Hi.
I purchased a Maestro 6 channel controller plus battery pack and recharger from you. I have sine recieved 6 x Tower Pro servos to hook up to the Maestro. Immediately two servos were not working and since every time i have plugged the maestro in each time a servo has stopped working. I now have only two operational. Can you please tell me what the problem could be?
Cheers
David Knight
Update. I now have only 1 servo working??? It’s the servos …they are dead. What could be causing this? There’s hardly any load on them.
Update: The last servo just stopped working as well???
Can someone please give me an idea what’s happening?
This can’t be right.
Ok update: The 6Volt battery pack you sent me. I just charged it and it is now flat after only a couple minutes of use. I am going to recharge it and see if that is the problem.
David Knight
Hard to determine what is wrong without more information. But …
Try to isolate what works and what does not.
First, the rapid drain of the battery is a major concern. The battery shown in the pics should not die that quick. Possibly something is shorted somewhere.
Remove the battery and measure its voltage, discharged and charged. The battery looks like this one from Core electronics :-.
It is rated at 2.2 Amps for 1 hour. That is a massive amount of current to drain as fast as you state. When charged it will probably be around 6.5 to 7V. The upper limit of the Servo is 6V, I run these type of servos at no more than 5V. Probably the servos are ok at the higher voltage, maybe not. I have never tested their limit. The Core Electronics page for the Maestro shows a similar smaller capacity battery, so I am guessing it is not really an issue. But in your case, the quick drain of the battery is an issue. That needs to be fixed first. (NiMH cells vary between 1.4V and 1.1V charged and discharged)
Remove the servo connections from the Maestro, charge the battery, measure its voltage, plug it in, and measure its voltage. This way you can determine whether the current drain is the Maestro or a servo.
When the battery is sorted.
Remove a servo from the device shown in the picture, connect just it to the Maestro, see if it works.
Do this for all of them one at a time. This will determine if the servos are working or not. You could also measure the battery voltage when you connect the servo, this may help you determine where the problem is.
This is what I would do if I was trying to get it to work.
Regards
Jim
1 Like
Great tips there Jim.
Servo Power should be the rated voltage of the servos. Most TowerPro small servos are 4.8V to 6.0V for reliable operation.
Thanks for the advice.
I recieved a response from Pololu US this morning on powering the servos:
Hello,
You might be able to power some of those servos, but unless they all have a very low current draw, I imagine you will not be able to move all of your servos at the same time since that power supply can only source 2A. Typically, we recommend budgeting about 1A per standard servo, so you should probably have a power supply that can source about 6A. You should probably look up the stall current of your servos and add those together to get the better idea of the current requirement of your system. If your combine current draw is above 6A, you might consider powering some of your servos away from the Maestro board.
-Derrill
This response was in reference to a wall power supply I purchased yesterday. It was only 2amp.
Cheers
David
Didn’t think of the current drain when servo stalls. Good point.
I have found it pretty hard to kill these servos, so failing one after the other so quickly does not make sense. But if the battery cannot supply enough current that does make sense as the battery capacity drops with usage. This site lists the stall current at around 800mA, so Pololu rating of 1A is a good overhead. Also agree with Pololu that 6A through the Maestro board would not be a good idea. Probably powering the servos direct from a supply would be better. Hope you get it working.
Cheers
Jim
