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Power Packs for HEQ5 Pro

Astro_Baby

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Astro_Baby

Astro_Baby

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I recently upgrade my HEQ5 to GoTo and last night was the systems first test after two rebuilds of the HEQ5 to iron out snags.

Happy to say the mount worked perfectly and alignment was a breeze - the mount had stunning accuracy placing every target almost dead centre on the EP.

One small problem though - the GoTo slewing totally killed my 7aH battery pack after about 4 hours. This wasa bit of a syrpise because at Salisbury last year the pack kept the HEQ5 powered plus a hairdryer most of the two nights plus the torch for use in the tent and still had powere when it was taken home. Admittedly that was a non-GoTo mount.

Anyway the question is if the mount will exhaust a 7aH batter pack in four hours how long with a 17aH pack keep it running do you think ? Double the time ? If its only double then I probably need two packs for star parties or else buy a mains system for star parties and just one 17aH for use when I am mobele normally.

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Astro_Baby

Astro_Baby

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Deffo the slewing which eats the batteries - I tested it out at home with an AVO plugged in and the mounts pulling a lot of power.

Admittedly last night I was slewing more than I probably would under more normal cirucumastances as I was suffering 'kid with new toy' syndrome and wanted to put the rig through its paces in an attempt to see all 13,000 objects in the Synscan database in a single sitting :):):):)

I guess I really wanted an idea of how long a 17aH battery would hack it for under cold conditions and moderate amount of slewing required for public outreach type stuff.

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blinky

blinky

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If you had an AVO on it how much current was it drawing? A 7ah power pack will (In theory) supply 7amps for 1 hour or 1 amp for 7hours or any combination of that. The same stands for the 17aH pack, you can supply 17amps for an hour or 1 amp for 17 hours.

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Astro_Baby

Astro_Baby

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It pulls about 1.7amps in slew - its variable because it depends where the scope is going - ie if its having to slog 'uphill' from the horizon to the zenith even when its balanced well it draws more than if its 'down'hill'

Its hard to gauge power consumption though because I have no idea of the time the slews really take or how many slews I'd realistically make at someting like a public outreach event where the scope may have to do a 'grand tour' type of thing.

My bet is, based on last night, a 17aH is really only going to hack it for a maximum of 8 hours worth - that may be enough. I guess I'll have to buy and try.

I'm inclining to this one http://www.maplin.co.uk/Module.aspx?ModuleNo=224871 cos it has a power inverter to drive stuff like my heated tongs and normal hairdryer though power invertiors are notoriously inefficent.

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m.tweedy

m.tweedy

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I agree not cheap. However I have recently bought a 85 AH leisure battery for approx £65 and already had a charging unit (bought at Aldi for approx £12). The kind man at the auto shop where i bought it also wired up some triple cigarette lighter sockets to attach directly to the terminals. looks great and will last for a loooooooong time even with everything attached.

This is possibly a way you could look at.

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dph1nm

dph1nm

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It pulls about 1.7amps in slew - its variable because it depends where the scope is going - ie if its having to slog 'uphill' from the horizon to the zenith even when its balanced well it draws more than if its 'down'hill'
Any idea what the tracking current is? When these mounts first appeared there was lots of talk that they drew ~2A whatever they were doing, tracking or slewing.

NigelM

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jgs001

jgs001

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A little more info on the Maplin powertank. With guiding running, and the adjustments PHD is making, the powerpack run time drops to between 2 and 2.5 hours, that's with it only powering the HEQ5.

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Astro_Baby

Astro_Baby

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I didn't test the mount in normal tracking mode - but when the mount stopped slewing and was in tracking the current draw dropped to almost zero - I doubt the mount would pull so much when its just tracking personally.

I find it odd that some pople report the Maplin power tank with its 17aH as not lasting too long. My 7aH tank lasted almost 4 hours and that was with a serious amount of full speed slewing.

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Merlin66

Merlin66

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I've been there done that!!

I find an ideal solution for the HEQ5Pro (> 5 hours) and the LX200 ( the same!) as well as the various cameras ( DMK-firewire etc) and the Laptop ( Acer) is to have a series, in my case three, 20Ah gel cell batteries; the individual weight is a couple of Kg and I can charge them independently with a electronic charger in a cuple of hours. The ones I have are now two years old and still gong well.

You do need a good electronic charger to make these things last.

Well worth the investment. I found the 85Ah camping batteries toooo big to easily handle and the Power Tanks died quickly...

My 2.5c worth................

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AndyKeogh

AndyKeogh

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I didn't test the mount in normal tracking mode - but when the mount stopped slewing and was in tracking the current draw dropped to almost zero - I doubt the mount would pull so much when its just tracking personally.

I find it odd that some pople report the Maplin power tank with its 17aH as not lasting too long. My 7aH tank lasted almost 4 hours and that was with a serious amount of full speed slewing.

Well I have one of these and I will be taking it back to Maplin since I cannot get anywhere near 17AH out of it.

I have run controlled tests after charging the beast for 2 days and left it running one dew heater. After 7 hours the voltage had dropped to 11volts and it had delivered 5.72Ah. I.E only 33% of advertised capacity.

I will ask Albert if a capacity test report is available for the Astrotank.

Andy

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brianb

brianb

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turned out to a problem with the charging unit.

I think this is a common experience - both variants of problem appear to exist i.e. not turning off when fully charged (which wrecks the battery) and not fully charging (which helps to wreck the battery by discharging it more fully than is wise).

But I can't see the logic of the 7AH unit. In my experience a computerized mount is likely to take 2A maybe more under fast slewing & dew heaters can take 3 to 4A. If you want to run a laptop PC, cameras etc. off the rig then that obviously adds even more load. And, when the temperature is below "room temp", batteries don't have the same capacity. I'm using a deep cycle 70AH "leisure" (camping/marine) battery, this is adequate, still fairly easy to lift & recharges (at 7A) a lot quicker than the car jump start based power packs (0.5A). Strongly recommended - battery life is the last thing you should be worrying about on the odd occasion when you do get a decent observing session.

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oceanheadted

oceanheadted

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...

I'm inclining to this one http://www.maplin.co.uk/Module.aspx?ModuleNo=224871 cos it has a power inverter to drive stuff like my heated tongs and normal hairdryer though power invertiors are notoriously inefficent.

Astro Baby

The inverter is only 200W so you're not going to get much hair drying for that are you?? Our hair dryer is rated at 2kW.

Cheers

Alan

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