RC Helo battery pack

I have a RC helicopter that uses this battery pack.

double horse 9050 battery spare parts - $14.00 : shuangma helicopter, online shop

It is only 1300 mAh. The 2 cells are 18650s. I thought about trying to use better cells but I don't have the means to properly assemble it. Does anybody here know of a good source to get a better battery pack?

Try hobbyking.

You need to know the power requirements before sourcing cells. Just because it is the same size, doesn't mean it is the same thing.

The pack consists of 2x 18650 in series. The LEDs would light up but the motors didn't spin. A voltage check gave me around 3.8 in series so I knew one was dead. Ghetto rigging a couple 18650s worked. The LEDs were brighter too. I have another battery pack on the way. It's been 3 weeks already though. It would be nice to have more than 1300 mAh available.

You can't use capacity to indicate quality, because cells capable of higher power output have lower capacity. Today we can get 3400mAh cells, but those are spec'd to deliver 3.4A cont. max. Or you can buy a high power cell, it only has 2900mAh but can deliver 10A continuous.

1400mAh used to be a common capacity claim for lithium manganese cells. Very possible that your helicopter was meant to run on IMR cells. It's best to see what the requirements are before building a pack, but you say you ahve a pack on the way, so that ought to be fine.

I did a cursory search for the doublehorse 9050's maximum current draw but couldn't find what I was looking for. If you have a power supply capable of supplying a good number of amps, you could set it to 7.2V constant voltage, hook it up to your chopper, crank up the motor to high and lights on full blast and see what the current draw is, if you were really curious.

The original specs state that it is a LiPo battery. If it was contained in cylindrical cells, was probably IMR, hence the low capacity.

They claim 10-15 minutes per full charge of teh 1300mAh pack. This means more than 5A of current draw continuous from the pack, which is very rough on standard 18650, and not good for even the famed 3400mAh cell.