First Month with 50g

[Helix]

Yes, the battery warning pops up way too soon on the 50g. All the details are given in this thread.

I don't think it is possible to modify the alarm voltage, but it is possible to monitor the voltage. Btmon is a simple program that shows the voltage at normal speed (75MHz) and slow speed (12 Mhz). It is designed for the HP50g, and must be stored in port 2. It's very informative.

The backup battery lasts for years. I acquired my HP50g in 2007, and I've never changed this battery. When I replace the main batteries, the RAM content is still preserved.

[Claudio L.]

(04-23-2015 07:25 AM)Tugdual Wrote:  I wish I could have a 50g custom firmware to adjust alarm voltage to lower values more adequate for NiMh batteries.

Noted.
Here's what I've done about it (I think you'll like it):
newRPL so far has voltage readings with a calibration curve I measured myself, for different CPU loads. The idea for the future is to have the user configure the voltage level of the battery warning, and perhaps provide reasonable presets for alkaline, NiMH, etc, selectable by the user. My tests included test points that were way out of the normal use, to the point where the calculator would reset due to insufficient power. I used those points to determine "safe" values of voltage.
newRPL has already implemented 2 modes of operation:
slow mode at 6 MHz (and low power)
full speed at 192 MHz (draws a lot of power)

The system switches automatically between the two modes as needed (if a program takes more than 300 msec to run, it switches to fast mode automatically, otherwise it stays in slow mode, unlike the stock firmware which switches to fast mode all the time except when waiting for a key). The switching code is smart enough to read the battery voltage periodically, and if it drops below the "safe" value while running at full speed, it shows the battery icon and locks the system in slow speed mode, to let you keep using the same set of batteries for longer without risking a crash. When the batteries are low even for slow mode, the battery icon starts blinking, showing batteries are at critical level and need immediate replacement. If you can put up with the system being slower than normal, you'll get a lot more juice from your batteries. Now don't get fooled by "slower than normal". Slow mode newRPL runs programs 6x faster than the stock 50g at full speed, so even with your calc "locked" in slow mode it will be very usable, all the way until your batteries are depleted.