T o d d P a t t i s t wrote:
"Ian Johnston" wrote:



Mind you, since capacitors in the 10F range are available, not too
expensive, and about the size of an AA battery, it might be worth
using one. Just be careful folks - Very Nasty Things Indeed will
happen if you short one of these suckers. Stick a discharge resistor
across it for a start.


You also want to worry about the initial inrush current. My
initial setup seemed to work fine during testing and
installation. On the next day, however, the fuse blew when
I turned it on as the capacitor charged.


No kidding. The capacitor recommendation was an ugly hack recommended
to try to do something about an ill-considered rules change, which
really wasn't an actual rules change. It's been confusing people for
years. Following is from a 2001 posting from the manufacturer:




Hello All,

after successful reinstalling my newsreader, some advice from us as the
manufacurer of the Volkslogger would be useful (yes, I know, we should be
more active, or active at all, at this newsgroup, and from now on we will
....):

The circuit diagram in the VL manual is only a sample. In some cases
(depending on the inner resistance of the Capacitor, if is an array of
goldcaps or a real capacitor), a serial resistor is needed to avoid fuse
blowing (but not too much resistance because of voltage drop). The
Volkslogger itself draws about 120 miliamps at 12 V.

You can also use an array of 10 AAA accumulator cells.

Background:
------------------
When the Volkslogger got approval, the said requirement was not part of the
standard. We tried to build it into our firmware during the time, but we
didn't know which time frame should be used and if it would be approved by
IGC/GFAC and decided to let it as it was.

Until now, no firmware upgrade introduced this requirement, but now that it
is a wishfull ("should") part of the standard, we will think about it over
winter time. But be sure, we have much other things to develop (new
ultralight plane flight information system with color map etc., see our new
homepage www.ulfis.de )

I hope I helped you a little bit...

best regards

--
Georg Garrecht
Garrecht Ingenieurgesellschaft, manufacturer of the Volkslogger
Germany
www.garrecht.com