RC Model Reviews

I have a few unused 7.4v high C rating Lipos that I'm not using. I'd like to try the 9X battery mod with one of these. Is the high C rate (30 in this case) a problem? Can these batteries be used? I know they don't have the built in protection as the batteries suggested do, but they are already here and I'd like to put them to use if possible.

Thanks in advance for any advice.

The mod will work just fine with a 2S lipo pack and the high C-rating won't matter at all.

That is great news indeed!

Much thanks!

I did this DIY battery mod to my both of my 9X's and it works a treat, you're a legend Bruce THANKS!

Stupid question - doesn't the 9x use a MC7805 regulator that requires a minimum of 7.0 volts to achieve the regulated 5V? This could potentially cause some questionable operation if voltage gets below spec with 2 Lith cells.

The regulator dropout voltage is 1.5V at the current the transmitter draws (it is higher at the full rated current).

That means the 2S lithium can drop as low as 6.5V from its nominal 7.2V. By that time it's pretty near flat anyway -- having reached 3.25V per cell.

So in practice, not a problem.

The transmitter alarm will sound when the lithiums drop to 3.3V per cell -- still leaving the dropout voltage plus a safety margin.

Thanks - I haven't had a chance to measure the operational current yet, happy to hear it is not pushing the regulator. I suspect with the Fly Dream unit installed, it will be quite low. I am quite excited about the ability to update the transmitter code - I intend to optimize for fixed wing electric use (removing some mixers, adding a throttle mixer (with offset), eliminating all heli stuff) so that I can fit the most amount of MY models.

Scott