What is the trick to replacing rechargeable batteries please

[Amanda Ripanykhazov]

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?

 

[GregS]

In article <a25715e6-9ba6-41be-887a-5b36c9b77c8e@c5g2000vbh.googlegroups.com>, Amanda Ripanykhazov <dmanzaluni@googlemail.com> 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?

The connections are welded. Maybe several thousand degrees will
take it off. Normally you bend them off.

Soldering to batteries can be risky both safety and damage.
To solder, Dremel scratches in the metal. Use a very hot iron
at about 750 degrees F. Time is the important part. You want to
heat it up quickly and solder so it has time to cool. Metal strips can be replaced with ordinary
wire.

greg

 

[William Sommerwerck]

I often wonder why people don't call the manufacturer first. Is it that
difficult?

I would contact iRobot and ask them what the recommended procedure is.

On the assumption that iRobot is not stupid, and knows that the batteries
will eventually have to be replaced, it seems reasonable that the wires from
the batteries connect to a push-on terminal on the main board. If this is
so, you'll have to get the iRobot batteries.

 

[mike]

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?
You sure they're not sub-C?

They're spot welded.
DO NOT SOLDER TO THE NEW BATTERIES. GET BATTERIES WITH TABS AND
SOLDER TO THE TABS.
Replace 'em ALL at once. Weak ones will be killed by the new ones.
"Not exactly, but that's the result."
I am pretty sure they aren't lithium!)
If you're gonna replace cells, shouldn't you be CERTAIN
what they are? Last thing you want is a robot running around
your floors ON FIRE!
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?

Yes, it will.
Is there some trick to doing this

If you're gonna solder on batteries,
Wear safety glasses. Put 911 on speed dial.
Order up a whole set of tabbed cells to replace the ones
(actually ALL of them)
you ruin by overheating. Make sure you understand the charging
regimen so you can order the correct type of cells.

Now you're ready to ruin some new cells. Have at it.

OR,
you can take it back where you bought it and say, "fix it!"

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?

 

[mike]

Amanda Ripanykhazov wrote:

On Feb 19, 2:17 pm, "William Sommerwerck" <grizzledgee...@comcast.net
wrote:
I often wonder why people don't call the manufacturer first. Is it that
difficult?

I would contact iRobot and ask them what the recommended procedure is.

Thanks for that everyone: I will try it.

Obviously no one calls iRobot for this question. they just want to
sell their expensive batteries. The last thing hhey want is to advise
on how to take the battery compartment apart. They even go to the
length of putting special screws on it to prevent anyone taking it
apart (using a triangular headed screwdriver: Has ANYONE ever come
across that on any other unit of any type whatsoever?)
Yes, it's common to prevent people who don't know what they're doing

from hurting themselves and suing the company. Certification agencies like
UL make a distinction between things that require a tool to open
and relax requirements in those areas. But people are idiots,
so vendors use fasteners that require uncommon tools to protect
them from themselves.
Your post suggests that you need that protection, but you're insisting
on learning the hard way.

REMEMBER THE SAFETY GLASSES.

I'd send you a picture of the battery pack that exploded after I
"fixed it" but it exploded so violently that I never found most of it.
The hot electrolyte spots on my glasses was my learning experience.

 

[Archon]

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

 

[Amanda Ripanykhazov]

On Feb 19, 2:17 pm, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:

I often wonder why people don't call the manufacturer first. Is it that
difficult?

I would contact iRobot and ask them what the recommended procedure is.

Thanks for that everyone: I will try it.

Obviously no one calls iRobot for this question. they just want to
sell their expensive batteries. The last thing hhey want is to advise
on how to take the battery compartment apart. They even go to the
length of putting special screws on it to prevent anyone taking it
apart (using a triangular headed screwdriver: Has ANYONE ever come
across that on any other unit of any type whatsoever?)

 

[D Yuniskis]

Hi Amanda,

Amanda Ripanykhazov wrote:

On Feb 19, 4:18 pm, Archon <Chipbee40_Spa...@yahoo.com> 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)

In general, you don't want to remove the tabs unless absolutely
necessary. Use them as "attachment points" to which you *can*
solder. Trying to make a connection to the battery (cell)
itself is an exercise in frustration and danger (batteries don't
like heat; soldering irons are hot -- do the math)

If you *must* remove the tabs, you can usually just wiggle
them back and forth repeatedly until metal fatigue causes
them to fail. You will end up with a small cluster of
"bumps" on the battery case as the "welds" usually stay behind
(i.e., you will find an equivalent number of *holes* in the
removed tab)

 

[Archon]

Amanda Ripanykhazov wrote:

On Feb 19, 4:18 pm, Archon <Chipbee40_Spa...@yahoo.com> 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

Hi Amanda, I haven't checked out the construction of the Roomba battery

as yet but I'm guessing your problem is the original links between the
batteries is not an easily solderable metal, maybe stainless steel?. In
the link I gave you they are replacing all the batteries so soldering to
the original batteries was not a required. The metal case of the
batteries can usually be soldered to but its not recommended as others
have stated. You may need a special flux and a high wattage iron to make
decent connection to the original welded tags. JC

 

[Dave Plowman (News)]

In article
<a25715e6-9ba6-41be-887a-5b36c9b77c8e@c5g2000vbh.googlegroups.com>,
Amanda Ripanykhazov <dmanzaluni@googlemail.com> 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?

The easiest - but more expensive way is to buy 'tagged' cells. These can
them be soldered without damage to the cell - a very real possibility if
you solder to them direct. But since they're less common on the retail
market the prices tend to be high. You might find somewhere local that can
weld tags to batteries for you. If you're lucky like me. ;-)

--
*Despite the cost of living, have you noticed how it remains so popular?*

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Amanda Ripanykhazov]

On Feb 19, 4:18 pm, Archon <Chipbee40_Spa...@yahoo.com> 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

 

[William Sommerwerck]

Just to add, it's sometimes cheaper to buy a different make of
battery that may be on offer and rob it of its cells to fix another.

This is not generally a good idea. Replacing the bad cells in one battery
with new, good cells, is likely to cause cell reversal during operation. You
should generally replace all the cells.

It's also useful to have some way of measuring each cell's capacity while
discharging it, so you can roughly match the cells' capacities.

 

[Dave M]

Amanda Ripanykhazov wrote:

On Feb 19, 4:18 pm, Archon <Chipbee40_Spa...@yahoo.com> 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
LARKBATTERY@AOL.COM

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

 

[Dave Plowman (News)]

Just to add, it's sometimes cheaper to buy a different make of battery
that may be on offer and rob it of its cells to fix another.

--
*Reality is a crutch for people who can't handle drugs.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[John Tserkezis]

On 20/02/2010 12:17 PM, William Sommerwerck wrote:

Just to add, it's sometimes cheaper to buy a different make of
battery that may be on offer and rob it of its cells to fix another.

This is not generally a good idea. Replacing the bad cells in one battery
with new, good cells, is likely to cause cell reversal during operation. You
should generally replace all the cells.

I think that's what he means. Rob one (unusable brand) battery to
replace the cells of your (wanted brand) battery. As long as the cells
themselves are the same, it's all good.

It's also useful to have some way of measuring each cell's capacity while
discharging it, so you can roughly match the cells' capacities.

The cells are sometimes stamped, if not, you can get a clue from the
label of the battery case (the outside plastic case). They may not give
you too much information other than the brand and model, but they
usually do state the Ampere/hour capacity.

 

[Jim Yanik]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in
news:hlmo5e$4d8$1@news.eternal-september.org:

I often wonder why people don't call the manufacturer first. Is it
that difficult?

I would contact iRobot and ask them what the recommended procedure is.

On the assumption that iRobot is not stupid, and knows that the
batteries will eventually have to be replaced, it seems reasonable
that the wires from the batteries connect to a push-on terminal on the
main board. If this is so, you'll have to get the iRobot batteries.

Or take the pack to a Batteries Plus store or other rebuilder and have a
new pack built. Usually at a lower cost than a new OEM pack.

--
Jim Yanik
jyanik
at
localnet
dot com

 

[Jim Yanik]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in
news:hlnd8g$ctl$1@news.eternal-september.org:

Just to add, it's sometimes cheaper to buy a different make of
battery that may be on offer and rob it of its cells to fix another.

This is not generally a good idea. Replacing the bad cells in one
battery with new, good cells, is likely to cause cell reversal during
operation.

You also have OLD cells with lots of charge cycles mixed with new cells,and
the old cells will fail sooner.

You should generally replace all the cells.

Agreed.

It's also useful to have some way of measuring each cell's capacity
while discharging it, so you can roughly match the cells' capacities.

agreed.

--
Jim Yanik
jyanik
at
localnet
dot com

 

[whit3rd]

On Feb 19, 10:54 am, Amanda Ripanykhazov <dmanzal...@googlemail.com>
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.

Two cautions: if this is a battery of multiple cells in series, you
must
replace ALL cells at once. It is important that all the cells have
the same batch number and age if they are charged and discharged
in series.

Second caution, the contents of these (NiCd or NiMH) is a caustic
liquid, buy tabbed cells rather than trying to get the case up to
soldering
temperature. The tab ends can take solder temperature or spotwelding
without hazard.

 

[hr(bob) hofmann@att.net]

On Feb 19, 7:42 pm, Jim Yanik <jya...@abuse.gov> wrote:

"William Sommerwerck" <grizzledgee...@comcast.net> wrote innews:hlnd8g$ctl$1@news.eternal-september.org:

Just to add, it's sometimes cheaper to buy a different make of
battery that may be on offer and rob it of its cells to fix another.

This is not generally a good idea. Replacing the bad cells in one
battery with new, good cells, is likely to cause cell reversal during
operation.

You also have OLD cells with lots of charge cycles mixed with new cells,and
the old cells will fail sooner.

You should generally replace all the cells.

Agreed.

It's also useful to have some way of measuring each cell's capacity
while discharging it, so you can roughly match the cells' capacities.

agreed.

--
Jim Yanik
jyanik
at
localnet
dot com

You can solder to the tabs or to the remains of the tabs where you
have pulled them off. Scratch the metal before you solder to get them
to take the solder. Use flux also. Replace all batteries, using NMH
rather than NiCad, as they have larger capacity. they are sub-C, I
have had to replace my wife's roomba batteries, so know first-hand

 

[John Tserkezis]

On 20/02/2010 12:42 PM, Jim Yanik wrote:

This is not generally a good idea. Replacing the bad cells in one
battery with new, good cells, is likely to cause cell reversal during
operation.

You also have OLD cells with lots of charge cycles mixed with new cells,and
the old cells will fail sooner.

Sure, but surplus battery packs would more then likely be very similar,
if not a little on the depreciated side.