Hello everyone,
I`m making big project and I need a powerful supply for it. I used to power my arduino mega with 6 x AA batteries (9V - 1500 mAh) but I need more and started wondering what could work.
What I prefer is 8-10V power supply with about ~1 Ah or more. What kind of power supply you would recommend?
I thought about Li-Ion cell pack, which gets ~8V and ~8000 mAh. But then charging it comes as next problem, its expensive and not convenient. Then I thought maybe a power bank, but then most of them gets 5V or type usb 3.0 gets to 12V and its a bit too much I think, because with this output it becomes hard to control my robot, its gets really sensitive with motor control. And yet, how works arduino powered with power bank?
Any help will be appreciated. Thank you!
For how long exactly do you want to power your arduino anyway?
If charging Li-ion was a problem then how did you plan to charge your AA's ?
I would suggest you use a powerbank with 5v output and then use a boost converter to bring it to your desired voltage. Charging problem is solved automatically if you use a powerbank, also you get to choose your preferred capacity.
I don't think it's a case of how long does he want to power the arduino, but how much power the motors/servos are using. Speaking on that, the OP didn't mention what, other than a robot.
I'm taking it the motors are what require the higher voltage, and require several amps stalled. A little more information might help people from having to guess
Noobian:
For how long exactly do you want to power your arduino anyway?
As long as possible. It is more convenient if you don't need to charge your robot every run.
Noobian:
I would suggest you use a powerbank with 5v output and then use a boost converter to bring it to your desired voltage. Charging problem is solved automatically if you use a powerbank, also you get to choose your preferred capacity.
That would be nice. I could get my wanted 9V easily from 5V but the problem is the auto shutdown. I need to do a little research about it.
I am a big fan of LiPo.
Here is a charger for under $13 that can handle 2 and 3 cell packs (7.4 and 11.1V) and plugs in to the wall.
That same company has a few different batteries to choose from.
hollowltu:
That would be nice. I could get my wanted 9V easily from 5V but the problem is the auto shutdown. I need to do a little research about it.
You won't face an auto shutdown problem if you draw more than 100mA. Your project needs much more than that so you won't have to worry about it. 
So I guess that's the best option, you could easily buy a 20,000mA power bank and it would power your project for a loong time, and the best part is that you don't have to worry about buying a separate charger.