Need REGULATED power supply for GOTO mount?

[shane shaw]

I have a meade 12" classic and was wondering what I need to buy and where I can get it, to be able to connect direct from the mains power to my scope........

Many thanks

[Starless (Brian)]

Originally Posted by AstralTraveller

This discussion is very timely as I'm about to buy a battery/battery pack of some kind.

My first battery pack lasted only a couple of years and I'm not too happy about that. I accept that I didn't treat it well - it was discharged too deep too often, not always kept charged and charged with a cheap charger. So I plan to do things right the second time. I will get ample capacity and use a good trickle charger. The thing that I'm now wondering about is whether an AGM or marine battery is necessary or will a standard gel cell do.

I know in the end it will be a value judgment but I'd like to hear as many points of view and share as many experiences as possible before parting with the $$$.

Oh yes, and I'd like to stir up the ant's nest .

thanks,
David

Astra Traveller,
Call me.
I can source your requirements
for batteries at wholesale though work.
Can also advise on chargers as a result
of a couple of years research into solar
power systems.
Be warned there is a critical mas of BS
available on the subject.

[Kokatha man]

Originally Posted by Starless

Astra Traveller,
Call me.
I can source your requirements
for batteries at wholesale though work.
Can also advise on chargers as a result
of a couple of years research into solar
power systems.
Be warned there is a critical mas of BS
available on the subject.

Hi Starless: just wondering why you haven't posted your own "critical mas (sic) of BS" on the subject to AstralTraveller in this open forum - it might help other people as well; which after all, is part of the whole philosophy behind IIS!

Myself and a number of other folks on this forum have stated their own professional qualifications/expertise re this subject: not that this detracts from the imortance/relevance of electrical/electronics hobbyists' contributions in any way!

It's just that open postings on the forum allow others to scrutinise and respond in a fair and objective manner to anyone's inputs (as Karl, for instance, has on mine on occassions.)

Certainly couldn't take more effort than a pm or email to an individual, and has the potential to be of wider benefit. As for the battery sourcing, you and me are in Adelaide and AT's in Wollongong: but if your sources extend interstate I'm sure others could also benefit.

Finally, putting your "research" and other appraisals/understandings up front, and able to be scrutinised, might actually help you brother: there is "a critical mass of BS" out there that only hands on, and significant practical experience can quantify; notwithstanding whether I (or anyone else) possesses specific professional qualifications.

Cheers, Darryl.

[Fox]

Originally Posted by AstralTraveller

This discussion is very timely as I'm about to buy a battery/battery pack of some kind.

My first battery pack lasted only a couple of years and I'm not too happy about that. I accept that I didn't treat it well - it was discharged too deep too often, not always kept charged and charged with a cheap charger. So I plan to do things right the second time. I will get ample capacity and use a good trickle charger. The thing that I'm now wondering about is whether an AGM or marine battery is necessary or will a standard gel cell do.

I know in the end it will be a value judgment but I'd like to hear as many points of view and share as many experiences as possible before parting with the $$$.

Oh yes, and I'd like to stir up the ant's nest .

thanks,
David

Ha! I'll second that, a very timely post. I have an LXD75 and was using a 12V/7AmpHr battery, it has only lasted about 2 years - I think I discharged it too much. Anyway, with recently adding a dew heater, 7AH is not enough, so I have been searching for some type of powertank. Dick Smith and Tandy have nothing really to suit unless I just get a jumper box. Should I just settle for a 12Amp/Hr sealed lead acid from JayCar and be done with it... ??? Fox

[Kokatha man]

Holy mackerel Fox - jist read dis flamin thread, or any of half a dozen contemporary/recent ones on IIS re power supplies.

Not to be too rude though; go to a flamin auto shop and get one of their jumpstart "powerpacks" - get one of at least 17Ah (preferably greater capacity) and choose a dandy little coloured number that tickles your fancy!!!!!

Cheers, Darryl.

[shane shaw]

it's ok if you know what you are doing but it is far more complex then just going to an auto shop. Plug the wrong thing into the scope and heh presto fry circuit board and $1000's to replace.

[Kokatha man]

Originally Posted by shane shaw

it's ok if you know what you are doing but it is far more complex then just going to an auto shop. Plug the wrong thing into the scope and heh presto fry circuit board and $1000's to replace.

No, it's not really Shane - but you will note that I advised Fox to read the other posts/threads on this subject (of which I've personally responded umpteenth times to basically the same questions.)

Fox has a mount that runs off a 12 volt DC supply: the two main considerations for him to take into account are (1) what is the current drain (in amps) of his mount and hence the size of the powerpack (ie capacity to deliver specific current over time - determined by the product's stated amp-hourage rating) and (2) the standard male take-off plug (that seems to come with every unit I've examined) being a "positive tip" type (presuming the Meade uses this polarity configuration.)

My comments were also a bit tongue in cheek; but all this (and much more) is available in current and recent threads to anyone, beginners included, to digest.

Cheers, Darryl.

[shane shaw]

hey Darryl no probs mate, I was just adding my 5 cents. Do you now if this mount is the ame as the Meade ? and if so do I need to same as what has been talked about here. I had an e-mail from a friend and he advised me to get a


You can run the scope from mains by using a 15V or 18 V Notebook PC adapter, needs at least 25 Watt, most adapters can supply aropund 70 W.
The Dick Smith M9698 works fine for me.


have a good one and thanks for the info mate.

[Dennis]

Originally Posted by Kokatha man

>snip
...(2) the standard male take-off plug (that seems to come with every unit I've examined) being a "positive tip" type (presuming the Meade uses this polarity configuration.)
>snip
Cheers, Darryl.

Just a warning for those newbie’s with Vixen gear – their tip is Centre –ve and outer +ve.

I use a Brother labeller to type and fix labels onto my mains adapters, stating the equipment it is to be used on, V, A and whether its centre +ve or –ve. Too easy to make mistakes in the dark, or under the feeble light of a dim red torch.

It seems that not all equipment is reverse polarity protected, which is a barbaric practice for modern astronomy gear.

Cheers

Dennis

[Kokatha man]

Hi Shane - not sure what mount you're referring to - there seems to be a bit missing in your post.

If the mount you're referring to is a Meade (as in your signature) then I can only repeat what I've said to Fox. If you use a battery with too little capacity (amp hour rating) you are, with any prolonged useage during any one night, effectively deep-cycling the battery; and as such the SLA (sealed lead acid) battery in the powerpack will have a more limited lifetime.

Reading your other thread, it seems your Meade employs a 12volt DC to 18 volt DC convertor to operate the mount: you state there "When the scope is on the Amps peak either at full or 1 less then full." - you will need to be a bit more specific here Shane: where is the amp meter in the circuit - is it part of the mount or have you placed one in series with any of the leads - and what exactly are the values (number of amps) showing?

As others have suggested, the battery powerpack could well be at fault; but you will also need to ascertain the convertor's functionability. A multimeter should determine if the output of the convertor to the Meade mount is 18 volts, but only an amp meter in line with one of the leads from the convertor to the mount will determine if it is delivering the required current; that or setting up a dummy load for the convertor to test it. (presuming the meter you mentioned doesn't do this!)

Another option (and I stress here, because I am not familiar with this particular mount's voltage and current requirements; to make absolute certain of what the mount requires) is to power the mount with a regulated 18 volt DC supply that can deliver the current required and see if that operates the mount as intended.

If the problem presents on two different batteries then I would be looking at the convertor - that or (shudder) the mount: presuming all the connections are fine.

Cheers, Darryl.

[Kokatha man]

Originally Posted by Dennis

Just a warning for those newbie’s with Vixen gear – their tip is Centre –ve and outer +ve.

I use a Brother labeller to type and fix labels onto my mains adapters, stating the equipment it is to be used on, V, A and whether its centre +ve or –ve. Too easy to make mistakes in the dark, or under the feeble light of a dim red torch.

It seems that not all equipment is reverse polarity protected, which is a barbaric practice for modern astronomy gear.

Cheers

Dennis

And take heed of Dennis's post!!!

[UniPol]

I have been using a Powertech 12V/4 amp switchmode power supply (MP-3240) for a couple of years now and it has performed flawlessly. It powered my 10" LX200 GPS, EQ6 and HEQ5 mounts with ease.

I also bought a Celestron Powertank17 at the SPSP three years ago and it hasn't missed a beat. It also ran the mounts mentioned. You know when the voltage drops on the Powertank because the LX200 starts to do silly things and the red LED on the EQ6/HEQ5 mounts start to blink when slewing. I know the Powertank wasn't cheap but it has been used to light up my house in a few blackouts, listen to the radio at the same time and use the siren to scare off the possums. The red light is too bright for star parties but a bit of red cellophane placed over it seems to work well.

Cheers,

Steve B

[shane shaw]

thaks darryl the manual states each bar on the ammeter represents 0.1 ampere(100 milli-amperes) of current draw. there are 10 led bars so does this mean 1 amp .

In additiaon to the battery I have now it shows that there is 50% charged and I haven't even touched it since last night. ?I think the battery has had it.

thanks

[Fox]

Kokatha, Shane etc. thanks for the info, no offence taken at all btw, I am just learning about different battery designs and their do's and don'ts. Yes, I have a Meade LXD75, Autostar and (now) Kendrick dew heater. I agree that the LXD75 is probably drawing about 1 amp, possibly 1.5 slewing, and the 3-inch Kendrick is another 0.7 amps or so. Yeah, I am in effect deep cycling my 7AH SLA in one session, which is not good. So I am after maybe 12AH or even 18 AH now, and I like the idea of a 'dedicated' powertank or jumper purely for the convenience (and gimmicks) of an all-in-one box. If I get a 12V jump starter - is connection directly to the jumper leads OK? Thanks, Fox.

[Zuts]

Hi,

Jump starters are usefull coz in a pinch they also start the car. Another option is a Jaycar deep cycle gel battery. I have one to power my SBIG. It's a lot smaller than the jumper pack but still weighty. I have a 26 amp hour one that cost me around 100 AUD. You would also need to obtain a cigarette lighter plug as well.

Paul

[Kokatha man]

Originally Posted by shane shaw

thaks darryl the manual states each bar on the ammeter represents 0.1 ampere(100 milli-amperes) of current draw. there are 10 led bars so does this mean 1 amp .

In additiaon to the battery I have now it shows that there is 50% charged and I haven't even touched it since last night. ?I think the battery has had it.

thanks

So the mount's ammeter reads 1 amp draw: not a very high current drain - and if you're saying the battery was fully charged up and not used, and has dropped to 50% charge overnight, then the battery's kaput, I would say! From where/what are you reading that the battery now is only 50% charged?

Try a set of jumper leads from the car battery if you can, just make sure the polarity from them to the convertor is absolutely correct! If this enables the mount/scope to function ok, then almost certainly your battery is the culprit!

[Kokatha man]

Originally Posted by Fox

Kokatha, Shane etc. thanks for the info, no offence taken at all btw, I am just learning about different battery designs and their do's and don'ts. Yes, I have a Meade LXD75, Autostar and (now) Kendrick dew heater. I agree that the LXD75 is probably drawing about 1 amp, possibly 1.5 slewing, and the 3-inch Kendrick is another 0.7 amps or so. Yeah, I am in effect deep cycling my 7AH SLA in one session, which is not good. So I am after maybe 12AH or even 18 AH now, and I like the idea of a 'dedicated' powertank or jumper purely for the convenience (and gimmicks) of an all-in-one box. If I get a 12V jump starter - is connection directly to the jumper leads OK? Thanks, Fox.

Fox - a jumpstarter/powerpack from an automotive place will have a cigarette lighter socket on the side of the unit: it will also come with a lead with a ciggy plug on one end and a standard plug that should fit into your scope mount (at least it does for the HEQ5 Pro.)

As said before, just as long as your Meade mount runs off 12 volts and the central tip of the plug that goes into the mount is the correct polarity. All the jumpstarter/powerpacks I've looked at have a positve polarity centre tip, which conforms with the HEQ5 requirements. Just check these things re your Meade requirements.

This lead with the ciggy plug and mount plug doubles as a recharger for the powerpack when you've only got your car to recharge from (ie for when there's no mains around.) If the Meade requires a negative tip plug on the mount you can convert them with a simple electrical alteration - getting a new plug from Dick Smiths etc. Get at least a 17 Ah powerpack.

[shane shaw]

1 last question. I am going to Dick Smiths today to pick up a power supply.

The battery pack I had that is no good has a charger and I was wondering after reading the specs if this could be used ?

model:wja - DC 12v 500
input: 240v AC 50Hz
output: 12v DC 500mA

now not being electrically minded I read this and think that it outputs 12v or 500 milli amps ? is this styrong enough or not enough and can I use it or wy can't i use it

thanks guys

[Kokatha man]

Originally Posted by shane shaw

thaks darryl the manual states each bar on the ammeter represents 0.1 ampere(100 milli-amperes) of current draw. there are 10 led bars so does this mean 1 amp .

In additiaon to the battery I have now it shows that there is 50% charged and I haven't even touched it since last night. ?I think the battery has had it.

thanks

Shane - this LED bar ammeter, is this on your mount or the powerpack? You need to know how much current (amps or milliamps: 1amp = 1000mA) as well as what voltage your mount requires.

So if the mount operates off 12 volts and draws (requires) 1 amp then you'll need a REGULATED 240 VAC (ie mains supply) to 12 volts DC power supply capable of supplying at least 1 amp at the output - preferably 1.5 to 2 amps. Even more if you're thinking of running other gear off the power supply. If your mount requires 2 amps to run then you'd be looking at something that delivers 3 or 4 amps at 12 volts output.

Voltage output (DC of course) sufficient current capability (in amps) and REGULATED OUTPUT are your criteria!

Cheers, Darryl.

[Kokatha man]

And of course the correct plug tip polarity of the plug from the power supply to your mount: ie, is it a positive polarity tip or a negative polarity tip that is required for your mount?