mAh???
- Thread starter Chusco411
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Oddjob
Flashlight Enthusiast
It stand for milliamps per hour. Basically the capacity of the battery which equates to runtime. The higher the number the longer the runtime. Someone correct me if I am way off base.
jbosman1013
Enlightened
no correction needed
trailstoride
Newly Enlightened
mAh means milli Amp hour. It is a rating of a batteries capacity. Roughly speaking a XXX mAh battery can supply XXX mA for one hour. However, alkaline batteries have a high internal resistance that limits the current available, making them a poor choice for high current usage.
NiMh batteries use thiner internal construction as the mAh increases beyond around 2000 mAh. Witness the poor durability of the 2500mAh AA Energizer batteries. Sanyo Eneloop, and other "low self discharge" NiMh batteries perform better at 2000/2100 mAh.
Lithium batteries have the lowest internal resistance and highest energy density. Primary lithium batteries are good choice for high power, or long shelf life applications.
Rechargeable lithium batteries are 3.0V or 3.6V and don't directly have NiMh or alkaline battery equivalents. They also require more care and protection from over discharge and over charging. Over charging a lithium battery will cause a fire and possibly an explosion!
NiMh batteries use thiner internal construction as the mAh increases beyond around 2000 mAh. Witness the poor durability of the 2500mAh AA Energizer batteries. Sanyo Eneloop, and other "low self discharge" NiMh batteries perform better at 2000/2100 mAh.
Lithium batteries have the lowest internal resistance and highest energy density. Primary lithium batteries are good choice for high power, or long shelf life applications.
Rechargeable lithium batteries are 3.0V or 3.6V and don't directly have NiMh or alkaline battery equivalents. They also require more care and protection from over discharge and over charging. Over charging a lithium battery will cause a fire and possibly an explosion!
so I have found lithium AA with 2900 mAh and NiMh with 2700 mAh. Does that mean that the lithium should last longer than the NiMh? Also would a flashlight's brightness be increased with either of these 2 options over alkaline. I am asking about initial brightness because I know after some use that lithium or NiNh with be brighter.
Thank you
Thank you
trailstoride
Newly Enlightened
It depends on the flashlight. The lithium AA has the lowest internal resistance, allowing it to deliver higher current (mA) and higher voltage (1.7V vs 1.4V for NiMh). So initially an unregulated fashlight will be brighter on lithium. However the runtime may be shorter for the 2900 mAh lithium than the 2700 mAh NiMh due to more power going to the flashlight.
Now if your 2700 mAh NiMh sits for a week or two, it may only have 2200 (or less!) mAh left due to self discharge. So in if your flashlight sits unused for a while, the lithium will be brighter and last longer! High mAh (2500 or more) NiMh have rather rapid self discharge rates. Lithium has a very very low self discharge - and are rated for 10 years.
Now if your 2700 mAh NiMh sits for a week or two, it may only have 2200 (or less!) mAh left due to self discharge. So in if your flashlight sits unused for a while, the lithium will be brighter and last longer! High mAh (2500 or more) NiMh have rather rapid self discharge rates. Lithium has a very very low self discharge - and are rated for 10 years.
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Yep, ALL batteries suffer from the "Peukert effect". The faster you drain them, the less total energy they produce. NiMh's, lithiums, and lithium-ion's suffer very little from the Peukert effect, whereas a standard alkaline batteries tends to suffer more.
