Originally Posted by danielchtong
At least you accept that the NiMH tech is pathetic at best.
NiMH is only 1.2V nominal ,and it's difficult to get batteries to provide much more than 1-1.5A of current when fully charged. Pentax should have designed the system for 5 x NiMH instead (6V), although that means putting in 5 x Alkaline or 5 x LiFe (e2 Lithium) would over-volt the system.
Originally Posted by danielchtong
The one that I am using is 3.2vx2 - well within the 10% generally accepted voltage tolerance level.
As an electrical engineer who has designed microelectronics, that is
not an "accepted voltage tolerance." 10% is
guaranteed transconductance. Don't confuse TTL, motor and other systems with microelectronics.
The Pentax K100D/K200D are designed with a regulator that takes 4.8-6.0V nominal. 10% of those would be 4.3-6.6V. The cut-off seems to be 4.5V and the maximum is 6.5V. So what you're suggesting is already at the limits of the
absolute maximum input voltage for the regulator.
Originally Posted by danielchtong
The RCRV3 is the renewable substitute of the not quite environmentally friendly CRV3.
Doesn't mean it's correct.
Just like the "more environmentally friendly" sealant changed in 1985 on the STS' SRB O-rings drastically reduced it's tolerance to weather and the 1997 change to CFC-free insulator increased the number of break-offs of insulation from the STS' SFT that struck the STS' Orbitor a full order of magnitude (from over 10 to over 100). Yes, both were "environmentally mandated" material changes (most people don't know that, and the media heavily under-reported these facts).
Engineering 101: When you design a system to work with specific materials, anytime you change the material to one it was
not designed for, you have exponentially increased risk.
The original O-ring design on the STS was risk mitigated, using the original sealant material. That changed in 1985, when the replacement sealant did not insulate against the weather like it insulated against moisture. Not surprising, the next four (4) cold weather launches saw a massive strike in O-ring breaks. Same deal on the change to CFC-less insulation that took effect in 1997. You went from only about 10-12 break-offs to over 100 on every single launch due to the tensile strength reduction in the new RF type.
Li-Ion (RCR-V3) is
not LiMg (CR-V3)
Originally Posted by danielchtong
A device (and there are many) designed for CRV3 or 2AA batt can also be powered by RCRV3.
"Can" is the word here. I've yet to see a single vendor certify RCR-V3 or use in their CR-V3 powered devices. The characteristics of Li-Ion are radically different than LiMg. Li-Ion is regulated very, very different, and each vendor has varying tolerances and requirements.
Originally Posted by danielchtong
I have to agree that the voltage variance (of some fly by night vendors without an industry wide standard ) may not be acceptable . That was at least the case prior to the launching of regulated RCRV3.
All Li-Ion is "regulated." This myth that Li-Ion batteries exist that are not regulated is just that, a myth. It is chemically impossible for a Li-Ion cell to operate at 3V without being damaged.
Originally Posted by danielchtong
There may be a reality or trend.
There is
no industry or certified accepted Li-Ion "standard" with any end-user device manufacturer. You are violating the engineering specified and certified operations of a device when you use RCR-V3, period. I'm not making this up, it's not "trend," it's reality.
CR-V3 is LiMg, not Li-Ion.
Originally Posted by danielchtong
Whatever. But it does not alter the fact there are a lot of users worldwide prefering an insignificant overvoltage (under 10%)
Users, yes. Engineers, no.
Originally Posted by danielchtong
than a major undervoltage ( 6V cf 4.8V).
The K100D/K200D are designed to operate at 4.8-6V. I've personally measured a "cut-off" voltage of 4.4V on my K100D.
Just because the AF motors are "not as peppy" doesn't mean it's an under-volt. It's regulator was designed for that input voltage.
Originally Posted by danielchtong
Oops. My apology to the OP as we seem to have hijacked this thread
We're talking about battery issues that may contribute to malfunction. I've designed microelectronic circuits, and I would
never put in a voltage that my regulator was not designed for. 6.5V max is the absolute maximum.
And to get 3.2V out of a Li-Ion material, you're getting dangerously close to the voltage where Li-Ion cells die. That's fact. It's also why RCR-V3 can never be a replacement for CR-V3, despite the marketing. LiMg is nothing like Li-Ion.
Your "environmentally friendly" argument is as futile as people who argue we shouldn't use CFC-based insulation in aerospace applications for "environmental reasons." Thank God our US military stopped using that junk on some of our arsenal, as I've professilonally seen it nearly cause a failure during a launch.
Engineers design systems to mitigate risk, they can never fully eliminate it. I've seen how over-voltage causes transconductance and radically reduces semiconductor lifespan (when it doesn't destroy it immediately). Your solution is
not accepted by 1 single manufacturer of end-user devices that utilize CR-V3, period, fact, end-of-story, no "trend," just 100% industry reality.