Originally Posted by Jayjr1105
Always wanted to invest in some decent rechargeable batteries with a good trickle charger. Going to bookmark this for the charger info. How would these do in a Trailcam that takes 8 AA. Cold weather tolerable?
When it comes to use and not storage, as temperature decreases so does capacity performance of NiMH batteries, but low temperatures for storage slows down self-discharge to en extent but this practice was made mostly obsolete with low self-discharge batteries. I don't have reliable hard data to provide but here are some resource links from Candle Power Forums I found in researching this:
See Posts #11, 14, & 17: http://www.candlepowerforums.com/vb/showthread.php?296372-Cold-weather-AA-NiMH-performance
See Post #51: http://www.candlepowerforums.com/vb/showthread.php?279092-New-Imedion-2400mah-LSD-AA-Batteries/page2
Note stored in freezer for 24 hours but discharged at room temperature: http://www.candlepowerforums.com/vb/showthread.php?241606-AA-battery-tests-incl-freezer-test
A good charger makes all the difference. The great thing about smart chargers is most of them go to trickle charge when the battery is full (enough current just to keep the battery full but not overcharge, most of my chargers trickle current is 20-30mAh after charging is complete). So you get the benefit of fairly fast charging without any negative impact on the batteries (see my recommended charge currents below).
Let's assume a battery capacity of 2,000mAh for AAs and 800mAh for AAAs (very common capacity ratings for LSD NiMH batteries). A rule of thumb is to never charger a NiMH battery at close to or higher than it's capacity, and a current of half the capacity or less is much better. Charging currents for AAs I'd recommend 400-700mAh (1000mAh in a pinch if the charger has a good cooling design, like the MH-C9000 or BC-1000), and AAAs 200-400mAh (500mAh in a pinch). Another thing to keep in mind is that a charge current that is very low can actually be a bad thing (not counting smart chargers trickle mode when full) because at lower currents it's harder to detect the slight drop in voltage (-Delta V). An example of this would be charging a 2,000mAh AA at 200mAh. While not a bad thing on the surface it could cause the smart charger to miss the very small voltage drop and overcharge the battery slightly, as the voltage drop is more pronounced at higher currents.Edited by Ben the OCer - 10/20/13 at 9:51pm