Difference between NiCad and NiMH batteries

Dendrites.

Corkey05 wrote:
Charge rate is different, so you're taking a chance of battery damage if you change to NiMH.

"Nickel-based batteries are best fast charged; a lingering slow charge causes “memory.”

Ni-Cad memory is one step removed from a MYTH..

Fact: If you charge and discharge to EXACTLY the same points hundreds of times EXACTLY the same point. Memory develops.. The fence post gets a different amount of sunlight every day so unless the batteries are FULLY charged in the day and FULLY discharged at night no memory save for 100% and that's kind of the factory setting.

NASA. orbits satellites After hundreds of orbits with EXACTLY the same load on the batteries and EXACTLY the same numbers of full sunlight they develop memory.


now.. Filaments.. that's another issue

As you discharge the battery metal from the housing is "Eaten" by the chemicals inside generating electricity.

As you charge metal is "regurgitated" as it were and deposited MOSTLY back on the shell (housing) however not always.

FIliments eventually develop. and for those a very very very fast charge can pop 'em like a fuse. Restoring the battery

You call it memory
It is really a shorted cell.

Frankly, Barney, I WOULD change to NiMh batteries....they are superior.....and I would bet dollars to donuts that that cheap solar charger for your step light is engineered no different from NiMh or NiCd.

Thank you Corkey. I think I will just stick with the original type NiCad batteries. Seems that the NiMH give a little bit more charge per battery and that is why I was asking. Thought maybe they were a later improvement or something.
Barney

I agree with Corkey.

Charge rate is different, so you're taking a chance of battery damage if you change to NiMH.

"Nickel-based batteries are best fast charged; a lingering slow charge causes “memory.” Nickel- and lithium-based batteries require different charge algorithms. A NiMH charger can also charge NiCd; a NiCd charger would overcharge NiMH. Do not leave a nickel-based battery in the charger for more than a few days"

The above taken from Battery University

That said, I changed to NiMH for my solar powered shed lights and they worked fine.