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LiFePo 80ah Battery First Use Report for an Imaging All Nighter

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#1 John Miele

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Posted 18 October 2020 - 12:57 PM

Moderator: I was not sure whether to post this here or the equipment forum but the report is geared towards imaging use, so I chose B&II forum. Please move to equipment forum if needed...

 

Batteries are critical to those of us who seek dark skies where power is not available. I spent a lot of time researching my power requirements and battery technologies and chose this battery...

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

I paid $369 which I felt was a excellent deal for an 80ah (960watt-hour) lithium battery and it also included a 10amp charger. Unfortunately the price has jumped to $459 today just three weeks after I ordered minefrown.gif .

 

This battery weighs only 19.8 lbs has a BMS, two USB side ports, and a carry handle. It is extremely easy to carry around. Yes, it was over twice the price of a good AGM 100ah battery but the light weight and depth of discharge (DOD) capacity are worth it to me. One can discharge a LiFePo battery to 80% and still maintain thousands of cycles of life. So my 80ah battery should easily provide up to 64ah for 5000 cycles. I will likely expire long before this battery does at my current rate of clear nights! AGM batteries should not be taken much below 50% to preserve life. So in one sense, an 80ah LiFePo battery is equivalent to a 128ah AGM which would weigh on the order of 80 lbs and easily cost over $200 which brings the price gap even closer.

 

Since the laptop runs at 19.5V, other items run at 12V and some items run at 5V, I decided to normalize everything and work in Watts from here on. I estimated my power requirements to be around 41 Watts/hour for my setup which consists of the following powered items:

 

  • Mach1 mount
  • ASI174mm mini uncooled guide camera
  • ASI1600mm Pro cooled main camera
  • ZWO EFW Filter wheel
  • Dew Not DN09 heater strip
  • Dewbuster control unit
  • Moonlite focus motor
  • Dell lattitude E6430 laptop (using a PWX voltage converter, display, wireless, and bluetooth all turned off, and with battery removed)

 

To simulate a road trip to a dark site, I charged the battery fully overnight but then disconnected the charger when I woke up. The battery sat idle all day. I then connected power at 6:45 pm and ran the system until  6:45 am this morning, I measured the no load voltage on the battery in the morning to be 13.08V. The voltage-DOD curves are very flat so it's hard to get a really accurate reading, but I interpolated from some tables and think I had about 35% capacity left. So I used 65% capacity over 12 hours which is well below 80% and easily covers my longest possible night. Working backwards, my system was using (0.65)(960)/12 = 52 Watts/hour. So my initial estimate of 41 Watts/hour was low by 26%. Not sure why that was, but I am good with what I have. I put the battery back on the 10amp charger at 6:45 am and it fully charged somewhere between 4 and 6 hours. I did not check often enough to obtain the exact recharge time.

 

So in summary, this battery is perfect for my needs. As long as the build quality was good, and only time will tell that, I should be set for life with a single battery that can run the entire rig all night long anywhere I go.

 

Disclaimer: I am by no means a battery expert. This is only my laymen's opinions and I may have got some of this wrong! Please keep that in mind.

 

cs...John

 


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#2 Jim Waters

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Posted 18 October 2020 - 01:03 PM

You got a good deal on the battery but... the battery is LiFePO4.  LiFePo  Po is Polonium.  A rare and highly radioactive metal with no stable isotopes.

 

Li - Lithium

Fe - Iron

P -  Phosphorus

O - Oxygen


Edited by Jim Waters, 18 October 2020 - 01:06 PM.

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#3 John Miele

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Posted 18 October 2020 - 04:27 PM

Hmmm...I thought I felt strangely warm after handling that battery...lol.gif lol!

 

I told you I was no battery expert and now you can see I was right...haha...thanks for the correction!


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#4 kel123

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Posted 18 October 2020 - 04:37 PM

Great solution for you needs. I have been kicking the can down the road because of budget. Unfortunately, the pandemic is making them even more expensive.

Meanwhile, I guess this should really be in the equipment forum.

#5 Huangdi

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Posted 18 October 2020 - 05:44 PM

Welp... It works until temperatures drop. I've used those batteries before and if you can't manage to keep them really nice and warm during a cold autumn/winter/spring night, you're looking at less than 50% power. That's why I like my big heavy clonky AGM deep cycle battery. And I'll gladly get a second one 😁

But if it works for you, good!

Edited by Huangdi, 18 October 2020 - 05:45 PM.


#6 John Miele

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Posted 18 October 2020 - 05:51 PM

The temperature last night was in the mid 40s and everything seemed ok. I would not be imaging at remote sites if it's predicted to go less than the low 30s so if they can perform well in that temperature range, I'm good. Are you talking about subfreezing temps?



#7 Raginar

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Posted 18 October 2020 - 09:04 PM

Moderator: I was not sure whether to post this here or the equipment forum but the report is geared towards imaging use, so I chose B&II forum. Please move to equipment forum if needed...

 

Batteries are critical to those of us who seek dark skies where power is not available. I spent a lot of time researching my power requirements and battery technologies and chose this battery...

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

I paid $369 which I felt was a excellent deal for an 80ah (960watt-hour) lithium battery and it also included a 10amp charger. Unfortunately the price has jumped to $459 today just three weeks after I ordered minefrown.gif .

 

This battery weighs only 19.8 lbs has a BMS, two USB side ports, and a carry handle. It is extremely easy to carry around. Yes, it was over twice the price of a good AGM 100ah battery but the light weight and depth of discharge (DOD) capacity are worth it to me. One can discharge a LiFePo battery to 80% and still maintain thousands of cycles of life. So my 80ah battery should easily provide up to 64ah for 5000 cycles. I will likely expire long before this battery does at my current rate of clear nights! AGM batteries should not be taken much below 50% to preserve life. So in one sense, an 80ah LiFePo battery is equivalent to a 128ah AGM which would weigh on the order of 80 lbs and easily cost over $200 which brings the price gap even closer.

 

Since the laptop runs at 19.5V, other items run at 12V and some items run at 5V, I decided to normalize everything and work in Watts from here on. I estimated my power requirements to be around 41 Watts/hour for my setup which consists of the following powered items:

 

  • Mach1 mount
  • ASI174mm mini uncooled guide camera
  • ASI1600mm Pro cooled main camera
  • ZWO EFW Filter wheel
  • Dew Not DN09 heater strip
  • Dewbuster control unit
  • Moonlite focus motor
  • Dell lattitude E6430 laptop (using a PWX voltage converter, display, wireless, and bluetooth all turned off, and with battery removed)

 

To simulate a road trip to a dark site, I charged the battery fully overnight but then disconnected the charger when I woke up. The battery sat idle all day. I then connected power at 6:45 pm and ran the system until  6:45 am this morning, I measured the no load voltage on the battery in the morning to be 13.08V. The voltage-DOD curves are very flat so it's hard to get a really accurate reading, but I interpolated from some tables and think I had about 35% capacity left. So I used 65% capacity over 12 hours which is well below 80% and easily covers my longest possible night. Working backwards, my system was using (0.65)(960)/12 = 52 Watts/hour. So my initial estimate of 41 Watts/hour was low by 26%. Not sure why that was, but I am good with what I have. I put the battery back on the 10amp charger at 6:45 am and it fully charged somewhere between 4 and 6 hours. I did not check often enough to obtain the exact recharge time.

 

So in summary, this battery is perfect for my needs. As long as the build quality was good, and only time will tell that, I should be set for life with a single battery that can run the entire rig all night long anywhere I go.

 

Disclaimer: I am by no means a battery expert. This is only my laymen's opinions and I may have got some of this wrong! Please keep that in mind.

 

cs...John

They make these neat power analyzers I use on my 80ah LiFE battery.  It's nice to see how much you're using at a given time and it also keeps track of how much you've used until you unplug it. 

 

  https://www.amazon.c...971055376&psc=1



#8 Huangdi

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Posted 18 October 2020 - 09:09 PM

The temperature last night was in the mid 40s and everything seemed ok. I would not be imaging at remote sites if it's predicted to go less than the low 30s so if they can perform well in that temperature range, I'm good. Are you talking about subfreezing temps?


If I got it right, 30 degrees Fahrenheit is roughly 0°C. During an average winter night, temperatures here in Germany easily go below -5°C, possibly even -10. When that happens from what I've seen, these batteries tend to discharge a LOT faster. But if you live/image in a "warm" environment, then it likely is of no concern to you!

Edited by Huangdi, 18 October 2020 - 09:10 PM.


#9 don314

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Posted 18 October 2020 - 09:16 PM

I'm with you on LiFePO4 batteries, I needed something light.  I got one of these to keep track of the battery capacity:

 

https://www.droking....t-Digital-Meter

 

Using the watt-hour value shows how much of the battery capacity is used, so you can calculate whats left, and you can reset the display after charging the battery, so you always start at zero.  If you reverse the leads, you can monitor the battery charging rate.  The 20 amp range is good for this application.  These can be had on amazon (search for "drok battery monitor"), but they ship from China, so they take awhile to arrive.  Since I purchased mine a few years ago, I see other companies offer similar products with shorted lead times, but at higher cost, but the current range is 100 amps, not as good as the 20 amp range.

 

EDIT

I misspoke, now in stock in USA 

Amazon:  https://www.amazon.c...aps,157&sr=8-40


Edited by don314, 18 October 2020 - 09:49 PM.


#10 sabersix

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Posted 18 October 2020 - 09:27 PM

The LiPo discussion above about Polonium is incorrect.

 

https://en.wikipedia...osphate_battery


Edited by sabersix, 18 October 2020 - 09:28 PM.


#11 calypsob

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Posted 18 October 2020 - 09:39 PM

thats an amazing deal for 80ah 



#12 John Miele

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Posted 19 October 2020 - 03:11 PM

I'm with you on LiFePO4 batteries, I needed something light.  I got one of these to keep track of the battery capacity:

 

https://www.droking....t-Digital-Meter

 

Using the watt-hour value shows how much of the battery capacity is used, so you can calculate whats left, and you can reset the display after charging the battery, so you always start at zero.  If you reverse the leads, you can monitor the battery charging rate.  The 20 amp range is good for this application.  These can be had on amazon (search for "drok battery monitor"), but they ship from China, so they take awhile to arrive.  Since I purchased mine a few years ago, I see other companies offer similar products with shorted lead times, but at higher cost, but the current range is 100 amps, not as good as the 20 amp range.

 

EDIT

I misspoke, now in stock in USA 

Amazon:  https://www.amazon.c...aps,157&sr=8-40

This looks nifty and useful. I might get one. Should be a lot more accurate than the method I used to determine how much capacity I had used.



#13 pedxing

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Posted 19 October 2020 - 05:05 PM

Welp... It works until temperatures drop. I've used those batteries before and if you can't manage to keep them really nice and warm during a cold autumn/winter/spring night, you're looking at less than 50% power. That's why I like my big heavy clonky AGM deep cycle battery. And I'll gladly get a second one

But if it works for you, good!

LiFePO batteries work fine in low temperatures, I've used mine for long imaging sessions at ~10°F. 

 

In fact, they work better than lead-acid batteries at low temperature. At 0°C, for example, a lead-acid battery’s capacity is reduced by up to 50%, while a lithium iron phosphate battery suffers only a 10% loss at the same temperature.

 

What you can't do at low temperature is -charge- the battery. You must wait until they warm up above 0°C before putting them on the charger or you will damage them.


Edited by pedxing, 19 October 2020 - 05:05 PM.


#14 fewayne

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Posted 19 October 2020 - 05:17 PM

Just to be clear, the digital meter can be left in series the whole night? Obviously you lose a tiny bit of charge to power the meter, but usually ammeters aren't left in-circuit for very long. If it can, and the meter's own power draw isn't much, I am totally buying one.

 

Oh, I see, 0.8 mA with the light off and 2.8 with it on. Think I can live with that :-)


Edited by fewayne, 19 October 2020 - 05:20 PM.


#15 nimitz69

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Posted 19 October 2020 - 06:12 PM

Since I have an observatory I have no need for any batteries .... however, to power my life sized, fully robotic, operator on the inside Dalek I needed a 24v system and adding 2 40lb AGMs was not all that palatable. So entry the LIFePO4 60 Ah 24v solution. I bought one from a Chinese battery manufacturer. The battery was $245 and $230 for air freight to the U.S. a 12v would have been significantly cheaper ..... because you can discharge them to well down to 80% or more, unlike conventional AGMs you can get away with smaller Ah battery .....

4A9F8AE9-EEDD-4F7A-B829-FBACA23591EE.jpeg

 

battery sits comfortably under my seat and is easily removable at only 19 lbs ....


Edited by nimitz69, 19 October 2020 - 06:13 PM.


#16 fewayne

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Posted 21 October 2020 - 10:47 AM

Who among us does not need a full-size Dalek in their observatory?




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