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.

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.

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

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?

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?

Originally Posted by Mr Browning

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

Running the same one and it is once a week for a six gun safe, not too humid place but can be bad for condensation.

If leaving for longer periods I top up with disposable ones.

Raising the temp is a good start to dehumidifying but you also need to vent, keeping the humidity down is part temp and part air flow. Just bringing up the temp inside of a sealed up safe just means the moist air inside it is warmer - which is the ideal breeding ground for rust. A couple of holes near the bottom of the safe, and a couple near the top will mean that the bulb heat should draw cold air in at the bottom and it will pass out the top slightly warmer.

I run a small 12v PC fan 24/7 in one of my safes and that works well. For lighting I run 5 of these (bloody bright!) on a micro switch so they turn on when the door is opened https://www.aliexpress.com/item/4000...archweb201603_

I haven't had time to do anything decent in my Liberty yet so just run the disposable packs in it and change them out every month or so.

Originally Posted by Mintie

Raising the temp is a good start to dehumidifying but you also need to vent, keeping the humidity down is part temp and part air flow. Just bringing up the temp inside of a sealed up safe just means the moist air inside it is warmer - which is the ideal breeding ground for rust. A couple of holes near the bottom of the safe, and a couple near the top will mean that the bulb heat should draw cold air in at the bottom and it will pass out the top slightly warmer.

I run a small 12v PC fan 24/7 in one of my safes and that works well. For lighting I run 5 of these (bloody bright!) on a micro switch so they turn on when the door is opened https://www.aliexpress.com/item/4000...archweb201603_

I haven't had time to do anything decent in my Liberty yet so just run the disposable packs in it and change them out every month or so.

I admit I'm definitely on the edge of my knowledge here in terms of humidity and rusting, but since warmer air can hold more moisture, as it warms the relative humidity decreases with all other things being equal, meaning that water shouldn't want to condense out of the air onto metal. Also the light bulb should over time warm up the firearms themselves, reducing likelihood of condensation on them when the air temp drops in the house overnight or with a weather change. In effect I'm not really removing moisture from the cabinet, just altering the conditions to the degree that rusting won't take place.

Edit - where I'm unsure is whether the fact that the safe isn't fully sealed will mean the warm inside-safe air will just pull more moisture from outside. If it doesn't, my relative humidity will drop as the inside temp rises, meaning the air will be effectively drier in terms of available moisture for rusting. If it does pull outside moisture, then I have to hope that I don't climb considerably over 60%, where rusting really takes off. I'll toss a temp/rh sensor in there to see what happens... maybe will leave one outside at the same time if I get my act together.

I'm a bit stuck with the venting since I can't cut big holes in the safe, so air movement will always be limited without a major change to how the safe is designed. I considered gutting a dehumidifier down to bare bones components and putting it in there and run a drain hose out through the floor of the safe, but in the end the heat it gave off would likely be enough, and in that confined a space I could realistically risk cracking wood stocks. Even with just a miniature bulb there's a real risk of drying things out, so I'm going to have to play with the bulb wattage or add a thermostat like @2post suggested. In a bigger safe, or gun room for that matter, I would definitely start targeting airflow and humidity directly.

Are you running those light strips off a battery or external supply?

Originally Posted by Mr Browning

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

FWIW - Mitre 10 sell the same dehumidifier for $20.

Originally Posted by Mintie

FWIW - Mitre 10 sell the same dehumidifier for $20.

Yeah bought 3 on special from M10 and my experience with them is they are hopeless.
My safe is already in a very dry environment but the indicators on the units change colour within days indicating they heed to be recharged.
I also don't think they contain a vast quantity of gel crystals.

As I said, that is my experience, YMMV.