Hello all.

A few days ago I've made a big screw-up when I've connected by accident the battery to my hexa with the inverted polarity.

The Power Module almost melted instantly, and of course the hexa died at the moment. Nevertheless the APM still lives for I connected it to the mission planner by USB and it works fine like if nothing had happened. Blessed Power Module!

So I decided to buy a new 3DR Power Module. Unfortunatelly now it's only sold with XT-60, when my hexa came all with Deans, but I thought that was a minor setback that could be resolved with an adapter.

So when my new Power Module arrived, it came without being wrapped with the heat-shrinking tube and the comparison was inevitable.

Besides the evident differences on the plugs, and the bad PM being with the solder in bad conditions, I've found out a big missing part in the new PM.

Please watch the enclosed pictures, and tell me if the new PM (with the XT-60) is really incomplete and have to send it back to the seller, or if it's just a more recent model and everything is fine without the need of that part.

I say thank you in advance for your help.

Best regards,
António Cabral

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Replies to This Discussion

The new one has no BEC circuit, so yes, return it.....

The little board on the back is part of the switch mode power supply of the BEC.

Hi António,

the "black patch" with the soldering stripes at both ends, which is soldered diagonally, is the resistor which is used as a shunt in order to measure the current. I would never use the power module with this badly soldered resistor, as a loss of connectivity would cause immediate power-loss of your copter.

The missing part on the opposite is a switched power regulator which supplies 5V for the arduino board.

I would be more than surprised if this power module would have worked even if connected to the battery with correct polarity.

I am sure, you got a defective power module.

Sorry, bad news.

BTW: I am using the following switched regulator for my copter which is quite similar to the one on the power module (or even the same):


and instead of the shunt I use a hall sensor based device (ACS758 by allegro)

>I plugged it in backwards

That sucks man but like how do you even do that?

Yep.  The daughterboard is definitely missing from your new power module.

Sorry, man.

I use to buy Turningy nano-tech 5000mAh batteries and they don't come with deans or XT-60 and I hate soldering batteries, so this time i bought an adaptor deans with the kind of plug of the batteries to save that trouble. The problem is that if you don't pay attention you can invert polarity at the slightest touch as it has happened. The Pm melted instantly and part of the connector. I was impressed as it never happened to me before. Tough luck.

should I ask the obvious?  Why aren't they making the PM with the deans connectors any more?  Sorry if this is common knowledge.  Haven't been keeping up with my group comments lately....

Do yourself a huge favor. Practice soldering to learn how to do it right. Then solder XT60 connectors onto your batteries and anything else that gets connected between the battery and power distribution.  The 3DR PM comes with XT60, and most power distribution boards come with XT60.  Ditch the stacks of adapters.  Everyone one of those adapters is a point of failure that you do not need.

I ask myself that same question. When I bought my ARF it was all deans with an XT-60 to Dead adaptor for the battery. Now it's all XT-60. At least they could have been coherent and keep selling both options, otherwise we'll have to be soldering to readapt some piece everytime we need to change some part.

Well, I've learnt that lesson in this case. I know how to solder, just have a thing for soldering batteries, and for sure I would prefer to have all with XT-60 from the start in the drone, and specially for the batteries to come standard with the excelent XT-60 plugs. With those it would be impossible to have accidents like I had.

Yes, you're right and the accompanying tunnel vision that occurs when you're trying to solder fat wire to a deans connector will  result in more cross polarization and burn outs.  I am amazed that the APM survived. 

It's a pitty, because I've bought it in a store with good reputation and I believe they'll replace it or at least refund it. As someone asked but somewhat its post disappered, this seems (I think) to be a legit product that excaped QC.

The old PM was replaced for it was dead as a rock immediatly after that fatal touch with the battery. The molten solder and that diagonal resistance are the prove of it. Untill that happened it worked perfectly. Too bad for the accident and more for buying the defective PM. I had the hope that that missing part was some kind of evolution, but this forum proved I was wrong! :P


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