|Re: Death of a Calculator|
Message #3 Posted by Michael Meyer on 30 Oct 2003, 11:25 p.m.,
in response to message #2 by Jim Chumbley
Scary. Not good. I see that Rayovac also has the promise to "repair or replace any device damaged" by their batteries. What a hassle, though.
I know most older HP's used rechargeable cells that were lower voltage... in fact, many here on the Forum have warned the opposite: don't use disposable batteries due to their HIGHER voltage. NiCd's also have 1.2v per cell. I haven't had any trouble doing this, but it makes sense that a higher voltage could put a failing chip over the edge.
You just can't win.
I suspect your failure was a fluke, but it makes sense to use disposable cells in the newer calcs. They should last a nice long time with the lower power requirements of modern circuits and LCD displays.
The rechargeables, especially NiMH, are notorious for a sudden dropoff of voltage, which doesn't allow much warning before they go dead.
The jury is far from out on these new cells. So far, in devices like toys, they've been awesome-- taking as little as a few minutes to "top off". I'm also hoping that the internal circuits allow for longer cell life without internal pressure build-up, leading to leakage. I also wonder if they cut off before becoming completely drained. Great for cell life, but bad for a device like your calculator.
Thanks for the warning, Jim. Again, I don't see much role for these in calculators, as once built into a standard HP pack, they'd charge at the slower rate anyway.