Archive for the ‘Li-Po/Ion/Fe Batteries’ Category

Time for another try at a Znter rechargeable LiPo battery with USB port for charging in the form of a 9V 400 mAh battery as an alternative to traditional 8.4V NiMH or 9V Alkaline battery. With our initial bad experience with the 1500 mAh Znter ZNT18650 that came dead and after opening it up we were not that happy with the build. The 9V rechargeable battery from Znter however looked much more interesting as it actually comes with higher advertised capacity than pretty much all 8.4V NiMHs and falls a little short in capacity compared to the best 9V alkaline batteries in terms of mAh. It is most likely a single cell LiPo battery with a step up voltage converter to output 9V in the size of a standard 9V alkaline battery. Fortunately the 9V 400 mAh Znter battery we got was what it was supposed to be and not with a dead LiPo cell inside, so we headed to testing its capacity…

Doing our regular 0.05A test we use for the 9V Alkaline and 8.4V NiMH batteries we got 338 mAh out of the rated as 400 mAh Znter battery, a really good result compared to 8.4V NiMHs we have tested so far. That result is also on par with an average performing 9V alkaline battery, but the Znter can be recharged and reused via a standard USB, so it is much more convenient. Things however get even more interesting when we look at the voltage curve during the discharge tests as it is essentially flat up until the end of the available capacity and we do not normally see this with NiMH or Alkaline batteries, it is the expected behavior for power banks however. The pretty stable at 9.51V output during the whole discharge test means much higher capacity in Wh compared to traditional batteries with the same mAh results where the voltage is dropping during the cycle. As a result we can say that we are quite happy with this particular product from Znter and it can be a really good alternative to traditional 9V Alkaline and 8.4V NiMH batteries.

The performance of the 9V 400 mAh Znter USB Rechargeable LiPo Batteries in our tests:

– 338 mAh at 0.05A load

– 3.212 Wh at 0.05A load

We were looking for something interesting to test and stumbled onto the Znter 18650 LiPo batteries on Hobbyking’s website, so we have decide to give them a go and see if this alternative to 18650 Li-Ion battery cells. The Znter ZNT18650 is a lower capacity cell, but comes with an on-board micro USB port for directly charging the battery with a regular USB cable. We have ordered one of these Znter ZNT18650 1600 mAh batteries, but what we have received had left an unpleasant taste in or mouths and it is the reason why we would just recommend that you stay away from these. Instead of the 1600 mAh capacity that we have ordered we got a cell that was market with 1500 mAh capacity and on top of that it was not charging (the indicator light was blinking when USB charging cable is connected).

Expecting a dead battery cell we have decided to open up the battery and at least see how it is made and to confirm that the LiPo cell is indeed at very low voltage, so that the charging electronics is not able to charge it. Our suspicions were confirmed, the LiPo cell was indeed with a voltage close to zero, but what we did not like even further about this product is the implementation. The LiPo cell is a round one enclosed in a metal casing with the charging electronics on top, however the board has to small solder joints with a little piece of cable sticking out that is essentially making contact by touching the plus and minus terminals of the battery. You can forget about using this battery with high discharge currents, that is if you manage to actually get a working one. Again to tell that you should just avoid this product as you might get a dead one and even if it is working it is not that well made to make it as a decent alternative to 18650 LiIon batteries for use with higher discharge currents.


The 1S 3.7V 300 mAh Gens Ace 30C LiPo batteries are designed for use with small scale RC helicopters such as Blade mCPX and other similar models such as WLtoys v922, Turnigy FBL100 and others. These are intended to be used as an alternative to the stock battery and provide higher capacity and higher discharge rates to ensure longer flight time and better performance. We are used seeing very good results from Gens Ace batteries so far and we are having high expectations for these batteries, but let us see how they will perform in our tests.

Official Battery Specifications:

– Capacity: 300mAh
– Voltage: 3.7V
– Max Continuous Discharge: 30C (9A)
– Max Burst Discharge: 60C (18A)
– Weight: 7.8 g
– Dimensions: 42.3×18.83×6.98 mm
– Charge Rate: 1-3C Recommended, 5C Max
– Discharge Plug: E-Flight Ultra Micro


We have started the tests with a 1C discharge rate (0.3A) for the 1S 3.7V 300 mAh Gens Ace 30C LiPo battery and we’ve managed to get 308 mAh as a maximum capacity. This is a bit more than the manufacturer rating for this battery or with other words good start for the battery as we were expecting the Gens Ace meets its capacity rating. However what comes as a not so good surprise is that the constant discharge rate is about 20C maximum and not 30C as the specifications say it should be. Andjust to be sure it is not a problem with a particular unit, we have tested multiple batteries and all of them were not able to show better results. Gens Ace also sell 1S 300 mAh batteries with 15C rating and there could be some mix-up, however the boxes of the four batteries we have tested say that we’ve received the 30C model and not the 15C (we have ordered the one with 30C discharge rate). So a bit of a disappointment from this particular product from Gens Ace, but this just shows that not all of their products may be so good as we expect them to be.

The performance of the 1S 3.7V 300 mAh Gens Ace 30C LiPo battery in our tests:

– 308 mAh at 0.3A load (1C)
– 284 mAh at 1.5A load (5C)
– 280 mAh at 3.0A load (10C)
– 267 mAh at 4.5A load (15C)
– 214 mAh at 6.0A load (20C)
– 20 mAh at 7.5A load (25C)