battery chargers, again
in [Design]
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From: Joerg on 29 Sep 2009 14:54 who where wrote: > On Mon, 28 Sep 2009 15:43:21 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > > >> The same happened to me after dusk on the road from Durness to Inverness >> in Scotland. The old Ford Cortina just stopped, no more electric. Looked >> around, opened fuse box, the big one was gone. "Oh s..t!" ... no other >> cars traveling that road at this late hour. I did meet one horse though, >> alone, just wandering about (you see those a lot there). I seriously >> doubt it would have agreed to carry me to Inverness. So I slowly walked >> back and lucked out, found the fuse in the dirt. It had simply fallen out. > > Lucas, Prince of Darkness? ROFL! For those not in the know: http://www.mez.co.uk/lucas.html -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jim Thompson on 29 Sep 2009 14:57 On Tue, 29 Sep 2009 11:54:56 -0700, Joerg <invalid(a)invalid.invalid> wrote: >who where wrote: >> On Mon, 28 Sep 2009 15:43:21 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >> >>> The same happened to me after dusk on the road from Durness to Inverness >>> in Scotland. The old Ford Cortina just stopped, no more electric. Looked >>> around, opened fuse box, the big one was gone. "Oh s..t!" ... no other >>> cars traveling that road at this late hour. I did meet one horse though, >>> alone, just wandering about (you see those a lot there). I seriously >>> doubt it would have agreed to carry me to Inverness. So I slowly walked >>> back and lucked out, found the fuse in the dirt. It had simply fallen out. >> >> Lucas, Prince of Darkness? > > >ROFL! For those not in the know: > >http://www.mez.co.uk/lucas.html Old potentiometer shafts fit automotive AG holders ;-) ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Coming soon to the elementary school in your neighborhood... I pledge allegiance to Dear Leader Barack Hussein Obama and to the community organization for which he stands: one nation under ACORN, unchallengeable, with wealth redistribution and climate change for all.
From: Joerg on 29 Sep 2009 15:04 John Devereux wrote: > John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> writes: > >> On Tue, 29 Sep 2009 11:47:02 GMT, Jan Panteltje >> <pNaonStpealmtje(a)yahoo.com> wrote: >> >>> On a sunny day (Mon, 28 Sep 2009 19:42:11 -0700) it happened John Larkin >>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >>> <sps2c51m3rnppq9vn8hu6rr11353l8cm51(a)4ax.com>: >>> >>>> The second two has status LEDs. Connected to the 1.8 volt battery, >>>> "charging" was off and "charged" was lit. >>> It would have been interesting to measure the voltage while it was connected. >>> It perhaps just applied 14 V and did see no current. >> 1.84 volts, charger connected or not. Zero current between charger and >> battery. >> >>> Voltage OK, no current = battery charged. >>> How many [k]V do you think would be reasonable to have it try before detecting a current? >> Why doesn't it apply a current-limited voltage and, well, charge the >> battery? It is a battery charger, after all. >> Maybe the designer was only familiar with tuk-tuks which only have a magneto ;-) >>> That would require a multi sequence startup. >>> First apply high voltage with low current limit to see if any mA flows. >>> If not -> kaput -> exit. >>> Then normal voltage with normal current limit. >>> >>> A bit unreasonable to expect all that from a simple charger. >> A simple charger, like the old transformer-rectifier types, or any >> normal switching regulator, would dump current into a dead battery. >> These new ones are deliberately programmed to not. > > Don't lead acid batteries charge at "constant voltage"? > > That is, it is traditionally safe to apply a constant e.g. 14V to a good > "12V" battery, and the charging will be self-limiting. When it's full, > the current drops to a safe minimal value. > > But if you had a battery where 5 out of 6 cells are shorted out, then > you are relying on that one good cell to terminate the charge > safely. But it never will, your constant-current charger will keep on > pushing maximum current through it, electrolysing the fluid. All that > deadly explosive hydrogen gas and lethal sulphuric acid... A lawsuit > waiting to happen... > It ain't rocket science to detect when a battery voltage inexplicably plateaus or refuses to rise as expected and then issue an error signal. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 29 Sep 2009 15:08 Jim Thompson wrote: > On Tue, 29 Sep 2009 11:54:56 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > >> who where wrote: >>> On Mon, 28 Sep 2009 15:43:21 -0700, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>> >>>> The same happened to me after dusk on the road from Durness to Inverness >>>> in Scotland. The old Ford Cortina just stopped, no more electric. Looked >>>> around, opened fuse box, the big one was gone. "Oh s..t!" ... no other >>>> cars traveling that road at this late hour. I did meet one horse though, >>>> alone, just wandering about (you see those a lot there). I seriously >>>> doubt it would have agreed to carry me to Inverness. So I slowly walked >>>> back and lucked out, found the fuse in the dirt. It had simply fallen out. >>> Lucas, Prince of Darkness? >> >> ROFL! For those not in the know: >> >> http://www.mez.co.uk/lucas.html > > Old potentiometer shafts fit automotive AG holders ;-) > But not in the Ford Cortina. It was some sort of newfangled specialty fuse where you couldn't accidentally short the battery side with a falling wrench. Other than that the car was good to me. Always started on the 2nd or 3rd crank. It had to because the battery would unlikely have given me more than five. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 29 Sep 2009 16:16
John Larkin wrote: > On Tue, 29 Sep 2009 08:46:49 +0100, <news(a)rblack01.plus.com> wrote: > >> In article <ok02c551ujbtjfrhi03c6seqies88jshkd(a)4ax.com>, >> jjlarkin(a)highNOTlandTHIStechnologyPART.com says... >> >> [snip tale of poorly engineered battery charger] >>> I have an Agilent DVM that has a serious hardware problem that they >>> obviously hid with firmware. >>> >> Details? Name and shame! >> >> We were looking for a 6.5 digit DMM at about the time you posted your >> troubles with the Keithley. So we struck them off the list and bought a >> 34410A instead. It's not one of these is it? > > It was the 34401A. The VF display driver kicked horrible spikes out > the input connectors. They fixed the firmware to fudge it out on the > lower AC voltage ranges. > > Hook a scope to your 34410A input, one side against ground maybe, and > see what you see. > The topper was a rented and I might add, very pricey, Agilent spectrum analyzer. Did EMC debug at a client, rolled up my sleeves and by afternoon had the unit shipshape. Or so I thought. Fired up the analyzer, and many nasty spikes in the 250MHz region were still there. Bit my lips so no cussing would slip out. How is this possible ...? Turned off unit under test, spikes still there. Hurumph! Turned out they emerged from the analyzer display. I had to go to a hardware store there, buy some sort of chicken coop fencing and drape that over the analyzer's face. Turned DUT back on, total silence. Pathetic. I should have take a photo and sent it to Carly back then. [...] -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |