Can NIMH batteries replace NICD batteries in a cordless phone?

[erikiksaz]

...apparently not. The guy at Radioshack told me to take the NIMH replaceable battery instead. I told him the original batteries were NICD, and asked if it mattered. He said it didn't, and sold me the NIMH. I plugged it into my cordless phone, which originally had a NICD battery. I sat the phone on the charger, and walked out of the room. To my suprise when i walked back, i smelled smoke. So, was that one battery just fux0red, or are you not supposed to replace NICDs with NIMHs?

 

[element]

It does not matter as long as you got the voltage and polarity right. Smoke means you didn't get one or both of those right.

 

[RossMAN]

I wouldn't replace NiCads with NiMH's.

What kind of cordless phone do you have?

Why not update and buy a new cordless phone? These days you can have a 900MHz cordless phone with built-in caller ID in the handset, speakerphone, digital answering machine and redial all for $69 or less.

 

[habib89]

i think (and i'm basically guessing) that nicd's and nimh's charge differently since they have different chargers.. even if a charger charges both, like my rayovac charger does, it has a switch.. so i'm guessing it's the charging of the battery, and not the fact that the phone itself uses nicds, that matters...

 

[erikiksaz]

Crap, woops, i didn't mean smoke, there was just this burning smell. But I just liked this one cordless phone because it was a headset.

 

[element]

It's true they charge differently. NiMHs have more current capacity and therefore require more current to charge. however they have the same voltage, so replacement of NiCDs with NiMHs would with the same charger not burn anything up. At worst it would leave the NiMHs insufficiently charged. At best they would work just fine (given more time to charge for example).

Sorry I didn't go further into detail in my previous post, it was getting late last night.

edit: however in your case you either got the voltage or polarity wrong. the number of cells determines the voltage. Each cell has the same voltage between NiCds and NiMHs.

 

[madthumbs]

NIMH's should NOT be overcharged. I don't think NiCD chargers prevent this.

 

[element]

Originally posted by: madthumbs
NIMH's should NOT be overcharged. I don't think NiCD chargers prevent this.

Neither should be overcharged, it will damage the cell to overcharge. Meaning shorten its life.

Read this link for more info than you ever wanted to know on NiCds, NiMHs, and the differences between them, including charge rates and the like.

Basically if you quick charge, you need checks for overcharging, but if you trickle charge, you only need to keep the NiMH battery on the charger longer to get a full charge.

 

[erikiksaz]

But the plug on the NIMH could only fit in one way, i don't understand how polarity would be a problem. Other than that, the voltages were the same too, same for the mA rating. Now i'm just confused...

 

[Jerboy]

NiCd and NiMH chargers are compatible with eachother if you mean "charging" it. The difference is how it regulates it. Those cheap ass constant current chargers don't have much difference and just slight difference in charging current between NiMH and NiCd. Smart chargers have different charging algorithm for NiCd and NiMH.

NiMH in cordless phone could mean shorter life.