Increase Flight Time of U818A HD Quadcopter.

LoneRCRanger

LoneRCRanger

Well-Known Member
Back again with another question. My U818A HD uses one 3.7 volt, 500mAh Li-Po Battery and has a maximum flight time of about 10 minutes. I want to increase the flight time to 30 minutes by piggy-backing , in parallel connection, two additional batteries. This would allow the 3.7 volt match to continue while allowing the Ampere Hours power support to be increased from 500mAh to 1,500mAh. From my understanding about electricity (which is on the level of the number of pickles you can squeeze into a jar), as long as the voltage remains the same, increasing the amperage should not overwhelm the electronics as the electronics will only use the power it needs. This is similar to where having a larger fuel tank in your car doesn't mean you get overwhelming power, just thatyoucan go farther.

Does this sound plausible?
 
No it doesn't sound like a good idea although other people may have a different idea. My experience is with small quads.

The issue is by adding two more batteries you are increasing the weight that has to be lifted. My 500mAh battery weighs about 15g; adding two you are increasing the weight by 30g. From a quick look, it looks like the weight of the U818A is 104g so you would be increasing the take off weight almost 30%.

While the U818A might be able to lift that extra weight, to do so the motors are going to have to work harder and consequentially drain the batteries faster. When adding a bigger battery you quickly reach the point of diminishing returns. You could easily find by adding that much more weight your flight time is actually going to shrink, assuming it can lift itself in the first place.

These "toy" quads are engineered to be able to lift a certain amount of weight with a certain battery, motor and propeller size. These are highly interrelated so it is difficult to just change one and expect your performance to improve.

The only reasonable way to increase your flight time by adding a larger battery, is to somehow remove weight, say from the frame, so that the weight with extra/bigger batteries doesn't exceed the original designed weight.

Bruce
 
bbodnyk hit the nail on the head. You should be able to find a ~600-720mAh battery that fits and doesn't add much weight. This will help a bit and as the battery ages and loses capacity should still keep you at a decent flight time.
 
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