Before you buy a Power Bank from Talent Cell or Others Please Read This

[curtisca17]

I bought a Talent Cell 8.3Ah power bank to take with me on an airplane to image the total solar eclipse in 2017 and have used it occasionally since for public outreach and for some simple power needs.  I never really used it for a demanding power application and never paid much attention to its design and ultimate performance.  But now that I have a detailed understanding of lithium battery technology I decided to buy several additional capacity versions of these to test when I read about folks having problems using them powering their ZWO AM5 mounts or their ASIAIRs.  I was surprised to learn that these are not designed to be 12V power supplies like the portable power stations from Jackery, Bluetti, etc. nor like a stand alone 12V LiFePO4 batteries.  In fact, they don't even output 12V when a load is supplied.  Now, as I mentioned, they do work with much of our astronomy equipment since many 12V devices can handle some level of voltage below 12V.   But there are limits.  And, even in those cases that work, we will not get the advertised capacity of the power bank since the voltage drops rapidly below 11V.   I made a video of my tests which show that the output voltage is not what you should expect from a 12V battery and explain how they scrimped on the design to minimize cost and reduce the size and weight of these power banks.  I do show one model of the Talent Cell power banks which is a "true" 12V battery.  So if you are thinking of purchasing a power bank from Talent Cell or anyone else, or if you have one you might want to view the video.   You can find it here https://www.youtube.com/watch?v=2Zm-tGT40No

Best Regards,

Curtis

[ONIKKINEN]

Yep, you should never use a "dumb" unregulated 12V power supply as a primary power source for astro kit. I have had 2 small ones like this, (a Celestron 84wh one and a car jump pack) and both become unusable after just a few minutes of load.

For travelling astrophotographers a proper power station like a jackery or similar is a must have in my opinion.

[Richard N]

Yes. Unregulated power banks based on LiPo batteries will soon drop below 12 Volts. My AZgti mount is very sensitive to this (in part due to the additional voltage drop of the power lead). I now use Lithium Iron Phosphate batteries. So far no issues. 

[curtisca17]

Richard -  these power banks do not use Lithium Polymer cells, which I assume is what you mean by LiPo.  They use LiNiMnCoO2 which is not a problem if designed correctly like a Jackery which uses the same cells.

[curtisca17]

53 minutes ago, ONIKKINEN said:

Yep, you should never use a "dumb" unregulated 12V power supply as a primary power source for astro kit. I have had 2 small ones like this, (a Celestron 84wh one and a car jump pack) and both become unusable after just a few minutes of load.

For travelling astrophotographers a proper power station like a jackery or similar is a must have in my opinion.

Well, not exactly.  Talent Cell does offer one version of a power bank with LiFePO4 which does not have a voltage regulator which works perfectly fine.  As does any LiFePO4 battery as the voltage remains above 12V for at least 90% of its capacity.  Voltage regulation is required for any power supply using LiNiMnCoO2 like a Jackery because the cell voltage will not add up to the voltage of a 12V battery with an even number of cells.  4 cells in series give 14.4 - 14.8V so a voltage regulator is needed.  3 cells fall too short of 12V and, hence, don't provide 12V.

[ONIKKINEN]

11 minutes ago, curtisca17 said:

Well, not exactly.  Talent Cell does offer one version of a power bank with LiFePO4 which does not have a voltage regulator which works perfectly fine.  As does any LiFePO4 battery as the voltage remains above 12V for at least 90% of its capacity.  Voltage regulation is required for any power supply using LiNiMnCoO2 like a Jackery because the cell voltage will not add up to the voltage of a 12V battery with an even number of cells.  4 cells in series give 14.4 - 14.8V so a voltage regulator is needed.  3 cells fall too short of 12V and, hence, don't provide 12V.

Well, that might be a California thing, but here where the average imaging temperature is well below 0 an unregulated power supply (of any type) will simply be trouble waiting to happen.

[Richard N]

38 minutes ago, curtisca17 said:

Richard -  these power banks do not use Lithium Polymer cells, which I assume is what you mean by LiPo.  They use LiNiMnCoO2 which is not a problem if designed correctly like a Jackery which uses the same cells.

Some do use LiPo batteries. My Tracker power bank does. But as you say, it’s all about the design. 

[curtisca17]

1 hour ago, Richard N said:

Some do use LiPo batteries. My Tracker power bank does. But as you say, it’s all about the design. 

Good to know.  I am not familiar with that brand.

[curtisca17]

1 hour ago, ONIKKINEN said:

Well, that might be a California thing, but here where the average imaging temperature is well below 0 an unregulated power supply (of any type) will simply be trouble waiting to happen.

I stand corrected.  

[900SL]

I checked mine with a voltmeter under load at 50% reserve, was running 12.4V and no issues with any gear. I only use it for a lightweight travel rig, so a cooled camera, ASI Air Pro and tracker, no dew heaters.

I think the max draw was 1A on the 12V 5.5 x 2.1 socket. I don't plan on using it in cold weather. 

This does have a dedicated 12V/24V outlet, 12V USB-C PD  and possibly onboard regulation. So far I'm pretty happy with it

 

[Elp]

Time will tell. I bought a 72W 100WH one and it's the only one which powers my whole AP rig as one power source, feeding the asiair then using the 12v outs in the asiair to power my mounts including my gem28 and my cameras. I mention this as my gem28 is sensitive to voltage drop, it refuses to work in the same configuration with my "regulated" Celestron Lithium LTs designed for 12v out usage "with minimal voltage drop". 

Amp draw has more of an impact I believe because if I have dew heaters plugged in something else turns off so they need to be powered separately. It's also happened when I used a usb WiFi extender.

Edited July 30, 2023 by Elp

[curtisca17]

41 minutes ago, 900SL said:

I checked mine with a voltmeter under load at 50% reserve, was running 12.4V and no issues with any gear. I only use it for a lightweight travel rig, so a cooled camera, ASI Air Pro and tracker, no dew heaters.

I think the max draw was 1A on the 12V 5.5 x 2.1 socket. I don't plan on using it in cold weather. 

This does have a dedicated 12V/24V outlet, 12V USB-C PD  and possibly onboard regulation. So far I'm pretty happy with it

 

That is a completely different design from the 12V power banks.  It is sold as a 24V down to 12V DC but I suspect it has the same design flaw for supplying 24V that the Talent Cell has for supplying 12V.  Talent Cell also has some of these 24/12V models as well.  I am quite certain that the 12V output works well supplying 12V for almost all of the capacity, but will most likely drop well below 24V once any load is applied.  It all has to do with cutting corners on the number of cells in series using LiNiMnCoO2 cells.  Since I haven't tested one of these I may be wrong about the 24V output and would be curious to hear from any one who has actually checked that voltage with a load.

[curtisca17]

26 minutes ago, Elp said:

Time will tell. I bought a 72W 100WH one and it's the only one which powers my whole AP rig as one power source, feeding the asiair then using the 12v outs in the asiair to power my mounts including my gem28 and my cameras. I mention this as my gem28 is sensitive to voltage drop, it refuses to work in the same configuration with my "regulated" Celestron Lithium LTs designed for 12v out usage "with minimal voltage drop". 

Amp draw has more of an impact I believe because if I have dew heaters plugged in something else turns off so they need to be powered separately. It's also happened when I used a usb WiFi extender.

That is the model I bought back in 2017.  It has the same design problem, trying to get away with 3 LiNiMnCoO2 cells in series, as most of the other designs.  The voltage drops below 12V as soon as a load is applied.  It works with my Celestron 6Se and iOptron Cube Pro even down to 10.3V but others have reported problems with these power banks on the ZWO AM5.  Amp draw will certainly drop the voltage faster.   

[Elp]

This was one of the reasons I opted for a hem15 over an am3. Goto with the latter is almost twice the amp draw at 1.7A compared to 0.8A.

[EarthLife]

The easy solution to this problem is to use a boost regulator on the 12V output, something like this will give a couple of amps capability .. https://www.ebay.co.uk/itm/374835259124

You can get higher current/power units from places like AliExpress etc if you want more output current capability.

You will get more than 12V output from the boost regulator/converter, you simply adjust/set it to say something like 13.5V or 14V, which is perfectly fine. Once set you will have a constant regulated DC supply for whatever you want. Just try not to drain the power banks battery too much as some battery types don't always recover too well from being over discharged.

 

Edited July 31, 2023 by EarthLife
typo

[Carbon Brush]

I think many of the above posts have nicely demonstrated how 'specmanship' on sales flyers does not always match up to reality.
How do we tell the difference between the good and unsuitable if we are non technical?
Saying buy Bloggs, or Smith branded and avoid Jones brands works today, but not next year when models have changed.

You need a handful of car bulbs, a few bits of wire and a voltmeter. Nothing advanced.
A car sidelight is about 5W/6W. That is 0.5A on a 12V supply.
Brake or indicator lights are 21W, or 1.75A.
Headlamps vary but think of 55W usually, or about 4.5A.

Measure the powerpack voltage on zero load. Then measure it on assorted lamp loads.
If it drops by more than 1V between no load and a brake light, it is not suitable.
If it drops below 12V on a headlight, it may cause issues when slewing a big scope.
A small powerpack might shut down on headlamp bulb inrush. nothing unexpected here.
If it provides 16V on no load, read the specification for the camera & mount before connecting! It could get expensive!

You next test involves a clock. Read the amp hour rating from the powerpack.

Connect a number of bulbs to discharge the powerpack in 3 to 5 hours.
Set it going and monitor the voltage at intervals.
For example a 10Ah pack should power a 1.75A brake light for 10/1.75 = 5.7 hours.
Fine at room temperature. Now repeat the test at 3-4C. Put the powerpack in your fridge and run the test again.
Do not try this test at -18C in your freezer. Lithium cells don't work this cold and you can cause damage.
Lithium is fine to freezing point-ish and perfrms almost as well as at room temperature.
As an aside, if you did this test using a lead acid battery, you would see a significant performance dip in the cold.

You can see I have avoided having to know anything about cell chemistry, internal protection circuits, regulators, etc.
The test equipment is nothing more than any of us have kicking around the house or garage.
The results are produced in daylight and give you the confidence your powerpack won't let you down half way through imaging.
More important. You know the powerpack is not risking wrecking your £1000 mount or camera.

HTH, David.

 

[Richard N]

1 hour ago, Carbon Brush said:

I think many of the above posts have nicely demonstrated how 'specmanship' on sales flyers does not always match up to reality.
How do we tell the difference between the good and unsuitable if we are non technical?
Saying buy Bloggs, or Smith branded and avoid Jones brands works today, but not next year when models have changed.

You need a handful of car bulbs, a few bits of wire and a voltmeter. Nothing advanced.
A car sidelight is about 5W/6W. That is 0.5A on a 12V supply.
Brake or indicator lights are 21W, or 1.75A.
Headlamps vary but think of 55W usually, or about 4.5A.

Measure the powerpack voltage on zero load. Then measure it on assorted lamp loads.
If it drops by more than 1V between no load and a brake light, it is not suitable.
If it drops below 12V on a headlight, it may cause issues when slewing a big scope.
A small powerpack might shut down on headlamp bulb inrush. nothing unexpected here.
If it provides 16V on no load, read the specification for the camera & mount before connecting! It could get expensive!

You next test involves a clock. Read the amp hour rating from the powerpack.

Connect a number of bulbs to discharge the powerpack in 3 to 5 hours.
Set it going and monitor the voltage at intervals.
For example a 10Ah pack should power a 1.75A brake light for 10/1.75 = 5.7 hours.
Fine at room temperature. Now repeat the test at 3-4C. Put the powerpack in your fridge and run the test again.
Do not try this test at -18C in your freezer. Lithium cells don't work this cold and you can cause damage.
Lithium is fine to freezing point-ish and perfrms almost as well as at room temperature.
As an aside, if you did this test using a lead acid battery, you would see a significant performance dip in the cold.

You can see I have avoided having to know anything about cell chemistry, internal protection circuits, regulators, etc.
The test equipment is nothing more than any of us have kicking around the house or garage.
The results are produced in daylight and give you the confidence your powerpack won't let you down half way through imaging.
More important. You know the powerpack is not risking wrecking your £1000 mount or camera.

HTH, David.

 

All good info. However the voltage drop on some power cables can be significant too. 

[curtisca17]

19 hours ago, EarthLife said:

The easy solution to this problem is to use a boost regulator on the 12V output, something like this will give a couple of amps capability .. https://www.ebay.co.uk/itm/374835259124

You can get higher current/power units from places like AliExpress etc if you want more output current capability.

You will get more than 12V output from the boost regulator/converter, you simply adjust/set it to say something like 13.5V or 14V, which is perfectly fine. Once set you will have a constant regulated DC supply for whatever you want. Just try not to drain the power banks battery too much as some battery types don't always recover too well from being over discharged.

 

Yes, one can put a band aid on a bad design to get it working, but there is no free lunch.  A boost converter will give the voltage needed but will not be able to do it for the rated capacity.  So, for instance, you are paying for 72Wh at 12V but only getting, say 55Wh.  I don't consider that fair advertising. 

[curtisca17]

18 hours ago, Carbon Brush said:

Do not try this test at -18C in your freezer. Lithium cells don't work this cold and you can cause damage.
Lithium is fine to freezing point-ish and perfrms almost as well as at room temperature.
 

You can see I have avoided having to know anything about cell chemistry, internal protection circuits, regulators, etc.

 

Nothing wrong with your suggestion for testing with simple equipment.  Good input.  But avoiding knowing about Lithium chemistry, or at least Lithium battery specs has led to incorrect information about Lithium battery operating temperatures.  Lithium batteries are rated to supply current down to -20C so a -18C test would be ok.  Of course, all battery chemistries become sluggish at lower temps, but the nice thing about Lithium is it performs much better than lead acid at cold temps.  

Now, do not charge below 0C as that is a completely different situation which will lead, at first, to loss in battery capacity as the Li ions plate as Li metal on the cathode, and eventually in the worst case form dendrites which short through the separator leading to catastrophic failure.

I like simple tests like you proposed, but I also like understanding things more than not.  But maybe that's just the physicist in me.

 

Best Regards,

Curtis

 

[AstroKeith]

3 hours ago, curtisca17 said:

Yes, one can put a band aid on a bad design to get it working, but there is no free lunch.  A boost converter will give the voltage needed but will not be able to do it for the rated capacity.  So, for instance, you are paying for 72Wh at 12V but only getting, say 55Wh.  I don't consider that fair advertising. 

I believe a so called boost converter will allow you to get the stated capacity out a lot of the time.

Advertising gives a capacity which is either a) available from a lower regulated voltage output, ie 5V USB, or b) unregulated 12V output allowed to drop down to 10V (or even less). Neither of these is right for most astronomy set ups. So using a boost converter allows you to get a useable voltage right up to the point where the pack shuts down at say 10V. You will lose about 5% with a good converter, but in case a) that will already be factored in.

I've started to use USB C to 5.5/2.1MM converters that have a PD trigger circuit in them. See below. With a power pack with PD or equivalent outputs I'm getting the rated capacity at a perfect 12V. 

 

[adyj1]

56 minutes ago, AstroKeith said:

I've started to use USB C to 5.5/2.1MM converters that have a PD trigger circuit in them.

Today I learned these existed... 😮

Ordered a couple from ebay 👍 

Ady

[Shimrod]

1 hour ago, AstroKeith said:

I've started to use USB C to 5.5/2.1MM converters that have a PD trigger circuit in them. See below. With a power pack with PD or equivalent outputs I'm getting the rated capacity at a perfect 12V. 

 

 

 

19 minutes ago, adyj1 said:

Today I learned these existed... 😮

Ordered a couple from ebay 👍 

Ady

 

Could either of you share a link for these? I also seem to struggle to find my power cables but have a gazillion USB cables lying around! I think it would be handy to have a couple of these in my cables box for emergencies.

[JOC]

I hasten to say that I haven't tried one of these on astro equipment, but FWIW I own one of these and have been impressed so far:  https://www.amazon.co.uk/BEAUDENS-Portable-Generator-Phosphate-Emergency/dp/B07MC7TV2G 

[Carbon Brush]

Ref @curtisca17.
Yes the acceptable temperatures for charge and discharge do differ.
Given that I am trying to suggest simple tests, it is easier not to push to the limits.
In addition,  I do not know what manufacture cells are being used by an individual.
This is a further argument for simple tests that do not approach the safe use boundaries.

Does this matter? Yes. Not all cells are created equal😁

I am currently working on a design that may mean cells getting used near their manufacturer published limits.
As an example one cell I am looking at is good for discharge to 80C - but don't expect full cycle life.

In addition for safety approvals, cells have to withstand 80milli-ohm discharge abuse without fire or explosion.
Further they have to withstand oven at 130C without fire or explosion.
They don't need to work after short circuit or cooking - just not destroy their surroundings.
Would an unamed cell from a product sold on fleabay or amazon marketplace pass these tests?
 

 

 

[Clarkey]

4 hours ago, Carbon Brush said:

Would an unamed cell from a product sold on fleabay or amazon marketplace pass these tests?

Are you suggesting that unregulated tat is being sold on these sites? Surely not. 😃