actually, i did the same with my phone before... replaced it with another model with same volts. it worked, but i couldn't charge my phone... im not sure about your case.. but you should be cautious since it's different models, it might not be that compatible and may blow your hands up someday.. so, goodluck (kidding)

Hi guys, i just got a nokia 3500 cell phone a few weeks ago...it has a small batter (bl-4c rated at 860mAh 3.7V)) that doesn't have much of a charge.
I have an older nokia phone that has a bigger battery (the bl-6c rated at around 1130mAh and is also 3.7V)..i put it in the 3500 and it worked! i wanted to know if it is okay to use this batter for the 3500 and if the stock charger for the 3500 will recharge this batter okay.thanks
fabs