On 15/12/2010 08:38, RussellMc wrote:
>>>> Is my technically good 5 cell solution not acceptable?
>>>   From a physical point of view if you use four cells you can get a
>>> readymade holder in a variety of roughly cubiod shapes (personally I
>>> tend to preffer the elongated square style). I don't think i've ever
>>> seen a 5-cell AA holder for sale and if it did i'd guess a single layer
>>> would be the only reasonable option.
>>>   From a practical point of view batteries sold retail seem to come in
>>> packs of 4 and multiples thereof. So a four cell soloution neatly uses
>>> one pack of batteries. A 5 cell soloution uses 1.25 packs...
>> Exactly!
> I see nothing in the above which would discourage me from using it as
> a solution in your application. custom battery pack and interesting
> [tm]  shape or buying batteries other than 4 at a time would seem to
> be well down the list of problems that you are liable to face. Ifthese
> seem like major issues then you may not want to start on a switcher of
> similar capability.
>
> 5 cylinders will stack flat reasonably well with 4 x North-South and 1
> x East West, at the cost of 'a little customisation',
>
> 5 cylinders pack in a 3-2 truncated pyramid (not quite close packed)
> or 2-2-1 in a square with bump or 3-2 with the 6th space that would
> make it 3-3 (or 2-2-2) available for related stuff.

My thoughts exactly. To me this kind of stuff is what engineering is (at=20
least partly) about - finding your way round small (or large)=20
inconveniences using a certain amount of ingenuity - certainly a non=20
standard battery pack should not be something to "avoid" if it may well=20
improve the design in a technical sense.
It's no fun when it's all "done for you"... :-)   (and always limits you=20
to standard solutions)
That said, I understand the idea of having an initial plan and sticking=20
to it, but keeping an open mind and being willing to experiment is=20
always good (seems to have been the general theme with quite a few=20
suggestions here)

> Whatever.
>
> That said, the TPS63020 does look like a nice solution.
>
>

Yes, although it seems to only be available in a QFN package.. (though=20
not a reason not to use it, just a bit fiddly and some avoid them=20
completely - personally although I don't mind them too much, I might be=20
tempted to see if there is an equivalent in a more prototype friendly=20
package)

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.