Melting mBot 4xAA Battery holder


I have a huge problem with 4xAA battery holders that come together with mBot: THEY KEEP MELTING.

I tested three holders and all three melted.

With first to packs I thought that the problem was with a shortcuircut because I stuffed the holder between brass studs and the mBot chasis (battery holder did not have isolating tape over battery connections).

In third test I used only a (new) battery holder an mCore (protected with supplied plastic box) both lying on a wooden table (one on top of the other). I made a program (breathing lights) and run it on mCore for three (maybe four) hours. It was funny though that I did not smell anything until I unplugged everything and put it in my rucksack. Then it started to smell realy bad and after 30 minutes I realized that battery connections burned through the plastic holder.

Does anyone else have problems with the battery holders?


Hi lelap,

Could you take some pictures to show your application scenario?
Also, please also take two pictures to show the battery holders which are melting?


Hello. Thank you for immediate response.

Images are posted below.


At TechTown, where I do robotics consulting, we’ve had a similar issue. See attached photo.
Melted mBot Battery Holder

We use EBL 2300 mAh NiMH batteries. They seem to be ok after the meltdown.


Hi lelap & aramperez,

Thanks for sharing these info. I have forwarded such kind issue to related department to do further research and make improvement.

As for the faulty battery holders, where did you buy them? You can contact the shop where you bought the robot to check the warranty and ask for replacement if they are under the warranty period.

If there is any problem, feel free to send email to



I bought it from your German distibuter - Eckstein GmbH (Though I am from another European country). I will have a word with them.


Sorry for the delay, I expected a notification that someone had replied to my posting.

The battery holder is the original that came with the mBot kit. We did not buy any new holders.


Hi aramperez,

Sorry for the confusion, actually I mean where you bought the mBot robot? You can contact the shop where you bought the robot to check its warranty.



I have the same issue. Atfer a short period of usage the battery holder melted…


Hi zeon,

Sorry to hear that!
Did it automatically get melted while mBot doing normal running?
Could you please kindly send receipt of the mBot to email address daisy@makeblock,com?



This is an update for my previous post.

I had no problems with returning the malted battery holders at Ecktein GmbH. But instead of 4xAA holder they supplied me with a 6xAA holder saying that that is what they got from the manufacturer (Makeblock). The problem with 6xAA batery holder is that it supplies more voltage than advisable for mCore board and (banana) plug is to big to fit in what mCore has for external power supply. So now there is no way for me to power up all my robots at once:(

To try prevent the battery holder from melting always remove batteries from the holder emediatly after usage!
Never leave your robot (being powered with batteries) without supervision!


Hi lelap,

The 6AA battery holder is for the other robots like Starter, Ranger, Ultimate. It is not for the mBot robot.
Could you ask the Ecktein GmbH to provide you the 4AA battery holder instead of 6AA battery holder?

Besides, thanks for sharing your experience, that’s a good notice.



As soon as I saw the bill saying they would send me 6xAA batery holder I told them that I need 4xAA. But they said that that Makeblock sent them 6xAA holder (as a replacement) and that is what they are shipping to me.


Hi lelap,

In this case, could you please ask the Eckstein GmbH to contact our related colleague or email directly to solve this problem. If we really send the wrong battery holder to the distributor, we will correct it.
I suspect that Eckstein GmbH should be the second or third agent since we don’t see it in our official distributor list for Germany.In this case, we can’t check the delivery record, please kindly ask Eckstein GmbH to contact us directly for solving the problem.