Hi Colleen,
I don't want to disappoint you, but I think it would be a slight waste of time to try and do things
again that many others have already done better ...
There must be many "reviews" on the various technologies for rechargeable batteries around, but without searching at all these would satisfy my personal curiosity (and then some) ...
Wikipedia:
Rechargeable battery,
NiCd,
NiMH,
Li-ion ... Especially the NiCd article is informative (also about the other types) and maybe
Memory effect can clear up some myths too?
Quite comprehensive for my taste.
In short:
NiCd: Do
not overcharge (!!!!) Deep discharge is okay and may even revive cells that have become "lazy". Discharge-before-charge is not a problem and
might even be helpful with previously overcharged cells, but the "memory effect" is overrated at best. Fairly low self-discharge rate, hence good for powering low-power appliances (clocks, RCs etc) for a long time.
NiMH: Higher energy density, but also higher self-discharge rate. Low internal resistance, so good for high-powered (high drain) devices with limited runtime. Do not deep-discharge,
do not discharge-before-charge! Do
not "store" discharged, but rather medium charged or so. Store (almost) discharged.
Li-ion: Highest energy density, lowest self discharge, best of both worlds but expensive and with a limited "shelf life" and rather "fragile" versus abuse (overcharging, discharging, extreme temperatures etc). These become useless over time even if they're not used - they "age" - buy when needed
not "ahead". Recharge often.
Do not discharge-before-charge! Do
not "store" discharged, but
always medium charged and
store cool.
These are only the most popular technologies, new/better technologies are emerging all the time, but each will have it's specific requirements, benefits and disadvantages. So:
For each application
pick the right technology ... RTFM of your device and if it says NiCd use NiCd, if it says NiMH use that etc. NiMH are good cells, but some device do not perform well with those as they expect higher voltage levels so the cell
seems to be 'depleted' rather fast, but it's not, it's just not the right cell for that device. Things like that ...
For each technology
use a suitable charger ... (and
RTFM!!)
Often "bad behaviour" by rechargeable batteries is mostly a result of bad design (cheap crap!) in either the appliance that uses them and/or the charging device (cheap crap) - not necessarily bad or ignorant behavior by the user. Using the wrong type of batteries in the device at hand and/or the wrong charger (too cheap) however
is a user error.
But really ... go and read on Wikipedia (or elsewhere) ... I cannot possibly reproduce that here.
Cheers! Arp