I am running a project off of 2 x (4 x AAAA(300mAh) 1.2v in series) in parallel, to achieve 4.8v 600mAh. After a full charge I am reading 5.7v at peak charge, I am using an Extech EX330. Will this cause issues with my arduino 5v micro?
bamboosam:
After a full charge I am reading 5.7v at peak charge...
Load? Open circuit?
Open circuit
5.7V is under the absolute maximum voltage of 6.0V. The battery voltage will drop under load. Were I in your shoes I'd connect the micro and recheck the voltage.
I charged up 3 x AA NiMh batteries. Got 4.26V. Then put a 50 mA load on it (like a Uno connected up). It dropped to 4.22V.
Extrapolated to 4 batteries that would be 5.67V under no load, and 5.63V under load. It's a bit high, but within absolute maximum ratings.
I think you will find that fully charged NiMh cells will only hold that higher cell voltage for a pretty short duration and then settle into a fairly flat discharge voltage for most of their duration until taking a pretty sharp decrease in cell voltage near the end of their capacity. Ni-cad cells have a similar 'flat' discharge curve, unlike lead acid or Li-po cells that have a pretty linear discharge voltage rate.
http://www.atbatt.com/pics/fckeditor/image/lr44-discharge-chart.jpg
Lefty
I have used 4xAA rechargeble batterys before, measured at about 5,5v, and did not have any problems with that so far
i even use them to connect through the arduino connector, but passing through the on board regulator means you lose about 1 volt (tested on my mega1280)
hope this helps