Battery Review: Miady 12volt 20AH LifePo4
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- Опубліковано 31 тра 2024
- Today we'll be conducting a review of the Miady 20AH Lithium Iron Phosphate battery.
During this Review we tested the following features of the battery:
Over-Voltage Disconnect: 3:08
Discharge Test: 3:55
Capacity Test: 5:47
Charging Parameters: 7:10
For a quick review of our results, you can skip ahead to: 7:48
~~Battery Link~~
Miady 16AH: amzn.to/342Yox2
Review: • Battery Review: Miady ...
Miady 20AH: amzn.to/3yMq49C
Miady 36AH: amzn.to/3bXv1mI
Review: • Battery Review: Miady ...
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Great video. I watched numerous videos about this battery and they pointed me in the right direction. I purchased one along with a 2 amp LiFePO4 charger. I fully charged the battery and load tested it. My results were 19.76 ah. Close enough for me.
I liked it so much I not only purchased a second one but also purchased a10ah model. There are times I operated equipment portable and one time I only need 10ah. I need to keep my weight to a minimum since I am back packing. There are times I
need 20ah and rare chases I need a 40ah pack, so I just parallel the two big batteries. I'm sorry that I purchased a second 20ah battery only because the 34ah would have been a better choice.
For only $81 on Amazon, I thought it was well priced.
Barry
Well, I decided to take apart my new Miady12V 20AH (256Wh). It's caulked in real good. So, you'll have no choice but to damage the plastic case to get to the cells. They caulk the sides as well as the very bottom of the box.
There are 12 gray unmarked cells that sit horizontal. 6 cells on one side, 6 cells on the other (tack welded), with the BMS on top. Look to be LifePO4 32700 cells, Probably between 6,000 - 7,000 mAh each. My guess is closer to 6,000 mAh as capacity tests I've seen so far seem to fall short of the advertised 256Wh rating.
Most likely a 4S 3P configuration:
Speculative:
3.2V x 6,000 mAh = 19.2W x 4S = 76.8W x 3P = 230.4Wh
3.2V x 6,200 mAh = 19.84W x 4S = 79..36W x 3P = 238.1Wh
3.2V x 6,500 mAh = 20.8W x 4S = 83.2W x 3P = 249.6Wh
3.2V x 7,000 mAh = 22.4W x 4S = 89.6W x 3P = 268.8Wh
I haven't done a capacity test on this 20Ah version yet. But, I have a few of the 8Ah and 16Ah versions and they've been around 90 - 95% capacity. So, I'm expecting similar with the 20Ah version.
I've been happy with the 8Ah and 16Ah versions so far. Just wish they didn't round-up the marketing expectations.
Thanks for your excellent demonstration. I purchased the same battery a week ago and have tried several lithium charges in an attempt to reach charge capacity without success. It maxed out at 13.6v. I agree totally with your findings. I will return my battery today.
Lol at the little handle. "Is that a lunch box? No, I brougt electricity!"
Really enjoyed the review, thank you!
Thank you!
I have 14 of these 20ah Miady batteries and so far in 12v parallel they held up with a good 2000/3000 inverter, I’ve split that bank into 2 now, the 24v & 48v setups I have them in now has worked out better for me so far with both banks on pure sine wave inverters.
Good information, just subscribed, looking forward to more videos.
Great review....Peace
Thanks for the video. I just got four of these to replace 8 smaller SLA batteries for a UPS. I have the batteries balanced for running them in series and I am about to tweak the settings on the UPS to optimize charging for these. Not sure if I can adjust bulk charge voltage, but I think the UPS is expecting SLA voltages so I might be able to just set that and be ok. I'm hoping for longevity over using the full capacity, so I'm OK with ~80-90% charge.
I have this exact battery, I have 5 of them but I'm uneasy about hooking them up in parallel for solar set up. Currently I'm looking at CHINS batteries for a more steady bank and maybe I'll use these Miday for small battery generator banks. Do you think these batteries are relatively safe?
Giving you a like just for your choice of an unusual load for testing.
😘Super test 👍🏾👍🏾👍🏾👍🏾
Thanks for the review. Have you been able to play around with it to get the full 20 - and perhaps a higher disconnect? I was thinking of trying one for basic emergency back up.
Thank you! I haven't had a chance to play around with it just yet, but I do plan to use it in a small portable generator build, so I should have some results to report next weekend for capacity. The BMS can't be modified though, so unless you have a charge controller that allows you to create a custom profile (something like 14v bulk, 13.6 float) then you're probably better off waiting for the 36ah to come back in stock, or going with the 16 and just creating an adapter for the terminals. And honestly, the charge controllers with custom profiles tend to run as much as this battery, so I can't really recommend it if you're looking to pull full output. If you consider it as a 17ah or 18ah battery, it'll serve pretty well.
Great video! Which inverter were you using for the discharge test?
Thank you! I'm using the Bestek 500 watt Pure Sine Wave Power Inverter (MRZ5011BU) for the discharge test.
Now I want cotton candy.
Me too
I just purchased one of these batteries off of Amazon for $69. This was so much lower than any other battery for that price. So to me it’s probably worth it, even if you have to charge it at a lower amp rate. Did you ever see if you could spoonfeed it and get it up to 20 amp hours of total capacity?
I've been testing for months now, and I'm still not able to get up to full capacity. If I had to guess, the reason these batteries are so cheap is because they're not grade A cells capable of hitting full capacity.
@@smallscalesolar Hello and thanks for replying. What was the best AH measurement that you’ve been able to attain. Also, what amp-load are you using for the discharge? Finally, when you charge it, what voltage-level are you using for end-of-charge, or are you charging until the battery’s internal BMS disconnects? Maybe I can test mine to compare if I know how you’re exercising yours…
I've used over 20 of the 16ah miady batteries. Some charge higher than others. What's the problem? Low grade cells, some of the cells will reach the cut off threshold too soon, the BMS will disconnect, and not allow a full charge. Overall the 16ah is still a good value, I have some in the field that have been powering low power communications equipment for over a year with no problems. These are fine for low current draw solar setups, like IOT devices. The equipment I run uses 15-25w
The Capacity issue doesn't bother me as much as the over-voltage disconnect. Still, If I buy a 20ah battery, I expect 20ah. The biggest fault in this battery though is that it requires a custom charge controller. The standard LiFePo4 setting will trigger the over voltage disconnect as it is set at 14.2, rather than the 15.2 that would typically be seen in a LiFePo4 BMS.
@@smallscalesolar Yup, I get it. But for the price it's not horrible. I use epever, charge controllers, and I can program it to max out at 14.2, the battery will actually fully charge if you let it absorb at 14.2 the cells do not have to hit 3.65v to be fully charged, they will just have to absorb longer at a lower voltage.
Interesting. I wonder if a person could swap one of these and a charge wart into an old LSA powered wet/dry vac or jump/compressor combo…
This is a question, because I really don't know. It seems each lifepo4 battery have a built in bms, battery charging system. So the internal cells go through charge balancing each time the battery is charged. What if two Miady are charged in series at 24v. Would both battery get charged balanced, even though they may not perfectly be equal in the internal impedance. My guess is the bms makes both battery to have the same internal impedance. Or is that just wishful thinking.
Additionally, I wonder because Amazon reviewer said Miady comes without the internal cells balanced. So when you test a new battery, the capacity is underperforming because it is unbalanced. Therefore always charge a new Miady multiple times to get the internal cells balanced before doing the capacity test. A long time ago I read that when a battery has multiple smaller battery cells connected in series, the cell with the lowest internal impedance gets used the most. And I suspect the lone cell drives the total voltage measured by the bms to get out of acceptable range sooner than later and the bms cuts off capacity. Just guessing though.
So, I really think this battery can pull full capacity, based on my tests on the other Miady batteries and using different charging parameters. I agree with the commenter that the cells are not well balanced from the factory, and really do need to be top balanced with a trickle charge to reach full capacity.
All that said, because of this battery's particularly low overvoltage disconnect (14.2ish), charging this battery is so annoying that I don't think I'd ever put in the effort to actually reach full capacity. It's easier and cheaper to just consider this an 18ah battery (and this is still a great price for 18ah).
Thought I was only one that used a cotton candy machine to test batteries!!!!
It's definitely the best testing device, in my opinion. You get a motor, a heater, and a treat all at once.
I have two of these exact batteries. I also have a 2 amp LiFePO4 charger and have charged both of the batteries around 30 times so far (they are used for amateur radio portable operation). That charger has an upper 'float' of 14.4vdc. Neither of the batteries I have seem to have a low cut-off voltage. I haven't tested to see where they do cut off but it's somewhere above 14.4 volts. ALSO, I purchased a Powerwerx Solar Charge Controller for 12V LiFePO4 Batteries. It also has an output of 14.4 volts and it also provides a full charge. So I disagree with the thought of not recommending the battery. It (they) have worked great for me.
I've read comments in other reviews that they've fixed the low voltage cutoff. But I can only test based on the battery I've been sent. In my case, there is a very clear fault in the BMS setting preventing the use of a standard LiFePo4 charger. However, I still use the battery with a lower charging cutoff for a small DC system just fine. I think at the price point, there are better options that actually meet capacity.
@@smallscalesolar My apologies. I did not intend to insinuate that your test was faulty or misleading. And re-reading my earlier comment, I can see how it might be taken that way. You made a judgment call on the battery you had to work with and I completely understand your misgivings regarding the recommendation to others (or lack of one). If I had done the same or similar test and got the results that you did, I'm sure I would be saying the same thing.. I very much like your videos and respect your honest opinion on such items. Keep up the good work.
Do you think these batteries might work with an ebike or a UPS?
Great review btw
If you have a DC charger that lets you set your charge parameters to meet this battery's unusual BMS settings, it would work just fine for those purposes. However, if you're looking for something a little more universally usable, the 16AH version of this battery is probably the better choice. I do genuinely like the weight and size of this battery, but the charge parameters just make it really difficult to use.
Thank you!
@@smallscalesolar do you think its a good idea to put 4 in series (probably of smaller capacity) for a 48v electric bike
It's not clear if the 20ah is capable of series connection. I am unable to find a spec sheet for this specific battery, however if you went with the 16ah, those can be series connected up to 48v.
How long does it takes to recharge from solar power
That depends entirely on how much solar you have available. The recommended charge rate is .5C, so in this case in would be 10amps. That means with a proper charge controller and enough solar, you could fully charge the battery in about 2.5 hours (the charge rate slows as the battery nears full).
It's a good idea to only charge batteries below a 0.5 C rate or lower,. 5amps for a 10ah battery , 2-3 amps even better. A lot of batteries say 1C or 10 amps for a 10AH battery, however they will heat up with high current charge and discharge, while there is no real fire danger with lithium IRON phosphate excessive heat will damage it , along with charging when frozen! Not all bms will prevent charging a frozen battery!
Everyone can benefit from having a 100 ah battery, and a couple 100 watt solar panels, and at least a2kw inverter, anything larger needs more batteries, and going to at least 24v is a good idea, the extra benefit of a 12v system is you can connect it to your car! And charge it in an emergency, like this polar blast the whole country is in during Christmas 2022, (Santa has brought the north pole with him this year) it can be used for power outages, as well as lowering the monthly power bill, about $100 for a 100 watt panel, or a used 250-350:watt panel for $50 bucks roughly, even in slot of apartments, you can get away with a single 250-300 watt+/- panel, or a couple 100 watt panels at least, and hide the batteries under a chair it other furniture. And the inverter next to it, and a extension cord, to what ever is using the power, an auto transfer switch can switch back to grid, without you knowing, when the battery is depleted. If everyone had a system 4x this size it could cut grid use by a lot, especially during peak demand, and ppl will have emergency power!!
Punching a metal screwdriver into a box with a lithium battery might not be a wise thing.