Arduino with battery back-up

Hello,

I've researched for a good half day on this topic, I have found lots of information about it and found out this is very possible and would like to dive into this. I just wanted to bring up my own forum topic to ask questions specifically about the idea of powering my Arduino mega with the typical D/C jack then having run an alternate power as back up, to test out potential power outages and what not.

Ideally, I would like to know if I have any restrictions to using a mega and ethernet shield with this.

Also, I plan on using based on research, Battery Booster. I'm looking for advice, input, details I should be considering. I need help also discovering an idea on what circuit or logic I need to use to toggle the power sources.

Thanks in advance for any suggestions or tips.

While not nearly as small, I use one of these to power my Yun. It is about the same size as my plastic enclosure the Yun lives in. (Idk, like 3"x3"x1"?)

It has USB power in and USB power out. It charges itself and powers external devices when it sees power input, otherwise it just powers external devices. So far it has provided me with hours of Yun time, and the indicators still show 100% charge. It is overkill for me but so damn convenient to have less cords on the desktop when programming and experimenting.

I know my link shows it as being spendy, but there are ENDLESS alternatives at all ranges of pricing. This one I actually got free when ordering a monitor.

–Dan

Although this is very cool, I like the idea. I'm open to a variety of price range as I'm in an explore stage of my project but I'm also concerned on how I will be able to toggle between my main power supply which is the 9v Dc Jack plugged in, Versus when i need the battery power to kick in. If both power sources are plugged in does the Arduino know which source to draw the power from? Will there be issues?

The product I linked to would be transparent to the arduino. There is no manual toggling. The battery pack is essentially ALWAYS powering the arduino, and only sometimes being charged (when you are powering it from a wall wart or USB port). Do you have a UPS for your computer? Imagine a tiny 5V version of that.

–Dan

So productively this product it sitting between my constant voltage being powered and recharged and if i lose power from my outlet say, this pack will keep power running through my arduino until the battery dies basically?

TLuck: So productively this product it sitting between my constant voltage being powered and recharged and if i lose power from my outlet say, this pack will keep power running through my arduino until the battery dies basically?

Exactly.

Theoretically, the Arduino favours DC jack power over USB power (if >7.2volt). It has an onboard mosfets to automatically switch between DC and USB sockets. Practically, I have heard of problems there. Time to dissect my Mega. Leo..

Edit: Measured things. Hope I have done it right. My Mega (other ones could be different) switches to DC socket power when that is more than 7volt. The onboard mosfet stops any current TO the USB socket. But does not stop current FROM the USB. When USB voltage is slightly higher (>0.1v) than the onboard's 5volt, it STILL USES the USB power.

dankgus -

Can you tell me how much that newegg unit weighs?

jboyton: dankgus -

Can you tell me how much that newegg unit weighs?

I just put it on my kitchen scale. 261g including the little 6" USB cable cable. It's rated at 10400mah so it's pretty serious overkill for what I am using it for.

dankgus:
I just put it on my kitchen scale. 261g including the little 6" USB cable cable. It’s rated at 10400mah so it’s pretty serious overkill for what I am using it for.

Thanks, 261g = 9.2oz. 50Wh is about the capacity I need. Any idea what the battery technology is? I need something that is cold tolerant as well as reasonably light.

I have no idea what battery technology it is using. I'll look close this evening to see if there is any indication on the outside of the housing or manual, and also if I can easily pop the end cover off.

--Dan

No indication on the device or in the manual. Here is the actual manufacturers page. Scroll down and it says the batteries are "LG grade A Li-ion polymer cell".

Thanks for taking the time to find that. I appreciate it.