=20 > On Tue, Feb 5, 2013 at 2:11 PM, Josh Koffman > wrote: > > Hi all, > > > > As part of the project I'm working on, I'm trying to figure out the > > best way to power it via batteries. In previous projects I've used > > small LiIon and LiPo cells, which have worked quite well for my > > purposes. My applications are typically medium-low drain (say, under > > 300mA max), and the cells I've gotten have worked well, powering the > > device for the desired amount of time before requiring a recharge. > > > > For my current project, I'm thinking about switching to AA NiMH cells. > > The advantage here is that high capacity rechargables are readily > > available (~2500mAH), and if all my cells end up flat, I can switch to > > alkalines with no problem. The problem here is that I was hoping to > > use 4x AA batteries, which while taking up a good amount of room in a > > beltpack style case, is manageable. Due to the cell voltage of a NiMH > > cell, I don't think I'm going to get enough input voltage that I can > > then regulate to a nice 5V. I could go up to 6 cells, but it starts > > taking up a lot of space. > > > > I'm curious what other people have done in this situation. I could go > > to two LiIon or LiPo cells in series, but the cylindrical cells are > > too large for the capacity I'm looking for, and rectangular cells > > aren't easily swapped out (ie no one makes a holder for them). > -----Original Message----- > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf > Of Marc Nicholas > Sent: 05 February 2013 19:17 > To: Microcontroller discussion list - Public. > Subject: Re: [EE] Battery Power Conundrum >=20 > Hi Josh, >=20 > I might be stating the obvious here, but wouldn't this be an ideal scenar= io for > a switching boost regulator? Josh will need a buck-boost to get a regulated 5v supply from either 4 NiMh= (4.8v nominal) or 4 Alkaline cells (6v nominal, slightly more with fresh c= ells). A SEPIC topology with coupled inductors will allow a common ground = and higher efficiency. Mike =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .