Anyone tested this batteries. https://smile.amazon.com/dp/B07X7MD2JK - the 16AH versiom. Although price has gone up, it seems too good be true.
Miady testing
- Thread starter msears
- Start date
I do have a shunt. I will create a diagram and maybe take some photos. It is a bit messy as the design has evolved over time Come on, who decides on 7 batteries to start with? The system is built to have security cameras/wifi about 1000 feet from my house.
Why do you need 112Ah LFP to run cameras / wifi?
$350 plus tax is cheap for 112Ah
here is the picture.
Each Battery is connected to the a terminal block (Bus bar) each cable is exactly the same length. The Terminal block connects to the posts. I use the posts to hook up to my lifepo4 charger. Between the terminal block and the negative post I have the Shunt installed to measure the flow of current and the battery SOC.
Also connect to the postsk is my LOAD and CHARGE Controller.
My system has multiple cameras(.5 amp), POE switch (.25 amp) , and long range Wifi (.25 Amp). I use 24 AH in 24 hours. The system without any energy from the solar lasts about 4-5 days. My solar setup is 300watts, but I live up north and it is VERY cloudy all winter. On a sunny day, I can completely charge the batteries from empty, but this time of year I get next to zero sun. On the worst, darkest day, I can't even keep up with the load during the day. I use a generator to top up the batteries to keep them between 40-80%
Each Battery is connected to the a terminal block (Bus bar) each cable is exactly the same length. The Terminal block connects to the posts. I use the posts to hook up to my lifepo4 charger. Between the terminal block and the negative post I have the Shunt installed to measure the flow of current and the battery SOC.
Also connect to the postsk is my LOAD and CHARGE Controller.
My system has multiple cameras(.5 amp), POE switch (.25 amp) , and long range Wifi (.25 Amp). I use 24 AH in 24 hours. The system without any energy from the solar lasts about 4-5 days. My solar setup is 300watts, but I live up north and it is VERY cloudy all winter. On a sunny day, I can completely charge the batteries from empty, but this time of year I get next to zero sun. On the worst, darkest day, I can't even keep up with the load during the day. I use a generator to top up the batteries to keep them between 40-80%
@Will Prowse tested them:
Cheaply made, 13-14Ah vs. 16Ah rated
However, Will charged to BMS cut-off with no absorption phase and objected to the cell voltages being too high. I've seen many "dumb" BMS with cell protection specified as 3.75±.05, and those cells were pretty much within that range... High 3.7X and a couple of 3.82 or something, so I think the BMS is doing its job, just not optimally. The cut off at about 0.5C current (at about 2:07 in the video) vs. a normally terminated charge with an absorption phase might account for some of the lost capacity. In my case with the 6Ah unit, the 0.5C charge started tapering at 6.1Ah, so that's about 94% of the total.
I purchased the 6Ah version just because they're so cute, and I could get is same day for an extra $2.99. This also identifies me as impatient with delay of gratification issues even about something for which I have zero use, but get seduced by its cuteness. Anyway...
As received, it at 3.7Ah of capacity, 0.2C:
Note that I terminated the charge after about 100mAh to double check the charger settings then restarted it. That's the little sawtooth pattern in the brown line at the 5 minute mark.
0.5C charge to 14.6V:
Values at charge termination:
This is a good sign as output almost always equals input.
0.2C discharge commencing...
Cheaply made, 13-14Ah vs. 16Ah rated
However, Will charged to BMS cut-off with no absorption phase and objected to the cell voltages being too high. I've seen many "dumb" BMS with cell protection specified as 3.75±.05, and those cells were pretty much within that range... High 3.7X and a couple of 3.82 or something, so I think the BMS is doing its job, just not optimally. The cut off at about 0.5C current (at about 2:07 in the video) vs. a normally terminated charge with an absorption phase might account for some of the lost capacity. In my case with the 6Ah unit, the 0.5C charge started tapering at 6.1Ah, so that's about 94% of the total.
I purchased the 6Ah version just because they're so cute, and I could get is same day for an extra $2.99. This also identifies me as impatient with delay of gratification issues even about something for which I have zero use, but get seduced by its cuteness. Anyway...
As received, it at 3.7Ah of capacity, 0.2C:
Note that I terminated the charge after about 100mAh to double check the charger settings then restarted it. That's the little sawtooth pattern in the brown line at the 5 minute mark.
0.5C charge to 14.6V:
Values at charge termination:
This is a good sign as output almost always equals input.
0.2C discharge commencing...
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Agreed based on all of my charging experience and the 55mAh difference above.
Did you charge CC/CV or BMS cut-off?
Try a CC/CV to 14.6V with a tapering charge and see how much that adds?
Not a lot on the 6Ah unit, but that added 5% vs. a 0.5C cut-off like @Will Prowse's test.
Not a lot on the 6Ah unit, but that added 5% vs. a 0.5C cut-off like @Will Prowse's test.
I'm tempted to cycle the shit out of this thing and see what happens... 
I'm not excited about a 7 hour round trip per cycle, but the specs do say 6A discharge and 3A charge... Hmmm.... that's only about 3 hours per cycle... Here we go! I'll report back in 10 cycles...
I'm not excited about a 7 hour round trip per cycle, but the specs do say 6A discharge and 3A charge... Hmmm.... that's only about 3 hours per cycle... Here we go! I'll report back in 10 cycles...So far...
This is as stressful as it can be and stay within limits. I have a mere 1 minute wait between cycles, so
Charge (about 2 hours)
wait 1 min
Discharge (about 1 hour)
wait 1 min
...repeat...
There is negligible heating. The bench surface it's on is at 77°F. The sides and top are at 83°F and the bottom surface is 88°F. These measurements were taken about 3000mAh into the 8th charge.
Initially, capacity was declining, but it seems to have recovered somewhat. While we're seeing declining capacity, it at least meets rating at 1C discharge following 0.5C charges to 3.65V/cell (0.05C cut-off).
At about $456/kWh, it's not much of a value, but it's doing what it says. I occasionally need 12V to run a little something, and it's infrequent enough that keeping a little 12V fully charged for that purpose isn't really practical, and entropy always puts a 12V supply under/behind something else. Having this thing on the shelf sitting at whatever SoC that I like will be handy.
- 6455*
- 6411
- 6405
- 6405
- 6393
- 6378
- 6386
- 6389
- 6393
- 6400
- 6397
This is as stressful as it can be and stay within limits. I have a mere 1 minute wait between cycles, so
Charge (about 2 hours)
wait 1 min
Discharge (about 1 hour)
wait 1 min
...repeat...
There is negligible heating. The bench surface it's on is at 77°F. The sides and top are at 83°F and the bottom surface is 88°F. These measurements were taken about 3000mAh into the 8th charge.
Initially, capacity was declining, but it seems to have recovered somewhat. While we're seeing declining capacity, it at least meets rating at 1C discharge following 0.5C charges to 3.65V/cell (0.05C cut-off).
At about $456/kWh, it's not much of a value, but it's doing what it says. I occasionally need 12V to run a little something, and it's infrequent enough that keeping a little 12V fully charged for that purpose isn't really practical, and entropy always puts a 12V supply under/behind something else. Having this thing on the shelf sitting at whatever SoC that I like will be handy.
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After:
the initial 0.2C as-received discharge
1 0.2C discharge
10 1C discharges
IR still measures exactly 44mΩ
10th 1C discharge: 6397mAh
Curves of 1st, 5th and 10th discharges (voltage vs. time.)
There's some variability with time on the x-axis, but that's how this software works. Voltage vs mAh would be better.
the plots represent only a 27mAh difference...
I'm NOT testing the BMS in these. I'm testing to rated cell limits, 2.5V low, 3.65V high, so I'm trusting the BMS is working.
After a full charge, I did confirm that under a 3A charge, the battery went open circuit at just over 15V. My charger lost the display when it happened, so I don't have an exact number, but it fell and battery voltage was available quickly.
I have not tested the LVD.
I need to shuffle some equipment around, but I'm going to cycling this battery. I can set this aside and just have it cycling. I'm going to try to get 100+ cycles on it to see if we can get a meaningful cycle life estimate.
the initial 0.2C as-received discharge
1 0.2C discharge
10 1C discharges
IR still measures exactly 44mΩ
10th 1C discharge: 6397mAh
Curves of 1st, 5th and 10th discharges (voltage vs. time.)
There's some variability with time on the x-axis, but that's how this software works. Voltage vs mAh would be better.
the plots represent only a 27mAh difference...
I'm NOT testing the BMS in these. I'm testing to rated cell limits, 2.5V low, 3.65V high, so I'm trusting the BMS is working.
After a full charge, I did confirm that under a 3A charge, the battery went open circuit at just over 15V. My charger lost the display when it happened, so I don't have an exact number, but it fell and battery voltage was available quickly.
I have not tested the LVD.
I need to shuffle some equipment around, but I'm going to cycling this battery. I can set this aside and just have it cycling. I'm going to try to get 100+ cycles on it to see if we can get a meaningful cycle life estimate.
In Will's video, the connection wires between Will's CBA4 and the battery look pretty hinky and it looks like he is not using the 4-wire capability of the CBA4. I'm sure there will be a difference in voltage measurements taken at the battery terminals vs. those taken at the CBA4 terminals. There will be some losses in the wires though I am curious just how significant they will be.
RCinFLA
Solar Wizard
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If you ever plan on series stacking them, I did not see anything about series stacking on Amazon description. Check manf site. Many of the low cost 12v self contained LFP use low voltage BMS's not suitable for series stacking.
If manf does not specifically state the series stack limit assume you cannot, ofherwise you won't know until you need the BMS cutout.
If manf does not specifically state the series stack limit assume you cannot, ofherwise you won't know until you need the BMS cutout.
Welcome to the forum.
At 0.2C the wires had negligible impact on the results as evidenced by the flatness of the discharge curve. Had he chosen a cut off above 10V, then it could have caused a premature cut-off and slightly reduced capacity.
At 44mΩ resistance on this tiny battery, I do not consider this budget line of batteries suitable for series connections UNLESS they were tested and found to have highly similar characteristics and performance.
Delta-V
Solar Enthusiast
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- Sep 20, 2019
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Well, I've recently been tinkering with the Miady 12V@8Ah (Amazon) version.
I had 2 objectives: First, replace a 12V@8Ah sealed lead-acid starter battery for my Champion 3100W inverter generator. This battery keeps dying if it sits too long (several months). Second, I have a bunch of hunting field cameras where I've been using those sealed lead-acid 12V@8Ah universal batteries (UB1280), like what you put in a UPS, as external batteries. They too aren't lasting as long as expected. Especially, since the cameras are only taking motion detected pictures.
So far, I'm happy with it. I'm having a better experience than Will did in his YouTube video. I've done 3 crude capacity tests, it just exceeds expected capacity, about 104Wh (rated 102.4Wh). I used a basic test setup, a Watts-up meter with a 750W Modified sine wave inverter, pushing an old-school 60W incandescent light bulb, Averaging ~77 Watts (or ~6 Amps), about .75C rate, with inverter inefficiencies. It probably would have done better if I'd gone with a .2C rate (1.6A or 20 Watts). The inverter would shut-off at about 10.7V
The battery arrived at 12.2V. I fully charged it, but it fell way short of expected capacity on my 1st test, around 66% or so. But, when I charged it the 2nd, 3rd, and 4th times, it did meet expected capacity. Perhaps Will had the same experience, only basing his capacity test on the 1st charging of 2 different batteries.
I took mine apart to see what's inside. It came apart much easier than Will's approach (no hammer or tin-snips needed, ha ha). I just used a pocket knife blade to pop the glue off around the lid seam. Came off intact no problem.
It's filled with 16 18730 LiFePO4 cells, GZNF18730HP-2000mAh 3.2V, 6.4Wh, purple in color, 4S4P configuration. Looks to be these
It looks similar to what Will shows in his video, but only half the number of cells.
The listing on Amazon didn't have a datasheet or maximum discharge/ charging rating. So, I tried the battery to start the generator, it wouldn't even turn-over. The BMS would immediately cut power off to the battery. I'd have to disconnect a wire then reconnect it to reset the BMS. So, it won't work as a generator starter battery.
I did a test to see what the maximum Amps would be. Briefly reached 32A for a few seconds or so, but the BMS would keep cutting-out. I was able to maintain a continuous 28A for a good 15 minutes or so. Then I checked the battery and it was very very hot! I quickly took the cell pack out of the case and put a desk fan on it to cool it down. After doing some Googling, looks like the maximum discharge rate was 3C (or 24A). Ooops! I wish they mentioned that on the Amazon listing. The 16Ah datasheet someone posted kind of coincides with this. Although, it has 42A for max discharge, which is more like 2.6C (instead of 3C as noted in the 18730 cell spec page) . So, the 8Ah version is probably similar at 8Ah x 2.6C = 20.8A (or 266 Watts) for max discharge. Probably based on BMS limitations.
The BMS does cut-off at about 15V (3.75V per cell) over-charge, and about 9V (2.25V per cell) over-discharge.
Overall, I'm happy with the battery so far. I'll do some more tests. I'm already dropping $20+ buying new sealed lead-acid batteries. Might be a good option spend an extra $10 ($30 total) to get a battery that'll last longer for field cameras.
I did also buy some Headway 38120HP LiFePo4 Cells. 4 of them work great as a starter battery for the generator. I just gotta find a decent BMS for it now.
I had 2 objectives: First, replace a 12V@8Ah sealed lead-acid starter battery for my Champion 3100W inverter generator. This battery keeps dying if it sits too long (several months). Second, I have a bunch of hunting field cameras where I've been using those sealed lead-acid 12V@8Ah universal batteries (UB1280), like what you put in a UPS, as external batteries. They too aren't lasting as long as expected. Especially, since the cameras are only taking motion detected pictures.
So far, I'm happy with it. I'm having a better experience than Will did in his YouTube video. I've done 3 crude capacity tests, it just exceeds expected capacity, about 104Wh (rated 102.4Wh). I used a basic test setup, a Watts-up meter with a 750W Modified sine wave inverter, pushing an old-school 60W incandescent light bulb, Averaging ~77 Watts (or ~6 Amps), about .75C rate, with inverter inefficiencies. It probably would have done better if I'd gone with a .2C rate (1.6A or 20 Watts). The inverter would shut-off at about 10.7V
The battery arrived at 12.2V. I fully charged it, but it fell way short of expected capacity on my 1st test, around 66% or so. But, when I charged it the 2nd, 3rd, and 4th times, it did meet expected capacity. Perhaps Will had the same experience, only basing his capacity test on the 1st charging of 2 different batteries.
I took mine apart to see what's inside. It came apart much easier than Will's approach (no hammer or tin-snips needed, ha ha). I just used a pocket knife blade to pop the glue off around the lid seam. Came off intact no problem.
It's filled with 16 18730 LiFePO4 cells, GZNF18730HP-2000mAh 3.2V, 6.4Wh, purple in color, 4S4P configuration. Looks to be these
It looks similar to what Will shows in his video, but only half the number of cells.
The listing on Amazon didn't have a datasheet or maximum discharge/ charging rating. So, I tried the battery to start the generator, it wouldn't even turn-over. The BMS would immediately cut power off to the battery. I'd have to disconnect a wire then reconnect it to reset the BMS. So, it won't work as a generator starter battery.
I did a test to see what the maximum Amps would be. Briefly reached 32A for a few seconds or so, but the BMS would keep cutting-out. I was able to maintain a continuous 28A for a good 15 minutes or so. Then I checked the battery and it was very very hot! I quickly took the cell pack out of the case and put a desk fan on it to cool it down. After doing some Googling, looks like the maximum discharge rate was 3C (or 24A). Ooops! I wish they mentioned that on the Amazon listing. The 16Ah datasheet someone posted kind of coincides with this. Although, it has 42A for max discharge, which is more like 2.6C (instead of 3C as noted in the 18730 cell spec page) . So, the 8Ah version is probably similar at 8Ah x 2.6C = 20.8A (or 266 Watts) for max discharge. Probably based on BMS limitations.
The BMS does cut-off at about 15V (3.75V per cell) over-charge, and about 9V (2.25V per cell) over-discharge.
Overall, I'm happy with the battery so far. I'll do some more tests. I'm already dropping $20+ buying new sealed lead-acid batteries. Might be a good option spend an extra $10 ($30 total) to get a battery that'll last longer for field cameras.
I did also buy some Headway 38120HP LiFePo4 Cells. 4 of them work great as a starter battery for the generator. I just gotta find a decent BMS for it now.
nifty-stuff.com
New Member
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I know Will wasn't really a proponent of this battery, but it's almost too interesting not to try!
Also, I just want to say, this was TOO funny and (unfortunately?) is what gets me into a ton of projects that are fun, but completely useless to me. LOL!
Also, I just want to say, this was TOO funny and (unfortunately?) is what gets me into a ton of projects that are fun, but completely useless to me. LOL!
nifty-stuff.com
New Member
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Add me to the list of peeps that couldn't pass-up testing a handful of these, so I got 4 of the 12.8v 8amp models to play with.
Datasheet says they can be put in parallel and series (up to 4), and I want to play with a few configurations of both.
They also say they can be used as drop-in for most SLA. I'm going to try some tests with using it in my basic UPS (I've read about the potential issues with float-charge voltage, etc.), so we'll see how that goes.
$130 shipped doesn't leave much $$ at risk if either the batteries don't live up to their marketing and / or I mess something up (probably both will end up happening)
Datasheet says they can be put in parallel and series (up to 4), and I want to play with a few configurations of both.
They also say they can be used as drop-in for most SLA. I'm going to try some tests with using it in my basic UPS (I've read about the potential issues with float-charge voltage, etc.), so we'll see how that goes.
$130 shipped doesn't leave much $$ at risk if either the batteries don't live up to their marketing and / or I mess something up (probably both will end up happening)
This is super useful; I have to characterize Miady's new 32Ah battery for a work project. Can you give me some pointers on what equipment/software you used to generate this graph? Also, any recommendations for equipment/methodology to get this in mAh instead of time? Happy to post my results back here for the community!
Also, despite having a degree in EE, this is my first foray into the world of batteries, so apologies if I'm asking super basic questions. Feel free to be kind, mocking, or mad; doesn't matter to me just so long as you help me out!! ??
My setup involves icharger 206B clone hobby chargers that are correlated. Mine have been modified to broadcast the data via wifi to allow capture and logging to DataExplorer. You could simply use the built-in logging to capture the data for later download or live capture via USB cable (need a USB to serial driver).
Given that the testing has supported that they meet their rated capacity, the chart would just scale.
Given that the testing has supported that they meet their rated capacity, the chart would just scale.
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