Hi there, I'm sure at least some of you have tried to optimize portable power solutions as I am currently doing. What I want is the following:
- Li-ion battery pack with good capacity
- 12V DC cigarette lighter outlets to run mount
- 240V AC pure sign wave output to charge my laptop/mount
- Light (optional)
- Reasonable price
Everything you need can be done via a 12v battery. I was fossicking around for an inverter for my laptop when it occurred to me that there are plenty of car chargers for laptops ...$18 later I had ordered one and I can now run everything for a night off an 98AH battery. When I pack up I put it on charge so the next clear night in 3 weeks it's charged.... well, it's charged by the time I wake up really.
If you really want to run an inverter, go for it, but if you want to keep it simple, auction sites are your friend.
My only contribution would be to add that whatever option you choose, have some form of backup. If you're anything like me, things will go flat / fail to be charged right when you need them...
I got most of my power needs from Jaycar, I only got 9ah batteries but a few of them as I had a multi-battery charger already and bought a marine cigarette socket.
They also stock plenty of power convertors for cigarette sockets, I got 1 with about 6 power settings and multiple connectors for about $15. So it can do my phone or just about anything else so far.
I used silicone over the terminals and the marine cigarette socket to keep the dew out.
A few batteries 9ah and the socket all for under $100. The cheap pine for a bracket and its keeps them all nicely in my DOB base with no trip hazards. I preferred to swap over a smaller battery if needed, than lug a larger AH battery around.
Steve
Ps. The marine socket plug also come with 1,2 or 4 socket heads for multiple connections.
Andrew, I would be very cautious about using cigarette lighter outlets and connectors. There are many previous posts here on IIS bemoaning their poor reliability, especially in cold and wet/dewy conditions when observing/imaging. A few extra dollars spent on better connectors will pay off in the long run. Merit plugs are the next step in quality and reliability, but perhaps the best options are Anderson Plugs. I would recommend you spend some time getting a clear picture of what connectors system will be best for your use and particularly the operating conditions. These need to be 100% reliable.
Would agree this is one of the most important parts as a power outage due to a connector is frustrating when everything has been set up and the power goes due to a dogey connection. I dont mind LiPo but found an eq mount sucks these dry quickly. Dob goto and altaz seem to fair better. Agree you need to know your requirements of power and the conditions you will use them in as some types of batteries and kit fair better with weather extremes of hot and cold.
Jaycar has some good options. Plugs that a firm or screw in tend to work well. That is why i like the azeq6 connector.
One point to be made is placing the sockets facing straight down not parallel to the ground which ever one you buy. Water is pretty reluctant to run back up hill.
We have a 4 point marine socket mounted on a wooden ledge in the boat. The sockets point strait down and the ledge provides additional water protection. We have fished in rain and heavy sea spray and never had a problem.
Be ware that a lot (all maybe) of the amazon car starter batteries quote a mAh thats not at 12v but instead at 3.7v which is the voltage of a lipo cell. (Probably jay car too)
you can tell because the wattHours is amp hours (42) x voltage == 155Wh
They probably have 4 cells to get >12v so you can divide the amp hours by 4. then maybe half it again if you are likely to average 2Amps of usage to find the true time the battery will last.
And thats assuming they arent inflating the numbers anyway.
I have that Jackery 240 and can say it's an amazing bit of kit. I decided not to look at deep cycle marine batteries. Too many things to consider, especially about keeping it above a certain power level.
Jackery is also slightly expensive, and you can do the same thing (I've also got this) with a LiFe Po4 battery, and adapters to your mount. I bought the adapters from Jaycar for cheap. The battery cost $110.
LiFe Po4 is also a lithium battery (not the same as the Jackery) and will give you more recharge cycles than marine batterys, is MUCH lighter, easier to carry, smaller, and can discharge to a smaller capacity.
If you're new to this, I recommend staying away from the old tech, and embrace the new
PM me if you want pictures of the battery setup, happy to show more if you want.
edit: forgot to add, Jackery is a regulated 12V lithium power bank. That means you will get 12V minimum (usually circa 13v) no matter the capacity. Other lithium batteries will drop voltage as you use the battery. For my mount (EQ6-R) a stable power supply is a must.
There is another power bank coming called the Bluetti AC50S (not to be confused with the older AC50) that is also regulated. It's out in the UK and US and Japan, but no local adapters yet. It will also charge faster than the Jackery, which is the Jackery's only main problem (mains charging peaks at 48W). I've been chasing the company to release an Aussie version, which they will do but they are slow.
I have that Jackery 240 and can say it's an amazing bit of kit. I decided not to look at deep cycle marine batteries. Too many things to consider, especially about keeping it above a certain power level.
Jackery is also slightly expensive, and you can do the same thing (I've also got this) with a LiFe Po4 battery, and adapters to your mount. I bought the adapters from Jaycar for cheap. The battery cost $110.
LiFe Po4 is also a lithium battery (not the same as the Jackery) and will give you more recharge cycles than marine batterys, is MUCH lighter, easier to carry, smaller, and can discharge to a smaller capacity.
If you're new to this, I recommend staying away from the old tech, and embrace the new
PM me if you want pictures of the battery setup, happy to show more if you want.
edit: forgot to add, Jackery is a regulated 12V lithium power bank. That means you will get 12V minimum (usually circa 13v) no matter the capacity. Other lithium batteries will drop voltage as you use the battery. For my mount (EQ6-R) a stable power supply is a must.
There is another power bank coming called the Bluetti AC50S (not to be confused with the older AC50) that is also regulated. It's out in the UK and US and Japan, but no local adapters yet. It will also charge faster than the Jackery, which is the Jackery's only main problem (mains charging peaks at 48W). I've been chasing the company to release an Aussie version, which they will do but they are slow.
I’m also in the market for a good power solution for astronomy. I do have the celestron lithium 158Wh LifePro but I haven’t yet used it in anger but not convinced it will power everything. I have a Prima Luce Lab Eagle4S computer and the focuser, mount, dew straps and cooled camera will all plug in to that whilst the Eagle needs a good power source. I could use the Celestron just for the mount and the Jackery for everything else. Would it be sufficient?
I’m used to older deep cycle batteries telling me how many amp hours they provide but the Jackery doesn’t seem to say what it provides. What is it?
I have carried out my final measurement, I can get 24 hours continuous operation from 12V 48Ahr, that is with a 20% margin added. I think that would be enough for my needs
I have carried out my final measurement, I can get 24 hours continuous operation from 12V 48Ahr, that is with a 20% margin added. I think that would be enough for my needs
What exactly can you power for 24 hours? Not a mount constantly spewing that’s for sure 🤣
For the mount, its within margin of error, my mounts steppers only pull 330mA @ 6V on average with just RA, or about 160mAh @12V when converted with a DC-DC converter, I will be swapping things out later, so this may change, but modern drivers drop the voltage to hold the current, so the total power consumed by the steppers is usually low.
Leaving lots of headroom for other things, e.g. my camera only draws 280mA @ 7.2V, or about an extra 160mAh @ 12V, it becomes lower if you turn off the screen. if for instance I set it up for external power (very easy to trick the camera)
If you got fancier, say threw a guiding camera and some small PC to run PHD and other stuff, e.g. an intel compute stick, well the camera is max 500mA @ 5V, and the compute stick is 10W max, so adding a max of 200mAh for the camera, and a max of 790mAh for the computer,
For a total of about 1.3Ah consumption max, you could throw on a focuser, filter wheel and other accesories with that capacity battery and still be well within margin.
Your still looking at an expectation of greater than 24 hours runtime before the battery becomes flat.
My Jackery can last about 5 hours at best, powering my EQ6-R, dew heater, and Surface Book 2. The latter usually draws 40-45W from the battery when idle, but can spike to about 100Wh when pushed. It's a powerful laptop, and so draws a commesurate amount of power.
But mostly it sits in the 40-45Wh range.
The Jackery is 240W (my one anyway, there are other options), and with about 90% usable capacity, that means circa 215Wh. That puts it at just under 5 hours draw to zero.
I usually run it down to about 30%, then plug in my other LiFe PO4 battery to keep it at that level.
That's a 192Wh battery, which will give another 3-4 hours or so if required (usually isn't).
edit: oh and as for your link, be really careful with any power supply that can't guarantee 12V output. Deep cycle batteries can as they usually pump out 13-15V pretty reliably, but only until 50% capacity.
Lithium is different; not all lithiums are the same. Look for a regulated DC output. Jackery has a regulated output which will guarantee 12V output.
I actually wrote to the company in that link many months ago, and they confirmed their unit wasn't regulated.
This is important for many mounts that stall and don't slew correctly when they get undervolted power. The EQ6-R (my mount) is one of these.