In article <be098e53-ccbd-4fa5-8213-99cb32a0fef0@googlegroups.com>, kt77 <kawill70@gmail.com> wrote:>On Tuesday, July 18, 2017 at 2:19:33 PM UTC-7, Steve Wilson wrote: > >> You still never made it to 14.5V >> It looks like you need to put your battery on charge after every trip. > >The Black & Decker 2 amp battery charger/maintainer detected full charge an= >d switched to maintain mode. The voltage read 14.26 volts at that point. T= >hat voltage is consistent with the 14.2-14.5 volt range mentioned on the W8= >JI website that I referenced earlier.I'm not sure that the reading of a voltmeter says it all. What do you see on an oscilloscope? (Same remark about car alternators. High current peaks seem to counter sulfation.) Groetjes Albert -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst
Automotive electronics - Honda charging system
Started by ●December 7, 2016
Reply by ●December 2, 20172017-12-02
Reply by ●February 9, 20182018-02-09
On Saturday, December 2, 2017 at 10:12:35 AM UTC-8, Albert van der Horst wrote:> I'm not sure that the reading of a voltmeter says it all. > What do you see on an oscilloscope? > (Same remark about car alternators. High current peaks seem to > counter sulfation.)I wish I had an oscilloscope and could view the charging waveform. The charger does appear to use a switching regulator. Even so, I have a feeling that the average voltage and average current would still be meaningful in terms of charging the battery. This particular charger does not have a Desulfate Mode which would also be very interesting to view on an oscilloscope. That's a very interesting comment on alternator rectified current peaks helping to counter sulfation! Here is a new data point that might be of interest. My car had not been driven for a full two weeks and the battery voltage only dropped to 12.59 volts. I connected the Black & Decker 2 Amp Charger/Maintainer and it stayed on charge for 3.25 hours. If the charger maintained 2 Amps during that period, it would have put 6.5 Amp Hours into the battery which is rated at 52 Amp Hours. That would suggest that the battery had a 12% discharge while sitting idle for two weeks. The battery had been fully charged prior to driving the car. Temperatures were in the range of 50-70 degrees F.
Reply by ●February 9, 20182018-02-09
kt77 <kawill70@gmail.com> wrote:> On Saturday, December 2, 2017 at 10:12:35 AM UTC-8, Albert van der Horst > wrote:>> I'm not sure that the reading of a voltmeter says it all. >> What do you see on an oscilloscope? >> (Same remark about car alternators. High current peaks seem to counter >> sulfation.)> I wish I had an oscilloscope and could view the charging waveform. The > charger does appear to use a switching regulator. Even so, I have a > feeling that the average voltage and average current would still be > meaningful in terms of charging the battery. This particular charger > does not have a Desulfate Mode which would also be very interesting to > view on an oscilloscope.> That's a very interesting comment on alternator rectified current peaks > helping to counter sulfation!1. Sulfation occurs when the battery ls left discharged for a long time. This is why you want to keep the battery fully charged. 2. when the engine is running, the alternator quickly charges the battery to capacity, then the charging current drops to near zero, in the tens of milliamperes range. Modern engines start so quickly that very little energy is needed to start the car. 3. during charging, the battery only accepts current when the alterator peaks are above the battery voltage. So it only charges in pulses on the alternator peaks, and discharges the rest of the time to supply the normal load (headlights, engine ignition, fuel injection, radio, heating and cooling, cruise control, etc.) As long as the battery is fully charged, it won't have any sulfation.> Here is a new data point that might be of interest. My car had not been > driven for a full two weeks and the battery voltage only dropped to > 12.59 volts. I connected the Black & Decker 2 Amp Charger/Maintainer > and it stayed on charge for 3.25 hours. If the charger maintained 2 > Amps during that period, it would have put 6.5 Amp Hours into the > battery which is rated at 52 Amp Hours. That would suggest that the > battery had a 12% discharge while sitting idle for two weeks. The > battery had been fully charged prior to driving the car. Temperatures > were in the range of 50-70 degrees F.When the car is shut off, there is a small current load to run the keyless entry receiver, the burglar alarm system, etc. The battery drain is usually less than 50 milliameres. If you let the car sit for two weeks, and the drain was 50 mA, the total amp-hours would be 50e-3 * 24 * 14 = 16.8 amp-hours. Since the B&D only put back 6.5 amp-hours, your idle current drain would be (6.5 / 16.8) * 50e-3 = 1.93e-2 = 19.3 mA However, we don't know how well the B&D is calibrated, and what condition determines shutoff, so all estimates are only approximate. But it looks like your battery and alternator are fine. Keep the charger so you can help out your cute neighbour when she leaves an interior light on overnight.
Reply by ●February 10, 20182018-02-10
"Steve Wilson" <no@spam.com> wrote in message news:XnsA884B1F01F4DCidtokenpost@69.16.179.23...> 1. Sulfation occurs when the battery ls left discharged for a long time. > This is why you want to keep the battery fully charged. > > 2. when the engine is running, the alternator quickly charges the battery > to capacity, then the charging current drops to near zero, in the tens of > milliamperes range. Modern engines start so quickly that very little > energy > is needed to start the car.<snip> I recently discovered that my driving pattern causes sulfation (seemingly, not fatal). Frequent short starts to move the vehicle (~daily), infrequent trips adequate to charge the battery (>10 mins). It's just marginal enough (whether because of my driving pattern, or if it's a weak alternator) that it takes 5 years to develop. It's a '95, not a particularly new car, so it's missing some of the features you noted. Full recovery (in terms of ESR; capacity unknown) was obtained after floating the battery at 14.4V for 48 hours. This drew very little current overall, less than 10 amperes at first, dropping to 0.3A through the last day. Will see if it behaves for the rest of the winter (solid so far), and if it still acts like new next winter. Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: https://www.seventransistorlabs.com/
Reply by ●February 10, 20182018-02-10
"Tim Williams" <tiwill@seventransistorlabs.com> wrote:> I recently discovered that my driving pattern causes sulfation > (seemingly, not fatal). Frequent short starts to move the vehicle > (~daily), infrequent trips adequate to charge the battery (>10 mins).> It's just marginal enough (whether because of my driving pattern, or if > it's a weak alternator) that it takes 5 years to develop.I'm retired and only drive 1,500 kilometers per year. It's a bunch of short trips for groceries and parts from the hardware stores, with lots of sitting in between. The battery is a couple of years old, and I often monitor the quiescent voltage before starting. Oddly enough, the battery measured 12.4 volts when I bought it instead of the normal 12.6 volts as mentioned in numerous web sites such as the Battery University. It still measures around 12.4 V, but varies with temperature. I though the battery was bad when I purchased it, but it seems to be holding up quite well. It has no trouble starting the car in -30c weather after several days of cold soak. I'm not surprised you are seeing a dropoff in capacity. Around here, battery warranties seem to expire in 3 years, so they expect the battery to die soon after. Most sites recommend a new battery after 6 years of service, so you may be due for a new one. I don't think you can attribute your performance to sulfation - the battery has to be almost dead and sitting for guite some time. Then it won't accept a charge. I'd check the voltage under light and heavy loads. If there's not much difference, your alternator is probably OK.> It's a '95, not a particularly new car, so it's missing some of the > features you noted.> Full recovery (in terms of ESR; capacity unknown) was obtained after > floating the battery at 14.4V for 48 hours. This drew very little > current overall, less than 10 amperes at first, dropping to 0.3A through > the last day.My previous car was a Ford Taurus. It was designed to destroy the battery, and often charged at around 13.5 volts or less. I finally had to remove it after each trip and put it on a constant current/constant voltage lab supply. I set the voltage to 14.5 Volts and 5 A. Like you, it measured 5 Amps at the start, then it quickly dropped to several hundred mA after about 5 minutes. So I think the battery was OK. How do you measure ESR?> Will see if it behaves for the rest of the winter (solid so far), and if > it still acts like new next winter.> Tim
Reply by ●February 10, 20182018-02-10
On Sat, 10 Feb 2018 20:18:31 GMT, Steve Wilson <no@spam.com> wrote:>My previous car was a Ford Taurus. It was designed to destroy the battery,A mechanic once told me. There are TWO four letter "F-Words". He allows his children to say the first one, but not the word FORD. (Unless the first four letter F-Word, precedes the word FORD).
Reply by ●February 10, 20182018-02-10
On 02/10/2018 04:18 PM, oldschool@tubes.com wrote:> On Sat, 10 Feb 2018 20:18:31 GMT, Steve Wilson <no@spam.com> wrote: > >> My previous car was a Ford Taurus. It was designed to destroy the battery, > > A mechanic once told me. There are TWO four letter "F-Words". He allows > his children to say the first one, but not the word FORD. (Unless the > first four letter F-Word, precedes the word FORD).I have two of them, a convertible stick-shift Mustang (my car, which I love) and a turbo-four Fusion (my wife's car, whose dashboard displays I cordially dislike, but which makes her happy). No worries so far. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
Reply by ●February 10, 20182018-02-10
Steve Wilson wrote:> How do you measure ESR? >Drive it through a known load and measure voltage and current at energization, and the ESR will be in series with that and should be determinable with those instantaneous readings. Doing so with small, medium, and heavy loads would allow one to dial it in even more precisely.
Reply by ●February 10, 20182018-02-10
On Friday, February 9, 2018 at 2:29:37 PM UTC-8, Steve Wilson wrote:> 2. when the engine is running, the alternator quickly charges the battery > to capacity, then the charging current drops to near zero, in the tens of > milliamperes range. Modern engines start so quickly that very little energy > is needed to start the car.I agree if the voltage regulator settings allow it. The problem today is that new cars are often light on charging to reduce alternator load and increase fuel economy. My car is in that category and the highest alternator voltage I've seen after a cold start is 14.25 volts and that was on a cold day. As soon as the engine warms up the voltage drops to the range of 13.5-13.8 volts. I may only see ten minutes where the charge current would be adequate for charging the battery. Ten minutes appears to be fine if the battery is in good condition and near full charge. It's a different story with a discharged battery or a sulfated battery. I think others have stated that automotive charging systems today are not designed to recharge a discharged battery. I also wonder if there is a secondary problem with the temperature compensation typically used with voltage regulators. If I restart my car after a short trip, the engine is still warm and the alternator voltage may be 13.8 volts or less. The battery may still be relatively cool inside and need a higher alternator voltage to charge adequately.
Reply by ●February 10, 20182018-02-10
<oldschool@tubes.com> wrote in message news:82ou7dhs9kpj4laurck7fitir5rhjs3n32@4ax.com...> On Sat, 10 Feb 2018 20:18:31 GMT, Steve Wilson <no@spam.com> wrote: > >>My previous car was a Ford Taurus. It was designed to destroy the battery, > > A mechanic once told me. There are TWO four letter "F-Words". He allows > his children to say the first one, but not the word FORD. (Unless the > first four letter F-Word, precedes the word FORD). >Does it begin with F and end with U-C-K? Although that's a nine letter word, hmm. Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: https://www.seventransistorlabs.com/
