battery chargers, again
in [Design]
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From: Joerg on 28 Sep 2009 17:51 John Larkin wrote: > On Mon, 28 Sep 2009 09:04:17 -0500, Tim Wescott <tim(a)seemywebsite.com> > wrote: > [...] >> One new battery is cheaper than one tow truck ride. Do the math. > > Our insurance covers the truck ride. > But not if you get stuck umpteen miles north of Tonopah, the cell phone shows zero bars and the only thing you see is the bloated carcass of a dead cow. BT. Anyhow, your car insurnace covers a tow? Ours (Farmers) doesn't AFAIK. Did you have to buy that extra? -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jim Thompson on 28 Sep 2009 17:53 On Mon, 28 Sep 2009 14:45:18 -0700, Joerg <invalid(a)invalid.invalid> wrote: >John Larkin wrote: >> Last time a car went dead in the garage, my wife's Fit, I hacked up a >> charger from an old DSL wall-wart and a sabre saw as a series current >> limiter. The garage geometry makes it essentially impossible for us to >> push a car uphill to the street to jump it. Now The Brat left her Echo >> in the garege for a month or so and it went dead, too. ... > > >It is not normal for a car battery to discharge so far over just a >month, not in the climate zone your are living in. Unless the battery >was shot to begin with or something in the car was left on. > > >> ... So I figure >> it's time to buy a real charger. Went to Kragen Auto Parts and bought >> two (one for here, one for Truckee) chargers. They are all "smart >> chargers", namely switchers with electronics, these days. >> > >Big mistake :-) > >Electronics <-> cars, IME not a good combination. > > >> The battery is really dead, 1.8 volts. The first charger hums and >> outputs nothing. Tried the next one: it hummed for maybe 3 seconds >> then sparked and smoked inside. >> >> Went back to Kragen and traded up, two better chargers. Neither >> charges... no current, battery steady at 1.8 volts. Both have their >> "charging" LEDs off and "charge complete" LEDs lit. >> >> Back to Kragen, 3rd time, got all my money back. Passed by Bob Pease's >> place all three trips, same collection of rusty VWs everywhere. >> > >Why didn't you stop at Bob's place for a beer? He'd have given you a >real charger, meaning a transformer, a rectifier, a power cord with plug >(or maybe without plug), some old meter, probably all neatly assembled >on a piece of plywood with some cinge marks on there. And it sure would >have worked. > > >> A charger that puts zero amps into a dead battery does that by design, >> and there's only one reason to do that: to convince people they need a >> new battery. Kragen's sales pitch was exactly along those lines; "Tt >> won't charge, so all the cells are shorted." >> >> So I went to work and nabbed a cute little Lascar bench power supply. >> It current limits at 1.2 amps, so I just cranked it up. The battery >> went instantly to 16.5 volts, then settled down to 12 or so in a few >> minutes, and is creeping back up. >> >> Interesting. >> >> So I guess I'll buy a couple of 3 amp or so lab supplies, with nice >> volt and amp meters, instead of battery chargers. They're handier to >> have around anyhow, cost about the same as a "good" charger, and >> aren't booby trapped. >> > >Until one fine day ... *FOOMP* ... and there goes the "Panazonc Special" >output electrolytic. > > >> What Kragen is doing is fraud. >> > >It certainly was junk if it didn't even have any status display. A good >charger must be able to start from zilch. Interestingly, I found out >that many designers of SMPS do not have foldback limit, they just error. >Maybe they don't know how to do that anymore these days. John has not indicated how _long_ the "charge" remains on his battery. Or take a hydrometer reading?? To me, 1.8V indicates a fully "sludged" battery. ...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: Tim Wescott on 28 Sep 2009 17:54 On Mon, 28 Sep 2009 14:51:40 -0700, Joerg wrote: > John Larkin wrote: >> On Mon, 28 Sep 2009 09:04:17 -0500, Tim Wescott <tim(a)seemywebsite.com> >> wrote: >> >> > [...] > >>> One new battery is cheaper than one tow truck ride. Do the math. >> >> Our insurance covers the truck ride. >> >> > But not if you get stuck umpteen miles north of Tonopah, the cell phone > shows zero bars and the only thing you see is the bloated carcass of a > dead cow. BT. > > Anyhow, your car insurnace covers a tow? Ours (Farmers) doesn't AFAIK. > Did you have to buy that extra? AAA. -- www.wescottdesign.com
From: Joerg on 28 Sep 2009 18:11 Tim Wescott wrote: > On Mon, 28 Sep 2009 14:51:40 -0700, Joerg wrote: > >> John Larkin wrote: >>> On Mon, 28 Sep 2009 09:04:17 -0500, Tim Wescott <tim(a)seemywebsite.com> >>> wrote: >>> >>> >> [...] >> >>>> One new battery is cheaper than one tow truck ride. Do the math. >>> Our insurance covers the truck ride. >>> >>> >> But not if you get stuck umpteen miles north of Tonopah, the cell phone >> shows zero bars and the only thing you see is the bloated carcass of a >> dead cow. BT. >> >> Anyhow, your car insurnace covers a tow? Ours (Farmers) doesn't AFAIK. >> Did you have to buy that extra? > > AAA. > Ok, but last time I checked they were quite a bit more expensive in insurance rates than Farmers. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Tim Wescott on 28 Sep 2009 18:34
On Mon, 28 Sep 2009 15:11:54 -0700, Joerg wrote: > Tim Wescott wrote: >> On Mon, 28 Sep 2009 14:51:40 -0700, Joerg wrote: >> >>> John Larkin wrote: >>>> On Mon, 28 Sep 2009 09:04:17 -0500, Tim Wescott >>>> <tim(a)seemywebsite.com> wrote: >>>> >>>> >>> [...] >>> >>>>> One new battery is cheaper than one tow truck ride. Do the math. >>>> Our insurance covers the truck ride. >>>> >>>> >>> But not if you get stuck umpteen miles north of Tonopah, the cell >>> phone shows zero bars and the only thing you see is the bloated >>> carcass of a dead cow. BT. >>> >>> Anyhow, your car insurnace covers a tow? Ours (Farmers) doesn't AFAIK. >>> Did you have to buy that extra? >> >> AAA. >> >> > Ok, but last time I checked they were quite a bit more expensive in > insurance rates than Farmers. But nice when you're back of the beyond with a car full of screaming kids and that cow is starting to look like dinner. -- www.wescottdesign.com |