I'm almost done with my home automation project (website, voice recognition, alarm clock and 7" touch display) and now I need it to run 24/7 even during power outages. But I'm horrible at eletronics, so I need a "plug and play" solution.
My needs are:
-It should last at least 6 hours (my system uses something about 500ma for the arduino and 500ma for the display), so as I understand it has to be at least 6000ma, maybe 4500ma can be enough.
-I want to let it pluged all the time, if power is on use power and recharge the battery if needed, if power is out use the battery.
-Have to be in the 4,5v - 5,5v range because of the display limits.
Paul_KD7HB:
How many 5 volt batteries have you found so far?
Paul
Hahahahah, that's the first problem...
But I saw some 4v and 6v that I tought I could try to regulate to my needs, but the problem is, as I already mentioned, that I'm not any good at mounting complex circuits, so I would need something already assembled.
I googled "Arduino Battery Backup" and found a few options (like this one), but they weren't designed to supply 1A @ 5V.
Are you sure you really need that much? Your current estimates sound really high. Maybe they are the peak currents required as opposed to the average? How did you determine your power requirements?
Also, if you are using 1A @ 5V, the battery current is going to be higher satisfy conservation-of-energy laws. Assuming your voltage converter if 90% efficient, your battery current is going to be (5V * 1A) / (3.7V * 0.9) = 1.5A. If you really need to supply that current for 6 hours, you'll need a 9Ah battery. For the electronics that you've described, that sounds huge.
Paul_KD7HB:
I have several Arduiono projects that run 24/7/365 off 12 volts. what is so special about 5 volts?
Paul
The display that I'm using can't be powered directly from the Arduino because it draws to much current (500ma) and has a input voltage limited to 4,5v to 5,5v. And I would need the battery / charger to power the arduino and the display.
BigBobby:
I googled "Arduino Battery Backup" and found a few options (like this one), but they weren't designed to supply 1A @ 5V.
Are you sure you really need that much? Your current estimates sound really high. Maybe they are the peak currents required as opposed to the average? How did you determine your power requirements?
Also, if you are using 1A @ 5V, the battery current is going to be higher satisfy conservation-of-energy laws. Assuming your voltage converter if 90% efficient, your battery current is going to be (5V * 1A) / (3.7V * 0.9) = 1.5A. If you really need to supply that current for 6 hours, you'll need a 9Ah battery. For the electronics that you've described, that sounds huge.
For the Arduino I'm just guessing, since my multimeter is broken and I still waiting the replacement, and I acctually don't know even if I know how to measure it.
I'm using an Arduino Mega with an Ethernet Shield and an Easy VR 2.0 Shield (Voice Recognition) and a 433mhz transmitter at 3.3v.
And for the display I'm using the information from the datasheet.
Hmm, it seens pretty straight forward, just what I wanted, and as a pro it seens very compact.
Just plug a 5v 1A charger, and has 2 usb outputs (1A and 2,1A)...
I couldn't find anywhere, but probably there is no problem lefting the charger pluged all the time right?