Hi, I'm doing a garden irrigation project with an Arduino. The Arduino is powered by a solar panel connected to a battery, it has a couple of modules attached to it (hc-05 and ds3231 for bluetooth and time), it's connected to a ground humidity sensor, and also to a solenoid valve. I'm new to this kind of projects so I don't know what's the best way to keep all the components safe from the elements (they're gonna stay outdoors). Any tips on how to keep everything safe? What cables to use? Can I use normal crocodile/jumper wire cables if protected by a tube over short distance? Are there boxes you'd recommend to buy/make to keep the arduino and sensors safe? Anything else to keep in mind for this project?
Keeping moisture and small insects out of your project box is not easy!
I would recommend keeping as many components as possible inside a weather proof plastic project box. These have rubber seals around the lid. Avoid those with metal screws to hold the lid on place, the screws will rust (they are not made of stainless steel). Avoid boxes with clear/transparent lids, these will become cloudy over time Also use grommits to pass cables into the box, or use panel mounting sockets and plugs.
Do not place the battery inside this box. Batteries can release gases when charging & discharging and need to "breathe".
Thank you! I'm not having much luck finding a weather proof box without metal screws. As for the battery, is it fine to just leave it beside the box? How do I connect cables to it, I assume it's not enough to just connect them and leave them as they are?
No. Of all things, the battery is probably the most vulnerable component of the whole project
Electricity and moisture do to make happy bedfellows
So I should leave it inside the box and make sure I regularly open it to change air?
The battery needs to be in a waterproof box or at the very least the battery connections should be waterproof. It could be a separate box if that suits your project. All connections between elements of the project must be waterproof too
There is no need to periodically open the box to change the air because it will not be damp, will it ?
Someone earlier in this thread said that batteries can release gases when charging & discharging and need to "breathe", so that's why I thought to periodically open the box. The original plan was already to have a waterproof box.
Some people use a Tupperware box with good results
That depends on what type of battery that you are using
Perfect, that's really useful.
It's a 12v lead battery. This is the link to the product, but it's in Italian.
12v batteries like that do off gas when charging. They are often used by farmers for electric fences and don’t seem to suffer too much being in a reasonably enclosed shelter. Look up the parts at farm shops. Also you can put conformal coatings on electronics to protect against moisture. Be aware of heat sink requirements. Use waterproof connectors often called through panel connectors. Also consider adhesive heat shrink tubing on external connections for a watertight seal. Tinned wire is more resistant to corrosion
Ok, thank you!
Hello System64
Take a view here to get some additional ideas.
I have an automatic driveway gate that is powered by two of those batteries. The controller and battery box is black plastic and exposed to the hot summer sun and heat. The batteries overheated each summer and vented acid and gas and destroyed the connectors and wire. The batteries had to be replaced each year.
I finally realized the problem and added rainproof vents to the box. That solved the heat problem and also added aluminum tape to the box to reflect the sunlight. No more battery problems.
It's going to be covered on the top, so hopefully the sun should not be an issue. I'll consider the vents and a DHT11 sensor to monitor temperature and humidity.
Can you elaborate on this? I hope you don't mean:
Just 'regularly' go out, doesn't that conflict with what you are doing? 
The battery under the hood of your car is not exposed, but it gets much hotter in there than it ever would outside. It's also dealing with with vibration and other debris. The battery goes along for the ride whatever the weather decides to do. Look at some of these 18 wheeler, the batteries are many times visible near or under the cab.
What you do see in batteries that are exposed is uv sunlight damage causing the battery to crack apart dramatically shorting it's life.
IMHO, best practice is electronics in a suitable weather proof/resistant box and the battery both contained in a larger 'semi' waterproof 'box'... just enough protection to keep it out of the sun but allow air to flow.
This eliminates 'connections' between separate, external items and lets you carry the whole thing around as one or mount it as one.
Good luck
That is an SLA in your link - Sealed Lead Acid, it's not going to out gas (because it's Sealed).
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Recently I came across this project in another forum: PicoW with solar on my garden - Raspberry Pi Forums
The casing caught my eyes and I asked for the details. You can see it. The components are not same but for the casing part, you will defenately get some ideas.
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