Servo Buying Guide

Hi there,

I am currently building something with plans I got from the internet. It’s a project that uses a Raspberry Pi Model 3 to send signals to an Arduino nano via serial which in turn controls a HiTec 805bb servo. The plans uses an Turnigy5A spec for limo (8-26V). I am confused as what the SBEC is used for here. I can’t seem to find anywhere that sells it. Is there something u guys have I can use in it’s place? Or are there any servos that may deliver similar performance I can use without it? Thanks again


The Turnigy 5A (8-26v) SBEC is a DC to DC regulator.
It takes a LiPo battery input 8 to 26V and produces a constant 5V output, up to 5A.
BTW a LiPo 8 to 26V capable of 5A would be a pretty powerful LiPo.

All you need is a 5V DC supply rated up to 5A.
Something like this but it is rated up to 26A and needs mains connection and should be housed in a case else the mains connection could be touched by someone. (dangerous)

This is also a mains device but at 5A.

Then there is a device like this. Can be set to 5V, can deliver 5A. Wide range of input. (battery)
This might be a good replacement for the Turnigy 5A (8-26v) SBEC.

Can you provide the internet link, it may help in seeing what the total power needs to be ??



Hi Marco,

Welcome to the forum :grinning:

The HiTec 805bb is a monster servo so it’s definitely a good idea to power it externally and check your supply can handle its 800mA draw.

Is there a reason the plans you are working from use a Pi to command an arduino to drive the servo, instead of driving the servo from the GPIO of the Pi itself? You would need at least a logic level converter to increase the GPIO logic up to where the servo can recognise it but it may be an option to simplify some of the hardware in the mix.


My plan is to run Alexa on the pi, I thought it would be best to operate the servos and independently go the Alexa


That’s fair enough, if Alexa is using a lot of CPU resources it could be tricky to be running the servos in parallel on the same machine without having one or the other hang. You’ll still need to check that your control commands are consistently managed and the Arduino never leaves the servos without instructions.

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Hi James

5V @ 5A is 25W
25W @ 26V is a little less than 1A.
Assuming 85% conversion efficiency this would be 1.13A @ 26V, increasing in proportion as the input voltage decreases. That would be 3.7A @ 8V.
Cheers Bob