cheap 20,000 mah LiPo battery

[astronymonkey 536]

Ive been looking for a lightweight high capacity battery for some time to power my secondary heater at 0.3amps and 2 heater straps at 0.25amps each, so no drive or anything as I use a dob.

ive just found on amazon an "Anker 2nd gen Astro pro2" 20,000mAh LiPo battery for just under £50. It outputs at 9v and 12v and also has 5v usb ports along with an onboard level meter.

apparently Anker have a good name in the tech world and although it only outputs 1.5amps at 12volts (upto4.5amps at 5v). I was wondering if there is any reason why this wouldnt fit the bill for powering my dew prevention kit.

with my current draw only being 0.8amps am I right in thinking that id get 12.5hrs use if I assume a 50% usable capacity from the battery.

I had considered a tracer battery but the 22ah version is a few hunderd pounds and although this can deliver 10amps this would be more amps than I need which is probably what you are paying for.

Cheers

[StuartJPP 5,023]

Be careful, the 20,000mAh rating is at 3.7Volts.

The watt/hours rating is 74W/h (20*3.7) whereas a 12V, 12A battery has a watt/hour rating of 144W/h.

At 12V output the rating is approx 6A/h.

I have got one if these and they are pretty good but then I have only got an AstroTrac to power...

[ronin 3,795]

That looks very interesting for the small grab and go I use, ETX70 that is 9v.

I suppose at 6v it could power an EQ5 with dual motors as well, the rating from AM would seem to imply it could as I guess you are looking at a max of 4 amps. Especially as in either option I am not looking for all night power likely around the 2 hour mark.

Need to look a bit more for specifications etc.

To save me time looking can it be recharged from a car connector?

Thinking of via a USB lead into a car/USB converter.

Edited June 18, 2014 by ronin

[astronymonkey 536]

here's a link to the manufacturers website .. http://www.ianker.com/product/79AN7906-BA

Im just looking at the sums and I see what you mean Staurt about the W/h calc. but when I look at the Ah reading and the spec that says 1.5amps at 12v I was assuming that this would drain the 20Amps over 13hrs.

But what you are saying suggests that this is dependant on the voltage as watts = Amps x volts.

At the moment I use a 17ah 12v jump starter which has 204w/h which easily does me , but if the numbers dont stack up then this LiPo wouldnt fit the bill....

all pretty confusing !

cheers

[WayBig 24]

Hi astronymonkey, did you get one do these Ankers?

Anyone else tried one?

I'm thinking about one of these - significantly cheaper than a tracer.

My 10 inch auto dob runs at 12v, probably only draws an amp most of the time.

Cheers

[astronymonkey 536]

Hi chris

I never got one in the end as I wasnt sure what amount of power it would deliver at 12v and how long it would last.

im now considering a 12v yuhasa golf battery at 22ah which are about £30 but im waiting to lidl or aldi to get intelligent chargers back in stock as id not have anything that can charge it

if you do get an anker though it would be interesting to here what you think of it.

Cheers

[keithatrochdale 182]

Don't forget LiPos don't like cold, they loose about 30-40% of capacity.

[Davey-T 15,498]

Don't forget LiPos don't like cold, they loose about 30-40% of capacity.

Apparently these folks were using Deben Tracer batteries to trek across the Artic, probably be a bit chilly 

Dave

http://www.thecoldestjourney.org/?gclid=CKHXvqfe4MACFUjHtAodtW0ASg

[WayBig 24]

Stuart- how did you work out the watt hours, I couldn't see it anywhere in the listing (perhaps it's in the manual and you only get to find out once you've bought one!)

...just keen to get as much info as possible to enable me to work out which will be best.

Thanks

Chris