Thank y'all for your comments First to Art: My etch-a-sketch has been customised by a man in the back of Glossop market. It has 802.11.ac wi-fi,, 4G connectivity and satellite connectivity. It is powered by a small water turbine so can be used anywhere a faucet is available. One bug, that answers Dave's comment, is that it cannot sustain runs zeros longer than two. For that reason I have had to negotiate a cut in pay of a penny to avoid a run of six zeros in my salary advice. :-) Seriously. I should have specified a NiCad battery since this is part of my retro 1978 clock and NiMH were not around back them. And it is my recollection that NiCads can be safely trickled at C/20 albeit with some degradation. And on further reflection it might be simpler to use a non rechargeable battery. A good PP9 will supply about 400mAH which will cover a lot of short outages. __________________________________________ David C Brown 43 Bings Road Whaley Bridge High Peak Phone: 01663 733236 Derbyshire eMail: dcb.home@gmail.com SK23 7ND web: www.bings-knowle.co.uk/dcb *Sent from my etch-a-sketch* On Tue, 30 Oct 2018 at 16:52, AB Pearce - UKRI STFC < alan.b.pearce@stfc.ac.uk> wrote: > Several things, apart from (as already noted) NiMH don't like float charg= e. > > You don't have any cut out mechanism when the battery reaches full charge= .. > You don't have any temperature monitoring of the battery - rolls into the > previous point. > > Check out the Linear technology devices at Analog Devices. > The LTC4060 does NiMH up to 4 cells, which won't be enough, and you would > need to limit the input voltage as it doesn't go to 12V input. > > The LTC4079 looks like it will be right up your street though, 4 > resistors, 1 capacitor and 1 thermistor, 2.7V to 60V input range, 1.2V to > 60V output range, 10mA to 250mA charge current. > > https://www.analog.com/media/en/technical-documentation/data-sheets/4079f= ..pdf > Biggest hassle is it is in a DFN package. > > Then in the switching battery chargers there are LT1512, LT1513 and > LT1513-2 that would look hopeful. These use more components though. > > > > > > -----Original Message----- > From: piclist-bounces@mit.edu On Behalf Of > David C Brown > Sent: 30 October 2018 14:49 > To: Microcontroller discussion list - Public. > Subject: [EE} Am I carrying KISS too far? > > Power supply for a circuit with a handful of CD400 chips. > > 12vdc from wall-wort charges a 9volt NiMH through a series resistor. CMO= S > runs of battery. > Just the two components. What have I overlooked? > > __________________________________________ > David C Brown > 43 Bings Road > Whaley Bridge > High Peak Phone: 01663 733236 > Derbyshire eMail: dcb.home@gmail.com > SK23 7ND web: www.bings-knowle.co.uk/dcb > > > > > *Sent from my etch-a-sketch* > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .