I've got a ray 100 handheld vhf with tired old nicad batteries. i would like to rebuild the battery pack with nimh batteries. will the current battery charger work with the different type batteries?
battery packcharging
- Thread starter cat30
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Probably not, but can't say for sure.
Fast charging of NiCd batteries is very different than charging NiMH batteries. It has to do with detecting when the charge is complete. Slow charging with the old charger "may" work. I also prefer NiMH because they have no memory effect, but you may want to reconsider using NiCd if you want to be safe using your old charger.
Fast charging of NiCd batteries is very different than charging NiMH batteries. It has to do with detecting when the charge is complete. Slow charging with the old charger "may" work. I also prefer NiMH because they have no memory effect, but you may want to reconsider using NiCd if you want to be safe using your old charger.
NiCad and NiMh Have Different Charging Characteristics
Little that I remember from a number of years ago when NiMh's were just hitting the scene and I was contemplating much the same as you are now is that their charging regime is very different than NiCad's.
NiCad's build up an internal resistance as they reach full voltage and they stop taking the charge even though the wall charger doesn't shut off. Plug in the charger, walk away, and the battery generally will charge OK.
NiMh's continue to accept a charge at their max rated voltage of appx 1.4v (that's 1.4 volts per cell). If current is still being applied when they reach 1.4v, they tend to overheat as their internal voltage increases, and the battery function is permanently lost. Some of the very early budget NiMh trickle chargers (very low amp rate in relation to the battery size/capacity) tended to detect only when the full voltage had been reached. Then they stopped the charging. These days the chargers are sophisticated ("smart"). They detect how the battery is accepting the charge and adjust and pulse the current/voltage which allows faster charging and is also necessary to prevent damage to the battery.
More info can be found at the following links:
http://en.wikipedia.org/wiki/Nickel_metal_hydride
http://en.wikipedia.org/wiki/Nickel-cadmium_battery
Little that I remember from a number of years ago when NiMh's were just hitting the scene and I was contemplating much the same as you are now is that their charging regime is very different than NiCad's.
NiCad's build up an internal resistance as they reach full voltage and they stop taking the charge even though the wall charger doesn't shut off. Plug in the charger, walk away, and the battery generally will charge OK.
NiMh's continue to accept a charge at their max rated voltage of appx 1.4v (that's 1.4 volts per cell). If current is still being applied when they reach 1.4v, they tend to overheat as their internal voltage increases, and the battery function is permanently lost. Some of the very early budget NiMh trickle chargers (very low amp rate in relation to the battery size/capacity) tended to detect only when the full voltage had been reached. Then they stopped the charging. These days the chargers are sophisticated ("smart"). They detect how the battery is accepting the charge and adjust and pulse the current/voltage which allows faster charging and is also necessary to prevent damage to the battery.
More info can be found at the following links:
http://en.wikipedia.org/wiki/Nickel_metal_hydride
http://en.wikipedia.org/wiki/Nickel-cadmium_battery
Batteries Plus
I have had battery packs rebuilt at Batteries Plus. I do not know if they are in your area.
I am sure that there is a different charging sequence for NiCD vs NiMH, so I doubt that they would work.
I have had battery packs rebuilt at Batteries Plus. I do not know if they are in your area.
I am sure that there is a different charging sequence for NiCD vs NiMH, so I doubt that they would work.
If I were to do this
I would look at the lithium ion's. This is the latest technology, and supposed to be better than the nimh. If you are going to spend the money, might as well go for the latest.
I would look at the lithium ion's. This is the latest technology, and supposed to be better than the nimh. If you are going to spend the money, might as well go for the latest.
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