constant 12v power?

[EzyStyles]

Hi,

On many occasions, I seem to run out of battery on my mount. Using a jump start kit 17amp which lasts only 8 hours. Gets quite frustrating when you are in the middle of imaging something at times and you have to call it for the night. Is there some sort of constant 12v power pack without recharging just simply plug the 12v cable into the mount and 24/7 on?

Thanks.

[GrampianStars]

theres 240V ac from the mains with an ac to dc inverter ;)
or get to "Cheap Auto Parts" and buy another 17Ah jump-start for $40

The trick is to recharge every day mine are on constant trickle charge in the day, until I put in the solar power :thumbsup:

[gbeal]

Eric,
I'm no sparkie, but the idea that a 17amp battery gets drained by a mount in one night seems starnge, no doubt someone else witrh the required nouse will pipe up here.
If you are near power, perhaps try what I use.
I have a pier in the ground, which I place the mount on. It is near the hanger, and in placing the pier into the ground I also laid a wire from the hanger to this pier. Inside I have an old computer power supply feeding 12 volts down this wire. At the pier end I have about 4 RCA plugs, facing down to avoid the weather, and I use these for dew heaters, etc. I have also one specifically for the mount. It seems to handle it all well. Of course, if you are not close to power, the idea falls apart.
Gary

[EzyStyles]

thanks for the tip guys. i think the reason why it gets drained so fast might be me looking for objects on my laptop screen scrolling around all the time :P

[RAJAH235]

Eric, you just need a much larger capacity battery.. or a very long extension lead... :P
More details on where you are setting up,(home)? & gear used etc req'd..
:D L.

[EzyStyles]

Hi thanks for your help. I setup my equipment in my backyard so it doesn't need to be portable at all. I run a long power cable for my laptop.

[toc]

Why cant you just use a standard plug pack? I use a 12V 1amp powerpack connected to a LONG extension cord for my Autostar controller.

[Starkler]

Ezy what you need is a regulated 12V power supply similar to the type used to power a CB radio. Jaycar or Dork Smith should be able to help you out.

[EzyStyles]

It happened again tonight! ran out of battery 1/2 way as i have been imaging for the past 2 days so the power pack wasn't fully charged. Call me crazy but i got grumpy and frustrated, drove down to my local K-Mart (24hours) and got myself another 17amp power pack (off the selve is fully charged) so I can continue with my imaging session tonight. K-Mart is refundable :P

A regulated 12v power is exactly what i need! never knew. Thanks Geoff.

How much are they btw?

[Starkler]

This one (http://www.jaycar.com.au/productView.asp?ID=GH1379&CATID=27&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=381)does 5amps and should be beefy enough.

[[1ponders]]

Geoff do you know of one comes with the trusty ol' ciggie lighter connector but the same amp?

[Starkler]

I dare say you would have to make a lead with a cig lighter socket connector on the end.

How long do these 17a/h jump packs take to recharge? I wonder if it can be used while plugged in to 240V and charging at the same time :shrug:

A multimeter to check the output voltage under charging conditions will tell if its safe to connect equipment.

[xstream]

Eric,
If you still want a portable battery supply, go to Super Cheap and get their 1200amp, 24Ah jump starter about $130.00 from memory.
I get peeved because it never seems to need charging even after a 6-7 hr session it still says full. I been trying to find out how long this thing will last. :lol:

[EzyStyles]

thanks for the reply guys. ouch $130 is quite alot for a battery pack but thanks anyway john.. due to my limited budget, i might just get a regulated 12v one instead from jaycar. thanks for the link geoff.

[Starkler]

It will be a switchmode type supply. Dont let any moisture or dew get on it or its likely to go bang and possibly take out your scope drives with it.

[Johno]

As someone here has already hinted, you must use a regulated power supply. Don't be tempted to use an ordinary plug pack. Their voltage will swing around depending on the load and some can go as high as 18v under low load. The Jaycar power supply mentioned earlier looks excellent and 5 amps should be more than enough for the mount and heaters etc as well (although the heaters are not so fussy about voltage regulation). One thing to be wary of though is that the cheaper switchmode power supplies like this one may generate a bit of RF noise but that is unlikely to bother you unless you have a very susceptable camera. If it's a problem just add a ferrite choke to the output power lead.

As far as the battery packs go the jump starter units are like car batteries and are not designed for deep cycle. They work best when they get a short hit (like cranking the engine over for a couple of seconds) then get charged again. Using them as we do for many hours at a time and possibly draining them will seriously shorten their overall life. The best sort of batteries to use for this application are those that are used in electric vehicles such as golf carts etc. They are designed for deep cycling. The problem with them is they are expensive. A 20 Amphour 12v battery will cost around $200. Then there's the charger and other bits and pieces and you'll have a very nice long lasting power pack but not much change from $300. $300 will buy you at least 6 el-cheapo jump starter power packs. The rule is keep them topped up, even if you only use your scope for half an hour, put the battery back on charge when you're finished.

John.

[33South]

I got a little 33ah beauty (ST-1233) for about A$100.00 (shipped from Perth, collected from Castle Hill) - but there's lots of others.

http://www.magellan-power.com.au/standardrange.html

Or talk to Bryan

Tel: (02) 9659 1004
Email: bryan.ford@magellan-power.com.au (bryan.ford@magellan-power.com.au)

[Johno]

That looks like a really good unit for that price.

[33South]

Yep, it is -
I just had to make a fused connector for it from Jaycar bits.

[toc]

Does this mean that slewing/tracking will be less accurate, or that their is potential for damage? (or both?)

I havent ever fried anything, but I have never had much luck with accurate GOTO's...

[alandee]

It always worries me when I run the extension cord outside overnight, the amount of dew around at the end of a night is disaster waiting to happen.

I've got a celestron power tank 17 ahr which is cool, it has a radio built in to annoy the neighbours all night and a killer halogen light for packup, but I've just contacted magellen for a 33 a hr to run the scope and dewie. Great contact. Thanks.

[Johno]

This depends on how bad/good the plugpack is. It also depends on how tolerant the mount electronics are to voltage and ripple. When you heavily load a power supply there is potential to get a 50Hz or 100Hz AC ripple component superimposed on the DC. This is more likely with an ordinary plug pack than with a regulated power supply.

It is definately possible that the plugpack could cause some slewing or tracking errors. When you are slewing with both motors running the plug pack is heavily loaded and therefore its output voltage will be at a minimum. (Perhaps there are heaters switching on and off too). If the load is too high the voltage will collapse and if it goes low enough it can definately scramble the mount's brains:screwy:. The same will happen if a battery goes flat. I've read several accounts of this on the CN forum. Try running your mount on a fresh battery and see if it behaves any differently.

Given that you have presumably been running the plug pack for a while it is unlikely that it will cause any serious damage.

I would strongly suggest using a regulated power supply instead of the plug pack. Otherwise why not just use a battery - no long cables, no worries about electrical noise, no voltage problems and it's portable?

John.

[EzyStyles]

just got myself a 12v regulated powerpack from d1cksmith. $65 . no more charging batteries for me :) lasted the entire night from 6pm - 6am.

cheers all.