dew prevention on big dob

[Daz Type-R]

thanks again for help.

so if I just used skywatcher tank for the goto and a 38 A/H battery for the heaters that be it. but how do I connect dew controller to 38 A/H battery? as it has a cigarette-lighter type plug.

lol told you crap at this stuff

 

tony

 

Ideally it would need to be the other way around, the 38 a/h battery for the mount and the 17 a/h battery for the dew system.

 

But this then means you need to start carrying around 2 batteries, 2 batteries need to be kept charged etc etc.

 

All the kit weights enough as it is, I think you need to look at getting shot of the 17 a/h power tank and just look to get a bigger sized leisure battery (something like what a caravan / motor home would use but perhaps not as big).

 

As for connecting it, out of everybody on here I have the most simplest connections ever, battery, crocodile clips which lead to a female cigarette socket, and a plastic box to put the battery in lined with 1" thick foam.  Simple.

 

But do take a look in the DIY section here on EMS, there are some fantastic examples of battery packs, wiring, carry cases etc, some fantastic stuff or just go down the cheap and cheerful route I do, box, foam, battery, crocodile clips, and your sorted.  You can make it as simple or as complicated as you like!

 

But do think about your battery size, that is the most crucial thing in the pot.

[tuckstar]

Just been looking at this as it happens.

http://www.leisureoutlet.com/caravans-and-motorhomes/12v-Socket-Adaptors-and-Extensions_2/Streetwize-Auxiliary-12v-Socket.html?gclid=CjwKEAjwns6hBRDTpb_jkbTv1UYSJACBhberoIl6fsBR2VLcFIwR17HSwWPLJOid2YFQOACmviyeXBoCmADw_wcB

http://www.ebay.co.uk/itm/like/191244306150?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&device=m&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

And I brought one of these for use at home.

http://www.amazon.co.uk/gp/aw/d/B00159RAT4/ref=mp_s_a_1_1?qid=1412431419&sr=8-1π=AC_SX110_SY165

Edited October 7, 2014 by tuckstar

[+Ibbo]

that first link Andy I had trouble with and ended up shorting out up at Belper

cheap and nasty

I would not recommend it

[tuckstar]

Thinking I'd want something bit more robust anyway. Thanks for the heads up.

[+seven_legs]

can anyone recommend a leisure battery that would be suitable for my needs.

and again thanks everyone

[Tweedledee]

For very rough figures I would allow a total of 1 amp for all your proposed dew control and 2 amps for your goto mount. So 3 amps should cover everything.

 

At 3 amps, a 17 amphour battery should theoretically last 5.7 hours and a 38 amphour 12.7 hours.

 

Cold temperatures can cause the battery to lose power much more rapidly, however, you will probably use the dew controller to reduce the power usage slightly, and the dob goto mount will only be drawing full power intermittently, when finding objects. This means that the power usage will be very variable and unpredictable and may therefore give considerably better or worse battery life than those calculated above. Making an insulated box for the battery will help in cold conditions. The Tracer Lithium Polymer batteries apparantly perform well in temperatures down to minus 20 C (at which I would not be performing). They are one quarter the size and weight of equivalent capacity lead acid batteries, but are about 10x the price.

 

As suggested by others, it would be far better to get a battery well on top of its job, ie; the largest capacity you can afford. Otherwise if you want to try and get away with a 17 amphour battery then be prepared that you may be lucky and it lasts all night, or may pack up after just 3 or 4 hours.

 

Give your 17 amphour a good trial and then you will know if you need to spend more money.

 

If you don't build a battery box, these connectors are really cheap...

http://www.ebay.co.uk/itm/12V-Female-Car-Battery-Clip-To-CigarLighter-Socket-Plug-Connector-Adapter-Fuse-/331089015543?pt=UK_In_Car_Technology&hash=item4d167172f7

Edited October 7, 2014 by Tweedledee

[+seven_legs]

thanks a lot. that helps.