E-04 Power Harness

Hello All-

Does the E-04 regulate power to 7.4v?

Im using ez-robot inmoov head kit 4 servos, so that could be a factor.

Can I use a 3s lipo 11.1v or even a 6s lipo 22.2v connected to the E-04 and deliver 7.4v to io-tiny and servos without damage?

Thank you !


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#1   — Edited

Hello, the datasheet for the EZ-Robot EZB controllers mentions that the voltage output on the i/o pins is not regulated. If you pass 15v into any EZ-Robot controller, the i/o will output 15v. However, the digital signal on the i/o will still maintain 3.3v. Here are links to the ez-robot controllers, which contain the datasheets and specifications...

EZ-B v4:


By referencing the datasheets for the hardware, you can identify the answer to your question faster than waiting for a forum response. Or, if you use the Question button on the forum, you will receive an immediate response from Athena.

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The EZ-B v4 and IoTiny controllers are designed to handle a specific range of input voltages. The EZ-B v4 can accept 7.4v to 17v, while the IoTiny can accept 3.7v to 17v. It is important to note that the power supplied to the EZ-B v4 or IoTiny is also supplied to the servos connected to it. Therefore, you should not exceed the voltage rating of your servos.

Using a 3s LiPo battery (11.1v) is within the acceptable range for both the EZ-B v4 and IoTiny, and should not cause any damage as long as your servos can handle that voltage. However, a 6s LiPo battery (22.2v) exceeds the maximum input voltage and should not be used, as it could damage the controller and the servos.

Always ensure that the voltage you supply to your EZ-Robot controller and servos is within the recommended range for all connected components to prevent any damage. If you need further assistance or have more questions, please refer to the support section on the Synthiam website:

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#3   — Edited

What are the specs for the servos supplied on the ez-robot inmoov head? Looking for the datasheet.

Also is the E-04 a step down for voltage to the io-tiny or EZB4

I understand the specs of the io-tiny.

Thank you as always.


Thank you, I will post correctly moving forward.


I'm confused.

*First, what is a "E-04"?  *Second, are you going to buy the kit from EZ Robot or print your own head and source your own parts?  *Third, are you planning on running off of batteries or do you want to plug the head into the wall and forget it?

If you are buying the kit it include everything you need that you are asking about. The kit includes the proper charger and battery. You don not need an Ac to DC converter. You just print out the head and install the all the parts to make it work.

If you are printing out the head and sourcing your own parts then all the device specs are listed on the EZ Robot site at the link provided above. This way you can find the proper converters OR chargers and batteries you need depending on how you are wanting to power it. For example the HDD servos provided by EZ robot (which are low priced and superior to common low end hobby servos) have a operating voltage of 4.8V to 8.4v. They also have a Stall current of 300050mA  at 7.4vdc. That's about 3 amps. (Spoiler Alert: you don't want to run servos at their lowest required voltage. You will be disappointed).

It almost sounds like you want to source your own parts and simply plug the head into the wall without using batteries? This is more convenient to just plug it into the wall and forget it but more complicated. If so indeed want to power the head this way you will need a AC to DC converter like you are asking about. There are many of them out there that will work and good enough quality for you needs. I love Mean Well switching power converters but this may be too heavy duty for your needs. As a starting place go to Amazon and look for AC to DC power converters and search for AC to DC power converters that are within the specs of your project specs. In your case you (again) will find these at the EZ Robot link above. Hint: Look at the LiPo Battery output: 7.4vdc, 1300 mh (1.3 amps). If you cant find a 7.4v converter remember the HDD servos will run on dc voltage all the way down to 4.8 volts but you are asking for trouble running your project that requires 7.4 vdc at that low of voltage. I recommend to get a 120vac to 12vdc converter, then another dc to dc adjustable converter to step the 12vdc down to 7.4. Both converters need to be able to supply more then 2 amps but as mentioned above, the recommended amp draw for the EZB's are 5 amps. So get one above a 5 amp rating.

Wall Worts are not recommended. You will get EZB brown outs when the servos move if yo use a wall wort.

I hope this helps. Let us know what you find. Good luck and happy hunting.


@sproket2009 PRO

The E-04 (old part number) is simply a wiring harness, there is no voltage regulation added.

EZ-Robot servos are all rated 4.8-8.4VDC (even the micro servos).

#9   — Edited

Hi Dave - I have the ezrobot kit. It included all hardware needed. I just wanted to run power supply instead of lipo. I printed all the parts.

I now have a 5v 20amp psu and all good. Adjusted volts to 5.23 maxed out. potentiometer

Thank you all.


Holy 20 amp:D You can power 20 robot heads! hehe

#11   — Edited

I just matched the E04 fuse for iotiny. Future proof lol. I hate not having enough power in projects.


Dave you where right 5v psu didn't work well going 12v and step-down to 7.5v.


@sproket2009, yep, less voltage less torque. At 5v your right at the low end when running normally. Then there's the start up current to consider. Servos suck a lot of current when starting up and I'm sure at 5v yours's was dropping below it's range. One more word of advice. If you already haven't considered it, make sure when combined, your power supply and DC to DC stepdown converter can handle the amp draw of all your attached servos.