Stealth Pilot wrote:
On Fri, 07 Aug 2009 21:52:49 -0700, Ron Wanttaja
wrote:

it is indeed a pity that tinytach cant be given the hint that a
replaceable lithium battery would see an aviation market open up for
them. two lithium batteries so that they can be replaced individually
without loss of power would seem a simple mod to make the tach really
useful.

They're losing the vast aviation market? :-)

From what I can see, the product is mostly aimed at the industrial
engine market, especially rental equipment. They know it's being used
on aircraft engines, but I suspect the number of actual installations in
airplanes is pretty small. Probably mostly in the ultralight world,
since anything with a Lycoming or Continental is already going to have a
tach drive.

As far as the non-replaceability of the battery, we'll see when the time
comes. The case is sealed plastic, so it should be possible to cut it
open. If nothing else, adding an external pack for a battery shouldn't
be tough.

It looks like Tiny Tach did, in fact, recently upgrade its commercial
tach from using external power to using solely the internal battery.
The version of their installation instruction that's online shows a
battery connection....

http://www.tinytach.com/tinytach/ima...structions.pdf

When I ordered the tach, I thought I'd have to supply power to it.
Since I thought I'd have to deliver power to the meter, I figured I'd
add a small voltmeter as well, since my voltmeter is a short-arc analog
gauge mounted just above the floor (tough to read).

I ordered the Martel Tools QM-100V....

http://www.martelmeters.com/pdf/QM_100V.pdf

....and this is one slick device. Self-contained LCD voltmeter in a
package the size of two postage stamps, less than a quarter inch thick,
surface mounts using a 7/32" stud on the back of the package. Didn't
use it, since the tach didn't need power after all, but I'll probably
add it the next time I rework the power.

Ron Wanttaja