FrSky Q X7 battery options.

[StevenGnz]

I will be changing my FrSky Q X7 to LiPo batteries when it arrives. While I use three cell LiPos in my aircraft, I see there is the option of using 2S or 3S LiPos in the Q X7. There is no information given about the regulator the Q X7 uses to bring the battery voltage to the Q X7 voltage. If it is a linear regulator there is almost no duration advantage in having the third cell. If it is a switching regulator ( with its current boosting ) the third cell will provide a 50% increase in duration over two cells. Sorry this is more technical than most flyers need but the open source nature of the Q X7 should include information on the hardware as it relates to this upgrade.

 

[StevenGnz]

I take it that the, no reply to my first post means that either no one knows or the information cant be given out by any one other than FrSky. If it had a switching regulator someone would have been singing the longer duration with three cells. They aren't so it doesn't. A large part of the reliability of an item of equipment is that all the parts of it are designed to be used as its operation demands. The PCB mounted battery socket is not designed for unplugging often. A separate charging socket, of suitable design needs to be installed on the outer of the case. If NiMH batteries are used this can be a two pin standard type charging socket & plug with low rate charger. If a two cell Lipo battery is to be used the charging socket & plug must have three connections, because the charger will need to have a balancer and that will require a third connection. The socket & plug must not allow a short between battery terminals when being connected, this rules out jack type sockets. Cannon plug & socket are reliable but a bit on the big side. circular DIN plug & socket would seem to be the best choice but I am not sure their contact system is up this purpose. A D9 plug & socket could be used which could if wired give you triple redundancy. Let me finish with a question, the Alex Datos manual says that the "SD card is better to be formatted as FAT32,". When I did mine I think it said FAT16, will this be a problem when my QX7 arrives?

 

[Wayne]

We use FAT32 here, not sure if FAT16 will work or not. Guess you can try it.

I would suggest running a NiMH pack in this radio. They work very well and give many hours of operation. With our charger, they are dirt simple to use. Just plug in and walk away. It will turn itself off after the charge is done. Probably only need to charge once a month or so depending on how much you fly.

I don't think a 3S lipo will fit in this radio. The 2S lipos we offer for this purpose barely fit.

With the new charge port FrSky has installed on the radios, I do think NiMH is the safer option!

 

[StevenGnz]

Thanks Wayne, I will as you suggest go with the NiMH AA cells. I have installed a charging socket and wired it in. I am for the moment while learning to set up the X7 from your User Manual, using nonchargeable cells. I agonized whether I should wire it so when the charging plug, is plugged in, it disconnected the (in my case ground) from the transmitter. While this protects the transmitter from any surges from the charger, it has the disadvantage that if that switch contact should go open while flying you loose battery power to the transmitter. In the end I left the switch out of circuit, that is, the charging socket is direct to the battery and transmitter. Which way is a charging socket usually wired?

 

[Wayne]

We wire ours so they are direct, the switch is not used.