From: "Alexandru-Cristian Sarbu" <[EMAIL PROTECTED]>
Hi, I'm looking for some rechargeable batteries for my DS. I would prefer Li instead of NiMh (I don't shoot many pictures at once), and I've saw some R-CRV3 advertised as having 3V and capable of 1100mAh. But... isn't 1100mAh a little low? Anyone here uses such things?
I've been watching these with some interest. Quick summary of information gleaned:
Rechargeable CRV3 batteries (R-CRV3) actually have a higher voltage (up to 1.8v) than standard CRV3 disposables (1.5v) or NiMh (1.2v). This is the reason that Pentax state they should not be used however (As 'tother Rob posted) Moby, and I think others, have produced CRV3 batteries that claim to operate within normal voltage and be safe to use. The claim this is accomplished via a 'protection device' built into the battery - whatever that is.
There are some rechargeable 'low voltage' recheargeable CRV3 batteries on the market which are actually just a couple of NiMh cells packaged together rather than LiOn batteries. Obviously there are no voltage problems here but no advantage either - just an expensive alternative.
Folks who have used R-CRV3 batteries in their cameras seem pleased with them. Advantages claimed are: a) Faster autofocus, sometimes significantly faster. This seems plausible if the batteries are operating at higher voltage, the flip side is that the autofocus mehanics will be stressed a bit more. b) They don't suffer the same self-discharge problems as NiMh i.e. you can charge and forget for a while before use. b) Greater usable capacity despite the lower theoretical capacity . I'm not sure I believe this and put it down to either rose tinted vision after laying out a lot of cash for batteries, or alternatively comparing to NiMh batteries that aren't fully charged. The distributors of these batteries make a big thing about the actual capacity (even at 1100 mah) being higher due to the camera reaching cut off voltage before a (2300 mah) NiMh is fully discharged - but I'm not sure the actual maths would justify this. Likewise there is a real issue in that you should not over discharge a R-CRV3 and if the full capacity is used bacause the camera is actually assuming different battery types you will be damaging the battery.
It isn't clear if the faster autofocus claims relate to the 'safe' voltage R-CRV3 batteries or the original higher voltage ones, or both.
Their distibutors claim that the expensive R-CRV3 batteries are actually 'more economical' than NiMh as they can be recharged many more times. Too say I'm highly suspicious of all their figures and testing methodologies is an understatement, I believe that LiOn battery technology is generally regarded as more fragile than NiMh. Time will tell.
My current view is that good quality high capacity NiMh batteries and charger are the current best and safest options for most usage patterns -ntil the Sanyo low discharge batteries come on the market you just need to remember to top them up every couple of weeks before use. If you use autofocus with big heavy lenses a lot it may be worth experimenting with R-CRV3 batteries, I am tempted myself although I don't have that autofocus need - we all like new toys :-)
Rob. -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.12.8/163 - Release Date: 08/11/2005
