Amanda Ripanykhazov wrote:
On Feb 19, 4:18 pm, Archon wrote:
Amanda Ripanykhazov wrote:
I am hoping this question isnt too basic for this forum but I am
trying to replace some rechargeable batteries (in a Roomba: I
understand that generally only one or two start malfunctioning over
time and that it is usually the same one). It MUST be easier than I
am finding it.

I can just about solder on a connection but these rechargeable C
cells (nickel metal hydride? I am pretty sure they aren't lithium!)
always seem to have some sort of electro-welded rectangular plate
connecting the batteries which wont come off with a normal
soldering gun? Or do I just have to apply an inordinate amount of
heat at exactly the position where the ;nick' seems to be in the
plate? Given the amount of heat I seem to have applied to it
already with no effect whatsoever, to me it seems that this might
damage the cell?

Is there some trick to doing this please or am i supposed to use a
dremel wheel to cut the plates off, leaving just the electro-weld to
which I solder the wire for the new cell?

Hi Amanda, You might want to look at this link, it details what to
expect.

http://www.robotreviews.com/hack2/battery.shtml

Theres a good link to thread of advice on which cells to buy etc

Good luck, I'm about to try the same on my Roomba, JC

Hi JC

Yes, I had seen that and have two batteries to do: So my problem is
probably in getting enough good cells in one of them if I can figure
out how (as Mike would put it) to join up two separate tabbed cells
without having a spot welder

It is noteworthy that the on line 'experience based' instructions say
that you can solder where there was spot welding beforehand. (They
dont tell how to get the tabs off in the instructions which I saw,
which is why I posted here)

Amanda Ripanykhazova

Amanda, Lark Battery (www.larkbattery.com) should be able to sell you what
you need. Their contact info is
LARK BATTERY CENTER
8302 NW 39th Expressway
Bethany, OK. 73008
(405) 946-5275


Send them an email describing what you need and get a quote from them. They
will sell you individual cells with tabs so you can build the battery
yourself, or if you wish, they will construct the battery for you (at no
additional charge). I have done business with them before, and I can
attest to their quality.
You will have to describe the battery construction or send a picture so
they can construct it. From the web link posted above, it looks to be 12
sub-C cells in series, arranged in a 6x2 pack. There appears to be some
additional wiring attached to the pack, so you'll have to attach it to the
new pack.
Lark Battery are good folks. No affiliation; just a satisfied customer.

Cheers,
--
David
dgminala at mediacombb dot net