Upgrade Your Mint Plus-iRobot Braava Robot Mop Using 3D Printing




About: Interested in 3D design and experimenting with 3D printing. Replacing broken items at home and improving functionality and design of everyday items.

Tired of battery packs failing and paying full price to replace them?
Wish you could easily replace the batteries with high quality rechargeable AA batteries?
Wish you could extend the operation of your robot without altering the sleek look and design?
Do you want an excuse to 3D print something or after a reason to learn all about 3D printing in a unique and fun way?

Well follow this Instructable to see how I did it.

Step 1: Replace Battery Pack

Remove the old battery cover and the run down cheap shrink wrapped battery pack.

Buy a 6xAA battery holder from any electronic store. Use sandpaper to remove some plastic from the edges to allow a better fit.

Cut the red and black wires away from the old battery pack, keep the white wire intact and keep little temperature sensor to attach to the new battery pack. If you are like me and threw out the old battery pack because you were sick of the low voltage beeping, that's ok you can easy connect the battery case wires to 2x single female DuPont connectors and make your own connections. The positive wire connects to pin 4 and the negative wire connects to pin 1. The pins are labelled from left to right if the robot is orientated with the plug connection at the top. It might be pretty hard for some people to solder these wires together so I have made it simple to buy the battery packs pre-made on eBay. Simply search for my "iRobot Braava or Mint Plus modified AA battery holder" you can buy it knowing I will do the handy work for you. If you are able to solder - good luck and ask me as many questions as you like.

Step 2: Add New Battery Pack

Drill a hole in the side to fit the temperature sensor, glue it in place with super glue.
Solder the wires together and cover with heat-shrink, or electrical tape if you don't have some.
Plug in the pack and slide it into place. It should be pretty snug and this will help the pack stay in place. You won't actually need a cover if all the wiring is tucked away neatly.

I added 6x 2300mah energizer batteries and so far the run time has been at least 2hours 30 minutes. This does my whole house which is all tiles and I only need to replace the water twice. I'm very happy with the extra run time and now if the batteries fail from overuse, I can go to the shops and get some new ones. No need to pay $50 for a battery pack (full of cheap low quality batteries).

Step 3: Upgraded Battery Cover

Ok, here is the fun part. 3D print a new cover to fit into the same space as the original, use the same screw and also help hold the batteries in place. I don't think I needed the cover with my robot, but, when it stands up charging my kids were attracted to the glint of sun shining off the batteries as it sat near the window charging. I decided to add a cover to keep everything protected and most of all, give myself another reason to 3D print something.

Step 4: 3D Printing

Do you have something at home that you want to make because you can't buy it in the shops?
3D printing is the way to go.

Download google sketchup 2014 to design a 3D model.
Use digital calipers to accurately measure and build your 3D model. The more accurate the design the better the final product will be.
Install the STL exporter extension.
Export your model as an STL file.

If you are new to 3D design programs there is plenty of information to help you out, especially on YouTube.

There are a few online 3D printing services available today offering differnet materials and costs but the only one you need to consider is www.3DHubs.com.

Once you have the STL, upload it into 3DHubs, select your town, choose a Hub, material and colour. Pay attention to the quality of print (low medium high or Ultra) My Watch mount was printed in Ultra and you can barely see any of the print layers, it is amazing. The print materials all have different characteristics so search online for form information. I find the hardest part is to pick a colour, I usually have something in mind but you can email the hub owner and ask for a link to the manufacturers page and that will give you an excellent idea of what your print will look like.
For example there are lots of different blues and greens available but some hubs simply list light green. Look online so you are not disappointed when your print arrives. Also some hubs charge less per print so shop around and you may find a slightly cheaper start-up cost or print per cm*3 which can save you a few dollars at the end of the print process.

Once you submit the order you will be amazed at how simple the process it, the communication from 3DHubs is excellent and you know exactly how the print process is going. I got a SMS to say the job was accepted, the print had commenced, the order was ready for pickup all in the space of a few hours! I walked down the road and picked up my order. If you are lucky enough to own a 3D printer - register it with 3DHubs, but if you can't afford to buy one, then this is the best and only website you should consider when you need to print an item.
If you can't design but want to print something out, thingiverse.com has a huge collection of models you can download and now print direct from 3DHubs. If you can think of it, somebody has most likely designed and 3D printed it.

The best thing about 3D printed plastic is it's durability, choice in colour and if something doesn't fit it's easy to fix. I have made a few parts now and they have printed a bit rough in areas so a simple touch up with some sand paper or a nail file. You can wash it off and it looks brand new.

Step 5: Perfect Fit Everytime

I'm not sure why but I am always surprised when my designs prints and then fits perfectly, apart from a minor touch up sanding to tidy up some rough edges of course.

Line up the two locking lugs, then push them into place.
With the other side of the cover manipulate the battery wires with a screwdriver and line up the screw, a few turns to lock it in but don't over tighten it.

Done. How good is that !
Now my first attempt led me to redesign the cover, uneven floor tiles meant the 1-2 mm clearance wasn't enough and it would get stuck in places. The wet floor and reduced clearance would mean the wheels would spin in place.

I reduced the height if the final design, again making changes to the sketchup model then uploading it the printing site for you to use.

Step 6: Conclusion

This is my first Instructable so if you want more information let me know. I can expand on areas and add more detail as required.

Upgrade your robot like I did, you won't be disappointed.

3D print something! Just do it. It's easy and a great way to explore computer modeling and printing something you designed yourself.

If you would like to read more about some other great 3D printing stories, checkout 3dHubs Maker Tales: https://www.3dhubs.com/talk/

If you want to look at any of my other designs in some more detail:


Otherwise download any model from here:


and 3D print it here:


Thanks for reading and don't forget to vote for my design, hopefully enough people like what I have created and I can score an amazing 3D printer or even a t-shirt thanks to 3Dhubs and Instructables.



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12 Discussions


3 months ago

Good work, I am planning to make the same solution for my Braava 390t because now after 15 Month the battery is draining very fast.

Can you please upload the 3D Model of your Battery Cover at Thingiverse? Otherwise I would have to Re-design it on my own.


2 years ago

Have you try to use High-performance Panasonic Eneloop batteries 2500 mA model listed below. I would like to know if it is compatible with Braava quick charger and how long it would take to charge the batteries. If these batteries use Panasonic charger like the one BQ-CC16 then it would take up to 4h to be fully charged.



3 replies
Charlie CaseLinningH

Reply 2 years ago

I use regular Eneloop batteries (not pro) and it works great. I first tried 2700 mAhr Powerex Ni-MH batteries and the unit would run for about 5 seconds then squawk at me. The Eneloop batteries work great and run for a long time.

I charge them in my Ni-MH charger, but am wondering if there is any problem charging them on the Braava charger. I did not install the temperature sensor when I built the pack because I wasn't intending on charging them with the Braava charger. But it's inconvenient to remove them for each charge, so I have changed my tune. I believe I will need to install the sensor before using the Braava charger to be safe. I still have the sensor from an old pack, but now I don't know how to connect it.

LinningHCharlie Case

Reply 2 years ago

without the sensor I could not make it work. it seems the robot is looking for some signals from this sensor. I bought a cheap battery pack on amazon and it works great. I did open it up and there are 2 little devices.
One needs to connect in series with neg and pos battery terminal as you would connect all batteries in series but with this little device in between the - and + terminal. I did not connect this device and it does not move and it should. it seems it is confusing. I just buy 2 extra packs and just replace it as needed to mop the entire house.


Reply 4 months ago

Indeed, just connecting the red and black power wires doesn't work for my Braava 380t. The Braava definitely expects something from the integrated electronics in the battery. One component is installed in series on the negative wire, and also links to the white wire. This seems to be a very small component. The other device (a white plastic package) is connected in series somewhere in the middle of the pack, and seems to be a temperature sensor (as the packaging shows 70°). I've tried adding these devices in an identical position and orientation in my battery pack, but when connecting to the Braava and turning it on, the robot just seems to drain the battery: voltage drops from 7,4 V to below 5V, and once below 5V the robot beeps 6 times and then just shuts down. I would recommend only using original replacement batteries, even though the lifetime (about 1 year in my case) and the capacity is limited. And indeed, they are expensive and you can't tinker around with electronics ;)

Charlie Case

2 years ago

I hope I'm not violating a message board policy, but I thought it would benefit people to know where to get the battery holder, connector and connector pins. It look a lot of investigation for me to find the connector. I am not affiliated in any way with DigiKey but that is where I found the parts that you can buy in low quantities. It may be a good idea to order extras since they are low cost and you will likely not be happy with your first try at modifying the holder.

Holder: BH26AAWND https://www.digikey.com/product-detail/en/mpd-memo...

Connector: WM18875-ND https://www.digikey.com/product-detail/en/molex-ll...

Pins: WM9661CT-ND https://www.digikey.com/product-detail/en/molex-ll...


2 years ago

Any chance you are still selling the pre-made battery packs and covers?

1 reply

Reply 2 years ago

No sorry. But the packs are easy to modify with a little bit of patience. You can buy the battery covers on Shapeways if you need them printed. Thanks.


Reply 3 years ago on Introduction

download a model from www.thingiverse.com then upload it to www.3dhubs.com EASY!


3 years ago

Thanks! I'm really happy with how it turned out plus it almost doubled the runtime just using better quality batteries. The 3D printing part is the best!​ I'm wondering if there are any other appliances out there that need an upgrade?