What power sources are people using?

[cshahar]

Hi. I recently bought a Celestron Power Tank, which is very portable, but I am not sure if it will meet my needs in terms of power duration and durability. I heard there have been issues with this particular model. There is a much heavier power pack made by Celestron, but the weight is a bit too much for me to deal with! I am getting too old to lug around such heavy equipment. Any thoughts of an alternative power source that is also quite portable?

Thanks,

-Charles

[michael.h.f.wilkinson]

I do not know which one you have, I have a 17Ah model (SkyWatcher branded, but they are also available in Celestron livery), upgraded to 22Ah when the 17Ah battery failed. One problem is that sealed lead-acid (SLA) batteries really do not like to be discharged very far, nor do they tolerate storage in a cold location very much. Mine failed probably as a result of a mixture of these two circumstances. I now store the battery in a warm location, and frequently recharge it, if it is not being used. The fact that the new battery unit is 22Ah also means that prolonged use discharges is less far in terms of percentages than the original 17Ah (if I draw 7 Ah from it, that only 32% not 41%). LiFePo batteries are better in many respects but also a lot more expensive. I recently found that there is a 20Ah drop-in replacement for my deep cycle 22Ah SLA battery, but that costs 229 euro as opposed to 49 euro for the SLA. It is also lighter, so that is an advantage.

My upgrade is shown here:

http://stargazerslounge.com/topic/215711-revamp-of-17ah-powertank-to-22ah/

[graemlourens]

Hi Charles.

I was fighting with this subject for a long time.

Tried Powertanks (aka Starter batteries) but the voltage drops so rapidly after a short period of time, and as soon as you have multiple pieces of eqipment like CCD, Filterwheel, Mount and so on draining battery, for a decent evening you need at least 20aH. As you should not decharge batteries lower than 50% you have to double your power requirement, so you're looking at 40-60aH battery.

In the end i went for a 100aH deep cycle batter, and did the connections myself, but that battery is 25kg ...

If weight is a big issue, then consider multiple small batteries, one per device.

I'd also advise you to run tests at home.

Connect all your eqipment to your battery that is fully charged. Let it run for 5h (average night for me) and see what voltage you then have on your Powertank.

If its still above 11.8V all is good, below will become a problem sooner or later.

Without CCD & Filterwheel (just having Mount & dew heaters) i was able to run for 3 hours on a 17aAh starterbattery before voltage became critical. But that battery would break very soon if you do that for 20-30 times.

Regards, Graem

[buzz]

For portable use, I use two  24VA sealed lead acid gel batteries. These are the sort used in golf buggies. One runs the cooled camera and the other does the rest. Their nominal is about 13.5V at full charge and they run above 12 V for some time. They feed a home made electonics hub that provides switching and fusing.

At home, I use a twin channel regulated DC bench supply with dual meters and run 13V out to the garden using good quality speaker cables. (I don't put mains equipment outside in the dew)

I was looking at the Tracer LiPo batteries but from what I can see, they drop slightly below 12V quite quickly and some equipment is a bit touchy about that.

For my laptop - I extend the battery with a PowerGorilla Lithum pack. Expensive but excellent.

[jnb]

Hi. I recently bought a Celestron Power Tank, which is very portable, but I am not sure if it will meet my needs in terms of power duration and durability. I heard there have been issues with this particular model. There is a much heavier power pack made by Celestron, but the weight is a bit too much for me to deal with! I am getting too old to lug around such heavy equipment. Any thoughts of an alternative power source that is also quite portable?

Thanks,

-Charles

Home build power tank in a toolbox on wheels. It will generally be cheaper, more flexible and higher capacity than any bought options and putting it on wheels solves most of the weight issues.

[Tinker1947]

You could look at Tracer's there sold by  FLO, i use a 14Ah on my GoTo Dob and estimate it will run for 8 hours easily they do go quite a bit bigger and while expensive mine is like carrying a bag of sugar about....

[ronin]

What are you powering exactly,

Single goto like an Alt/AZ, bigger equitorial, goto mount+dew shield+ccd ?

I bought the 4Ah tracer for a small goto, that seems to do it for about 3 or 4 hours.

Then found these: LiPo-Ebay

Which is what I will look at next, they are simply a lot less then the Tracers.

Equally if you tend to run the scope from a dark site and use a car go to Maplins and get a car adaptor lead and run the scope from the rear of the car. At home I use a Maplins mains/dc converter L06BR.

[tonylumley]

just be careful with lipo batteries, I use them for my R/C helicopters and they can be temperamental if you don't charge and store them correctly, they also can catch fire while charging so follow completely the manufacturers instructions,  and don't leave them unattended when on charge, not trying to teach anyone how to suck eggs, Lum

[tonylumley]

Ronin, sorry just seen the link, these are "Li-ion" lithium -ion batteries not as I took it "lithium polymer" batteries,

[ronin]

My fault I didn't really check the details.

They are a battery and seem to satisfy the requirement of a power source. That really is about as far as my thought process went, what type never really came into it. The OP wanted a small lightweight battery.

I was looking for something that supplied 12v for a couple of hours while sitting on the base under the scope of a small goto. Idea was piece of velcro on base, recipricol on battery splat the 2 together and it stays put and no cables to get wound up. They would do it, and buying a second Tracer just gets costly and they have this odd connector on the Tracers which seems to be another case of "Make it a custom item and they have to come back to us". Which simply I find annoying.

[cshahar]

Thanks everyone! I am going to read the posts a couple of times to try to figure out what is the best option here. My power needs seem a bit daunting: drive, solar filter, CCD, laptop, electronic focuser, probably a dew remover. Ugh!

[mcolbert]

...and I think that may be the reason some people build their own observatories...

michael

[Martin Meredith]

I run a 19aH Norauto car-starter thing to power an AZ-EQ6. Much cheaper than the astro-branded offerings (about 80 euros if I recall correctly). My sessions are usually under 3 hours and voltage is generally about 12.8 at that point. I've had no problems so far after more than a year of pretty intensive use (> 30 sessions, I estimate). And you get a free air pump...

Martin

[Physopto]

Hi. I recently bought a Celestron Power Tank, which is very portable, but I am not sure if it will meet my needs in terms of power duration and durability. I heard there have been issues with this particular model. There is a much heavier power pack made by Celestron, but the weight is a bit too much for me to deal with! I am getting too old to lug around such heavy equipment. Any thoughts of an alternative power source that is also quite portable?

Thanks,

-Charles

Hi Charles,

Have a look at the first item on this board."about charging power tanks". It does depend upon what you are going to power, I.e. How much power you need and for how long. If you are within reach of a 13 amp socket you can use a smaller battery but keep it on charge at all times. The charger can be in the house say and a long 12 volt lead taken out to the battery. If you do this make sure the charger has shor circuit protection. This is basically what I do at Star Camps. So it means you can get away with a smaller and lighter battery. Just a note the 22 Ah Tracer battery packs only take a small charge rate and are not suitable for this method as they cannot be charged at the same time as being used, without modifying their leads. Thus invalidating guarantees. I got one of the LiFePo batteries from them at some considerable cost and had it modified by them to be able to be charged at the same time as being used. This modification is now being fitted to all of the new batteries of that type, but they have upped the cost by a whopping £100 approximately. That sucks!

Best of luck what ever you chose.

Derek

[Physopto]

Hi Charles,

Have a look at the first item on this board."about charging power tanks". It does depend upon what you are going to power, I.e. How much power you need and for how long. If you are within reach of a 13 amp socket you can use a smaller battery but keep it on charge at all times. The charger can be in the house say and a long 12 volt lead taken out to the battery. If you do this make sure the charger has shor circuit protection. This is basically what I do at Star Camps. So it means you can get away with a smaller and lighter battery. Just a note the 22 Ah Tracer battery packs only take a small charge rate and are not suitable for this method as they cannot be charged at the same time as being used, without modifying their leads. Thus invalidating guarantees. I got one of the LiFePo batteries from them at some considerable cost and had it modified by them to be able to be charged at the same time as being used. This modification is now being fitted to all of the new batteries of that type, but they have upped the cost by a whopping £100 approximately. That sucks!

Best of luck what ever you chose.

Derek

This is just an update to this bit about tracer (deben) LiFePo batteries mentioned above. Several months ago I bought a 40 ah battery of this type and had a modification done for two connections. So that it could be charged at the same time as being used. I paid £650.

Since then they increased the cost by £100 and again just recently by another £100. This same battery now costs a Whopping £850.

The only differences I can see is they now use Neutrik SpeekON connectors instead of xlr.

The only reason I can think of is greed!!!!

Derek