I know, but it would be nice to eek out the last little bit if I can :)

My current choice is a impel buck converter and run the caps in series to g=
ive me 4F at 8.1v. This is about as much space as I can get to fit the powe=
r storage in and gives me a couple of hours of run time. I am sure I'll fin=
d more improvements as I go, but if I could stumble over a buck-boost that =
would fit, it would be nice to unlock those last few joules.=20

On 2013-10-21, at 10:56 PM, RussellMc <apptechnz@gmail.com> wrote:

> More anon mayhaps, but you can get about as close to zero as you'd want b=
y
> running a boost winding for an ancillary supply for the IC.
> Alsop, note that cap energy is largely exhausted at near zero volts as
> energy capacity is proportional to V^2..
>=20
> For say 8V max, energy % at 1V is (1/8)^2 ~=3D 1.6%.
> At 2V you have (2/8)^2 =3D 6.25%
> And at 1.8V (1.8/8)^2 =3D~ 5.1%.
>=20
> Getting the last few % is "nice" but odds are you will gain more by
> attention to design - lower track losses, good connections, capacitor
> quality ... .
>=20
>=20
>      Russell
> --=20
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