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Second Skywatcher Power Tank failed

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The title is self explanatory I hope! My second Skywatcher power tank which is about 18 months old has packed up despite not being overused or allowed to run flat. I wouldn't mind paying over the odds for the Power Tank if it was a reliable product, but frankly to see the second one go so quickly is ridiculous.

I've decided it won't be third time lucky with the Power Tank and would like to replace it with a suitable portable power supply of the type that Maplins or Amazon sell. Can anyone recommend one?

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A mobility scooter / leisure battery with a good smart charger would be a better option than a jump start battery. Deep cycle leisure batteries are designed for the type of use we put them through - long periods of discharge rather than the short high current bursts of jump start batteries. This is why power tanks / jump start batteries tend to fail.

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The title is self explanatory I hope! My second Skywatcher power tank which is about 18 months old has packed up despite not being overused or allowed to run flat. I wouldn't mind paying over the odds for the Power Tank if it was a reliable product, but frankly to see the second one go so quickly is ridiculous.

I've decided it won't be third time lucky with the Power Tank and would like to replace it with a suitable portable power supply of the type that Maplins or Amazon sell. Can anyone recommend one?

I have long given up on the power tank idea. For powering mounts, cameras, etc you'd need a battery with high capacity that can discharge a steady current for a long period of time. Most of the so called starter battery type packs are designed to discharge a huge amount of current at short bursts start up an engine. My SW power tank does not hold charge for long any longer and when I opened it I was surprised to see the battery was a deep cycle variety but it had still packed up. I cut my losses and bought a Tracer 22Ah lithium polymer battery that does last a nights work with the mount or the dew strip.

Alternatively you can go  for a  marine grade lesiure battery of about 100Ah and a suitable charger but the problem for me with this type of the battery is the bulk and the weigth.

Regards,

A.G

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I have a Tracer 14 Ah it runs my GoTo Dob for quite a long time, i have'nt run it down out of the green charge sector and it has around 16 hours use between charges, it will also fit in a pocket (bag of sugar size) weighs about the same as the bag of sugar and come with connector and charger, i think its worth the bit extra very please with it......

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Mine failed this week too, though to be fair it has been neglected for the last 6 months.

Checking out alternatives this evening - so will probably post soon asking for advice!

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They are built from a small standard lead acid battery and the reality is they are not suited to the described purpose of running a scope. They are not right for a long slow steady drain and they should not be drained beyond 50%. So we satnd in the dark with one doing a long slow drain and we drain them until things stop stop going whirrrr.

You need a deep cycle battery of some specification, they are designed for a similar use to that which we put a battery. However you may need a different charger for one.

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Going against the trend my Halfords ones are both fine, the first (smaller capacity) is 10yrs old now whilst the second (a 34Ah) is also good but it was only used for a few months before I installed a mains-powered cable to the pier. I've flattened the older one several times and it still recovered. Maybe it is more to do with the quality of the components used - both the battery and the charging circuits?

ChrisH

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Going against the trend my Halfords ones are both fine, the first (smaller capacity) is 10yrs old now whilst the second (a 34Ah) is also good but it was only used for a few months before I installed a mains-powered cable to the pier. I've flattened the older one several times and it still recovered. Maybe it is more to do with the quality of the components used - both the battery and the charging circuits?

ChrisH

I think you maybe right Chris, when I opened my SW power tank up I noticed that the boards were of low quality like some of the Maplin's DIY project bits and pieces and some of the components were secured using hot glue or similar. Not very impressive.

A.G

Edited by lensman57

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To my experience there are two things that will kill any battery.

1) To leave the battery flat.  Always recharge after use!

2) Overcharging. Power tanks often have simple chargers that has no voltage control. Use a "smart charger" with both current and voltage control!

/Thomas

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These jumpstarter batteries rebranded for portable astronomy are simply not the right tools for the job. You need a deep-cycle/leisure/caravan/boat/ battery, whatever you want to call it, but not a jumpstarter.

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I use either a 65amp leisure battery or my weapon of choice is a commercial grade booster pack, 5 years old charged nth times and still does a complete night.You could always get a lithium battery from the radio control community(I use them in helicopters and planes), they don't overcharge £ (no pun intended) but get a good charger (lithium charger) as they require special voltage limited chargers.I have never felt the need however as the extra battery weight isnt an issue given my scopes are heavy so a little extra does'nt cause an issue. 

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Anecdote suggests that the commercial powertanks are not that reliable. They try to use cheap small batteries, which are prone to failure, when what they should use are leisure batteries but leisure batteries cost more. On the other hand leisure batteries have a lot more capacity. The price per Ah for a 75Ah leisure battery is a lot less that a 17Ah SLA battery. I'm using a 14Ah SLA at present and expect it to die at which point a leisure battery will replace it.

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I have a Maplin jump starter that died and replaced the rubbish battery with a Tracer 40ah one, chucked out the tyre pump and jump leads to make room but you still get to keep the USB sockets ,lighter plugs and the light etc, you could no doubt do the same with the Skywatcher one and fit as big a battery in it as you can.

Also a lot lighter than a leisure battery if you're planning to hump it across any fields.

Dave

Edited by Davey-T

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I have a Maplin jump starter that died and replaced the rubbish battery with a Tracer 40ah one, chucked out the tyre pump and jump leads to make room but you still get to keep the USB sockets ,lighter plugs and the light etc, you could no doubt do the same with the Skywatcher one and fit as big a battery in it as you can.

Also a lot lighter than a leisure battery if you're planning to hump it across any fields.

Dave

That sounds interesting Dave, but I when did a search the price for that battery showed up as £549.00. Is this near what you paid for it or have I got something wrong here with the price?

Regards,

A.G

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I use a Tracer 14Ah it will do around 16 hours on a 300P GoTo Dob before the green gauge lights get down to the last one, came with a mains charger, car charger and cigarette socket connector....

http://www.firstlightoptics.com/batteries-powerpacks/tracer-12v-14ah-lithium-polymer-battery-pack.html

20140914_1641551.jpg

Edited by Tinker1947

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That sounds interesting Dave, but I when did a search the price for that battery showed up as £549.00. Is this near what you paid for it or have I got something wrong here with the price?

Regards,

A.G

I think it was about £350.00 but it seems to have disappeared from their site, you don't need that big a one, I needed it for mount, dew heaters, camera , laptop etc.

Dave

post-21198-0-64736400-1410711962_thumb.j

Edited by Davey-T

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Thanks for the suggestions. Not sure whether I want to spend the extra money on a lithium ion battery. 

Would something like this be a decent replacement:

http://www.maplin.co.uk/p/5-in-1-power-station-with-air-compressor-a67hy

"Built-in 12 V 17 Ah rechargeable sealed lead acid battery" or you could buy a 17Ah SLA battery and smart charger for less than that, which would also be more future proof as if (when?) the battery dies you can replace just the battery.

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