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12 V Lithium Battery Power Tank 48 Ah

equipment mount EAA ccd astrophotography
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#1 Michaeljhogan

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Posted 17 August 2019 - 02:01 PM

Hello i need a strong power tank for my Observetory i already have a 12v 17ah powertank but its not enough to run it

i have to run two dew straps a ASI294mc Pro a Intel NUC and the CEM120 mount all five together its way to much

they all lasted three hours the tank was nearly dead but as soon as i pulled out the two dew straps the red warning

light went off but the damage was done so i will now only use that tank on its own for the dew straps.

 

So anybody know much about these new Lithium power tanks and do they live up to the hype

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  • lithium-batterie-1000.jpg
  • lit.jpg


#2 Michaeljhogan

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Posted 17 August 2019 - 02:02 PM

Here is the old 12v 17ah tank that i will keep for the dew straps

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#3 ngc7319_20

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Posted 17 August 2019 - 02:25 PM

Theres also these...

 

https://dakotalithiu...2v-40-amp-hours

 

$600 though....


Edited by ngc7319_20, 17 August 2019 - 02:26 PM.


#4 sg6

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Posted 17 August 2019 - 02:36 PM

Searched for options for my 2 small scopes and found that Lithium ion were "better".

They cost less and the output does not drop as much after time. They both drop and so expect say around 11.5 maybe 11 volts.

 

Big problem is cost. A large capacity battery costs a lot. One that appeared in a search here says 12v 100Ah and £778, about $1000. Although I expect lesser cost ones as in other searches I have found Shido 4Ah motor cycle batteries range from £38 to £70.

 

As your 17Ah lasted 3 hours how long do you want one to go for ? Overnight say 8 hours?

 

Lithium will discharge for longer and still be usable. Think you can discharge to around 80%. They do not self discharge by a lot and anyway it reads that you will be regularily charging and using whatever.

 

I use 2 Li batteries and have been happy with them. Never had a problem charging and never detected any heating or warming of the batteries.

 

Lithium ion batteries do age, they say 500-1000 charge cycles then the efficency drops off. Just that if used regularily that could be say 3 years, likely more with the general weather. But a point.

 

The size is the question, at a guess you want around 60Ah - bit that is a guess only. Equally equipment seems to get added continuouly.

 

I would suggest looking at a replacement car battery in Lithium form. Half the reason is they seem to have circuitry to use a standard car battery charger.

 

May need to identify the construction as LiFePO run at 3.2v so for 12v the battery need a bank of 4. Li-ion run at 3.6-3.7v so 4 in parallel give 14.2v at startup. Just wonder if some try 3 banks and so fall a bit short in voltage terms.

 

Li-Plus-Minus

 

The above came up and looks fairly balanced.

 

Could you run a protected mains supply to the observatory?

Is charging by mains or by solar?



#5 ngc7319_20

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Posted 17 August 2019 - 03:25 PM

Cost is a factor to me.  I use these $35 12V 18AH sealed  lead acid batteries.  I get about 7 years of out them.  For an observatory where weight is less of an issue -- not transporting them anywhere -- I'm not sure Lithium is the optimal choice.

https://www.batterym...-battery-1.html

 

The other concern I might have is just the quality / lifetime of the Lithium units.  If the Lithium pack fails soon after the 1 yr warrantee is up -- $600 is a lot of money invested if it fails.



#6 Luca Artesky

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Posted 18 August 2019 - 03:28 AM

Hello i need a strong power tank for my Observetory i already have a 12v 17ah powertank but its not enough to run it

i have to run two dew straps a ASI294mc Pro a Intel NUC and the CEM120 mount all five together its way to much

they all lasted three hours the tank was nearly dead but as soon as i pulled out the two dew straps the red warning

light went off but the damage was done so i will now only use that tank on its own for the dew straps.

 

So anybody know much about these new Lithium power tanks and do they live up to the hype

Hello!

 

With those PLB you can run your scope for several hourse

 

For example, I personally use the 70Ah model with a GM1000, a PC, a QSI583 Special and it works fine up to 12 hours

My PC is an HP workstation laptop



#7 Michaeljhogan

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Posted 18 August 2019 - 12:10 PM

Hello!

 

With those PLB you can run your scope for several hourse

 

For example, I personally use the 70Ah model with a GM1000, a PC, a QSI583 Special and it works fine up to 12 hours

My PC is an HP workstation laptop

if their is only Two 12 V outputs how am i to run my mount ccd and Intel NUC ? can you post some images of the accessories

i need like Pegasus Astro Pocket Powerbox ?

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  • 12v-3fach-1000.jpg

Edited by Michaeljhogan, 18 August 2019 - 12:21 PM.


#8 synfinatic

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Posted 18 August 2019 - 01:07 PM

Sounds like you've learned that just like you can't drive your car from San Francisco to Miami on a single tank of gas, a 17ah battery won't run all your equipment all night.

 

What you really need to do is some basic math to calculate your power requirements and then add "some buffer" because all batteries drop voltage as they discharge.  Ie: a 12V lithium or lead-acid battery is just "nominally" 12V.  They will start out higher than that and then drop voltage over time.

 

You didn't say what model NUC you have- most require 19V DC so I assume you're using a step-up converter?  That also has an efficiency rating.  If you don't know what it is, 80% is reasonable guess.

 

Anyways you need to know the simple formula:

 

Amps = Watts / Voltage

 

And 1 Amp draw for 1 hour is 1ah (amp hour).  So basically your 17ah battery can last 17 hours with a 1 amp draw or 1 hour with a 17 amp draw.  (Well actually less, you'll never see 100% draw down as that would damage the battery.).

 

So for example your ASI camera's cooler requires up to 3Amps @ 12V.  So in 3 hours, it's going to consume 9ah out of 17ah from your battery (worst case).

 

Assuming your NUC is 19V and pulls 20W (reasonable guess) you'd need to convert that into 12V Amps:

 

20W  * 1.2 = 24W (assumes 80% efficiency of voltage conversion)

24W / 12V = 2A

 

Hence, 20W @ 19V equates to 2A @ 12V.

 

So between your camera cooler and NUC you might be seeing 5ah draw per hour.  So not surprising at all that your 17ah battery only lasted 3 hours.

 

Once you determine how many total Amps your equipment is drawing, you'll be able to select the correct size battery (or batteries) for your needs.  Lastly, be aware that many battery types can be permanently damaged if discharged all the way down.  Some kinds of batteries only want to be 50% discharged and no more.  Many Li-Ion batteries have built in battery protect circuits to prevent discharging below the point where they would be damaged.


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#9 astrovoyeur

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Posted 18 August 2019 - 01:39 PM

The problem with lithium 12v power pack is the amp hour capacities are based on a cutoff voltage of around 9 volts.  Which most 12v electronics aren't designed to function at.  

 

Your biggest bang for the buck would be a car battery.   A group 65 is rated at approx 55 amp hours to 10.5 volts.   I can usually get 5-7 years usage out of the bargain brand walmart sells for $50. 

 

https://www.walmart....oup-65/47308796


Edited by astrovoyeur, 18 August 2019 - 01:41 PM.

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#10 synfinatic

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Posted 18 August 2019 - 02:32 PM

The problem with lithium 12v power pack is the amp hour capacities are based on a cutoff voltage of around 9 volts.  Which most 12v electronics aren't designed to function at.  

 

Your biggest bang for the buck would be a car battery.   A group 65 is rated at approx 55 amp hours to 10.5 volts.   I can usually get 5-7 years usage out of the bargain brand walmart sells for $50. 

 

https://www.walmart....oup-65/47308796

This is a good point, although in practice things like dew straps and camera coolers are pretty tolerant.  Computers though, are very intolerant and really do want the specified voltage.  You can use a decent buck/boost voltage regulator to deal with the fact that 12V batteries are almost either over or under the specified voltage. 

 

Here's one which would work great for an Intel NUC for example: https://www.amazon.c...uct/B01DXEU4KA/

 

Car batteries aren't IMHO ideal because they're designed for short periods of very high amps and will see a lower life expectancy if you discharge them too much.  Of course, you can always get a really big car battery so your depth of discharge is lower, but then you're dealing with a larger/heavier battery.  If you want to go lead-acid, deep cycle batteries with their thicker lead plates are more appropriate.  Not to say you can't use a car battery, but it depends on how often you're using it as you'll still get a 100-300 cycles out of a car battery @ 50% depth of discharge.  It's just that you'll get more cycles at a deeper discharge depth with a deep cycle battery of equivalent capacity.

 

Also consider if you ever plan on traveling and doing a multi-night event?  In more remote/dark areas, finding AC power to charge your battery may be difficult so having additional capacity or the ability to discharge deeper may be useful to you.

 

Also: lead-acid batteries exhibit "self-discharge" and will loose power just sitting around after a few months.  Lithium batteries can sit a year and still have most of their power.  So keep your lead-acid batteries on a trickle charger when not in use.



#11 astrovoyeur

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Posted 18 August 2019 - 06:58 PM

 You can use a decent buck/boost voltage regulator to deal with the fact that 12V batteries are almost either over or under the specified voltage. 

 

 

Car batteries aren't IMHO ideal because they're designed for short periods of very high amps and will see a lower life expectancy if you discharge them too much.  Of course, you can always get a really big car battery so your depth of discharge is lower, but then you're dealing with a larger/heavier battery.  If you want to go lead-acid, deep cycle batteries with their thicker lead plates are more appropriate.  Not to say you can't use a car battery, but it depends on how often you're using it as you'll still get a 100-300 cycles out of a car battery @ 50% depth of discharge.  It's just that you'll get more cycles at a deeper discharge depth with a deep cycle battery of equivalent capacity.

 

Also consider if you ever plan on traveling and doing a multi-night event?  In more remote/dark areas, finding AC power to charge your battery may be difficult so having additional capacity or the ability to discharge deeper may be useful to you.

 

Also: lead-acid batteries exhibit "self-discharge" and will loose power just sitting around after a few months.  Lithium batteries can sit a year and still have most of their power.  So keep your lead-acid batteries on a trickle charger when not in use.

I'm very familiar with boost/buck converters and have been using one with a 12v lithium jumper pack for portable power.    However it can be very difficult to find legit lithium cells that are truly what they are labeled.  The technology is not only expensive when its legit but even more so when you find your pack is filled with sub standard counterfeit cells.  

 

As for whether lithium likes being stored fully charged is debatable.   I know DJI the maker of my drones, insist their lithiums not be stored fully charged and has a circuit built in the cells to discharge them to 50% after 2 weeks.   Lithium also becomes a hazard when fully charged and subject to heat. 

 

Another issue with the 12v lithiums is they typically have a minimum current draw allowed or they auto off in one minute.   Usually the threshold is around 50 -250ma depending on the brand.  I know of several brands that do this including Talent Cells, which is why I'm using a lithium jump pack.   It doesn't seem to exhibit the behavior.

 

As for the car battery, yes they are heavy 34lbs but that can be used to stabilize your scope.  I have one mounted on each of my scope carts, making them highly mobile. Recharging is a snap with the charging station setup in my garage.  They can also be quickly charged in the field using jumper cables attached to your car's battery.   

 

Overall, given car batteries are cheap, plentiful and made in the states I don't see how one can go wrong.     And based on my experience with the deep cycle batteries I've used over the years with my boat's trolling motor, I wouldn't waste the extra dollars for that either.   As it is I've been getting 5-7 years from a new battery or 2-3yrs from my car's old battery that I replace every 3 years.



#12 MikeMiller

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Posted 17 September 2019 - 12:36 PM

if their is only Two 12 V outputs how am i to run my mount ccd and Intel NUC ? can you post some images of the accessories

i need like Pegasus Astro Pocket Powerbox ?

I had this exact item that I got from Amazon. It caught on fire. (Well, it smoldered for a bit and I unplugged it right away.)

 

A better option is to use a better distribution box, the car-plugs are untrustworthy even when not flammable. Looking at them wrong will cause them to disconnect, and that might ruin an entire night of imaging for you. Also they are huge compared to nearly every other option.

 

While the Pegasus Powerbox is great, and I recommend it (I have 2 of them), they are expensive. Another good solution is Anderson Powerpoles. Before getting the Pegasus, I used one of these on my ota:

 

https://powerwerx.co...tribution-block

 

They also make ones with fuse holders inline and per-output.




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