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

2s-7-4v-500-mah-kingmax-25c-lipo-battery

The 2S 7.4V 500 mAh KingMax 25C LiPo batteries are compact packs used for remote controlled models that re supposed to offer decent performance for their small size. The batteries are rated for 25C constant discharge rate and higher burst ones, but are these batteries really capable to deliver such performance?

Official Battery Specifications:

– Capacity: 500mAh
– Voltage: 2S / 2 Cell / 7.4V
– Continuous discharge rate: 25C
– Charge time: recommended (1A/2C)
– Net weight: 30g
– Size: 53 x 30 x 10mm


2s-7-4v-500-mah-kingmax-25c-lipo-battery-capacity

We’ve started testing with a 1C discharge rate (0.5A) and the 2S 7.4V 500 mAh KingMax 25C LiPo battery was able to give out just 438 mAh capacity which was a bit disappointing considering the battery is rated at 500 mAh, this is a little over 12% lower capacity that advertised. Moving to higher discharge rates such as 5C and 10C (5 and 10 times the capacity) the battery handled quite well. At 15C constant discharge rate in the end the temperature of the battery was a bit hot at 55 degrees Celsius (still within acceptable levels) and the capacity provided was already less than half of what the battery could provide at 1C discharge. Moving to 20C discharge rate the battery reached the cutoff voltage very quickly, so the 2S 7.4V 500 mAh KingMax 25C LiPo batteries are definitely not able to handle 25C constant current load when they have trouble even at 20C.

The performance of the 2S 7.4V 500 mAh KingMax 25C LiPo Battery in our tests:

– 438 mAh at 0.5A load (1C)
– 429 mAh at 2.5A load (5C)
– 412 mAh at 5.0A load (10C)
– 207 mAh at 7.5A load (15C)
– 38 mAh at 10A load (20C)
– 22 mAh at 12.5A load (25C)

In the end 2S 7.4V 500 mAh KingMax 25C LiPo batteries turned out to be a bit of a disappointment with more than 10% lower actual capacity than advertised and not even close to the discharge rates they are supposed to provide. These batteries should have been rated at not more than 440 mAh capacity and discharge rate of 10C-15C and not 25C as they claim to be.

2s-7.4v-350-mah-zippy-20C-lipo-battery

The 2S 7.4V 350 mAh Zippy 20C LiPo batteries are small Lithium Polymer batteries mostly used in remote controlled planes and are available at really bargain price from Hobby King. They are 2S1P batteries with a capacity of 350 mAh and should be able to handle 20C discharge rates (20 times their capacity) according to the official specifications. These specifications seem quite reasonable, however we are still going to check if they are true in reality or not.

Official Battery Specifications:

– Capacity: 350mAh
– Voltage: 2S / 2 Cell / 7.4v
– Discharge: 20C Constant
– Weight: 21g (including balance & discharge plug)
– Dimensions: 40x20x15mm
– Balance & Discharge Plug: JST-XH & Mini JST plug


2s-7.4v-350-mah-zippy-20C-lipo-capacity

We’ve started the capacity tests of the 2S 7.4V 350 mAh Zippy 20C LiPo batteries with a discharge rate of 1C which was handled without any issues, though the maximum capacity we got was 337 mAh or a bit short of the 350 mAh that they should provide. Then moving to higher discharge rates of 5C with no problems, next was 10C discharge rate that the battery still managed to handle without issues even though the temperature got a bit high at 62 degrees Celsius at the end of the discharge test. Moving to 15C and 20C discharge rates the the battery still handles quite well, but the real problem is that it gets way out of the safe operational zone with temperatures of 78-79 degrees. These temperatures are way too high for constant discharge of at 15C or 20C rates, though the battery should be able to handle well momentary peaks of up to 20C.

The performance of the 2S 7.4V 350 mAh Zippy 20C LiPo Battery in our tests:

– 337 mAh at 0.35A load (1C)
– 332 mAh at 1.75A load (5C)
– 329 mAh at 3.50A load (10C)
– 305 mAh at 5.25A load (15C)
– 275 mAh at 7.00A load (20C)

1s-3-7v-600-mah-turnigy-nano-tech-35-70c-lipo-battery

The 1S 3.7V 600 mAh Turnigy Nano-Tech Litthium Polymer batteries are being sold by one of the largest online remote control model and accessory stores called Hobby King and the brand Turnigy is their own. The batteries under that brand are considered to be of quite decent quality and a very good value, though we are going to check how good their perform and if they match the official specifications. The Turnigy only batteries are the lower end and the Turnigy Nano-tech labeled models are considered to be better as they offer higher discharge rates and the 600 mAh Turnigy Nano-Tech 1 cell LiPos are labeled with a discharge rates of 35-70C (constant 35C and peak 70C) which seem pretty high for that small battery. These batteries usually find their place in small scale helicopters, quadcopters or planes, so it is very important that you know what they are capable of in order not to crash your flying RC model because of battery not handling as well as it should be and you now aware of its actual capabilities. Below are the official specs of these Turnigy Nano-Tech LiPo batteries.

Official Battery Specifications:

– Capacity: 600mAh
– Voltage: 1S1P / 1 Cell / 3.7V
– Discharge: 35C Constant / 70C Burst
– Weight: 15.8g (including plug & case)
– Dimensions: 79x7x19mm
– Discharge Plug: JST


1s-3-7v-600-mah-turnigy-nano-tech-35-70c-lipo-capacity

In order to test the capacity of the 1S 3.7V 600 mAh Turnigy Nano-Tech Litthium Polymer batteries we’ve started with a 1C (one time the capacity of the battery or with other words 0.6A) discharge rate and continued to increase it to 35C, the value that the battery should be able to handle at a constant discharge (that is 21A discharge). Our tests showed that the maximum useable capacity we’ve got at 1C discharge rate was 590 mAh which is only 10 milliamps shorter of the 600 mAh capacity by specifications which is not bad at all. However the official specs about the discharge rates this battery is capable of are far from the reality we’ve measured. At 35C discharge rate (21A) the battery is not able to handle properly even peaks, let alone provide a constant discharge. We can say that the battery is more like capable of peak discharge rates of 20C and constants discharge rate of 15C, though at 15C discharge rate (9A) we’ve measured a temperature of the battery of 59.5 degrees Celsius at the end of the discharge cycle. This temperature is at the edge of the safe zone for discharge of LiPo batteries, even though this temperature has been achieved with the battery standing on one place and if you are using it in a moving RC model the airflow will help in cooling it a bit and the actual temperature will most likely be lower.

The performance of the 1S 3.7V 600 mAh Turnigy Nano-Tech 35-70C LiPo Battery in our tests:

– 590 mAh at 0.6A load (1C)
– 545 mAh at 3.0A load (5C)
– 531 mAh at 6.0A load (10C)
– 506 mAh at 9.0A load (15C)
– 69 mAh at 12.0A load (20C)
– 18 mAh at 15.0A load (25C)
– 7 mAh at 18.0A load (30C)
– 5 mAh at 21.0A load (50C)

So the battery is not bad, however the actual specifications are a bit lower than the official ones. If you regard the battery as 1S 3.7V 590 mAh with a discharge rates of 15C-20C you might save yourself some trouble in finding out these more actual values the hard way.


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