Rick Lindsey

I've read about people using LiPoly batteries to run their rx and servos, but the only post I saw was about running them above their spec'd voltage (i.e. a 2-cell Lipo). Has anyone tried using a single LiPo cell to run rx and micro servos?

I couldn't find voltage specs on hitec or futaba rx's, but the fma M5 supposedly worked as low as 3.5V, and they also supposedly have a "low voltage" version of both their M5 rx and PS20 servos. I was wondering, though, if some of the cheaper 5g-6g servos (bluearrow, gws pico, esky, etc) would also work at lower voltages (why pay $22 per servo when you can pay $10-$14?). Some of the smaller servos (HS-55) specify that they cannot run at 6.0V, which would lead me to believe that they might work at lower than 4.8V.

The intended application is a modified free-flight model, something with a wee CO2 or large rubber motor, with a single LiPo,micro rx, and micro servo for rudder-only RC.

-Rick

exeter_acres

My Feedback: (2)

Not sure about the lower voltage.....but when people use 2C Lipo's...they also use a voltage regulator to keep everything within spec

Rodney

You can now buy receivers that work well on the lower voltage. I know FMA makes one and I'm pretty sure that I saw one other brand available. You may want to check for sure, but I think the standard FMA receiver will also work on two LiPos with no regulator.

Rick Lindsey

Rodney, do you remember the other brand? I found where I can buy the FMA low-voltage receiver and servos (www.fma-direct.com), but I'd like to see all my options. Especially since I've heard less than stellar things about FMA service... (sounds like they make good stuff, but are hard to get ahold of if things go wrong?)

Also, has anyone ever seen spec sheets for the typical 5g-6g servos, or has anyone ever tried to run them on less than 4.8V? I guess I'll start emailing manufacturers, but was hoping someone had experience with low voltage (single LiPo) systems.

As far as 2 LiPo/regulator goes, I'm trying to avoid any extra weight, since this will be going into a small free-flight plane without much thrust to get a heavy electronics package airborne.

thanks,
Rick

Rodney

No Rick, I do not remember the brand, maybe if you check on one of the electric forums they might know. As to FMA quality, I find them very dependable. It is a very small company, essentially one man with few employees, so communications and service can be slow at times but; in my mind, the excellent products make it worth my while.

Rick Lindsey

Thanks for the info! I did a bit more searching and discovered that GWS rx's are supposed to be good down to 3.5V, though the most appealing was the plantranco DSP4, another dual-conversion (ala FMA) that is good down to single LiPo voltages but quite a bit cheaper ($27 at balsaproducts.com, I believe).

I also found one reference that indicated Bluebird 303 servos would run down to 3V(just the 303, though... the same source indicated that the 306 wanted 5V). I'm hoping to confirm that, in which case I think I've found my "ideal" setup (that being a single ~150mAH LiPo, the plantranco DSP4, and a single bluebird 303).

As a bonus, that plantranco also comes in a version with a built-in ESC designed for single LiPo operation, so I may end up tempted to replace rubber or CO2 power with one of the little 3V motors I know I've seen somewhere (back to the search engine!). So much for Rudder-Only! (though I must admit, rudder/throttle sounds suspiciously like a Firebird...)

-Rick