Asked — Edited

Servo Causes Ezb V4 To Reboot

I purchased the Developer kit in hopes of trying out the Teddy Ruxpin project. I have the EZB v4 powered by the 6 rechargeable batteries like recommended; however, if I attach a servo to it, it will reboot if the servo attempts to move more that a few degrees. Is the rechargeable batteries only powerful enough to turn on the EZB? Do I need something else to actually run the servos that comes with the kit?


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Need more power - batteries are too low voltage or too low amperage.


So to power everything that comes in the Development kit, what kind of power do I need to use? And can it be connect via the power base?


To answer your question start by following the link DJ supplied. ;)


Thanks, I did. However, I would like to know how much power the entire dev kit requires and if the power base can be used to deliver that power. If it is not able to do that, then need to know how to go about powering everything in the kit correctly. For example, I am trying to do the Teddy Ruxpin project, what power was used there? If it was in addition to the Dev Kit, then I need to know what to purchase.



I share your pain, i started with a basic kit and NIMH batteries.

short answer:

  1. If you want to run from battery, you will need a Lipo Battery:

LiPo Battery Balancer Charger:

And a Dean to DC Barrel connector:

If you want to run from a power supply:

you can get one of these:

but you will need more than 20 Amps, if you have plans to add more servos in the future. Also you will need to add a power cord.

I have this one:


I'll post more details why the developer kit battery pack does not work with the EZR servos.



Thanks, that is exactly what I was looking for. I still have a lot to learn. Wish I knew that I would have needed the parts when I ordered the dev kit as the shipping is as much as the parts. Guess I will also be looking at trc electronics now. I have spent some time going thru all of the tutorials and been reading/searching the forums since getting the Dev Kit. The tutorial were pretty good for using/build the robot kits; but not much on the Dev Kit. I was thinking that the Dev Kit would be a great way to start with a small project, using a few servos, and doing just some basic moves and learning how to use the various components. Back to ordering parts and waiting...thx again...looking forward to your post on the details...


More details:

6 x AA Battery Holder (Included in the developer kit):

1900 mah.
6 x Rechargeable AA = 6 x 1.2 v = 7.2 v
1x - 1.3x C = Discharge rating

Lipo battery:

1300 mah
25C = Discharge rating (25x)
7.4 v
2S1P = means 2 cells in Series, 1 in Parallel 

The relevant difference between a Lipo and NIMH battery is the discharge rating:

the above Lipo battery can provide (discharged) at 25 x 1300 ma = 32500 ma

a NIMH battery can provide (discharged) between 1x and 1.3x 1900 mA = 1900-2400 ma

if you try to pull more mA than the max discharged valued, it will cause a brownout (battery voltage will drop) .

if you don't go with a Lipo Battery, you will need to choose a good power supply (10-20 A).

I had the same battery issues and someone mentioned 1.5A per servo, so i tried a power supply 7.5 2A, and i was surprised didn't work. The servo had no load and i got a brownout ?

I decided to measure the EZR servo current:

Idle <= 40 mA Continuous sweeping <= 400 mA Initial Peak/Burst = between 1800 mA and 2600 mA

Every servo is different, i tried other servos and the initial peak is near the operating value (400 mA - 600 mA).

To summarize if you are using the EZR servos, you will need a Lipo battery or a good power supply, the main culprit are the consumption peaks.

More info: (HTTP not HTTPS)


@ptp Thank you very much for the details. This helps a lot!