With the 4-6 Ah Multi Ah Power X-Change PLUS, Einhell offers a very strange tool battery.
You can switch this between a capacity of 4Ah and 6Ah. But why? According to the manufacturer, this offers a longer runtime in 6Ah mode and a higher number of cycles in 4Ah mode before it breaks.
That sounds very interesting and extraordinary. In short, I bought this battery, let’s take a closer look in the test!
The reasoning of Einhell
What is Einhell’s explanation why you should buy a 6Ah battery and then throttle it down to 4Ah?
Basically, the power of your devices will be the same in both modes. That means the output power at maximum is not lower at 4Ah than at 6Ah. But in 6 Ah mode you have more runtime than in 4 Ah mode, logically.
4 Ah = 72 Wh capacity
6 Ah = 108 Wh capacity
But why does the battery have “3x more life expectancy” in 4 Ah mode? If you always discharge a lithium battery from 100% to 0%, the cells are significantly more stressed than if you discharge it, for example, from 90% to 10% and vice versa.
This is how e-cars work to increase the durability of the batteries.
So in 4Ah mode, the cells of the battery are probably not discharged or charged as much and thus the shelf life is stretched.
Even if I think a 3x shelf life is a bit optimistic.
The (possibly) true reason
But there could also be another reason why Einhell is doing this.
As you may know, you are allowed to take a maximum of 100Wh batteries on an airplane. For anything above that, you need a special permit. This also partially applies to air freight!
Excitingly, the battery is only labeled with the lower capacity of 72Wh.
- 4 Ah = 72 Wh capacity
- 6 Ah = 108 Wh capacity
Means, if you take this battery with you on an airplane, it would probably “only” count as 72Wh.
But this is just a pure guess and whether this is all so “clean” I do not know. But why else would Einhell write the lower and not the higher capacity on the battery? So possibly the “transport thought” definitely plays a role here.
The battery
The Einhell 18V 4-6 Ah Multi Ah is a classic Einhell 18V battery that you can use in any 18V Einhell device that physically has room for it.
The weight, which is quite high at 998 g, is striking. The battery is also a good deal thicker than, for example, the 2.5Ah batteries. However, this is in the nature of things, because similar to the 3Ah or 4Ah battery, the Einhell 18V 4-6 Ah Multi Ah is built in two rows.
Presumably, this one will have 4x 18650 lithium battery cells installed twice, each with 3000mAh capacity.
Unlike the other Einhell batteries, the Multi Ah has a small display on the front that shows you the battery status in % and also allows you to switch the capacity from 4Ah to 6Ah and vice versa.
How does the throttle work?
But how does the throttling work? The Multi Ah Power X-Change PLUS battery seems to limit its voltage range depending on the set capacity.
Fully charged, I could measure a voltage of 19.93V in 4Ah mode, and 20.72V in 6Ah mode.
Empty (discharged with a hot air tool until it shut off) I was able to measure 17.336V in 4Ah mode and 16.846V in 6Ah mode.
- 4Ah = 19,93V to 17,33V
- 6Ah = 20,72V to 16,84V
So we have a slightly wider voltage range in 6Ah mode and therefore more capacity. If you also fully charge the battery in 4Ah mode and then switch to 6Ah, it will only show a charge level of 88%.
How much capacity has the Einhell 18V 4-6 Ah Multi Ah?
Unanimously advertises a capacity of 4Ah or 6Ah. But does the battery really have this capacity? Does the switching work?
- 4Ah – 4.02Ah / 72.3Wh
- 6Ah – 6.04Ah / 108.7Wh
Yes! In 4Ah mode, I was able to measure a capacity of 4.02Ah or 72.3Wh. In the 6Ah mode, we came to 6.04Ah or 108.7Wh.
So, the capacity specification fits.
Conclusion
Einhell offers a very interesting and unusual battery with the 4-6 Ah Multi Ah.
As far as I can tell, the battery also delivers what it promises! Thus, this offered the capacity of 6.04 Ah or 4.02Ah in the test.
Accordingly, switching between the two capacities works flawlessly.
However, I cannot conclusively say whether the battery really has a 3x higher cycle performance in 4Ah mode. However, it would be quite possible based on the measured values, since the battery is charged and discharged less strongly in this mode, which protects the battery cells.
