Powering my NexStar 8SE

[Mark.Tanner (Mark)]

What battery should I purchase to power my new NexStar 8SE?

The recommended batteries from the Celestron website are quite expensive and I suspect the price isn't necessary.

[Mark.Tanner (Mark)]

Does anyone have any suggestions? Links to certain batteries from Jaycar etc. would be very appreciated!

[astro744]

I think any 12V 7Ah battery would suffice. Just make sure when connecting you get the polarity right. Check with a meter to ensure centre of plug is + or - depending on what it needs to be since you can reverse it by connecting the wires opposite.

See also https://www.nexstarsite.com/OddsNEnds/PowerSources.htm

Just search for sealed lead acid batteries (SLA) often incorrectly called gel cells. Amazon sell them too for a bit cheaper. You can get 9Ah for less than cost of 7Ah at elsewhere but there’s not a lot in it.

Edit.
The 12V 7Ah or 9Ah batteries are fairly small and light and can sit on your tray between the tripod legs if you have one or on the ground. Get yourself a multistage 1-2A charger and when you’re finished with the battery for the night just put it back on the charge. This is what I am doing with my 12V 9Ah SLA which also happens to be deep cycle (it was cheap <$30 and has served me well this year). The charger may set you back about $90 for a 1.5A model which is all you need for 7-9Ah.

[Mark.Tanner (Mark)]

Thank you!

I'm considering this battery:
https://www.jaycar.com.au/12-8v-7ah-...ttery/p/SB2210

Connected to this battery adapter:
https://www.ozscopes.com.au/celestro...-nexstars.html

I'll also buy a charger and whatever cord is needed to connect it to the battery adapter.

Does that sound ok?

[astro744]

At first I thought the battery was expensive for 7Ah but then I noticed it is the newer technology Lithium. The Nexstar cord seems expensive but it will give you the correct plug but the polarity is still dependent on you connecting correctly to the battery and provided the female cigarette socket is correctly wired.

I’m not familiar with the telescope you have or it’s power polarity requirements, i.e. centre positive or centre negative. Get a pocket multimeter, cheapest you can find and that way once you connect the cords to the battery first test the voltage and see if it is generating centre pos or centre neg. It needs to match your telescope requirements. If opposite, reverse the connection at the battery.

It is probably reasonable to assume the cigarette socket is correctly wired as would be the Celestron cord but better safe than sorry.

This is the battery cord you need. (Link below). See if you can find one that has fully insulated alligator clips to avoid accidental shorting of the battery terminals. I use this battery for all my telescopes that need 12V. It’s nothing special but it works. If I need a reverse polarity I use a different cord.


See https://www.jaycar.com.au/cigarette-...clips/p/PP2007

Perhaps others who have a similar telescope can chime in with what they use. I use a 12V 9Ah SLA and similar cords that I hand made. I use an OzCharge 8A charger set at 2A and keep the battery connected to the charger when not in use.

[Tinderboxsky (Steve)]

This little unit has been powering my NexStar 8SE and my Ioptron MiniTower Pro for the last 6 years without a problem. It is capable of powering these mounts for many nights.
I leave the battery permanently attached to the battery charger (with trickle charge option to maintain charge levels) when not in use - important to maintain battery health.
The slightly smaller 7AH batteries would also be quite adequate IMHO.

[astro744]

Note charging a 12V battery can be done with any charger but maintaining battery health and longevity requires a multistage or smart charger. Such a charger will switch to trickle mode to reduced excess hydrogen and oxygen production requiring activation of the pressure release and loss of electrolyte. A smart charger will also boost charge rate when required to prevent under charging and lead sulphate crystals forming on the plates.

Here is some info: https://www.silvertel.com/images/tec..._batteries.pdf

Now the above applies to SLA (sealed lead acid) batteries. I am not sure on best practice for Lithium batteries and I recommend you search the web or perhaps someone else an answer. Note too the initial (bulk) charge rate is important and must not be too high but it does depend on battery type.

I have both a C-tek 2A charger permanently hooked up to a battery box housing a couple of motorcycle batteries giving me 4x 12v ports as well as 1x 18v port for my Losmandy Gemini I. (This was well built by the former owner but I find it a bit heavy). I’ll get a trolley for it one day but in the meantime I got 2x 12V 9Ah deep cycle SLA on Amazon that I hooked up to an OzCharge 8A charger, (set to 2A) in parallel. (I use one for my ‘scopes and I was going to replace a UPS battery with the other but the 9Ah is about 2mm too thick!). (Amazon had the 9Ah for $26 and the 7Ah for $34). I keep both on charge in parallel when not in use.

[Mark.Tanner (Mark)]

Thanks for the help everyone! It's been very informative and helpful I'm assuming the Celestron battery adapter will fit fine, but how do I make sure before I use it (and possibly damage something)? I.e. making sure the pin is in the correct spot and charge. I think it needs to be middle and a positive charge but I can't remember where I read that.

[astro744]

Try the user manual if you have (try Celestron web site). I did find this;
https://stargazerslounge.com/topic/2...ron-8se-power/

Note there is nothing stopping the user from accidentally or deliberately reversing the leads on the battery thereby reversing the polarity of the Celestron plug no matter how it’s marked. That’s why I suggested a small multimeter to test the powered plug before you connect to the ‘scope. To test connect the leads to the battery and make sure centre reads positive with respect to outer of the plug. If you’ve never used a multimeter I suggest you get someone else who has to help you because if you hook it up incorrectly you could get a false result.

I’m not familiar with the Celestron lead and for the price I would expect there to be a fuse inside the cigarette plug. If for some reason you are getting no voltage then check and/or the fuse, (with exactly the same rating).

[Mark.Tanner (Mark)]

How can someone accidentally reverse the polarity? Just connect it to the battery backwards?

I'll use a multimeter at the battery store, I'm sure they'd have one!

[Outcast (Carlton)]

Originally Posted by Mark.Tanner

How can someone accidentally reverse the polarity? Just connect it to the battery backwards?

I'll use a multimeter at the battery store, I'm sure they'd have one!

Yup... because at night, under a red light... the red terminal & clip isn't red....

This is the very reason I have pigtails off my battery & use Anderson Pole plugs... pigtails will only ever be removed when the battery is being replaced (therefore not in the field) & Anderson Pole plugs are impossible to connect to each other incorrectly... & they don't easily pull apart like cigarette lighter plugs do... another bonus..

[Mark.Tanner (Mark)]

That's a good point! I hadn't considered the red light. Thanks for the reply

[kon1966 (Kon)]

Have used this on my 8se and now my avx powers for hours. There is also a dual batttery setup.

https://www.celestron.com/products/powertank-lithium

[Mark.Tanner (Mark)]

Buying one of those would be great, but they're very expensive!

Originally Posted by kon1966

Have used this on my 8se and now my avx powers for hours. There is also a dual batttery setup.

https://www.celestron.com/products/powertank-lithium