On Mon, 1 Sep 2014 08:32:04 -0400, "Mike Marlow"
wrote:

Leon wrote:
On 8/31/2014 7:17 PM, Mike Marlow wrote:
Bill wrote:
James wrote:
HI Group, I have three Ridgid li-ion batteries that I'm considering
rebuilding. Has anyone done this? I've rebuilt Ni-cad battery packs
without any difficulty but haven't dealt with Li-ion before. JIm

My initial reaction is that doing that sounds potentially dangerous,
but you must understand what you are doing!


Not potentially dangerous at all Bill as long as you have the right
charger. If the batteries are registered for the lifetime warranty
though, it could be a waste of time since they'll be replaced for
free under the warranty.

Actually overhauling L-Ion battery cells are not as easy as simply
replacing cells. Most rebuild places do not deal with these type
batteries as each cell needs to be tested to be comparable with the
other cells that they will be mated with. It is more than simply
using the correct smart charger.

Yes - it is. Oversimplification on my part in my previous answer to Bill.
It does seem that more rebuild guys are saying they won't do L-Ion these
days - or maybe it just seems that it's more of them. Seemed to me that
when L-Ion first came out most of these guys were offering to upgrade old
NiCad packs to L-Ion. I haven't seen any commentary on a requirement to
pair cells, so if that's true it comes as news to me. Sourcing the
batteries can still be a bit of a task though.
A friend of mine just built a high capacity bank of lithium ion cells
for his electric Miata - 144 volt pack, each cell about twice the size
of a lb of butter. The protection circuits are "generic" - one per
cell, and what they do is basically bypass the cell during charging if
the cell temperature gets too high or (not sure) if the voltage gets
out of spec. The charge controllers/protectors are not specific to the
particular cells. There is a way to "turn on" the cell again if it
shuts down due to over discharge(low voltage shutdown protection)