odie
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Is it best to let these Ni-Cad batteries run completely dead before recharging......or, does it matter?
-----odie-----
-----odie-----
No, do not let them run completely dead because you run the risk of a condition known as cell reversal. If that occurs then the cells can't be charged. 3M recommends recharging the battery at the end of every day that It is used even if it is barely used. There are some types of batteries that may develop a "memory", but that is not the case for NiCad batteries according to the GE NiCad Engineering Reference Handbook. However, empirical data* shows that occasional deep cycling (not complete discharge) improves charge capacity.
* http://www.dtic.mil/dtic/tr/fulltext/u2/a105418.pdf
Is there any problem with not fully charging these batteries, then running them? How long do you charge your batteries? Is it a good paradigm to charge 1:1, hours used to hours charged?
I rebuilt one of my Trend batteries with 3 AAA and it only cost 18 for the batteries.I have used my Air Mate for 20 years. When the batteries where done I cut off the top of the battery case and saw three Ni-Cads. I took it to Batteries + and they replaced them for $29 total instead of $100 +. Next time I'm going to change to Lithuim Ion of the same voltage
I have the Smart Charger so the batteries are fully charged when the little green light comes on. I don't know if the Standard Charger has something similar. With the smart charger you can leave the battery connected and it will trickle charge as needed to keep the battery fully charged. If you have the standard charger then you have to disconnect it from the battery when fully charged to prevent overcharging. If I have used my Airstream all day then it may take as much as six hours to charge the battery, but I always fully charge it. My understanding is that you get the maximum battery life when you fully charge them and store them in a fully charged condition. My first battery lasted more than eight years which isn't too bad.
The batteries are expensive, but not all that bad when compared to some of my other rechargeable batteries I have. I recently replaced a couple DeWalt drill batteries that were nearly dead after only three years. They were $80 each or two for $130. The batteries for my Canon cameras are also around $80 apiece and they seem to last about four years on average.
I think that you typed one thing and meant the opposite. While some batteries have evolved such as is the case with camera batteries evolving from NiCad to NiMH to Li-ion, the Airstream battery has always been NiCad. Part of the reason could be that intrinsically safe certification of new batteries would involve expensive test lab time. Since 3M is pushing their line of Versaflo respirators, they may not want to put any more money into supporting an older design. Another reason is that there is no real need to go to newer technology batteries for the Airstream because the existing NiCad battery has plenty of stored energy to run the Airstream for at least nine hours. A battery with a higher Ampere-hour rating and bigger price tag doesn't scratch any itch.
- .... If your batteries are 2004, they are more likely to be NiMH than NiCad.
My memory is a bit rusty (or maybe it needs charging), but I think that NiCad cells have a rather abrupt "knee" in its stored charge somewhere around one volt. For all useful purposes, that could be considered fully discharged although there is still some (mostly useless) charge remaining. With the Airstream it's pretty easy to tell when the charge hits the "knee" because you won't be getting enough flow of filtered air.
- Regardless of Ni MH & NiCad: Do not run to 0%. Run down to 10% or 20% (but it's hard to say what that is with consumer electronics).
Ni MH (Nickel metal hydride) batteries are generally interchangeable (on a voltage basis) with NiCad. If your batteries are 2004, they are more likely to be NiMH than NiCad.
Interesting.....I didn't know that.......so, how come AA, AAA, 9v battery chargers have a ni-cad and NiMH setting?
-----odie-----