I have a cordless handheld vacuum cleaner (Electrolux Rapid ZB4103) which is powered by 3 rechargeable AA NiMH batteries (1.2V 1300mAh) connected in series and stacked (glued?) in a pyramid to fit within the case. The batteries are typically recharged by placing the vacuum unit on a changing base (base output is 8V 200mA).
The unit is perfectly usable but the batteries are old and losing the ability to hold a charge, rendering the vacuum essentially useless. I would like to simply replace the old batteries with new consumer-grade rechargeable AA NiMH (Panasonic Eneloop 1.2V 1900mAh) ones.
Question 1: Is it correct to assume that all rechargeable AA NiMH batteries charge at the same voltage and current, and that replacing one brand of battery with another should be safe to use with the original charging base?
Question 2: Given heat caused by charging, etc., is it reasonably safe to stack the new batteries by hot-gluing the bodies together?