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RE: Eclair ACL voltage for ACL motor?
Sounds good. Also the in-line voltage monitor is a great idea. With
a 14.4v pack, the camera should still be running nicely when the pack
is at EODV, so I would change batteries when the monitor reads 12v
with no load (camera off.) If you wait for the out of sync light to
come on, the pack will be discharged a bit too much for good
maintenance.
BTW, that out of sync light is cleverly hidden where no one can see
it when it comes on! I removed the yellow lens (it just unscrews) and
had our machinist make a brass boss that would screw in to its socket.
The boss was hollow and had a socket on top to hold a 1/8 inch fiber
optic that wrapped around the finder and terminated in a hole in the
rubber eyecup. This way the out of sync light appeared in the
periphery of the operator's view. Worked like a charm and saved my
bacon a number of times. Our replacement motor uses an LED and I
simply rewired it into the eyecup.
Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614
cinesota@yahoo.com 10/11/01 4:28:08 PM >>>
Thanks Wade! That was just the answer I was looking for.
I will build smaller on-camera packs for use in fairer weather and
build
some larger off-camera packs that I can keep in my pocket when it's
cold. Either way I will up the voltage to 14.4v. I'm also
researching
good reconditioning chargers that can handle mutiple voltage, nimh
cells. If anyone has any recommendations please send it to me.
I bought a nifty power cable that has a voltage monitor built in so I
can monitor just how much juice is going to my camera. I will keep
everyone posted on my results.
-Ray
Wade Ramsey wrote:
ACL-ers:
Yes, the single speed English motor can be operated safely on
higher
than 12v. In fact, it is wise to do it. The CP conversion is the
same old motor with improved electronics (better regulation,
variable
speeds) and a flywheel to lessen any tendencies to flicker from
speed
variations. But the motor itself is unchanged. We used a 14.4v.
battery for it and got more magazines per charge. To get the most
power from the motor you need to keep the voltage up.
The End-of-Discharge-Voltage for a Nicad is 1v per cell. A 12v
battery has 10 cells, so its EODV is 10v. But the ACL motor is
going
to struggle (probably fail) trying to pull a 400 ft. mag up to
sync
speed on 10v. You'll probably have change batteries before the
first
one is actually technically discharged. A 14.4v battery's EODV is
12v, since it has 12 cells. At the end of its charge it is still
giving the motor its rated voltage.
NiMH cells generally put out twice the Ah of current that a Nicad
will give and that is a big advantage. However, NiMH doesn't
basically have the ability to give a great amount of current under
heavy load like a Nicad does and this affects its cold weather
performance. In Minnesota you may be at a disadvantage if you have
to
shoot in very cold weather and can't keep the battery warm. Also,
NiMH cells have a much higher self-discharge rate (running
themselves
down on the shelf) than Nicads (which are bad enough already), but
manufacturers seem to be finding a way to correct this. The ones
I
bought recently are dramatically improved in this regard, at least
in
the AA size I got for a small flash unit. Anton-Bauer claims to
have
solved all these problems in their Hytron NiMH packs, but warn
that
the charging controls have to be much more stringent than for
Nicads.
If you recell your batteries with NiMH you may have much shorter
total
life for the battery, due to improper charging with your old
charger.
For more info than you probably want to know, see Anton-Bauer's
web
site and click on battery handbook. The specific page is:
www.antonbauer.com/handbook/handbook.html
Wade K. Ramsey, DP
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