Power Problem


Terry Johnson <tjohnson@...>
 

Dan, great desciption of the problem you are having. I have found that the AP control box cannot take an electrical surge whatsoever. Any device that you power up after you have already powered up the AP control box may cause the keypad to freeze. When I powered on my PC for autoguiding later, after I had completed polar aligning using the keypad, I found often enough, my keypad would freeze.
 
With respect to the Dew system, the Dew system cycles on an off as part of its design and will also cause the keypad to freeze.
 
If I am not using my Dew system, I have found that I can eliminate the keypad freezing by powering up the PC before I power up the AP control box which eliminates the surge. I have not had the keypad freeze when I power up in this order.
 
I am thinking of getting a smaller battery to power the AP control box and a larger one to power PC, CCD, Dew System, Inverter, television, air conditioner, espresso bar, heating blanket, ice maker, and so on.
 
Thanks again for your note...Terry Johnson

----- Original Message -----
Sent: Tuesday, June 27, 2000 6:22 AM
Subject: Power Problem

Terry,
 
Some comments on your power problems that are pending further testing on my part.
 
I started experiencing problems at the Arunah Hill Winter Star Party in January.  This is a real winter star party, with temperatures in the 10-20 degree range.  I was using a Kendrick 17ah that had serviced my needs since last summer.  I have the 155f7/600E GTO combination with Kendrick heaters (6" for ota, 2" for eyepiece, 1.5 for StarBeam finder) off one controller.
 
To maximize the observing time in cold weather, I did a lot of slews.  After about 2 hours (or less) the keypad would either freeze or reset. Like most people, I get nervous when my expensive electronic equipment has power problems.  To get by, I turned off my dew heaters, which is not part of the master plan.
 
Subsequent tests at home showed that the Kendrick battery could not power both scope and heaters in cold weather for long observing periods.  The combination of a depleted battery, a slew, and a heater duty cycle would *eventually* create an undervoltage spike below the Control Box minimum.
 
I purchased an Ultima D750U deep cycle battery (65AH, 750 CCA, 124min Reserve Capacity).  If you haven't heard of AGM batteries (http://www.optimabatteries.com/main.htm), this is state-of-the-art stuff. Not cheap, and not dainty.  The Reserve Capacity specification means this battery can feed a constant 25A drain for 124 minutes!
 
Anyway, I now had the reasonable expectation of powering both mount and heaters for a night of observing.  I was up at Arunah Hill three weeks ago, and I still get resets.  This was after about two hours in much warmer weather.
 
I've seen the comments about accessories and dual batteries.  I haven't seen mention that "accessories" also means dew heaters.  Either this has been overlooked, or assumed to be a non-issue.  What I've seen leads me to believe that the dew heaters should be powered separately.  Personally, I think this is a bit much.  I have more than enough battery to power both functions through one night, even in cold weather.
 
I've set up a test rig to measure both voltage and amperage.  My next round of tests will be at the Summer Star Party in August.  I'm going to use the AGM battery to power the mount, the Kendrick battery for the heaters.  Although this means I have to carry both batteries, I want the problem to go away.  If I can't find something that's not working properly, then this will become a permanent configuration.
 
I'll post my results when the facts are solid.
 
djc
 
BTW, the Control Box power cable appears to have a weak link at the input fitting.  The center contact on mine has lost it's spring tension. I field repaired it with electrical tape.  Since AP is not considering an immediate change in the fitting, I'm ordering a spare set of cables (two cables = $114.00).  After the SSP, I'll send the defective to be repaired.
 
 
 
 
 
 
>>> Terry Johnson <tjohnson@...> 15 Jun 2000 20:02:27 -0700 >>>
Marj, I spoke with Roland about a problem I was having with my 600GTO mount. The problem centers around the GTO keypad. I have explained the problem below in more detail. Would you please see that he gets this information. I will also provide a printed copy when I send you the equipment he requested.


Mark Jenkins <markj@...>
 

on 6/27/00 7:00 PM, Terry Johnson at tjohnson@... wrote:


I am thinking of getting a smaller battery to power the AP control box and a
larger one to power PC, CCD, Dew System, Inverter, television, air conditioner,
espresso bar, heating blanket, ice maker, and so on.
Let's see... You will be the one with the 50ft Winnebago complete with 10'
automated dome and hydraulic ram to "set your pier", satellite dish and 64"
projection TV at the Nebraska Start Party... right?

oooh, wouldn't that be cool! Hook up an STV to the 64" projection TV and
display dso's for all to see! Now that's sidewalk astronomy!

;-)

Just sitting here like a little kid at Christmas waiting for my 400GTO, 48"
pier and oodles of mounting hardware to arrive!

--
Clear Skies!

Mark Jenkins
markj@...
http://www.pcsincnet.com/astronomy/


rck <rkuberek@...>
 

Terry and group,

This is exactly what I do--two batteries, one 60AH deep cycle just for the
scope and one 100AH deep cycle for PC and Camera. Putting a dew
heater together with the scope on one battery (large or small) is just too
much. With just the dew heater (on the large battery) I get around 12.25
volts, but when I add the scope I get only around 11.75 volts and the keypad
freezes on GOTO often.

Regards,
Bob K.


Terry Johnson wrote:

I am thinking of getting a smaller battery to power the AP control box and a larger one to power PC, CCD, Dew System, Inverter,
television, air conditioner, espresso bar, heating blanket, ice maker, and so on.


Mark Jenkins <markj@...>
 

I have a 90AH deep cycle battery and man is it heavy! I plan on using this
for just the 400GTO. I want to get a 100-140AH deep cycle for Laptop, CCD
and Dew heater. The 100-140's are even heavier!

I found a nice solution to this bulky problem at Lowe's this last weekend.
It is a heavy duty large, black "tool box" on wheels. It has a metal handle
with a rubber comfort grip that slides into the box when not in use. I plan
on dedicating 1/2 of the bottom to power. I will have various outlets and
switches on the side of the box to accommodate several 12v DC, 2 to 4 120v
AC and of course a master switch for each circuit as well as a charger
hook-up. A self-contained, rolling power source that will be able to be
charged at any standard 110/120 household outlet. The rest of the box will
be foam lined and used to carry all the other equipment including the mount.

It also has a pull out top "tool carrier" that I plan on lining with foam
and utilizing as a potential eyepiece holder. The only downside to the top
carrier is its color. Yellow I will probably paint it black or red.

The top is flat and will make a nice table for star charts, red gooseneck
lights etc. It is really only limited to one's imagination what can be made
from this box.

It about $40-$50 if I remember correctly.

Nebraska bound I am!


--
Clear Skies!

Mark Jenkins
markj@...
http://www.pcsincnet.com/astronomy/



on 6/27/00 9:36 PM, rck at rkuberek@... wrote:

Terry and group,

This is exactly what I do--two batteries, one 60AH deep cycle just for the
scope and one 100AH deep cycle for PC and Camera. Putting a dew
heater together with the scope on one battery (large or small) is just too
much. With just the dew heater (on the large battery) I get around 12.25
volts, but when I add the scope I get only around 11.75 volts and the keypad
freezes on GOTO often.

Regards,
Bob K.


Terry Johnson wrote:

I am thinking of getting a smaller battery to power the AP control box and a
larger one to power PC, CCD, Dew System, Inverter,
television, air conditioner, espresso bar, heating blanket, ice maker, and so
on.


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Jeffrey D. Gortatowsky
 

All these power problems... you'd figure Roland, Marge, and Chuck would have
long since run into all this and solved the sensitivity if it's truely very
sensitive.

This 'sounds' like a problem that would drive people nuts. Are most of you
experiencing power problems? A quick survey. How do most of you power your
mounts? Just a one liner is informative enough.

This and polar alignment seem to be real bug-a-boos with GTO mounts. At
least on this group! <g> Or is it just a case of a vocal/wired few?

Jeff "New 400 GTO owner" G


rck <rkuberek@...>
 

"Jeffrey D. Gortatowsky" wrote:

All these power problems... you'd figure Roland, Marge, and Chuck would have
long since run into all this and solved the sensitivity if it's truely very
sensitive.
Actually, I was wondering if there is a some kind of regulator that
could be put on the circuit that would guarantee that the voltage
does not drop below 12 (for some period of time).

Bob K.


David A. Silva <dasilva@...>
 

Jeff

The battery stuff is not unique to AP mounts, which I found out last
weekend. I have a 17 AH gel cell that I've been using for my GM8 +/-
Kendrick's dew heater. Last weekend as soon as I plugged in the DH, the
GM8 would not slew. My battery has probably aged enough that it doesn't
have the oommph it used to.

I had read last year that many floks advocate separate batteries for
mount electronics. I didn't see the point, but I now do.

-David ( saving up for a GTO )

On Wed, 28 Jun 2000 08:54:10 -0700, Jeffrey D. Gortatowsky wrote:

This 'sounds' like a problem that would drive people nuts. Are most of you
experiencing power problems? A quick survey. How do most of you power your
mounts? Just a one liner is informative enough.


Chris Spratt
 

I use the 17amp Kendrick battery (standalone). I feel it is a bit small and to
ensure reliability I have to charge it before and after every observing session.

Chris. Spratt


"Jeffrey D. Gortatowsky" wrote:

All these power problems... you'd figure Roland, Marge, and Chuck would have
long since run into all this and solved the sensitivity if it's truely very
sensitive.

This 'sounds' like a problem that would drive people nuts. Are most of you
experiencing power problems? A quick survey. How do most of you power your
mounts? Just a one liner is informative enough.

This and polar alignment seem to be real bug-a-boos with GTO mounts. At
least on this group! <g> Or is it just a case of a vocal/wired few?

Jeff "New 400 GTO owner" G

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