CalgaryGuy
Enlightened
Hi, I have an un-regulated solar charger and I'm wondering if I use my Ni-Cd battery when it's about 80% charged, does that damage the battery?
Battery Damage When Not Fully Charged?
- Thread starter CalgaryGuy
- Start date
markdi
Flashlight Enthusiast
no
How would you know if its 80% charged since charging current will be varied from starting to end of process?
CalgaryGuy
Enlightened
I'm estimating it to be anywhere from 50% to 100%. Actually, anyone knows what's the voltage accross the Ni-Cd cell when it's 100% charged?
[ QUOTE ]
CalgaryGuy said:
I'm estimating it to be anywhere from 50% to 100%. Actually, anyone knows what's the voltage accross the Ni-Cd cell when it's 100% charged?
[/ QUOTE ]
Nobody can. It's not at all stable, which is why you don't see any chargers that detect charge status this way (unlike lead/acid and some other systems). You need to measure (or otherwise determine) the charge current involved and use time or use one of the other established charge termination techniques (minus delta V, temp rise, etc).
Doug Owen
CalgaryGuy said:
I'm estimating it to be anywhere from 50% to 100%. Actually, anyone knows what's the voltage accross the Ni-Cd cell when it's 100% charged?
[/ QUOTE ]
Nobody can. It's not at all stable, which is why you don't see any chargers that detect charge status this way (unlike lead/acid and some other systems). You need to measure (or otherwise determine) the charge current involved and use time or use one of the other established charge termination techniques (minus delta V, temp rise, etc).
Doug Owen
I've got some solar powered Luxeon yard lights; each has three 800mAh NiCd cells hooked straight to solar cells. They are made by SunGlow and sold at Sears originally with a florescent tube.
They've been out a couple months, some days full sun, some cloudy for a partial charge. So far, after about 60 cycles there is no apparent change in battery behavior. Despite having many cloudy days, when we do get a day of full sun shine, the batteries last as long as the first night when they were new and fully charged.
I think not discharging NiCd cells completely before recharge is the only way to introduce problems...
They've been out a couple months, some days full sun, some cloudy for a partial charge. So far, after about 60 cycles there is no apparent change in battery behavior. Despite having many cloudy days, when we do get a day of full sun shine, the batteries last as long as the first night when they were new and fully charged.
I think not discharging NiCd cells completely before recharge is the only way to introduce problems...
NiCads have always done comparatively well with this sort of abuse. You might get 300 cycles instead of the nominal 1000 cycle life. Their capacity will gradually decrease. I wouldn't use NiMH (or anything else I can think of) for this type of application. They really need smart chargers and lo-voltage disconnects for tough applications, like hand held power tools and other such with unknowable charge-discharge cycles. That would make the ni-cads last longer too.
