Comments by E S.
18 January 2016
Thank you for the quick and thoughtful response! I am also unsure as to how finicky these fans are; supposedly they are standard 5V small computer fans but probably super cheaply made and I don't want to risk overheating or ruining the batteries.
I hadn't thought of having two parallel systems... It sounds like a good idea if parallel batteries is a bad idea. I think I will go with that plan instead. Thanks again!
16 January 2016
Hello Jan, thank you for the informative article.
I thought initially that I knew what I was doing, but your comment about "not using parallel unless you know what you're doing" threw me off a bit.
What I want to do is run a group of six 5v fans, each drawing 120mA, from a battery pack (so the total draw should be 120x6=720mA). The run time needs to be 3-5 hours.
My original plan was to use two packs of 4 NiMH AA batteries (2500mAh each), in parallel. 8 batteries total.
By my calculations, that would provide a total of 4.8v and 5000mAh to the fans. So the run time would be 5000/720 = 6.9 hours at absolute maximum.
Do I have it correct? Many thanks!