Orpington Astronomical Society

Astronomy => Technical => Topic started by: Kenny on Sep 24, 2016, 15:56:36

Title: Battery potential
Post by: Kenny on Sep 24, 2016, 15:56:36
I ordered a replacement sealed lead-acid battery for my son's portable amp/speaker and the retailed sent the wrong battery. Once I pointed this out to them they sent a (correct) replacement but never asked for the wrong one to be returned, though it's early days and they still might.

Anyway, it's a 12v sealed lead acid battery (http://www.batteriesasap.com/mkbaest212vo.html) and it occurred to me this might be an opportunity for me to build a battery kit for my astro stuff i.e. star adventurer and (to be purchased) dew heater. However, the star adventurer only has a mini-USB 5V DC port.

So.... any bright sparks have ideas as to how I can adapt this for use? Or, we could 'inherit' it into the OAS kit list and use it with the HEQ5 mount which has a smaller (and possibly ageing) sealed lead acid battery.

Any thoughts?

p.s. it's 12V, 4.25AH / 5HR, 5AH / 20HR.
http://www.batteriesasap.com/mkbaest212vo.html
Title: Re: Battery potential
Post by: JohnP on Sep 24, 2016, 16:04:45
kenny, even small dew heaters can be relatively 'thirsty' so far as Amps are concerned & would quickly flatten a 5Ahr battery on a cold night out in the field...
Title: Re: Battery potential
Post by: Ivor on Sep 24, 2016, 21:34:58
It wouldn't be able to power both, if it was a small dew heater say for a camera lens you could get a night out of it. For a refractor sized dew heater you'd probably get an evening, I built my dew for the refractor and on full power it pulls .75AH.

It's not too hard to drop 12V to 5V but to be honest I pick one of these https://www.amazon.co.uk/Anker-PowerCore-20100-Capacity-Technology/dp/B00VJSGT2A/ref=sr_1_4?ie=UTF8&qid=1474738251&sr=8-4&keywords=portable+charger+20000mah for the star adventurer to save you messing about. A quick search I couldn't find the exact power consumption however based it being powered by 4 AA batteries that's at best 10AH so the above would see you though a long winter night with some change.