Roomba Battery Replacement

I’ve got an old Roomba that came with the 12x1.2v Sub-C NiCads.
I’ve rebuilt the battery twice when some of the cells reversed.
Both times it worked like a champ for a while.

It’s gone south again, let it run too long. Many of the cell are so poor that it’s not worth messing with.
I did cobble together a 4S 18650 pack and it did run – for testing purpose. But obviously I didn’t want to let it near the charging station.

iRobot wants a hefty price for a replacement. On Amazon, an OEM is $63.
There are plenty of cheap NiCad or NiMhs that claim all sorts of bogus mAhs that cant be had from a Sub-C sized battery. Way too many clearly fake 5 Star and lots of poor reviews too.

I have found a few replacements that seem to have 4S-2P 18650 packs with a BMS inside.


And the brand Melasta has all sorts of batteries/accessories associated with the brand.
Other similar packs just seem to be re-branded stuff. Looking up a maker and seeing junk and kids toys is not confidence inspiring.

If it’s crap, at least I can add to my ever growing pile of pulls.
And perhaps a rebuild down the way if it works well.

Somebody with a 3D printer could make money selling kits to replace batteries in all sorts of stuff.

Anybody have any experience with the brand or one of the Roomba batteries?

All the Best,