The only way I can see the memory battery making any real difference in the AA battery life is if you use the machine so infrequently that the battery is allowed to go flat. Then when you put a new set of AA batteries in they will have to charge the memory battery up completely.
Jeff Birt From: M100 <m100-boun...@lists.bitchin100.com> On Behalf Of Alex ... Sent: Wednesday, April 28, 2021 3:27 AM To: m...@bitchin100.com Subject: Re: [M100] T102 Current Drain I don't have any real measurements to back this up, but someone might find this anecdote useful. I feel like my 102's AA battery life was much better after I cut out the internal NiCd cell. This idea is supported by the fact that it again seems to go through batteries faster since I replaced the backup battery with a new one. Worth noting I run the machine on Eneloop NiMH cells, not alkalines. On Tue, Apr 27, 2021, 20:51 Peter Noeth <petern0...@gmail.com <mailto:petern0...@gmail.com> > wrote: I know this has been discussed before, but I was doing some testing on my T102 regarding current drain to gauge external battery life. I made an external 4D cell alkaline pack I use when watching TV and playing with the computer a few years ago, and was thinking of upgrading the capacity. There is no convenient A.C. outlet near by to my viewing position, hence the battery pack. I measured this on a 32K Tandy 102 w/REX installed. * 0.4mA - Computer off, no peripherals connected * 66.5mA - Computer on running a BASIC program, no peripherals connected * 67.2mA - Computer running a BASIC program and printing to my DPU-414 thermal printer * 71.8mA - Computer running REXMGR, no peripherals connected * 114.7mA - Computer running a BASIC program, printer connected but powered OFF * 130mA - Computer running a BASIC program with Unitek Barcode Wand connected I am sure a M100 would give similar results, but maybe a little higher in some cases, due to the T102 being mostly surface mount components and the circuitry optimized somewhat over the M100 The surprise was the marked current increase with the printer connected, but powered OFF. There is obviously some sneak current paths if the printer is not ON. Likely in the printers Centronics interface chip. This is good to know if trying to maximize battery life. The current draw increase with the Unitek Barcode Wand connected was expected, due to the fact that it has a very bright red LED, that is on all the time. The RS Barcode wand likely draws less when its button is pressed to turn on the dim LED. I like the Unitek wand better, as it reads codes that are not black on a white background, like on food cans and potato chip bags. Radio Shack just private labeled the HP wand for the 41-C calculator, which was low power and expecting white paper barcode labels and program listings. Regards, Peter
