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Power Tank or Tracer Lithium Loin battery or....?


Seamaster
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Hi, I need a power supply for my Celestron SLT127 .

I have very limited views (North) from my back garden and have yet to even set up my scope due to that and hardly any clear skies.

Can anyone suggest a power supply that A/ Doesn't involve any DIY input from me, and B/ Will have give me several hours of viewing and seeking on my GoTo?

Portability would be great to, so nothing that requires a team of oxen to cart about!

I have read good things on here about Baz batteries but am unsure what they are exactly over and above a leisure battery I.e. Modded in some way? Also I understand that he no longer does them?

Thanks.

Neil

Derby.

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Hi.


 


Yes you are correct, Martyn no longer does the "Baz battery", he got them free from work under the proviso that he made no money on them (which he didn't), unfortunately, Martyn can no longer get them.


 


I believe they are nothing more than a car / leisure battery, he got them in different power ratings (mine is a 75 A/H battery) and weighs about the same as a car battery, nothing fancy about mine, I bunged it in a plastic box and attached a couple of crocodile clips to it with a female cigarette port on the other end, I then power my dew kit with it, lasts days between charges.


 


I would shy away from the "proper" astro ones from Celestron + Skywatcher as these only tend to come in 17 A/H flavours with more gizmos than you can shake a stick at.


 


A simple leisure battery will suffice, something like what you may use in a caravan but a bit smaller (unless you plan on using it to power laptops, mounts, dew kits etc).


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Unfortunately we lost the customer of ours who was good enough to let me root through the battery bin of theirs. They let me have any that were any good, bearing in mind these had already been used and dumped.


 


If you are just running the scope and dew heaters, then a 17a/h battery should do you for a good few hours, but I doubt it will last an entire night. You then start getting into the bigger and heavier batteries. I would suspect a 38a/h battery would last you all night and maybe some of the next, but keeping them charged is important. They don't like being left depleted, and it can drastically shorten their working life. I keep mine on an "intelligent"  charger, these not only charge, but cycle the battery so it remains in the best condition, they can be left connected all the time. 


Don't forget they don't like the cold, this increases the internal resistance and can shorten the time they can be used by over half on a freezing cold night. This is why most people make up a DIY box, to help carry it and insulate it.


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Thanks for the informative replies guys.

To be honest I doubt I will ever be needing to be out all night, my other commitments just don't make that viable.

However I would like to think I could get a good 6-8 hours (likely never more than 4-6) of GoTo only usage out of it?

I don't run a heated dew shield.

Also space is limited as I don't have a garage and wish to remain married!

Would the Tracer Lithium Polymer 8ah pack suffice or do the Power Tank / Halfords packs offer better performance and value?

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I don't know if the tracer lithium battery you mentioned can handle the cold but like Martyn said, on a really cold night you can half the amount of usage, so for ease of maths , that would give you 4 A/H, I'm guessing a mount that is asked to track and with slewing to different objects would use approx 1 A/H, so that leaves you with 4 hrs worth of viewing (plus or minus an hour or two). Trouble with mounts though, if the volts drop below what they require, regardless of the amount of time you have used it, they will start to throw out errors or just stop completely, also, at 4 A/H if you used it for 4 hours, you would completely discharge the battery, which they don't like!

I would say 17 A/H minimum, that way in the cold you still won't have to worry about running out of power.

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Iam surprised you don't run a dew heater on the front corrector plate, they are proper dew magnets.


You don't need much insulation around them, I use a cheapo Decathlon exercise mat, and just make a basic 1/8" plywood box to go round it. i fitted a cigarette lighter socket in it to save messing about with clips.


Having seen the price of those Tracer lithiums, I don't know how you're going to sneak that one past the old wife radar.


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i would caution against low ah batteries, you will have voltage problems after a short while.  17aH i doubt would do it especially in the


cold.  can drop battery by up to 55%.  Even just slewing the mount i would not go below 70ah, its awful when mount plays up because of low voltage


after only an hour :(


 


 


Sheila


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or you could bring a silent generator (best LPG ,diesel and last petrol) - as I think i saw in the pictures from the qtrly meeting :-)


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or you could bring a silent generator (best LPG ,diesel and last petrol) - as I think i saw in the pictures from the qtrly meeting :-)

 

that would be mine :D  got fed up of battery problems in the cold :D

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