Sie haben keine Artikel im Warenkorb.
A year ago Michael Barton showed us a small building proposal for a DIY solar system. Like most such DIY camping, garden shed solar systems, this was based on lead gel batteries. Anyone who has ever dealt with lead gel batteries in this area will know that they are bad when it comes to high cycle numbers.
No matter what the manufacturers claim, the batteries must be replaced after a few years. But against what? The typical solar charge controllers are designed for lead acid and comparable battery types. You cannot simply connect a lithium ion battery here.
This is where the so-called LiFePO4 batteries come into play! Lithium iron phosphate batteries (LiFePO4) are wonderful replacements for classic 12V battery types.
Many of them are commercially available as 12V versions, can be charged with "normal" chargers and are cycle-proof!
In short, the ideal batteries for solar systems, in theory. To find out more about the practice, let's take a look at Creabest12.8V 42Ah LiFePO4 battery in the test!
Technical specifications
Voltage |
12.8V |
Capacity |
42Ah |
Total Energy |
538 Wh |
Standard discharge current |
50A |
Peak Discharge current(1S) |
300A |
Full charge voltage |
14.6V |
BMS low voltage protection voltage |
8V |
Storage temperature |
-20℃ - 60℃ |
Weight |
6.5KG |
Dimensions |
223x120x176mm |
The Creabest 12.8V 42Ah LiFePO4 battery in the test
Creabest advertises its LiFePO4 batteries as perfect for mobile homes, caravans, camping, boats, etc.
Fittingly, the battery is also kept in a very typical shape for a car battery, with 223x120x176mm and a weight of 6.5KG.
On the outside, the battery is made entirely of plastic, apart from the two connection terminals. These are simple screw terminals with a diameter of 6mm.
However, the interior looks a little different than in a traditional car battery. There are four lithium iron phosphate cells and a so-called BMS module.
The BMS module first ensures that the cells connected in series are evenly charged. It also offers some protection against overloading, deep discharging, short circuits, etc.
This happens invisible to you.
Charger included
Fortunately, Creabest includes a charger in the scope of delivery. This is ideal for initially charging the battery.
The charger has 14.6V and 8A, so it has quite a bit of power! A fan is also installed inside for this.
Advantages (and disadvantages) of lithium iron phosphate
But what are lithium iron phosphate batteries anyway? In contrast to lithium ion batteries, LiFePO4 batteries have a very stable cell chemistry.
That means they are very robust against physical influences, but also less sensitive when it comes to charging. If you charge a lithium-ion battery only 0.2V too far, it can fly around your ears. LiFePO4 batteries, on the other hand, are a little more forgiving.
Another advantage of LiFePO4 is the cycle strength. Normal lithium ion batteries manage around 500 cycles before the capacity drops noticeably. LiFePO4 batteries manage 2000 cycles, meanwhile there are even the first models that can manage 3000-4000 cycles.
In addition, there is very good power delivery capability, at the level of lithium-ion batteries, and very fast charging.
This makes these straight lead batteries superior in all respects. But compared to lithium-ion batteries, why do we use LiFePO4 so rarely?
LiFePO4 has a lower energy density. A lithium-ion battery is about 40-60% smaller and also a little cheaper with the same capacity.
Therefore we only see LiFePO4 in areas where either the fixed cycle is extremely important or the space requirement is not quite as important. In our case, this does not matter, especially since LiFePO4 has a significantly higher energy density than a lead battery.
So you save space and weight with LiFePO4.
The capacity
The most important thing is of course the capacity. To measure the capacity, I first fully charged and discharged the battery. Then recharged (with a laboratory power supply) until it no longer consumed energy.
I discharged the battery at 2A, which was admittedly quite leisurely, so it took a while to discharge.
In the first cycle I was able to measure a capacity of 530.74 Wh.
In the second cycle I was able to measure a capacity of 548.83 Wh.
The manufacturer's specification of the capacity is thus achieved or exceeded!
Also positive, the shutdown when the discharge was too deep took hold, at about 10.6V. The voltage curve is quite flat. If the battery is called, it supplies a voltage in the range 13, x-12, xV over an estimated 90% of the capacity. At the very end, the tension drops rapidly.
This is normal behavior for LiFePO4 batteries, see Wikipedia.
Can be charged on any lead battery charger?
A big feature of LiFePO4 batteries is the compatibility with devices that are actually intended for lead batteries.
But can you really use any lead battery charger for a LiFePO4 battery? The answer is a resounding yes and no. LiFePO4 batteries require a 12V charger with CCCV charging technology. CCCV stands for constant current constant voltage, meaning that the charger must limit the charging current as well as the voltage.
For example, you can charge a LiFePO4 battery on a laboratory power supply by setting the voltage to 14.6V and limiting the current to 2A, for example.
Most lead-acid battery chargers use this charging method! However, I don't want to put my hand in the fire for all devices to do this. Should you catch an incompatible device but the protective circuits should grip and that's it.
Conclusion
Yes, Michael Barton can only recommend LiFePO4 batteries in general, especially if you have a very cycle-intensive application. This can be with a solar system or a mobile home.
Here LiFePO4 are significantly more durable than lead batteries and yes Michael Barton speak from experience. You get lead batteries with 100Ah for around 100 €, but these 100Ah don't last long if you discharge the batteries deeper. In my small test DIY solar system I was able to use 100Ah lead batteries for maybe 2 years before the capacity dropped massively (+ - 20Ah).
A LiFePO4 lasts 2000-3000 cycles, which is even more than a lithium-ion battery would do.
In this case I can especially recommend the Creabest 12.8V 42Ah LiFePO4 battery. In the test, this could reach or even slightly exceed the advertised capacity of 538 Wh. In addition, this is not too expensive for a LiFePO4 battery and looks generally reasonable. The surge protection as well as the protection against deep discharge worked perfectly!
Thumbs up for Creabest!
Notice:The above content comes from Michael Barton's forum(https://techtest.org/die-exmatecreabest-12-8v-42ah-lifepo4-batterie-im-test/)