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I have the iRobot, a ping pong throwing robot.

I've used it for years without any issues. At one point, my cats chewed out the original AC Adapter but luckily I had another one on hand from another device that had the same specs.

The power specs on the product's website list: Includes: iPong® Robot, Remote Control, A/C adapter, Setup & Instruction manual Input: 100-240V ~50/60Hz 0.6A Output: 9V 2.0A

The label near the power port on the robot lists 6V --- 650mA

Now.. unfortunately I am not sure what the original Power Adapter had in terms of specs because it was a generic brand and I didn't label it. I do have a chewed up cable here which I believe was the one in question. This one lists Output 12V DC 300mA

Does it make sense that the robot shipped with a power adapter whose specs are not quite the ones of the robot's requirements?

Now.. the replacement adapter that I had been using for ~1-2 year has this output: 6V DC 650mA

But suddenly about a week ago, it still runs but the motor is spinning a lot slower and basically it is now longer flinging ping pong balls.. it just doesn't work anymore. But it worked for a long time.. I got a lot use out of it. So this confused me.

I opened up the robot, cleaned the parts.. removing cat hair and dust.. added a little machine oil and put it back together.. no change. Now I don't have any power meter tools.. or any multi adapters. But today I rummaged through all my existing power supplies for other products.. looking for the ones that had a connector that would fit inside my robot and I came accross only one that made my robot work.

This adapter has this rating: Output 13.5V DC 1000mA

Now this one clerly seems like overkill.. although it makes me wonder since the original adapter I was using.. the one I believe shipped with the robot.. is a 12V adapter.

Using the 13.5 1000mA adapter the robot now works perfectly and is doing a splendid job. I didn't run it for more than 10 minute so far but it seems good as new.

Now I am trying to figure out which replacement power adapter I should be ordering online... one that will please my robot but without sending it to an early death.

Can anyone elaborate please?

Thanks much!!

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  • \$\begingroup\$ Does the robot run directly of the adapter, or is it ultimately charging a battery? \$\endgroup\$ – Asmyldof Jun 7 '15 at 13:47
  • \$\begingroup\$ there is no battery pack, it runs directly off the adapter \$\endgroup\$ – vesperknight Jun 7 '15 at 15:19
  • \$\begingroup\$ You didn't happen to take any high-res in-focus pictures of the insides, did you? It's virtually impossible to determine what would be good and what would not without knowing what the robot does with the supply voltage. \$\endgroup\$ – Asmyldof Jun 7 '15 at 15:22
  • \$\begingroup\$ No.. I didn't. I did however just find the specs of the original robot I bought (there's been many revisions since the first one (mine) and these specs list the adapter as being Power Source: UL/CE, Listed 12 V A/C Adapter, Input 100V~220V Which is indeed the same as my chewed-up cable. So it makes sense then that my 13.5V adapter is making the robot work perfectly. What I dont understand is how come the robot seemed to be working great for so long using the 6V 650mA adapter. I'm starting to think I just need to find a replacement that is at least 12V 300mA \$\endgroup\$ – vesperknight Jun 7 '15 at 15:41
  • \$\begingroup\$ It is possible that the adapter started out as 7.5V and over time, with active use, poossibly sourcing more current (that depends on the Robot's internal power handling) than it should it wore down and dropped to 6 or even 5.5V. If the official spec is 12V, it's not very likely 13.5V will cause any major damage. You can replace it with a 12V adapter in that case, 300mA should be quite cheap, you could go for 500mA to be sure different build qualities don't affect anything (a well built 300mA could beat a shoddy 400mA in some applications) \$\endgroup\$ – Asmyldof Jun 7 '15 at 16:07
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In any case the ac/dc adapter need sufficient current to drive the robot. 1000ma seems to be sufficient for this application. Insufficient current will result in erratic behavior and or slow motor.

too low voltage could result in slower maximum speed or even insufficient voltage for the logic/MCU

Too high voltage could result in overheating / thermal shutdown. ... or even permanent damage!!! Because of exceeding absolute maximum rating of components

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