Practical Guide to Using Camera Batteries Dolgin EngineeringAlex Dolginwww.dolgin.net
How to quickly figure out run time expected from your battery? • what is "mah" battery rating? • 1Ah = 1000 mah A 1 amp hour battery contains enough charge to supply 1 amp for 1 hour. • A typical “handycam” style battery 7800 mah; a camera like PD170 uses 700 ma; run time is about 10 hours • amps are flow ( "this motor requires 2 amps to run at 1800 rpm.") Amp hours measure capacity, quantity, or amount of charge ("this 100 amp-hour battery will supply 2 amps for 50 hours before recharge." Amp-hours are amps times hours. • what is “Wh" battery rating? • Ah x V = Wh • 7800 mah x 7.2V = 56 WH • 6 Ah x 14.4V = 90 WH (Anton Bauer Dionics 90) • what is camera power consumption? • Typical large camera 15-25W (12V power) • Typical small camera 7-10W (7.2V power) • how long a camera runs on one battery? • Wh/W=Hours Mah/Ma=Hours 90WH/15W=6 hours 7800mah/780ma=10 hours • What is a 12 hour battery? Do they really exist? • No, one can not technically measure a battery in hours!
How to care for batteries to extend their service life • Do I need to discharge the battery after use? • No need to, actually it is bad for it • Do I charge right after use? • No, for extended storage it is recommended to keep them at 40-50% charge level • Are “No-Mem” batteries better? • Li-Ion batteries never had memory problems • Leaving on the dashboard in July? • Very bad; heat kills batteries
EBay and other generics - do they work? • Are they going to damage your camera? No damage to the camera as the battery chemistry inherently can not produce more than 8.4V, same as "real" OEM batteries. • Are they all the same? Some of generics (like Lenmar) come from more reputable established manufacturers than no name Ebay vendors. They are constructed more solidly and carry warranty (Lenmar carries 3 years). But they are more expensive than from Ebay. • What is so special about Sony generics/vs real Sony? Sony batteries have a special ID system designed in, so the Sony camera does not turn on unless it sees a real Sony battery. Many generics try to fake it pretending to be real Sony. But it does not always work out.
How long a battery is expected to last? • Aging • About 10%/year • Cycle life • About 350-500 full cycles • Deep discharge/vs. partial discharge • Partial discharge is easier on a battery • Overall service life 2-3 years