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Author Topic: MAX voltage level for 5v arduino question  (Read 588 times)
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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?
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After a full charge I am reading 5.7v at peak charge...

Load?  Open circuit?
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Open circuit
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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.
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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.
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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

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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
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