[RE-POSTING with correction of my earlier answer]

This term is given in an on-line glossary of technical terms provided by a fellow-translator; I cannot find substantiation for this elsewhere, but have generally found this glossary to be fairly reliable in the past.

Like colleague Elysée, my first thought was of course 'acceptation', but I was quite surprised when I couldn't find a single out of the many Google hits for this term that actually related to charging batteries; a lot of them seem to concern FR 'charge' in the sense of EN 'load/loading'. The fact that Googling "acceptation de charge" + "batterie" yields 0 hits only serves to reinforce my doubts.

The ref. below is the only occurrence I have found for this particular term, though at least clearly here it does indeed relate to the battery charging situation.

--------------------------------------------------
Note added at 22 hrs (2007-04-19 06:41:11 GMT)
--------------------------------------------------

Interestingly enough, this very comprehensive CA site:

http://www.buchmann.ca/default.asp

uses the term several time in the EN articles, but in those that have been (dubiously?) translated into FR, the term is omitted or skirted round!

--------------------------------------------------
Note added at 3 days22 hrs (2007-04-22 07:20:11 GMT) Post-grading
--------------------------------------------------

Gilles, I am more than anything worried by the notion of 'charge acceptance' = 'acceptation de charge'. Qu'en pensez vous ?

Asker, 'charge acceptance' refers to the battery's ability to accept recharging (which is substantially affected by temperature)

--------------------------------------------------
Note added at 3 days22 hrs (2007-04-22 07:21:22 GMT) Post-grading
--------------------------------------------------

I do think Gilles has got a point, inasmuch as this is not so much a 'pouvoir' to actively do something as a 'capacité' to passively accept something.