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AR7200BX vs. AR7300BX

I intend to use a BEASTX flybarless system on my 600/700 heli. Should I go with the AR7300BX?
Today's servos and especially so-called high voltage servos typically have a very high power consumption. When using Futaba BLS 451 servos for example these are very modest. Savöx 1258/Align DS610 are much more demanding, one alone taking up to 15Amps peak for the instance of a second. And for very extreme example take high voltage Savöx servos SB-2271SG HV. They demand up to 27Amps (1 Servo!) peak which you can see when measure the power consumption with an oscilloscope.

So besides using a good stable and high rated power supply you have to ensure proper supply of the servos with this power. But when only connecting one servo plug with power leads into the receiver this may insufficient and cause a "bottle neck" in power flow. There is no benefit if the power supply/BEC itself can deliver 20-25A when this amount of current is not able to flow to the consumers.

So the idea behind AR7300BX is to provide a power connection that allows for using thick power cables and directly connect these to the device, so the voltage loss due to wiring and plug connection is reduced to a minimum. In general for helis with standard size servo you should always use AR7300BX, because this will eliminate the "servo plug problem" as one important factor that may be critical for your power supply.

Anyhow, it mainly depends on how you power your system. I. e. when using an ESC with only one BEC line (and if this works without issues), then there will no benefit of using the AR7300BX as you already have a "bottle neck" at the power output. The small wire will not be able to transfer more than 5 Amps continuous current. Connecting this little wire to AR7300BX's high power input will not help very much here.

If on the other hand you have at least two or even three BEC lines then this can be different as you may solder the power wires from the BEC together to a EC3 high power plug. Then you have a much lower contact resistance compared to only connect the wires using the standard servo plugs, which is a real benefit for providing a stable power supply. Ideally you have a BEC or receiver battery that already comes with thick power wires. Here it is ideal to use AR7300BX.

When using a separate receiver battery i.e. on nitro or gas helis using AR7300BX is the ideal way to connect the battery to your RC system. In addition to the adequate connection plug here you have an integrated switch system for switching the heli on and off, so there is no need to buy an extra switch.