First job would be to identify the manufacturer/part number of the housing and crimps your looking for...
...then it should be easy enough to get them.
www.cpc.co.uk might be handy (part of Farnell), and eBay also good for bits if you know exactly what your after.
Jamie is right though...bitch of job to do well...even with the exact matching crimp tool for your crimps...which often cost hundreds to buy!
Might be easier just to make up extension leads from the battery end for your current ones? That's what I've done anyway. I know it's not quite as tidy, but it's much much easier to do!
Crimp joints = unreliable pain in the arse!!! Can't beleive the manufacturers of chargers haven't picked something more robust for this job, rather than connectors that are designed to be used inside boxes where the cables aren't handled during use.
Actually...I can...$$$$ Grrr!