HEQ5 Pro Power Supply

[Kunama]

Could someone point me in the right direction for a power lead & power supply for the HEQ5 Pro.

I have stepped out of the 18th century and given up on the manual mounts and bought one of these new-fangled GoTo mounts but it came without a power cord. I'm thinking along the lines of either a power pack or a compact 12v deepcycle battery.

I'll only be using it to drive the mount, no AP gear, laptops etc (I'm a few years from that sort of technology still)


Cheers,
Matt

[LewisM]

Matt, it's just a simple DC jack into the mount, and then either a mains AC/DC coverter or a simple cigarette light plug plugged into a battery pack.

At home, I use an AC/SC power supply from Steve Massey or directly from a 12 VDC battery pack (Supercheap Auto, around $90)

[LewisM]

I can send you a cig plug to jack lead if you want it - I have a couple spare, maybe even one of the u-beaut 20 metre ones (run it from the car)

[glend]

Matt you can't be in the 18th century if you have a syn-drum kit!

Its pretty easy to find 12v plug packs. If you get an Ac/dc plug pack just make sure it is rated to output 2amps (at least that's what the NEQ6 draws). That will allow you to run if off an AC extension cord at home (with the AC/DC plug pack. Plug is standard 12v+ on centre.

As far as the battery system is concerned, I am using a little 12v 7AH alarm system battery and it will drive my NEQ6 for an hour or two before needed a recharge. You can buy all sorts of power leads from Jaycar, even ebay. The big jump start battery packs will work as well but they are more expensive than an alarm system battery.

I see plenty of people at dark sites with generators, and massive batteries with special boxes and multi connectors etc but you don't need all of that.

[Kunama]

Thanks Cathy, Lewis and Glen, I'll call out to Jaycar this morning and pick something up. I have a 12v alarm battery so will try it out.

Thanks Lewis for the offer to send one, I should be able to get what I need at Jaycar.

[big-blue]

To add to Glens good advice, make sure you get the plug with the 2.1mm centre.
It looks almost identical to the 2.5mm type, which does also work but has a sloppy fit due to the slightly larger hole, and can plague your setup with momentary re-sets (due to momentary breaks in contact) as the mount slews and the cable moves.
This is another example of the lack of standardisation in astro gear.
Skywatcher and Celestron mostly us a connection with a 2.1 pin, whereas Meade uses a 2.5 ! ( & the 2.1 plug is then no good for powering Meade gear)
cheers

[Merlin66]

I've been using 20Ah 12V gel cell batteries (mobility scooter/ golf buggy type) for the past seven years. They are still as good as new!
I also use the voltage convertor 12v to 15V for both my HEQ5pro and NEQ6pro mounts.
Highly recommended!

[glend]

Ken, why 15 volts?

[julianh72]

I'm surprised that a 7 Ah battery is only "good for an hour or two" before needing a recharge. How many amps does the HEQ5 mount draw on average?

My Celestron SLT mount (which is smaller than the HEQ5) draws a bit over 1 amp peak (when slewing at maximum speed), but less than half an amp when tracking. I use a 7 Ah battery that I got from Jaycar for about $25, and it is good for at least 8 to 10 hours of use between charges. (Probably even more - it hasn't gone flat on me yet!) Jaycar sell a whole range of sealed lead acid batteries (SLA), including 20 Ah or more, as well as the chargers that you need.

[Merlin66]

The HEQ5 pulls between 1 and 1.8A depending on the slewing...
The mount can take 15V. This ensures that you never get a low voltage condition and drop-out.

[Kunama]

Thanks again all for the tips :thanx::thanx:

This is the plan: Tell me if it sounds OK

Small Pelican case with 2 x 12v 7 Ah sealed 'Alarm' batteries installed (connect in parallel) with 2 x 3amp fused and LED lit switched outlets fitted to the side of the case.

small powerpack/charger fitted inside the case with 240v inlet on the side of the case.

Howzat :question::question:

[Merlin66]

IMHO if your going to put such effort into building the "power pac" I'd use 20Ah batteries...also the charger must be a triple stage electronic charger for maximum battery life.

[Kunama]

Thanks Ken, The reason for going with this idea is that I already have the case, the 2 batteries & a small triple stage electronic charger, I would only need the outlets, inline fuses, switches and wiring.
Can you think of any wiring issues to look out for ............ I will solder and cover joins with heatshrink tubing

[Astro_Bot]

No need for switched outlets at 12V - no arcing or sparking at such low voltage and current, and unused sockets are air gaps, so no power drain at all. Better to get sockets with flip cap to keep out the dew (for corrosion resistance more than anything). eBay sockets are cheap and often include an inline fuse of 10 or 15A - I wouldn't recommend a smaller fuse as it's only short protection you need - there's no appreciable human shock hazard at 12V. Even with 10 or 15A fuses, you might occasionally need a spare fuse - I blow one every now and again.

You can get a bigger battery with more capacity with less space and weight, rather than two batteries in parallel. Just something to consider.

Right angle connectors at the mount stay in better - 2.1mm/5.5mm tip positive is right (as mentioned above).

If possible, get AGM (absorbed glass mat) batteries - they last longer and are typically roll-over and drop proof. With AGM, you won't need a ventilated box and can seal it "permanently" (though you might want to get into it anyway to change a fuse).

Size batteries based on long life, which means not discharging below 50%, though you can go to 60% to "juggle" sizes and capacities without too much harm. If you don't care about long life, then fair enough.

Any other plastic container would be cheaper and probably just as good as a Pelican brand case - "small" battery boxes at eg. Repco are cheap (around $25) and still pretty big. I suppose that's a matter of taste more than anything else.

I've used cheap 240V-to-12V power supplies off eBay without issues, but some people report problems, so check the reputation beforehand. "De-rating" is a good risk reduction strategy, e.g. double the current capacity you think you will actually use.

Just in case you were thinking about it, don't use a normal power supply as a charger! If you get a charger with "supply mode" you may be able to use it in lieu of a separate supply. But keep in mind that "supply mode" won't be suitable for charging, so resist the temptation to wire it up permanently - your charger needs to "sense resistance" from the battery and nothing else to run it's charging program properly. A 3-stage charger is the minimum.

And one last one: don't recharge through the outlet sockets - you'll probably blow a fuse.

Edit: Just saw the last couple of replies - I started typing before they were posted.

[Kunama]

The charger I have is the Sinergex Nitro 1000, a 4 stage charger with overload, rev pol, temp protection in a waterproof casing.
up to 14.4V @1A fully automatic battery monitoring
The case is Kinchrome Safe Case, medium.

The case size determines max battery size, a 12V 12Ah AGM should also fit well. This should be ample for my current usage pattern. I tend to pick a target and stay on it for some time rather than slewing all over the sky.

If this works out well, I will build a maxi version at a later stage.

Thanks for the input so far, I will post up pics once I get some work done on it (most likely Monday now)

[Kunama]

Nearly finished ..........

Kinchrome Safe case 30cm x 22cm x 13cm internal

12V 12Ah AGM Battery
Power fused at case
1 x Auto Lighter socket
1 x "Merit" type socket
1 x USB socket (yet to be installed)
1 x red LED switch (yet to be installed)
12 V 4 stage Sinergex Nitro Charger with isolator switch (prevents battery drain while still connected)

Fuse protected curly cord for HEQ5 with right angle 2.1mm plug.

Base of box lined with 35mm thick EVA foam, with cutout for battery.
Once the USB and switch are fitted all terminals will be covered to prevent any shortages.

[sharpiel]

That looks lovely Matt.

If you were to buy and build from scratch what would it cost?

[Kunama]

Thanks Les,
I was given the charger free when I last bought a new battery for my car. The case was from Bunnings on special for $29 some time ago, the wiring and plugs $30, battery sells new for around $40.

So my cost was $100 but a new setup would be probably double that.

I have a few of these cases, some being used for eyepieces, another for the Herschel Prism Kit etc. The big advantage for me is they stack well and are easy to carry.

[julianh72]

It's a lovely build, but it does highlight that sometimes its simpler and cheaper to just buy something straight from a Chinese factory, such as this jump starter from Jaycar for $100:
http://www.jaycar.com.au/productView.asp?ID=MB3692

Specifications:
• 17Ah SLA battery
• Work light
• 12VDC cigarette lighter socket
• Includes mains adaptor for recharging at home
• Includes cigarette lighter cable for in-car charging
• LED battery level indicator

(And it'll start your car if the battery dies!)

[Kunama]

I agree Julian (I actually have one of those $99 Jaycar jobs, but being retired, I have to keep busy somehow :shrug:)

[Astro_Bot]

... except that the batteries in jump starter packs are not deep cycle, are very cheaply constructed and usually don't last (compared to a deep cycle battery).