry switch could be the go.

Five meters of LED?? You'll get a tan just deciding which gun to pick.

I'm pretty far out of my depth, but aren't most laptop supplies voltage regulated not current regulated?

I agree that the LED's like stable current, though these light strips seem pretty tough, so I suspect because they're made for people like me it might tolerate things... or y'know... burn out

Have a DC PIR's off a defunct solar security setup similar to timattalon's that I pulled out of the bin (just need to check that it's still good)... I can just as easily run a micro switch though, just needs fiddling so it mounts properly.

For light I definitely prefer more light than less - some top down lights plus having some run down the insides of the door frame and underneath the cross bar supporting the barrels. Safes are already dark, plus dark guns, plus clutter, shadows, shelving etc etc and it sucks up the light. It'll be bright when it's installed, but once I pack it with junk I'm betting I still won't be able to see properly

Originally Posted by timattalon

Rather than generating heat, in my last one I set up a bathroom extraction fan and an inlet vent at the other end. I then put this on timer to run for about a couple hours during the hottest and coldest parts of the day. Getting airflow and stopping the temp differential solved my condensation issues and fan run at much lower wattages than the power (I think the 5 inch one I used was about 15 to 20 watts, but I cannot remember.

Thought about that - then thought about a dehumidifier, but the hole I would need to cut in the safe would be a lot bigger than I want. Considered a grill too, but don't want to drag it out of its hiding place to do it.

Originally Posted by timattalon

Try one of those garden solar sensor lights. I chucked one in the garage and put the solar panel in a window. Like these, https://www.bunnings.co.nz/arlec-330...light_p0181802

Brilliant in the garage....

Exactly that - I'm a firm convert to motion detecting light switches in transit areas like stairwells, hallways, enclosed porches, outdoor walkways etc. Can have them on PIR and then switch to on when you get to it, and switch to off when you leave, but you don't end up in the dark fumbling around because the PIR is working when the light isn't manually switched on. A 30-60s delay is usually all you need. It's actually what gave me the idea for the safe... dumb automation for everything!

I have a spare one of these if anyone wants it:

https://www.nuklearproducts.co.nz/co...at-foot-warmer

You can't cover them with anything but its worked well for me.

Originally Posted by mimms2

Aren't they just "on when dark"?

I'm sure there will be a thing. And afaik the actaul light sensig bit (LDR?) is DC, it wouldn't be too far out to make something work.

The ones I have work just like a sensor light on the outside of a house. Not the cheap driveway marker / garden decoration lights, but proper sensor lights. They come on for a set amount of time after they detect movement then go off afterwards.

Originally Posted by timattalon

The ones I have work just like a sensor light on the outside of a house. Not the cheap driveway marker / garden decoration lights, but proper sensor lights. They come on for a set amount of time after they detect movement then go off afterwards.

Can you shorten or lengthen the time they come on for?

I have a couple of these set up in my safes,no drilling, power cords etc needed as dehumidifier is rechargeable and sensor light runs off batteries (×3 AAA)... light only $30.00 & dehumidifier $80.00... could be an option to look at ?

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Originally Posted by seano

I have a couple of these set up in my safes,no drilling, power cords etc needed as dehumidifier is rechargeable and sensor light runs off batteries (×3 AAA)... light only $30.00 & dehumidifier $80.00... could be an option to look at ?

Sent from my SM-G930U using Tapatalk

You beat me to it.
https://www.alibaba.com/product-deta...477836463.html
Let the light be a light and control moisture separately.
Controlling temperature has its use though so how about a heat pad on the outside of the cabinet with a thermostat inside.

Originally Posted by Mr Browning

Can you shorten or lengthen the time they come on for?

Depends on the make/model of sensor, but yes, some do allow you to adjust for time (and sensitivity)

Originally Posted by 2post

You beat me to it.
https://www.alibaba.com/product-deta...477836463.html
Let the light be a light and control moisture separately.
Controlling temperature has its use though so how about a heat pad on the outside of the cabinet with a thermostat inside.

Someone posted about using a brewing drum heating belt a while back - seems like a neat idea. They seem to be a lot cheaper and more robust than other heat units on the market.

I do like the incandescent bulb idea because it's simple and cheap... most incandescents are something like 5% efficient turning electricity into light with the other 95% turning into heat... so really when it comes down to it incandescents are actually fancy heater units that happen to give off light rather than vice versa




So no one is seeing any glaring issues with the power supply, wattage, or wiring layout?

You are correct about an incandescent light bulb, I just thought putting a heat pad on the outside would be easier than drilling holes and you can use 230v stuff. I do recommend a thermostat as you’d be surprised how hot it can get.
What you are after is consistent temperature.
I have a heat pad that I used for home brew that you could sit you cabinet on also we use heat belts on refrigeration compressors and heat trace for freezer drains so there are lots of options.

Originally Posted by seano

I have a couple of these set up in my safes,no drilling, power cords etc needed as dehumidifier is rechargeable and sensor light runs off batteries (×3 AAA)... light only $30.00 & dehumidifier $80.00... could be an option to look at ?

Sent from my SM-G930U using Tapatalk

How often do you have to charge the dehumidifier on average?