Does anyone know how long this would power an NEQ6 for?

[nitram100]

http://www.firstlightoptics.com/power/tracer-12v-10ah-lithium-polymer-battery-pack.html

In my hunt for portable power I have narrowed it down to this. Would it last 4 hours for visual observing, a mix of tracking and slewing.

I saw the discharge document on the website, which indicates 30watt continuous load would give 3 hours until it dropped below 11volts but not sure how many watts my mount uses. 

Thanks, 

Martin

[Bizibilder]

That would last OK but you may be better off thinking of a leisure battery - say 85 Ah (or even 100 Ah) plus a charger/conditioner.  The combined price would be about the same and the battery would last much longer as it has a far greater capacity.  The only downside is that leisure batteries are quite heavy - OK for the garden but could be a problem if you cannot carry them.   I have used these folk and they were very good (usual disclaimer):  http://www.tayna.co.uk/Numax-Leisure-Batteries-S284-1.html

[VigdisVZ]

10 Ah is tiny for that price. I use a 19Ah car jump starter battery back for half that price. However if you're planning on adding cameras, laptops and heaters, you're way better off doing what Bizi said and get a real battry.

[nitram100]

How long can leisure batteries be left before they have to be recharged? Do they hold a charge for long? The thing that interests me about the battery from FLO is the portability and the ability for it to hold a charge for a long time. 

[VigdisVZ]

Top them off after each use and during downtime every 2 months and you're ok.

The battery jump starter is stronger, cheaper and still portable, and starts your car if you're in a tight spot. Put candywrapper or nail-polish on the built in light and you got illumination aswell.

[ArmyAirForce]

Lead acid batteries may be big and heavy, but you get lots of amps for your money, and they don't have a reputation for bursting into flames! I know of several modellers who have had serious house, garage and shed fires from Lithium Polymer batteries of much smaller capacity than this, even when using the correct charger. I don't know the reliability of the type Flo are selling, but personally, I'd be very uncomfortable having a LiPo in the house. Even Boeing have had problems, and they won't be buying cheap and cheerful.

The NEQ6 pulls about 1 amp I think when tracking, and about 2 amps when slewing to a target. You don't want to discharge any battery to a very low level, so let's say use 75%, which gives you 7.5AH, or at best 7.5 hours of tracking only, perhaps 3 hours with lots of slewing to new targets. Then you suddenly realise in the Autumn and Winter, you need dew heaters to stop the scope fogging up, there's a few more amps being pulled from the battery, and so your use time is cut once more.

It is your choice at the end of the day of course. The battery weight can't really be an issue considering the weight of the NEQ6 and balance weights. It's not a light weight set up to start with.

As for charging and leaving leisure batteries, people with caravans go away for a weekend, and are probably pulling more amps out of the battery than we would on a nights observing/imaging. They normally charge from the car on the trip. For astro use, It's no big effort to pop it on the trickle charger when you get home or the following morning. I always stick it on charge at the end of a session or next day. The charger automatically switches to a low maintenance charge after the battery is topped up, so it is always ready for next time.

[AlistairHowie]

Going back to the original question, then yes, you will have the power you need for your observing. Spend the extra £27 though and get the 14Ah version to be sure. Just so long as you are not going to want to add dew strips, electric focuser, CCD, etc down the line.<br />

<br />

I note you are on a mission to find PORTABLE power. Perhaps I'm getting weak in my old age, but there's not much portable about the 20-25kg weight of a 85Ah leisure battery. The Tracer batteries are VERY light and portable (just pop it in your jacket pocket).<br />

<br />

If you are happy to pay for the portability and need capacity, then look to the Tracer LiFePO4 batteries sold by Deben. They hold at 12.5V over almost all their discharge curve and have all the charge/discharge protection of the LiPo battery you linked to. They are very light compared to SLA and very forgiving in their use .

[AlistairHowie]

The Tracer batteries sold by FLO have FULL discharge protection and you can comfortably take them past 75% discharge.<br />

<br />

They are a different ball game in terms of quality and safety to ones modellers (of which I am one) use. I always store my RC lipos in a lipo sack in an ammo box. And even then I get nervous around them. Not so with the Tracer.<br />

<br />

If you are still worried about lipo safety, splash the cash and go LiFePO4, which are completely inert and safe.<br />

<br />

[nitram100]

Thanks a lot for the info guys, going to have a little think about it today and get ordering.

I will never need the amount of power a leisure battery would offer and the price difference once you factor in a good charger + leisure battery + case to store it in + cables that I may need, the Deben li poly doesn't seem that much more expensive and I can store it in a jacket pocket, which is amazing. Thanks a lot for the input guys! 

Also going to Everest Base Camp in September so the Deben Li Poly could come in extremely handy. 

Sorry for the next questions guys, just read on the Deben website that it has a cycle life of 300 cycles, does this mean it can only be discharged and recharged 300 times? 

[Carina Lass]

I use 110ah lead acid (liesure /deep cycle) - I don't believe in toying about.

I also have a 2kva inverter generator for weekends away.

Good plan is to go to your local battery shop and get a solar charger - it'll always be ready for you then. I have one that charges at just over 1/2 amp - which is fine because it gets charged gently between uses.

Mind you I have a 7ah for short evenings out or field nights.

[AlistairHowie]

Definition of cycle life from Deben website ... <br />

<br />

This is based on charging at a standard rate with a discharge from full capacity to 9V at 5A. Rest time of 30 minutes between charge and discharge. Cycle life is classed as when discharge capacity is at 70% of original. Note that the battery still has a useful life after this<br />

<br />

LiFeO4 offers 1,400 cycles.<br />

<br />

As a point of reference, I wonder how many cycles a SLA is good for. Time to head off to Google!!

[AlistairHowie]

Ta da!!<br />

<br />

The SLA provides 200 to 300 discharge/charge cycles. The primary reason for its relatively short cycle life is grid corrosion of the positive electrode, depletion of the active material and expansion of the positive plates. These changes are most prevalent at higher operating temperatures. Applying charge/discharge cycles does not prevent or reverse the trend.