# Replacing Ni-Cd with Ni-MH in solar light?

#### Noobster

Oct 28, 2013
18
I have some simple solar lights. Each light runs on a single Ni-Cd 1.2v AAA 300mAh battery. Ni-Cd AAA batteries are becoming hard to find. Would Ni-MH AAA batteries work (get recharged) in these solar lights?

#### BobK

Jan 5, 2010
7,682
The voltage and charging characteristics of NiCd and NiMH are quite similar. Solar lights are using trickle charging, so using NiMH should work just fine.

Bob

#### hevans1944

##### Hop - AC8NS
Jun 21, 2012
4,792
I was thinking of doing the same thing. I went to Wally World a few weeks ago and discovered some of the solar-powered walk-border lights did have NiMH cells but most had NiCd. I don't like NiCd. It recently got unseasonably cold here and three of four solar lights (different Chinese imports) all with NiCd cells failed to illuminate at night. That could be a coincidence I suppose, but I think I will try a NiMH cell this weekend. I think Best Buy and Radio Shack sell them here in the United States. I use the larger AA size in my portable Elecraft KX-3 transceiver and they give me good service there, so the chemistry is good.

#### BobK

Jan 5, 2010
7,682
I guess we got the luxury model, we have some that have a LiPo. They work better than the previous ones we had. Though I have had to repair 2 of the 4 (one failed resistor, one bad solder connection)

Bob

#### hevans1944

##### Hop - AC8NS
Jun 21, 2012
4,792
I guess we got the luxury model, we have some that have a LiPo. They work better than the previous ones we had. Though I have had to repair 2 of the 4 (one failed resistor, one bad solder connection)

Bob

Are you sure you mean LiPo, generally a lithium-ion battery in a flat polymer case? I bet your luxury model has LiFePO4 (lithium iron phosphate) chemistry.

I won't pay more than $2 for one; my wife will splurge as much as$4. Kids walking by sometimes steal them, so I am considering buried conduit plumbed into low-voltage lamps. We live in an urban environment with lots of college students and transients living in or passing through our neighborhood. We started with four lamps, three of which were subsequently stolen. Wife replaced those three but couldn't match the remaining original. I haven't bought any yet but hope to see some in my price range soon. The market seems to be flooded with these imported lamps. I wonder how efficient the solar cells are? Some are a lot larger in area than others, but I don't think that would translate to higher brightness. They all appear to have one white-light LED and a single cell.

#### BobK

Jan 5, 2010
7,682
No it is the cylindrical kind. I guess LiFePO4 may be the correct designation for them.

Bob

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