If you are building a DIY solar system (off-grid), a LiFePO4 battery is practically mandatory. LiFePO4 batteries are no longer overly expensive and are generally very unproblematic.
Most LiFePO4 batteries have a capacity of 100Ah. However, models with 200 Ah are now becoming increasingly affordable.
In this article we will also take a look at just such a cheap 200 Ah LiFePO4. You can get the Power Queen 12.8V 200Ah LiFePO4 battery for just over €500, which is more than a good price for this capacity!
Let’s take a look at the test to see whether the performance of the Power Queen 12.8V 200Ah LiFePO4 battery is correct in practice.
At this point, many thanks to Power Queen for providing the battery for this test!
Power Queen 12,8V 200Ah LiFePO4 Batterie im Test
With a capacity of 200 Ah, this battery is of course quite a chunk. It measures 53.2 x 20.7 x 21.5 cm and weighs around 22 kg.
Power Queen relies on its well-known plastic housing. This seems sufficiently valuable and stable. It is also completely sealed. We don’t have any “special” water protection, but a few splashes of water shouldn’t harm the battery.
The battery has two carrying loops on the sides to make it easier to transport.
The battery is connected as usual via two M8 screws or threads. Corresponding screws and covers are included.
Technical data
Power Queen 12,8V 200Ah LiFePO4
Voltage 12.8 V Charging voltage 14.4 V Capacity 200 Ah Energy 2560 Wh Maximum power 100 A Peak power 280 A Charging temperature 0℃ – 50℃ Discharge temperature -20℃ – 60℃
Why a LiFePO4 battery?
Why are LiFePO4 or lithium iron phosphate batteries so interesting? These batteries could potentially represent the “future” in the area of solar buffer storage, electromobility, etc. But why?
LiFePO4 batteries offer slightly lower energy density compared to traditional lithium-ion batteries, but in exchange for greater safety and durability.
Even the simplest LiFePO4 batteries can easily achieve more than 2500 charging cycles, while lithium-ion batteries usually only achieve 500-1000 charging cycles. In practice, the durability can be even greater since it depends heavily on the depth of discharge.
Power Queen advertises 4,000-15,000 charging cycles, which can be quite realistic. However, not at a 100% depth of discharge.
According to the manufacturer, at a 100% depth of discharge we get 4,000 cycles, at 60% depth of discharge we get 15,000 cycles. These are fantastic values, which unfortunately I cannot verify in practice. In my experience, LiFePO4 batteries are extremely durable!
LiFePO4 batteries therefore offer a potentially extremely long shelf life, particularly as solar buffer storage. Additionally, LiFePO4 batteries are not prone to thermal runaway and are not as sensitive to charging/discharging.
However, there are also disadvantages:
In return, they are slightly larger than lithium-ion batteries with the same capacity. This makes them less suitable for smartphones, notebooks and other devices where dimensions play an important role.
It is also important to note that LiFePO4 batteries must not be charged at temperatures below 0 degrees Celsius. Discharging is not a problem, but charging below 0 degrees can damage the batteries. Unfortunately, the battery does not have an under-temperature shutdown.
How does breaking measure the capacity of LiFePO4 batteries?
To measure the capacity of LiFePO4 batteries, I use an electronic load.
The DLB-600W is used here.
I discharged the battery to 10.8V. I sometimes repeated test runs to get more results.
The capacity of the Power Queen 12.8V 200Ah LiFePO4 battery
Let’s come to the capacity measurement, does the Power Queen battery really offer 200 Ah?
I measured the capacity at 10A/20A a total of 6 times. The capacity fluctuated between 212.13 Ah and 214.94A. Excellent! This far exceeds the manufacturer’s stated capacity.
It is also noticeable that the capacity did not fluctuate much between the tests, which is a good sign.
The average capacity was 213.9356 Ah or 2771.695 Wh.
Voltage curve
LiFePO4 batteries usually have a very flat voltage curve. This means that the voltage fluctuates only slightly during discharging.
This is also confirmed again with the Power Queen 12.8V 200Ah LiFePO4 battery. Here the voltage drops quite quickly to 13.1V. For about 60% of the capacity it stays above 13V before it slowly drops.
If the voltage falls below 12.6V, the voltage drops rapidly and the battery can practically be described as empty.
Due to this very flat voltage curve, it is unfortunately very difficult to estimate the current battery level of LiFePO4 batteries.
In practice
There is nothing negative or special to report here. I use the battery connected in parallel with a second 200Ah battery on a small off-grid solar system, appropriately with the Power Queen PQ2430 MPPT solar charge controller.
But it doesn’t really matter what kind of solar charging controller you use, the fact that this one comes from Power Queen makes zero difference.
Here the battery works exactly as you expect. I didn’t have any problems with the BMS breaking the connection or anything like that.
The battery simply works completely “passively” and unobtrusively. However, this generally applies to the batteries of the large Asian manufacturers. I’ve never had any problems here in practice.
I can’t say anything about durability, as I would have to use the battery for years, but I have used a 100Ah Power Queen battery for about 1.5 years so far and it has only lost around 2-3% capacity over that time.
Conclusion
In my opinion, the Power Queen 12.8V 200Ah LiFePO4 battery is absolutely recommended if you are looking for a simple LiFePO4 battery with a very high capacity!
The Power Queen battery does not offer any special features. We do not have a “smart” BMS, we do not have a low temperature shutdown or similar bonus features. We just have a normal BMS, which protects against deep discharge, short circuits and similar things.
But the most important thing about this battery is the capacity. Power Queen advertises 200 Ah, but I was able to measure a whopping +- 214 Ah on average. The manufacturer’s specifications are exceeded by a good deal (7%).
The battery is anything but too expensive. At the time of testing you can get this for around €500, which is €250 for 100Ah, which is a good price. Especially since I really can’t say anything negative about the Power Queen batteries. I use one of these in one of my off-grid solar systems (but it has now been replaced with this one) and have had 0 problems there.
Therefore, if you are looking for a simple battery with a lot of capacity and the common advantages of LiFePO4 technology, you have come to the right place.