Telescope Reviews: Same battery for mount and dew system?

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rflinn68
scholastic sledgehammer

Reged: 03/09/12

Loc: Arkansas

Same battery for mount and dew system?
#5514437 - 11/11/12 12:54 PM

I bought the ScopeStuff dual outlet cigarette lighter adapter with digital voltage gauge to use to power my CG5 or CGEM mount with my DewBuster controller. I have since been told NOT to do this because it could damage my mount. Is this true? Is anyone else doing it this way? Thanks

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wolfman_4_ever
Pooh-Bah

Reged: 07/15/11

Loc: El Segundo, Ca, So. Cal

Re: Same battery for mount and dew system? new

[Re: rflinn68]
#5514650 - 11/11/12 03:25 PM

how could it damage your mount if you are using the proper fuses inside the cig adapter? Won't pull enough current?

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rflinn68
scholastic sledgehammer

Reged: 03/09/12

Loc: Arkansas

Re: Same battery for mount and dew system? new

[Re: wolfman_4_ever]
#5515117 - 11/11/12 09:31 PM

Quote:

how could it damage your mount if you are using the proper fuses inside the cig adapter? Won't pull enough current?

I dont know, that is my question. I believe he said voltage spikes could damage the electronics in the mount.

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Arizona-Ken
Pooh-Bah

Reged: 08/31/08

Loc: Scottsdale, Arizona

Re: Same battery for mount and dew system? new

[Re: rflinn68]
#5515335 - 11/12/12 12:10 AM

Absolute wackery.

I have used dew control on my CG5 and CPC mount for years with no problem.

Arizona Ken

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wolfman_4_ever
Pooh-Bah

Reged: 07/15/11

Loc: El Segundo, Ca, So. Cal

Re: Same battery for mount and dew system? new

[Re: Arizona-Ken]
#5515353 - 11/12/12 12:22 AM

The current will fluctuate when it's pulsing but it's in the tenths range.. nothing you will notice..

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DwainM
member

Reged: 07/30/12

Loc: Rogers, AR

Re: Same battery for mount and dew system? new

[Re: wolfman_4_ever]
#5515611 - 11/12/12 08:33 AM

+1 to Dave's comment.
I've been using two small lawnmower style batteries with volt and amp meters connected and all you see is a pulsing current when the controller is duty-cycling the heaters.
I bought into the same line of thought but I've seen no evidence of anything that would cause a problem with the mount.
Dwain

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rflinn68
scholastic sledgehammer

Reged: 03/09/12

Loc: Arkansas

Re: Same battery for mount and dew system? new

[Re: DwainM]
#5515648 - 11/12/12 09:16 AM

Anyone else heard of this? OK, I will name drop, I was told this by Dr Clay Sherrod. I'm sure he knows what he is talking about. He told me "Do NOT use the same battery for your mount and dew control...." It sure would be more convienent for me to use just 1 battery. That is why I bought the dual outlet cig plug.

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DwainM
member

Reged: 07/30/12

Loc: Rogers, AR

Re: Same battery for mount and dew system? new

[Re: rflinn68]
#5515668 - 11/12/12 09:39 AM

Wow. My first post and I kicked the shin of a legend....
I'll be popular.

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BigC
Carpal Tunnel

Reged: 09/29/10

Loc: SE Indiana

Re: Same battery for mount and dew system? new

[Re: DwainM]
#5515865 - 11/12/12 11:54 AM

The only problem I see is the dew heaters could drain the battery so that the voltage becomes too low for reliable mount operation.

I would be surprised to see voltage spikes measured across the battery terminals .

If powering a goto mount,dew heaters,and active cooled cameras a large capacity battery pack is a very good idea.Some of the booster packs have only a 7AH battery inside ,better is one with a 15AH or 17AH .It will cost more and weigh more but will be more reliable.

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rflinn68
scholastic sledgehammer

Reged: 03/09/12

Loc: Arkansas

Re: Same battery for mount and dew system? new

[Re: BigC]
#5516205 - 11/12/12 03:25 PM

Quote:

The only problem I see is the dew heaters could drain the battery so that the voltage becomes too low for reliable mount operation.

I would be surprised to see voltage spikes measured across the battery terminals .

If powering a goto mount,dew heaters,and active cooled cameras a large capacity battery pack is a very good idea.Some of the booster packs have only a 7AH battery inside ,better is one with a 15AH or 17AH .It will cost more and weigh more but will be more reliable.

I use a full size car battery

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rflinn68
scholastic sledgehammer

Reged: 03/09/12

Loc: Arkansas

Re: Same battery for mount and dew system? new

[Re: DwainM]
#5516215 - 11/12/12 03:29 PM

Quote:

Wow. My first post and I kicked the shin of a legend....
I'll be popular.

HAHA! Its ok, I kinda set you up for that...Sorry. I'm still not convinced of this though which is why I asked the question here. Since I use a full size car battery maybe it will be ok? I just dont want to take any chances with my CGEM DX and CG5 mounts. I should try to get back in touch with him again and get some clarification on this though it seems many havent had a problem.

By the way...Welcome to Cloudynights!! I see you are right up the road from me

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rflinn68
scholastic sledgehammer

Reged: 03/09/12

Loc: Arkansas

Re: Same battery for mount and dew system? new

[Re: rflinn68]
#5516241 - 11/12/12 03:48 PM

Ok, I just sent him another email so hopefully I'll get some explaination on it soon. Actually I was hoping to hear what I have so far (that it is fine to use 1 battery). It sure would make things easier on me. I'm also hoping Uncle Rod will chime in with his thoughts.

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jrbarnett
Eyepiece Hooligan

Reged: 02/28/06

Loc: Petaluma, CA

Re: Same battery for mount and dew system? new

[Re: rflinn68]
#5516267 - 11/12/12 04:03 PM

I always use a single battery to run my mount (CG5, Atlas, CGE, Nexstar SE) and dew controller. Never an issue in decades. I use a splitter as you describe. I also use quality batteries (Optima deep cycle blue tops).

- Jim

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rflinn68
scholastic sledgehammer

Reged: 03/09/12

Loc: Arkansas

Re: Same battery for mount and dew system? new

[Re: jrbarnett]
#5516297 - 11/12/12 04:32 PM

Quote:

I always use a single battery to run my mount (CG5, Atlas, CGE, Nexstar SE) and dew controller. Never an issue in decades. I use a splitter as you describe. I also use quality batteries (Optima deep cycle blue tops).

- Jim

Good to hear Jim! I'm hoping I've been worrying about it for nothing and can get back to using 1 battery.

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DwainM
member

Reged: 07/30/12

Loc: Rogers, AR

Re: Same battery for mount and dew system? new

[Re: rflinn68]
#5516337 - 11/12/12 05:10 PM Attachment (22 downloads)

Thanks! It’s good to be here.
Actually my battery box is rather convenient with the two lawnmower battery set up.
I’m not doing AP (yet) so my power needs are pretty low.
Here is a picture of how both batteries fit neatly inside of one Group27 battery box.

Dwain

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rflinn68
scholastic sledgehammer

Reged: 03/09/12

Loc: Arkansas

Re: Same battery for mount and dew system? new

[Re: DwainM]
#5516502 - 11/12/12 06:46 PM

Just heard back from Dr Clay...I believe I'd rather be safe than sorry. He said I WILL eventually end up with a voltage spike of 40 volts or more if running more than one thing off a single battery. Some of you may be lucky but lucky has NEVER been associated with me so I think I will take his advice.

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Lord Beowulf
Pooh-Bah

Reged: 10/13/08

Loc: Cedar Park, TX

Re: Same battery for mount and dew system? new

[Re: rflinn68]
#5516676 - 11/12/12 08:28 PM

The funny thing here is that the most likely thing to cause a voltage spike like that are the motors in the drive itself. The heaters draw a good amount of current, but shouldn't be highly inductive. However, every time a motor cuts off there's a nice big reverse EMF spike. Diodes on the drive circuits are usually used to damp that down, and similar tricks could be used on the heater coils. There's no doubt that the more things that are connected, the higher the chance that something could go wrong, but I doubt those chances are all that high. Likewise a lot of people have the same fear about AC supplies and although I've never had a problem with any of mine, that doesn't mean it's not possible. Still, I suspect that most electrical damage to control circuitry in mounts has been due to ESD from the user in the nice dry cold air. And of course the ESD can damage a power supply and then cause havoc on what it's powering too!

Beo

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mgwhittle
scholastic sledgehammer

Reged: 08/24/11

Loc: Chattanooga, TN

Re: Same battery for mount and dew system? new

[Re: rflinn68]
#5516681 - 11/12/12 08:30 PM

I have no knowledge of battery operation so I am curious how you get 40 volts out of a 12 volt battery?

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rmollise
Postmaster

Reged: 07/06/07

Re: Same battery for mount and dew system? new

[Re: rflinn68]
#5516704 - 11/12/12 08:40 PM

Quote:

Ok, I just sent him another email so hopefully I'll get some explaination on it soon. Actually I was hoping to hear what I have so far (that it is fine to use 1 battery). It sure would make things easier on me. I'm also hoping Uncle Rod will chime in with his thoughts.

It IS possible to introduce some noise from the dew heater, which COULD bother a computer, I reckon. But the only problem of this sort I have ever had with a dew controller is creating interference on the Stellacam or Mallincam video cameras when I've run them and the heater off the same battery.

Still, I run the scope off a different battery to avoid _potential_ problems and to keep the battery up enough to run the go-to scope reliably. Many go-to mount problems caused by low voltage there are...

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Lord Beowulf
Pooh-Bah

Reged: 10/13/08

Loc: Cedar Park, TX

Re: Same battery for mount and dew system? new

[Re: rmollise]
#5516716 - 11/12/12 08:48 PM

Quote:

Still, I run the scope off a different battery to avoid _potential_ problems and to keep the battery up enough to run the go-to scope reliably. Many go-to mount problems caused by low voltage there are...

Yeah, following up on my last post, both switching power supplies and motors have the general behavior that the lower the voltage of the power supply, the more current they draw. The higher the current, the higher the back EMF when things switch. So actually a low battery can cause more problems than a fully charged one, and not just due to the dipping supply.

Beo

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