I've been trying to find the best battery solution for an arduino project for a while now. Thus far I've been powering the Arduino and two LED light strips with 12 Volt 1.2 Ah Lead Acid Batteries. This has worked out pretty well, but with each re-charge the battery life depletes a great deal.
So, I've found the following Lithium Ion solution:
but it will require that I include a voltage regulator in my circuit because anything above 12 volts will damage the lights (and the Arduino probably).
Does anyone see any glaring errors in the way the voltage regulator is positioned?
Also, what advantage do Nihm batteries offer over Lead acid, if any?
Lastly, I'm going to be traveling with this rig to europe and just wanted to make sure - there shouldn't be a problem with any of the electrical components as long as I used a grounded convertor right?
The 'Mega' has a maximum input voltage of 20V, so it doesn't need the regulator.
Your schematic is a bit strange. It implies that you are putting the capacitors in-line with the power supply. They should be from the input or output of the regulator to ground.
Do you have a charger to go with your LiPo battery pack? You have to be careful charging them, you cannot treat them just like lead acids or they can catch fire!
So, here is my suggestion..
NiMh are much more tolerant, so you could use a battery holder that takes 10 x 1.3V AA cells, each of about 2.2Ah which would about double your battery life. At 13V for fully charged cells, you probably would have a similar voltage range to your lead acid battery, so I doubt you would need the voltage regulator.
These batteries could be charged with a regular AA battery charger. Buy a good charger and you should get a lot of duty-cycles out of them.
The 'Mega' has a maximum input voltage of 20V, so it doesn't need the regulator.
No, that's the short term limit, the recommended max input voltage (for reliable cool running use) is 12V - in reality the more load you have (and with the Mega it could be a lot of peripherals) the lower the input voltage you want to keep the regulator from cooking the board (its surface mounted).
NiMH batteries have the advantage over lead acid in that they don't contain lead (heavy) and they don't contain acid (leaks)! They are much easier to charge too.
No, that's the short term limit, the recommended max input voltage (for reliable cool running use) is 12V
Very true, in general stick to 12V.
For her project, she's only driving the base of some Darlington's that get their collector current direct from the PSU, so she'd be okay. Certainly fine at the 13V from 10 MiMhs if she goes that way.