Jump to content


Celestron Power Tank problem

Recommended Posts

I have had a Celestron 7ah power tank for about 7 years. It has always worked just fine, but recently it didn't seem to be holding its charge and when recharged the "fully charged" green light seemed to come on very quickly (after a couple of hours charging).

A few nights ago the tank showed fully charged but showed its amber (needs charging) light within half an hour. After another half hour my LX90 could no longer draw enough power from it to slew.

Ysterday I recharged the power tank for about 4 hrs until it showed "fully charged" (which is very quick - it would normally take 12hrs). But when I switched it on tonight the amber "needs charging" light came on and a test with the spotlight beam showed it was not highly charged.

I am currently leaving the spotlight on to fully discharge the powertank and will then give it 24hrs charge.

Is this likely to fix the issue or has it finally come to the end of its lifespan?


Link to comment
Share on other sites

I'm afraid i cant help. I have only had my Celestron power tank for a month and only used it within the last 2 weeks for an hour here and there. They say you should charge it once a month in the winter for 24 hrs (if not used). If you use it for any amount of time on a session then you should recharge overnight.

As you already plan to do a full discharge and then a full 24 hr charge...................that is all i can suggest also.

See what happens.

If that fails to solve the issue then it might be time to replace it.

I'm really not sure of the lifespan of these packs.

Link to comment
Share on other sites

Firstly I'd say you've had great value if it's been working ok for 7yrs. That's a good recommendation :)

It depends how you are recharging it - you may need a deep cycle charger to bring it back to life - the supplied trickle charger won't restore it from totally discharged.

I left my 17ah one off for 6 months over winter and nothing would bring it back to life (all within it's first year lol). But you can get a half decent replacement battery for under £50 and give it a new lease of life. I fitted a replacement 17ah one very sucessfully - though it was a tad fiddly. :D

Edited by brantuk
Link to comment
Share on other sites

Hi Albireo380,

I had the same problem with my skywatcher power tank. I went & bought a fully automatic battery charger. I connected the positive & negative terminals & it charged it back up. It will also condition your battery to keep in premium condition, that is IF it isn't completely dead. Having had it for 7 years, that may be the case unfortunately.

If the battery is dead & won't come back then I would strongly recommend avoiding the celestron/skywatcher power tanks as they are grossly overpriced. You can buy better ones from Maplins which are about half the price & you can usually get them on sale too so you'd save even more money. Either that or look at a leisure battery, I bought one of these & it powers both my scopes & laptop all night long.


Link to comment
Share on other sites

Most 'powertank' and 'start n charge' type products use gel lead acid batteries. These have a limited life, regardless of how well you treat them.

The very best you can expect is a cumulative loss of capacity of about 0.015% daily. It doesn't sound much, but over a few years your battery degrades significantly.

Then if you leave it in deep discharge for any length of time it will increase it's internal resistance and drop it's capacity. You are stuck with this.

Then if your charger allows it to gas more than the internal catalyst will allow recombination, you lose capacity. Again, you are stuck with this.

So 7 years life is really good.

Take the box to pieces. Look at the battery size and hunt around for a good price on a replacement. Usually battery case sizes are standard within a millimetre or two. Gel batteries are suitable for shipping by parcel carrier, so you don't have to worry about collection.

Hope this is helpful.

Edited by DavidValentine
Link to comment
Share on other sites

Sorry Brant. I meant plugging the pack into a mains (as you do to charge...........but dont put it on charge) and then plugging the pack into the scope. So essentially the scope is working off the mains.

I can see what you mean about it perhaps frying the system. Some kind of regulator would be needed in the middle.

Silly idea but one i had to ask about.

Edited by LukeSkywatcher
Link to comment
Share on other sites

In my limited experience these lead acid type powerpacks do need regularly top ups from the mains even if not being used otherwise they can never fully regain their charge. As Brant UK has said 7 years is pretty good going. I use the maplin 3 in 1 powertank which is a huge saving over the Celestron version. May be time for a new one?????

Link to comment
Share on other sites

Okay, cheers Guys. I have looked after this powertank, recharging every month or so, but as you all say, 7 years is a good lifespan for one of these.

I have 2 17ah ones from Maplins, so they will do me at the moment.



Two 17ah from Maplins?

So why worry about a single 7ah?.

I have two 7ah Celestrons.

Can i rewire them so that i get a single 14ah?

Just kidding. I cant even rewire a plug.

Link to comment
Share on other sites

Ahhh I see what you mean Paul. We have a caravan battery that charges as it runs various lights, fridges, etc round the van. So it is deffo possible, but I don't know if field packs work that way. :)

The Celestron power pack is what? 12V?

What is the standard mains charge in the UK and Ireland?

Surely it is possible to plug the power pack into your house/garage mains via the DC adapter and then run the cigarette lighter thingie connected to the mount.

I suppose it all depends how far from your observing site (if in your garden) that the neartest mains plug is.

Probably wouldnt work for most (if any) people.

Not sure i am making my thoughts clear here.


House/garage mains>powerpack>scope

Edited by LukeSkywatcher
Link to comment
Share on other sites

  • 4 years later...

Just to jump in on this topic,ive had my power tank less than a year and maybe for the past month ive had problems with loss of power...ive always kept it topped up but now theres a noticable difference in performance...do i get a new one,or get a new cell and replace it within the case...buy a power lead and run the telescope off the mains?.. ice got a feeling that the dew heater pulls more power than the mount tracking objects and its initial setup..its the smaller celestron version..any help much appreciated..

Link to comment
Share on other sites

Hi ? welcome to SGL, have you got a real name, you can sign your posts with it.

If you're feeling flush you can replace the lead / acid battery with a Life Po Tracer battery which is what I did, then you get to keep all your connections.

Whereabouts in Kent are you ?


DSCF0424.JPG Power-pack.jpg

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.