61 replies to this topic

[Rosssiiii]

Hello everyone,

 

I have a battery like this:

 

https://www.amazon.i...Wgw4.EKDGUSZ-F2 O2JK1LuTUjd-8THNHZpKcczNuSWkRXBpY&dib_tag=se&keywords=ele+ELEOPTION+Batteria+ricaricabile+ricaricabile+12v&qid=1748021074&sprefix=ele+eleoption+batteria+ricaricabile+ricaricabile+12v%2Caps%2C1199&sr=8-5-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9tdGY&psc=1

 

when fully charged it delivers 11.9v and stays more or less on this voltage, dropping in some cases even to 11.7v.

I would like the device I have to power to remain fixed at 12v, how can I build a stabilizer or take an existing one and how much does it cost?

[Zambiadarkskies]

If you really need to, then I have used one of these in the past:  

https://www.amazon.c...1zcF9hdGY&psc=1

[scanner97]

FWIW, a lot of the nominal 12v astro gear out there is not actually too happy at 12v and wants a little more.   (Typically, most astro gear will work fine between 12v and about 14v.)  

 

Most batteries have a discharge curve and the voltage will drop over time as the battery discharges.  Some batteries have fairly flat curves and others less so.

 

You might want to consider an LiFePO4 battery at some point.  These start at about 13.6v when fully charged and drop to ~12.8v at 20% of full charge.   Most astro gear is perfectly fine with this.

 

If your gear is ok at 12.0 v, but the battery drops a little below, you could definitely add in a stabilizer like the one Gilmour linked.  They will typically have an input range (10-36v in that case) and a regulated output (12v in that case.)     

[Zambiadarkskies]

FWIW, a lot of the nominal 12v astro gear out there is not actually too happy at 12v and wants a little more.   (Typically, most astro gear will work fine between 12v and about 14v.)  

 

Most batteries have a discharge curve and the voltage will drop over time as the battery discharges.  Some batteries have fairly flat curves and others less so.

 

You might want to consider an LiFePO4 battery at some point.  These start at about 13.6v when fully charged and drop to ~12.8v at 20% of full charge.   Most astro gear is perfectly fine with this.

 

If your gear is ok at 12.0 v, but the battery drops a little below, you could definitely add in a stabilizer like the one Gilmour linked.  They will typically have an input range (10-36v in that case) and a regulated output (12v in that case.)     

Exactly.   12v is actually generally accepted by a ton of manufacturers as being 13.8v ( throw back to radio gear and vehicles).  A lot of astro gear tops out at 15v, above that use caution.....   LiFePo4 is the way to go if you can. A  regulator will expend battery power (to heat) in maintaining that constant voltage.  I eventually went to bigger and better batteries that can stand the current draw and voltage drop better.  

[terrypaula]

You might want to consider an LiFePO4 battery at some point. I, until recently, have been using a battery booster.  After three years it finally started to discharges way too fast to  be useful for imaging.  I started using a LIFePO4 battery and it stays charged, on average for around 10-20 imaging sessions before needing a recharge

I was so impressed at the LIFePO4 batteries performance I bought one for my boat's trolling motor.

 

I used to contract for Cray Computer and we used a clean voltage filter system from a company named "SOLA" .  The SOLA units filtered the incoming AC voltage to specifications making it easier to maintain and monitor the Cray computer systems internal system bus voltage.  The trouble with the system was cost as each SOLA filter sold for around 1k and they needed several of them per system.

[UP4014Fan]

That brings up a question?  How stable is the voltage from a Celestron Power Tank?  It seems to drive the scope just fine, but after about two hours, the MeLe called it quits and wouldn't restart, while the AVX/Focuser/StarSense Autoguider chugged right along.  I've resorted to plugging the computer back into its supplied 110 transformer, but I'd love to be able to run it off the tank along with the mount.  Since I'm the world's worst at electrical problems (I hated all the conversions in college Physics 102), would some sort of stabilizer benefit me in this case?

[WadeH237]

would some sort of stabilizer benefit me in this case?

Not likely.  It sounds like you need a battery with higher capacity.

 

If you put a buck-boost converter on it to maintain, say 12.8v, the voltage would remain stable until the battery nears exhaustion.  At that point, the converter would draw ever more amperage trying to maintain voltage, until the voltage dropped below the converter's input requirement.  At that point, your battery would be quite dead.  Perhaps dead enough to damage it.

 

There are things that reduce the voltage reaching your gear that are not necessarily depletion of the battery.  For example a cold battery delivers less voltage.  Long cable runs will give you reduced voltage at your gear, even if the voltage at the battery is sufficient.  Using a buck-boost converter near the gear is a great way to keep the voltage correct in the face of these things.

 

But a dead battery is still a dead battery.

[UP4014Fan]

That's what my gut was telling me, but I couldn't figure out why.  Running the MeLe off its transformer is no big deal here at the house.  I'm just looking down the road at a time when I might wander off to a dark field.  

This is like leaving the master on in the airplane with the alternator off or not working.  Everything works just fine until it all goes dark.  You know the voltage regulator fought a valiant battle to the end.  And then you buy a $1,000 battery...

Right now, I got enough problems with cable management!  

Edited by UP4014Fan, 23 May 2025 - 05:35 PM.

[Cliff Hipsher]

You cannot get something for nothing.  

 

What you really need is a rechargeable portable power station that has a Watt Hour (WH) capacity sufficient to drive your equipment for several hours.

 

As an example, if your equipment draws 20 Watts and you want to run the gear for 10 hours, you need a power source that has a minimum capacity of 200Wh.

[UP4014Fan]

You cannot get something for nothing.  

 

What you really need is a rechargeable portable power station that has a Watt Hour (WH) capacity sufficient to drive your equipment for several hours.

 

As an example, if your equipment draws 20 Watts and you want to run the gear for 10 hours, you need a power source that has a minimum capacity of 200Wh.

I get that.  I was more curious if anyone knew of a "tail off" or the power curve of a Celestron Power Tank.  

[Cliff Hipsher]

The easiest way to find out is it use an inline watt meter.

 

I used one similar to help design the power systems for my big camera drones.  When I got back into AP I used one to measure my rig power requirements so I could figure out what kind of Wh capacity I needed to power my rigs.

[XM381]

To stabilize the voltage you need a buck-boost converter like others have said.

 

Here's a 13.8v output: https://www.amazon.c...149&sr=8-5&th=1

 

Here's a 12v one: https://www.amazon.c...149&sr=8-5&th=1

 

And also as other have said, you still need enough watt-hours to supply enough power for the run time you're aiming for. A buck boost won't solve for a completely rundown battery.

 

[UP4014Fan]

To stabilize the voltage you need a buck-boost converter like others have said.

 

Here's a 13.8v output: https://www.amazon.c...149&sr=8-5&th=1

 

Here's a 12v one: https://www.amazon.c...149&sr=8-5&th=1

 

And also as other have said, you still need enough watt-hours to supply enough power for the run time you're aiming for. A buck boost won't solve for a completely rundown battery.

Oh, I get that.  I'm just wondering what the power curve of the Power Tank is (lead-acid battery, BTW), because it kept the scope happy, but the MeLe quit at two hours.  I'm willing to flatten out the curve some (that is, keep the output up) as long as I don't destroy the battery.  

 

And this is what I hated in physics and what I hated when I set up the UAS program at a major railroad - figuring amps draw vs. Watt hours.  In the case of the UAS program, the Federal Aviation Regulations use Watt hours to tell you how many LiPos you could bring on board - and, of course, the battery manufacturers use mAs to tell you the capacity.  That was big deal for both our corporate jets ("Go-Team" events) and when traveling on business.  

[scanner97]

Oh, I get that.  I'm just wondering what the power curve of the Power Tank is (lead-acid battery, BTW), because it kept the scope happy, but the MeLe quit at two hours.  I'm willing to flatten out the curve some (that is, keep the output up) as long as I don't destroy the battery.  

 

The voltage curve also depends on the discharge rate, but you can assume a lead-acid will likely drop below 12v at somewhere aound 1/3 of capacity.  Your PC is probably pulling between 1 and 2A, and the mount under 1A, so the two of them are going to be at 2A+.  If you have the standard power tank, I think that's 7AH, so not surprising there are voltage issues after 2 hours.  The mount is ok at a slightly lower voltage than the PC, which is why the PC quits first.  A lead acid will normally last a few hundred cycles.  Partial discharges will help it last longer, and total discharges will reduce the life, even if they don't kill it outright.   When you have to get a new battery, I'd definitely suggest a LiFe power station.  There are a lot of advantages to the LiFe chemistry.

 

And this is what I hated in physics and what I hated when I set up the UAS program at a major railroad - figuring amps draw vs. Watt hours.

 

There are conversion calculators but you can just multiply the current by the voltage to get power.  So a 7 AH power tank is going to be roughly 85-90 WH.  I think of a 250 WH power station as being on the small side, although it would be fine for a long evening with your gear.  If you had a cooled camera and dew straps as well, it obviously wouldn't last as long.

[XM381]

Oh, I get that.  I'm just wondering what the power curve of the Power Tank is (lead-acid battery, BTW), because it kept the scope happy, but the MeLe quit at two hours.  I'm willing to flatten out the curve some (that is, keep the output up) as long as I don't destroy the battery.  

 

And this is what I hated in physics and what I hated when I set up the UAS program at a major railroad - figuring amps draw vs. Watt hours.  In the case of the UAS program, the Federal Aviation Regulations use Watt hours to tell you how many LiPos you could bring on board - and, of course, the battery manufacturers use mAs to tell you the capacity.  That was big deal for both our corporate jets ("Go-Team" events) and when traveling on business.  

I don't own a MeLe and don't know which one you have, but looking at various ones on their website, the input voltage range is 12 to 20 volts. You are at the bottom end of the range as soon as you start and will drop below that minimum voltage pretty quick without voltage stabilization.

 

 

The lead-acid version of the Celestron Power Tank I saw online says it has a 84 watt-hour capacity. This is because it has a 12 volt 7 amp-hour battery in it. That battery can supply 7 amps for one hour, and the maths to convert to watts is 12 volts * 7 amps = 84 watts, so it will supply 84 watts for one hour. It's easier to use watt-hours when calculating capacity, like this: Say your rig draws 2 amps, 12 volts * 2 amps = 24 watts, that's 24 watts per hour (24 watt-hours). If your Power Tank can do 84 watt-hours, your rig will run for 3.5 hours, 84 / 24 = 3.5 , before the battery is dead. And keep in mind the published watt-hours are from Celestron's Marketing department, not the Engineering department, so the actual usable capacity will be less and decreases as the battery ages.

 

So you may have two issues, the voltage is dropping below the minimum input voltage requirements of the MeLe pretty quickly and even with voltage stabilization the total watt-hour capacity of your battery may not be enough to run your rig as long as you'd like.

 

I use a Jackery Portable Power Station Explorer 240, (240 Watt-hour) and can run all night. Scanner97's comment is spot-on. I think the Celstron Power Tank was meant to run a mount all night, but not a mount, cameras and PC.

Edited by XM381, 24 May 2025 - 07:13 AM.

[flightlogic]

That's what my gut was telling me, but I couldn't figure out why.  Running the MeLe off its transformer is no big deal here at the house.  I'm just looking down the road at a time when I might wander off to a dark field.  

This is like leaving the master on in the airplane with the alternator off or not working.  Everything works just fine until it all goes dark.  You know the voltage regulator fought a valiant battle to the end.  And then you buy a $1,000 battery...

Right now, I got enough problems with cable management!  

Speaking of airplanes.... I once started a V tail Bonanza and it just kept on cranking when I let go of the switch.  That was expensive.  I had to open the cowl, with it spinning and take some wrenches to the main wiring.

I use a good LifePo battery now for Astro.  Light weight and starts out at over 13.8

The ASI Air is happy and the cameras cool quickly.

[joshman]

This is why i roll my own power solutions, the commercial solutions are overpriced, and inadequate IMHO.

 

For remote imaging, I'd usually be camping, so i can tap into the 110Ah LiFePo4 in the back of the car to run my imaging rig.

 

The morning after a long chilly night. We had a light frost, so my dew heaters were running overtime.

 

I had my inline power meter on my setup to capture the particulars of the session:

As you can see it was up for 15 hours, and used ~40Ah / 512Wh to run everything.

 

My suggestion for a battery pack is to (naturally) make your own supply. If you're comfortable with a bit soldering and crimping connectors, it can be done pretty cheaply and easily. I definitely recommend LiFePo4 chemistry, and would not get anything less than ~50-60Ah of capacity.

Edited by joshman, 24 May 2025 - 06:20 PM.

[Rosssiiii]

To stabilize the voltage you need a buck-boost converter like others have said.

 

Here's a 13.8v output: https://www.amazon.c...149&sr=8-5&th=1

 

Here's a 12v one: https://www.amazon.c...149&sr=8-5&th=1

 

And also as other have said, you still need enough watt-hours to supply enough power for the run time you're aiming for. A buck boost won't solve for a completely rundown battery.

But can i use that with my battery that when is fully charged give lower voltage the 12v ?

that device will give an output of 12v if i take that version ?

 

I'm used to solder electronic components because of my hobby for FPV drones, but what cables do I need to buy to do the work ?

 

that on AliExpress could be good anyway ?

 

https://it.aliexpres...3630000490562_4

 

https://it.aliexpres...rch|query_from:

[XM381]

Rosssiiii,

 

Boost Buck converters give a constant output voltage, example for 12 volts output, they "boost" the voltage if the input is less than 12 volts and "buck" when the input voltage is greater than 12 volts.

 

The two you linked from Aliexpress will work fine. If you are just running a mount, the 3 amp should be fine, but you might need a bigger one if you have other equipment, cameras, computers, etc.

 

The battery you linked, says it's 1800mah, that's 1.8 amps for one hour. You might want to figure out how much power you need because this battery might not last very long. The Celestron Power Tank talked about earlier in the thread has about four times the capacity of this battery.

 

Here's the connectors to use:

 

https://www.amazon.i...aWxfdGhlbWF0aWM

[Rosssiiii]

Rosssiiii,

 

Boost Buck converters give a constant output voltage, example for 12 volts output, they "boost" the voltage if the input is less than 12 volts and "buck" when the input voltage is greater than 12 volts.

 

The two you linked from Aliexpress will work fine. If you are just running a mount, the 3 amp should be fine, but you might need a bigger one if you have other equipment, cameras, computers, etc.

 

The battery you linked, says it's 1800mah, that's 1.8 amps for one hour. You might want to figure out how much power you need because this battery might not last very long. The Celestron Power Tank talked about earlier in the thread has about four times the capacity of this battery.

 

Here's the connectors to use:

 

https://www.amazon.i...aWxfdGhlbWF0aWM

With 6A i should be safe right ?

 
Dispositivo	Volt	Ampere 	Watt
ASIAIR	        12V	0.7A	8.4W
GTI	        12V	0.5A	6.0W
ASI 120MM Mini	5V	0.2A	1.0W
ASI 585MC Pro	12V	2.0A 	24.0W

Edited by Rosssiiii, 28 May 2025 - 04:08 AM.

[fishonkevin]

Here is a good article on building your own battery box/power supply if you want to go that route. I built one using this as a guide, slight changes to accomodate my own equipment. In the field I run a Losmandy G11G, Beelink pc, 3 dew heaters, camera, and guide camera. When everything is hooked up and running, the monitor shows I can get 60hrs of power out of a 100ah LiFePo4 battery before recharge. I did use the same buck booster listed in the article, and can varify that it puts out 12.2 vdc continuously. It is on a seperate circuit from the rest of the box, and used only for the Beelink U-59 pc.

 

 https://popupbackpac...e-power-system/

 

 

 

[Drothgeb]

This is why i roll my own power solutions, the commercial solutions are overpriced, and inadequate IMHO.

 

For remote imaging, I'd usually be camping, so i can tap into the 110Ah LiFePo4 in the back of the car to run my imaging rig.

 

The morning after a long chilly night. We had a light frost, so my dew heaters were running overtime.

20230715_074320_rs.jpg

 

I had my inline power meter on my setup to capture the particulars of the session:

20230715_074440_rs.jpg

As you can see it was up for 15 hours, and used ~40Ah / 512Wh to run everything.

 

My suggestion for a battery pack is to (naturally) make your own supply. If you're comfortable with a bit soldering and crimping connectors, it can be done pretty cheaply and easily. I definitely recommend LiFePo4 chemistry, and would not get anything less than ~50-60Ah of capacity.

I’m with you. My wife and I are on the road for months at a time sometimes. To save some bucks, I bought a couple of standard 60ah LiFEPO4 batteries and installed battery monitors and some 12v outlets in them. One them gives me ~750 watts of power and only weighs 14lbs each. I use portable solar panels to charge them.

 

The power tank and etc options are nice, but I get much more power per dollar. Either way you want the higher voltage of a lithium battery.

 

 

[XM381]

 

With 6A i should be safe right ?

 
Dispositivo	Volt	Ampere 	Watt
ASIAIR	        12V	0.7A	8.4W
GTI	        12V	0.5A	6.0W
ASI 120MM Mini	5V	0.2A	1.0W
ASI 585MC Pro	12V	2.0A 	24.0W

I assume the numbers you listed are average consumption and the 6A should be ok, but I would be tempted to get the next bigger size because other than a few extra dollars it does provide additional capacity for peak consumption, like when the mount is slewing it uses more current than tracking, and future growth.

 

I think a challenge you are going to encounter is, if you add up your amps and compare that with the battery you linked in your original post, your have 3.4 amps per hour consumption and the battery can supply 1.8 amps for one hour. Your battery will be run down in about 32 minutes. ( 1.8 battery amp hours / 3.4 consumption amp hours = 0.52 hours capacity) You're going to need bigger battery. If you want to run for 8 hours you'll need about 27 amp hours of battery (3.4 amps * 8 hours), or 324 watt hours (12 volts * 27 amps) And no matter what the math says, batteries always run down quicker than you think they will, so give yourself some extra capacity above your calculations.

 

The link Kevin provided above has some good info.

 

Just to make it a little more confusing; as you see, everyone is talking about lithium batteries. You want lithium. Lead acid is cheaper but only half of the amp-hour capacity is useable because you will ruin a lead acid battery by running it down below about 50% more than a few times. This is not true with lithium, 100% of the capacity is usable.

Edited by XM381, 28 May 2025 - 09:08 AM.

[Drothgeb]

I assume the numbers you listed are average consumption and the 6A should be ok, but I would be tempted to get the next bigger size because other than a few extra dollars it does provide additional capacity for peak consumption, like when the mount is slewing is uses more current than tracking, and future growth.

 

I think a challenge you are going to encounter is, if you add up your amps and compare that with the battery you linked in your original post, your have 3.4 amps per hour consumption and the battery can supply 1.8 amps for one hour. Your battery will be run down in about 32 minutes. ( 1.8 battery amp hours / 3.4 consumption amp hours = 0.52 hours capacity) You're going to need bigger battery. If you want to run for 8 hours you'll need about 27 amp hours of battery (3.4 amps * 8 hours), or 324 watt hours (12 volts * 27 amps) And no matter what the math says, batteries always run down quicker than you think they will, so give yourself some extra capacity above your calculations.

 

The link Kevin provided above has some good info.

 

Just to make it a little more confusing; as you see, everyone is talking about lithium batteries. You want lithium. Lead acid is cheaper but only half of the amp-hour capacity is useable because you will ruin a lead acid battery by running it down below about 50% more than a few times. This is not true with lithium, 100% of the capacity is usable.

I’ve use lithium’s for my astrophotography, bass boat, camper, power storage/inverter in my truck, plus some odds and ends for many years now. You can run lithium batteries down to 100%. But you really shouldn’t go more than 90%, and they’ll last longer if you stop at 80%. 

[soojooko]

You can run lithium batteries down to 100%. But you really shouldn’t go more than 90%, and they’ll last longer if you stop at 80%. 

Yep. They don't like being fully charged either. Keeping lithium batteries between 20% and 80% charged seriously extends their lifespan.

 

I have also been using a 240wh/70ah LifePo4 battery for the last 2 years. It's been working really well for me. At £120, it was one of my best investments.