multiple Nimh vs dry cell

Greetings. I have this problem. I have a telephone that requires 3 AAA cells. I installed 3 AAA dry cells. it works good. LCD display is very sharp and bright. But then i thought. one day that the dry cells will surely get over and I will have to buy new ones. So instead of replacing new dry cells what if i install rechargeable ones. So i opted to buy 3 AAA NiMH cells.

I had always known that dry cells are rated at 1.5 volts whereas NiMH cells are 1.2 volts. I had understood that it doesn't make much difference.

After installing the NiMH AAA cells the lcd display was about 20% dimmer than previously seen. It clicked me that 3 NiMH cells will lead to a loss of 0.9volts in total. thats like 1 volt drop.

So i have few questions here.

Was my idea bad ? If we compare 6 Dry cells vs 6 NiMH cells then there is a voltage difference of whopping 1.8 volts. dry cells 1.5v x 6 = 9v NiMH cells 1.2v x 6 = 7.2v

Which means we need to consider atleast one more NiMH cell, isnt it. So 7 NiMH cells will be somewhat at par with 6 Dry cells. (there would be still a difference of 0.6 volts.

Am i right with all these ideas?

So how do i solve the dim lcd in my telephone. i am still short of 0.9 volts.

can i simply add one more NiMH cell in series. I would have to engineer a slot for it in the phone.

• NiMH cells are usually not charged when delivered new. You have to charge them first. Aug 2 '17 at 17:12