Asked — Edited

Ezb4 Trouble Shooting


What problem with my EZB4? When I start to run few heavy duty servo (4pcs), it is running normally. But It will auto restart when I add more servo (up to 8pcs)! Anyone can help to answer what problem with my EZB4 and any solutions?

Thanks your attention!

Ricky Ma


Upgrade to ARC Pro

With ARC Pro, your robot is not just a machine; it's your creative partner in the journey of technological exploration.


That is a simple answer. You are not providing enough power for the servos. Servos use electricity, the more servos you add, the more electricity is needed. If you do not provide enough electricity for the servos, the circuit will fail.

Use a better battery. What battery are you using? I recommend using a LiPo Robot Battery 7.4v 1300mAh combined with LiPo Battery Harness


You have a power problem... or more precisely lack of it... Use a 7.4v lipo or 7.2V nimh battery... If that doesn't help, then you are drawing too much power from the ezb... The ezb4 can only supply 5 amps continuous and 20amps in brief spikes.... If your servos are drawing more power than 5amps continuous then the poly fuse on the ezb may trip causing it to reboot


Good Morning DJ and Richard,

Thanks for your reply. I have used AC adaptor for the EZB4( last time DJ suggested me). So, what can I do to give more power to servo when it running and safety to work with EZB4?

Thanks for your help! Ricky Ma :)


What voltage is the adapter? How many amps is it rated for? You really should use Lipo batteries for projects that require many servos....


You have started a few conversations in the past regarding power adapters.

  1. In this thread, a low amperage power adapter was discussed and advice was given for more amperage

  2. In this thread i recommended a 6 amp power supply. Can you verify that you're using a 6 amp power supply? That may not be enough for the number of servos which you wish to run, which is 8.

In tests to use JD with an AC Adapter, we use a power supply of 20 amps. That robot uses 12 servos. The challenge with using an AC adapter is that you're limited because AC adapters are not generally designed for motors, at least 8 motors. Also, in order to achieve a high number of amps, 220 volt mains is required.

United Kingdom


In addition to what DJ and RR have mentioned above , I also suggest that you take a look at the tutorial and the end of this post, specifically, the amps, batteries and power supplies sections. This should help guide you to in to finding the correct power source for your robot and reduce the chances of running in to problems in the future.

Amps, Colts & Power Supplies Tutorial


Hi DJ,

Thanks for your reply! Yes, I used your suggestion AC adapter with 6amp power supply!

In this case, Is it I need to use others AC adapter with 20amps? If yes, I will buy one to try.

Actually, my human robotic will be finished in coming January 2016. Now, just how to use EZB4 program and solve the power problems!

Besides, I want to say EZB4 is really help to success my dream my work. And I don't mind to spent time and money to finish my robotics. In future, I will introduce EZB4 to Hong Kong because it is really good product for anyone!

Cheers! Ricky Ma :)


hi ricky ma

the adaptor is just for your batterie to charge.jd has a batt and runs on your wifi. do you have a blue metal case ?that came with the jd ?


@Nomad, @Ricky is not running a JD, and the adapter in the picture is not a battery charger, but a 6amp adapter (which would be fine for a few servos, but not sufficient to handle the inrush current from 8 servos).

As everyone else has said, need a 20 amp adapter.



che use the power chell? i didn know you may use the adator straight on power chell.


@Nomad, you can use a power supply (not a battery charger) directly with the power shell, or if you have a deans connector, directly to the EZ-B. See Steve's excellent tutorial (skip to step 7 if you just want to know what power supply to use, but the whole tutorial is worth reading)



i was just curious about this topic.i use the batt from here.

thanks for the link.


Hi Steve,

Thanks a lot your tutorial and I have reviewed. So, EZB4 maximum accept 7.4V 20amp adaptor. It is safety for using. But, EZB4 just give the current within 5V for servo or motor for 5-8pcs at the same time. It will still be restart again if use full servo (mean 24servo at sometime).

Therefore, don't use all heavy duty servo at same time with EZB4 or anyone have other solutions?

If yes, would anyone can help to suggest what model or brand of 7.4V 20amp adaptor?

thanks again Ricky Ma stress confused tired


@rickymahk2013 Look on eBay for a Meanwell power supply... They come in various voltages and amp output... I have a 60amp, 5V Meanwell that I use with my inMoov....

Or else just use a Lipo battery and be done with your power problems....

United Kingdom

It's not so much that the EZ-B can take up to 7.4v (it can take up to 16v), but the 7.4v limit is for the servos connected to the EZ-B.

If you need multiple servos to move at the exact same time which would be in excess of 20 amps, you could bypass the EZ-B and connect the servo power wires directly to a 7.4v high amperage power supply (high amperage as in 30, 40 or 50 amps depending on how many servos you have, and there max current draw which you would need to add togeather to get your total current).


On my InMoov I am using a 22 Amp, 6 / 12 Volt adjustable PS. from Pyramid. It has a voltage & amp meter in front. They also sell PS with higher amp.

The HItec HS-805BB (12) + EZ-Robot servo (12) are supplied by this PS.

The head also contains 4 EZ-Robot servos connected directly to the EZB. everything is supplied by the PS. adjust to 6.3 v.

To keep the system stable, I just make sure not to start all servos at the same time, by inducing a short time delay in each sub assembly.

Still intermittently, even with all servos in a release state, the EZB will start a servo without any command coming from a script. I suspect I will need to increase the voltage to 7 V at the EZB with a voltage regulator.


Hi All,

Thanks for everyone to reply and help!

Hi Steve, My robotics is connected EZB4 x 3 (see attached file)

User-inserted image

Question is :

  1. This connecting method, is it correct or too complicate?
  2. For safety, use 7v 20amp and moving servo quality within 20amp. In this spec., will not damage my servo and EZB-4? Or I can use 5V 60amp with EZB-4 (same as Richard)?

User-inserted image

Thanks a lot everyone again! Ricky Ma:) ;)

United Kingdom

For question 1, if batteries are not an option for your robot, then connecting servos directly to a power supply (as in your picture), you will need to connect a common ground between the power supply and the EZ-B as well.

For question 2, either the 7v 20 amp or 5v 60 amp power supply will work fine, but it really depends on how many servos you intend to have moving simultaneously. As long as the voltage you supply the servos are within the minimum and maximum limits for the servo (found in the spec/data sheets), you will be fine and you won't need to worry about that. What you need to work out though, is the maximum amp draw for the servos inrush (the point at when they start to move) when moving them at the same time, add this figure together, and that is the amp range for the power supply you will be looking for (plus a few extra amps on top as a safety margin is a good idea).

For example, if your servo inrush draw is 5 amps maximum, and you intend to move 10 servos at the exact same time, this would equal 50 amps (10x5=50), so a 20 amp supply would not be enough so you would need the 60 amp supply.

If the servos draw 3 amp maximum, and you intend to move 6 of them at the same time, this would equal 18 amps (6x3=18), so a 20 amp supply would be sufficient.

The thing to remember is the voltage has to be in the correct range, but with amps/current, you cannot supply "to much" as the device that draws amps will only take what it needs.


Hi Steve,

I brought a new power supply (5V 60A), But the EZB4 say "battery is low" and without any servo. Pls. see my attached photo as below:

User-inserted image

User-inserted image

So, is it I need to buy a high Volt power supply(e.g 7.4V, 12V)? or any wrong connecting methods with my EZB4?

Thanks for your help Ricky Ma


Disable the battery monitor in your project. Press the config button on the connection control to disable the battery monitor.

The tutorial for the battery monitor and ez-b power can be found here:

The course for the EZ-B v4, which contains this information and a lot more (including datasheet) can be found here:

PS, that looks like an adjustable power supply (hence the adjustable value). Ensure you have configured it for the expected voltage output before you begin connecting anything to it. A volt meter will be necessary for checking the voltage. Verifying the voltage will prevent anything from being damaged by exceeding voltages on your servos or sensors.


Appreciated for all experts to reply to me and help! Finally, I used DC 7.5V 46A for the EZB4. It is work for me!

Thanks again!

Ricky Ma :)