The multi rotor market is quickly growing, and one segment that is responsible for much of that growth is the 250 class FPV racer. These small quadcopter are built for speed and manuverability. They are most certainly not your DJI Phantom float around and get video quadcopter. These are buzz the ground at 40mph speedsters that put you in the pilots seat.
This is one of a series of reviews of one of the most common battery pack sizes for these: 3S 1300mAh. Be sure to see the summary review and the other detailed reviews of the others tested.
This is about as light as you can expect in the 1300mAh 3S category. 100g is well below the average 3s 1300mAh pack. They typically weigh in around 115-120g. The 15g savings really can make your quad feel more responsive. Flight time could also increase with this lower weight, unfortunately that isn't the case.
That low weight comes at a price. The cells used for this pack are not up to 35C standards. The internal resistance (IR) measured 33-40 mOhm depending on the pack (two were tested). That and the data indicate these are probably close to 15-20C.
What does that mean to you? Flight time will be reduced. You'll need to use more throttle to get the same thrust, so any efficiency gained from less weight is lost because more power is being turned into heat.
It also means that any quick movements will feel sluggish. It simply can't deliver the punch needed in moderate flight that pulls a modest 15-20 Amps.
Another concern is how hot this pack gets. At 135F you should begin to be concerned about damage to the battery. Under a mild 17.5A draw this pack went past that to 136F. Under a 26A load it topped out at 157F!
This first graph shows the 26A discharge test. It averaged 3.69V per cell through the first 50% of the test (520mAh). Then just 3.50V for the remaining 50%. More alarming is the temperature of the pack. It passed the 135F safe zone just past 50% of the test. This is due to the high IR. This internal resistance takes your packs energy and turns it into heat rather than power for your motors.
This next graph is a more standard test at 17.5A (13C). The voltage was 3.75V for the first 50% and then 3.54V for the remaining 50%. Definitely low enough to feel in flight. This low voltage triggered the low voltage alarm after just 3 minutes. It also required 42% throttle to get it to hover (compared to 35% with better batteries).
This is the two discharge tests on the same graph. You can see the effects of the higher load on the voltage provided.
Skip this one. The reviews look great on their website. However they don't publish poor/negative reviews. Middle of the road reviews are published but only after they increase the ratings the user gave (yes, they add stars to people's reviews).
Actual testing on the bench and in flight side by side with other batteries clearly shows this one is underpowered and over priced.