Newbie battery question

Hi,
Bought myself a Celestron Nextstar 80GT, expecting delivery tomorrow.
The d/loaded manual states it needs 8AA batteries. Could someone please tell
me if I can use rechargeable batteries and if yes, what is the minimum mAh I
need to buy.
Thanks in advance for any guidance with this.

Cheers
Chris.

"mrbingley" wrote in message
...
Hi,
Bought myself a Celestron Nextstar 80GT, expecting delivery tomorrow.
The d/loaded manual states it needs 8AA batteries. Could someone please
tell me if I can use rechargeable batteries and if yes, what is the
minimum mAh I need to buy.
Thanks in advance for any guidance with this.

Cheers
Chris.


AA batteries are 1.5V. Normal rechargeables are 1.2V.

On your scope the 8 batteries are connected in series giving 12V to operate
the scope. Normal (NiCad and NIMH) Rechargeables would give you 8x1.2V =
9.6V: 2.4V short of the requirement. The scope would likely operate as if
you were using flat AA's.

These ones seem to be 1.5V and you could give them a try:
http://www.maplin.co.uk/Module.aspx?...3043&doy=16m11 Ask maplin
which is the best charger for them as they're 2900mAh rather than those
chargers supplied with the usual 2300mAh batteries.

Another portable solution would be a small 12V battery of the sort used in
alarm systems. These can be bought from Maplin or sometimes B&Q. See:
http://www.maplin.co.uk/Module.aspx?...088&doy=16m11D

A 12V/1.2 Ah lead acid battery should be good enough for the scope you're
using. I use a 7Ah for the LX90 and a 1.2h for the Celestron 114GT. You'll
need a small cheap car battery charger to charge the lead acid battery.

You will need to be very aware of the battery polarity when connecting to
the scope of you could burn out the scope's electronics (could ruin your
observing session...). If you're in doubt, either find someone close to you
who can help (I'm in Surrey if you're close by) or stick with what you've
got.

A less portable solution is this:
http://www.maplin.co.uk/Module.aspx?...1384&doy=16m11 (the 12V
option). Again, be careful with the polarity.

Hope this lot helps. If you're unsure of the polarity issues, try the first
option with the lithium batteries.

All the best


Chris

mrbingley wrote:
Hi,
Bought myself a Celestron Nextstar 80GT, expecting delivery tomorrow.
The d/loaded manual states it needs 8AA batteries. Could someone please tell
me if I can use rechargeable batteries and if yes, what is the minimum mAh I
need to buy.
Thanks in advance for any guidance with this.

Cheers
Chris.


How about a 12V 17Ah 'powerstation' thingy from Maplin - item code is
N36BF - used with the celestron 12v car lighter lead?

The lead is probably quite pricey over here - I got mine while in the US
on holiday, but either woodland hills camera or adorama should have them
& ship to the UK, or a scout around ebay might turn one up. I know it's
in the Celestron 'starter kit' they're currently selling.

Here are some links to the cable:

http://www.telescopes.com/products/C...s_120 47.html

http://www.adorama.com/CNCBAU.html

And here's the Celestron power adapter range:

http://www.telescopes.net/celestron_...erTank17-18777

For comparison, here's the UK equivalents:

http://www.greenwich-observatory.co....cessories.html

http://www.dhinds.co.uk/pages/fullProd.php?id=223

HTH

G.
--
Graham J. Platt
graham (a) bowhunter (d) demon (d) co (d) uk
TRA #10112 L3
UKRA #1264 L3 RSO

mrbingley wrote:
Hi,
Bought myself a Celestron Nextstar 80GT, snip what is the minimum mAh I
need to buy.

Also, any autoshop rechargeable emergency car battery with 12V
cigarette output sockets will do the trick, e.g. -

http://www.buynshop.com/productinfophp3/EG-JS-BS2000

and does double-duty as a roadside flat safety item.

The draw amps from the scope is minimal. Product literature will list
the amp draw rate. Maybe someone here has a manual with the precise
figure for the NextStar 80GT?

The real power hog is an ancillary laptop, which IMHO should be run
from a completely separate battery from the scope. Use the cigarette
lighter DC/AC converter and provide supplemental power to your laptop
from the car battery, taking care to assure that you do not draw all
the power our of your car battery. Most of the DC/AC cigarette
lighter converters have an anti-flat circuit built-in; they will
cut-out before your car battery goes flat. Another power hog are dew
heaters.

The battery setup described above separates your laptop and the scope.
The position of the laptop is limited to a 10-12 foot extension cord
from the auto's cigarette socket. If you want to have the laptop and
scope at the same location, for example, for imaging or to use
planetarium software to drive the scope, then look at the separate car
battery just to provide extended supplemental power to the laptop.
That setup involves the car battery and a separate auto DC/AC
converter. The auto DC/AC converter is sold by most auto shops. It
is used to power high-end stereo systems and speakers in a car.

A complicated setup of two batteries, a laptop and scope is usually an
intermediate or advanced observer purchase. It is probably more than
you would want to start out with for a Nexstar 80.

- Canopus56

mrbingley wrote
Hi,
Bought myself a Celestron Nextstar 80GT, expecting delivery tomorrow.
The d/loaded manual states it needs 8AA batteries. Could someone please tell
me if I can use rechargeable batteries and if yes, what is the minimum mAh I
need to buy.
Thanks in advance for any guidance with this.

Cheers
Chris.

To Chris Taylor's excellent advice I would add one small point. If
possible try an agricultural merchant for sealed 12v gel filled
lead-acid batteries. A lot of them seem to keep a fair stock at very low
prices (better than anything I've seen on the web).

Denis
--
DT
change nospam: n o s p a m
v a l l e ys

DT wrote:
mrbingley wrote
Hi,
Bought myself a Celestron Nextstar 80GT, expecting delivery tomorrow.
The d/loaded manual states it needs 8AA batteries. Could someone
please tell me if I can use rechargeable batteries and if yes, what
is the minimum mAh I need to buy.
Thanks in advance for any guidance with this.

Cheers
Chris.

To Chris Taylor's excellent advice I would add one small point. If
possible try an agricultural merchant for sealed 12v gel filled
lead-acid batteries. A lot of them seem to keep a fair stock at very
low prices (better than anything I've seen on the web).

And to add to the info - don't use a very cheap charger on these
sealed lead-acid batteries since they don't like charging at
greater than 13.8 volts as they'll 'boil-off' the electrolyte and
it'll release through the pressure vent. Normal very cheap chargers
apply 14.5 volts or more and will cook the battery.

This is due the plate composition omitting antimony which lowers
the terminal voltage a little but does improve the gassing situation
when correctly charged at 13.8volts.

As with all things, get a battery charger made for the purpose.

An easy way to ensure correct polarity is to add a relay and diode
to the power system such that it switches the output on only when
the polarity allows the relay to close. This method avoids the problem
of losing voltage through a directly wired series diode in the supply
line. I can put up a web page if anyone is unclear how to wire this up.

HTH
--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

In message , Graham
wrote
mrbingley wrote:
Hi,
Bought myself a Celestron Nextstar 80GT, expecting delivery tomorrow.
The d/loaded manual states it needs 8AA batteries. Could someone
please tell me if I can use rechargeable batteries and if yes, what
is the minimum mAh I need to buy.
Thanks in advance for any guidance with this.
Cheers
Chris.
How about a 12V 17Ah 'powerstation' thingy from Maplin - item code is
N36BF - used with the celestron 12v car lighter lead?

My Maplin powerstation came with a lead to let you charge it from the
car lighter socket, this lead plugged into the lighter socket on the
powerstation will fit into the power socket on my Nexstar 114GT and
provides the right polarity.
--
Roger
52:54:41N 01:30:05W
Orion 127mm Maksutov, Canon 15x50 IS binoculars.
Member WPAOG (White Peak Astronomical Observing Group).

mrbingley wrote:
:: Hi,
:: Bought myself a Celestron Nextstar 80GT, expecting delivery tomorrow.
:: The d/loaded manual states it needs 8AA batteries. Could someone
:: please tell me if I can use rechargeable batteries and if yes, what
:: is the minimum mAh I need to buy.
:: Thanks in advance for any guidance with this.
::
:: Cheers
:: Chris.

Thanks to everyone for their input, been a great help.
I've got a "powerstation", so I've ordered a Celestron Cigarette power lead.
This should keep it running for quite a while between charging up of the
powerstation.
Once again thanks to all.

Chris.

Roger Smith wrote:

How about a 12V 17Ah 'powerstation' thingy from Maplin - item code is
N36BF - used with the celestron 12v car lighter lead?

My Maplin powerstation came with a lead to let you charge it from the
car lighter socket, this lead plugged into the lighter socket on the
powerstation will fit into the power socket on my Nexstar 114GT and
provides the right polarity.

I didn't think to try the one that came with mine! Thanks for the tip Roger.

G.
--
Graham J. Platt
graham (a) bowhunter (d) demon (d) co (d) uk
TRA #10112 L3
UKRA #1264 L3 RSO

mrbingley wrote:
mrbingley wrote:
Hi,
Bought myself a Celestron Nextstar 80GT, expecting delivery
tomorrow. The d/loaded manual states it needs 8AA batteries. Could
someone
please tell me if I can use rechargeable batteries and if yes, what
is the minimum mAh I need to buy.
Thanks in advance for any guidance with this.

Cheers
Chris.

Thanks to everyone for their input, been a great help.
I've got a "powerstation", so I've ordered a Celestron Cigarette
power lead. This should keep it running for quite a while between
charging up of the powerstation.
Once again thanks to all.

Bit late now, but anyway..... Not having thought to check the exact
battery ratings etc for my Nextar, I just used rechargeable batteries
anyway, and......it seems to work. However, this thread has got me
thinking. I've also got a solar powered electric fencer which isn't in
use all the time and which recharges a 12v battery. Might think about
rigging up a lead so that I can use that in future.

--
Holly, in France
Holiday Home in Dordogne
http://la-plaine.chez.tiscali.fr/