I am fairly new to the Arduino world (I have only used it during my studies for a few very simple projects). At the moment I have the opportunity to create something for an exhibition, but I could use some guidance on the hardware/electrical side of things, since the physics are not my strong suit.
I want to power both a strand of LEDs (this one) and an Arduino controlling these LEDs (unsure about the exact model, but I will probably opt for the simplest possible microcontroller) from battery, since there is no other power source available. Ideally it should be running 24/7, but I could periodically recharge batteries/a power bank for example.
What I would like to know is:
Is this feasible? If so, how much setup/tinkering does it require?
Are there any products you can immediately point me towards?
How would I connect everything together? Ideally, I'd like to avoid things like soldering, since I am on a tight deadline.
What do I need to consider? As an electronics noob, there are bound to be things I will overlook.
With a big enough battery you can power almost anything. Powering the 'Arduiuno' (assume NANO) with a battery bank is easy, the LEDs requires much more power. Normally they are powered from a wall wart but if that is not possible, do the calculations in watts of how much power the LEDs need for the time you want them to run. Then allow for conversion losses (80%?) and source a large LiPo RC type battery with a buck converter in between to drop the voltage to 5V. These are 66.6Wh (66600mWh) BUT they are LIPO so need a special balance charger and strict adherence to safety procedures. Worst case the exhibition may not even allow LIPO or LIFE. In that case LiFePO4 is ok, but much lower energy density. Cost will be a few hundred dollars.
It much depends how you are using your leds. All of them on at the same time at full brightnes (white) would make 1500mA. But they are acceptably bright even at 1/3 of that, 500mA. Now if you have some effects and they are not all on at the same time, it could make 250mA. At this point beefy powerbank, like 20 000mAh, would be ok for few days.
One of these safety (and usage) procedures it monitoring the battery constantly either in person (with a lipo alarm) or in the project design, such that the project shuts itself off at the 3V/cell minimum lipo charge threshold.
Go below that, and a balance charger will refuse to even charge it again and the battery is considered unstable at this point.
For that reason, I try to avoid lipos in my Hallowe'en props unless I'm just using a smart phone battery back up bank to power the Arduino (these have voltage protection, typically, built in).
I often use 12V 5Ah sealed lead acid batteries, very common, small enough and inexpensive as they are often used in building alarm system panels as panel battery backups in the event of a power failure. You need a way to charge it though (any battery for that matter).
I just bought a 90Ah deep cycle, standard lead acid battery (Interstate brand) for a 12V trolling motor on a fishing boat, cost $250 Canadian dollars and weighs about 50 pounds).
They are easily wired in parallel with an AC/DC wall adapter that can be used to charge the battery when you do have access to mains power.
If you want to get really creative,
is the sun available? You might use a solar panel to keep the battery charged, too, if you have the space for it.
Thanks for the suggestions! I doubt I could stomach anything that costs a few hundred dollars, as it is supposed to be a small project. Nonetheless, your input will help me research the cheapest option that is also safe to keep running unattended.
That is a good point you are making. Since it is taking place in a dark underpass, I wouldn't need the LEDs at peak brightness anyway. A beefy powerbank that I recharge once a week would be a feasible option I guess.
Once again thanks for the input. I think the things you are mentioning are out of my budget and not compatible with the setup though, as it has to get mounted inside of a frame that is just 6cm deep, so not a lot of room. Honestly, the more I am looking into this, the more unfeasible it seems, since sun is also not present. I might have to reconsider.
I built a good sized solar system, slept on top of the LiFePO4 batteries as they are very safe.
I will bet a few dollars your trolling motor has on it somewhere CCA or Marine Cold Cranking Amps. That means it is NOT a deep discharge battery. 99% of people with what they think are deep discharge are at best hybrids or standard starting batteries. 6V golf cart batteries or Trojans are the gold standard.
My batteries cost me over $6000.
That is the first intelligent thing I have heard from a user all day. What are the parameters of your project? Does it have to be addressable RBG? If you can substitute regular LEDs that you can write code for to make some sort of display then that will be a lot easier.
You originally linked to a lipo battery used in RC hobby, which is the type I was referring to in terms of battery monitoring and that you explained (correctly) needs an appropriate charger. I have a few steel ammo boxes full of these batteries and for the reasons I explained in post #4, I don't use them in my battery powered Hallowe'en props.
In short, these are not the same as your $6000 setup.
Even if you over discharge one by mistake, you can still resurrect it with the other like this:
Then buy the buck regulators you think you need for the components to dial in the right voltages (literally, just a screw to select the correct voltage).
(Heh, it's Hallowe'en building season so i just scooped 10 of these myself, they're like gold in this hobby)
Yep, it's a cranking battery, NOT deep cycle.
Meant for a lot of current for a brief period of time a few times a day. Plates are thinner and more of them.
Deep cycle has fewer thicker plates and can go to 50% SOC as often as you like. Lead Acid will last 200 cycles I think, my LiFePo4 will cycle from 100% to 5% 3000-5000 times.
Do an internet search for Trojan battery, they are the gold standard of Lead Acid Deep Cycle.
I think for the price of these my 15 year old, 6'6", 260lb offensive linesman (my son) can just carry more batteries to wire in parallel or row the dang boat faster!
That's better, but the brand I prefer is Battleborn. Not sure if they have a small 50AH, but they have 100 and larger. They are made in USA from round cells so cost a bit more but I swear by them. I have 7 years and counting on mine with no sign of deterioration.
That is ridiculous price, I paid about that for 100AH. Check with Battleborn dealer just outside Toronto I think. I am going out but will try to find name when I return. Send me a message so I don;t lose track of this.
