DIYbanter - Another shaver question

This is kind of a continuing saga of my Norelco electric shaver. After getting some great advice from various people on this group. I ripped out the old non working charger circuit and built a little 20ma constant current charger out of an LM317T. I have two 600mah nicads in there and charge them from my truck cigarette lighter jack. Usually a couple of days does the job and this works fine but I've wanted to increase my run time for awhile now (to handle those times when I just say screw it and don't shave for a few weeks).

The other day at a show a guy had a case of batteries with chargers. Each blister pack contained a charger with two 2000ma AA NIMH cells and he was was selling them for 2.00 a pack. I was able to buy two packs for two dollars and now I'm kicking myself in the ass for not making him an offer on the whole lot. But anyway I thought that it would be nice if I were to employ two of these batteries in my shaver. I was wondering though if charging them at a 20ma rate would eventually charge them or would that kind of a charge be detrimental to the cells? Lenny