Peabody says... > Basically, my understanding is that a lead-acid battery > is fully charged at about 12.6-12.7V, and that's what > the computer should keep it at. You can get by with > less, but at the cost of shorter battery life. But to > keep the battery at 12.6V, the voltage regulator should > NEVER go below 13.0-13.2V, and immediately after > starting the engine it should go to 14.4V for several > minutes at least to recharge the battery. As of now, > the only way I know to at least get that is to turn on > the headlights. Oddly, turning on the AC does not do > that. I just wanted to report that I was able to get my Honda dealer to do the service bulletin 12-041 flash update that's supposed to fix this problem for the 2012 Civic. That will be done tomorrow. But I suspect that allowing the battery to be less than fully charged, without doing anything about it, is a deliberate Honda practice on all their cars to keep mileage up. If I understand how a battery and battery sulfation works, there's no reason to ever have the alternator putting out 12.4V, which my Honda does most of the time. That would let the battery drop to 12.0-12.2V, which is roughly 50% charged, not fully charged. And at that level it will sulfate up and die much more quickly than if kept fully charged. So I suspect I'm still going to have to drive with the lights on after the SB is applied. But maybe it will help some. My voltmeter will tell the tale. However, if keeping the battery at 50% does not cause sulfation, then I'm wrong, and Honda is right. But everything I read says that's bad for the battery, and it should be kept at 12.6V which is near 100%. If anyone knows for sure about this, please post here.
Automotive electronics - Honda charging system
Started by ●December 7, 2016
Reply by ●July 5, 20172017-07-05
Reply by ●July 5, 20172017-07-05
On Wed, 5 Jul 2017 05:11:15 -0700 (PDT), pcdhobbs@gmail.com wrote:>>How does that help? �The voltage regulator is in charge of things. > >It is, assuming there's enough alternator output for it to be in regulation. Sounds like that's likely the problem. > >Cheers > >Phil Hobbs(Personally I'd cobble up my own regulator ;-) US 'CAFE' fuel economy standards are forcing car manufacturers into Rube Goldberg 'solutions'... Recently was provided a 'loaner' of a new Infiniti Q50 while my ancient, 'real car' (12 year old) Q45 was in for service. This Q50 had only a 2L 4-banger engine (provided by Mercedes no less). At each traffic light the engine is STOPPED with a jerk, then restarted... feels like a diesel start (compressed air ?) :-( What a disconcerting piece of crap! (I informed the dealer I wouldn't be buying any Infiniti product until they came back to providing a honking V-8 again, like my Q45. He sighed, said he agreed.) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I'm looking for work... see my website. Thinking outside the box... producing elegant solutions.
Reply by ●July 5, 20172017-07-05
On Wed, 05 Jul 2017 10:48:10 -0500, Peabody <waybackNO584SPAM44@yahoo.com> wrote:>Peabody says... > > > Basically, my understanding is that a lead-acid battery > > is fully charged at about 12.6-12.7V, and that's what > > the computer should keep it at. You can get by with > > less, but at the cost of shorter battery life. But to > > keep the battery at 12.6V, the voltage regulator should > > NEVER go below 13.0-13.2V, and immediately after > > starting the engine it should go to 14.4V for several > > minutes at least to recharge the battery. As of now, > > the only way I know to at least get that is to turn on > > the headlights. Oddly, turning on the AC does not do > > that. > >I just wanted to report that I was able to get my Honda >dealer to do the service bulletin 12-041 flash update that's >supposed to fix this problem for the 2012 Civic. That will >be done tomorrow. > >But I suspect that allowing the battery to be less than >fully charged, without doing anything about it, is a >deliberate Honda practice on all their cars to keep mileage >up. If I understand how a battery and battery sulfation >works, there's no reason to ever have the alternator putting >out 12.4V, which my Honda does most of the time. That would >let the battery drop to 12.0-12.2V, which is roughly 50% >charged, not fully charged. And at that level it will >sulfate up and die much more quickly than if kept fully >charged. So I suspect I'm still going to have to drive with >the lights on after the SB is applied. But maybe it will >help some. My voltmeter will tell the tale. > >However, if keeping the battery at 50% does not cause >sulfation, then I'm wrong, and Honda is right. But >everything I read says that's bad for the battery, and it >should be kept at 12.6V which is near 100%. If anyone knows >for sure about this, please post here. >There's a 'little' TC issue that must be met to ensure proper charge... <http://www.analog-innovations.com/SED/AlternatorRegulatorTC.pdf> Also see my patents about alternator regulators. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I'm looking for work... see my website. Thinking outside the box... producing elegant solutions.
Reply by ●July 5, 20172017-07-05
Jim Thompson says... > There's a 'little' TC issue that must be met to ensure > proper charge... > <http://www.analog-innovations.com/SED/AlternatorRegulat orTC.pdf> Thanks very much. Well I don't see anything on your graphs anywhere near Honda's 12.4V. It looks like you have an absolute minimum of 13V even at high temps. And I suspect if my Honda followed that, there would be no problem. Charging voltage aside, is the "off" voltage of a fully charged battery also temperature dependent - assuming you give it time to settle? So would the 12.6V I've been using as a fully-charged voltage be lower at higher temps? Is there a graph for that?
Reply by ●July 5, 20172017-07-05
Thanks Peabody and all others for your comments. My problem with the 2016 Camry was probably the result of driving the car only once every week or two without any long trips. That assumes that the voltage regulator has been working as intended. The charging system might have been designed assuming several trips per week and a mix of short and long trips. The parasitic current drain likely becomes a factor with infrequent use. If the parasitic current drain was 0.02 Amps, you would have 14.4 Amp Hours per month. A fully charged battery in new condition could be as low as 42 Amp Hours. The voltage monitor does sound like an excellent idea. Using the accessory socket, the voltage reading could be a little low in some cars depending on the wiring. Other loads could increase the E=IR voltage drop. The Toyota Manual includes a table showing battery voltage at different charge levels. The table shows 12.6 to 12.8 volts for Full Charge, 12.2 to 12.4 volts for Half Charge, and 11.8 to 12.0 Volts for Discharged. Those values assume 68 degrees F and engine off for at least 20 minutes to remove surface charge. Personally, I think you have to wait quite a bit longer than 20 minutes. The Toyota Manual also mentions that charge current is 5 Amps maximum. I wonder if that is a design goal under high electrical load at a specified engine RPM. I've also heard mention of a headlight test with the engine off. After one minute, the voltage should be above 12 volts. My battery also passes that test with the high beams turned on. I checked the specific gravity of my battery one more time and was surprised that it now reads 1.295. That is apparently about as high as it can get. The Black & Decker 2A Charger/Maintainer continues to charge the battery very slowly even at the float voltage of 13.68 volts. It appears that one deep discharge did not damage the battery.
Reply by ●July 5, 20172017-07-05
kt77 says... > My problem with the 2016 Camry was probably the result > of driving the car only once every week or two without > any long trips. That assumes that the voltage regulator > has been working as intended. The charging system might > have been designed assuming several trips per week and a > mix of short and long trips. I have a similar problem in that my gym is .75 miles from my house. That's not really far enough to recharge the battery, even if the regulator is at 14.4V. So if I do too many of those trips, with no longer ones in between, then I'm going to have to use the charger to bring it back up. I've never had a good feel for how long it actually takes to recharge fully after one engine start if the alternator is at max. My Civic starts very easily, so I wonder if it needs more than maybe 15 minutes to recoup. Could even be less I guess. > The voltage monitor does sound like an excellent idea. > Using the accessory socket, the voltage reading could be > a little low in some cars depending on the wiring. Other > loads could increase the E=IR voltage drop. Yes, I'd recommend you get one (Ebay - $10 or less), if for no other reason than you'll never have to wonder what's going on. And it might even surprise you. The supply to that socket goes through the ignition switch, but other than that I don't think there's much to alter the readings. It's going to be wired pretty strongly because of what it's supposed to be able to do. My monitor reads 14.4V with the headlights on, and that's right on spec. And the monitor itself is digital, and doesn't draw any significant current.
Reply by ●July 5, 20172017-07-05
On Wednesday, July 5, 2017 at 1:49:29 PM UTC-7, Peabody wrote:> I've never had a good feel for how long it actually takes to > recharge fully after one engine start if the alternator is > at max. My Civic starts very easily, so I wonder if it > needs more than maybe 15 minutes to recoup. Could even be > less I guess.I've also thought about the charge lost in starting. My car starts in a second or less in the summer, so I estimate that to be no more than 200 Amp Seconds. A 42 Amp Hour battery would equate to 151200 Amp Seconds although you would have to derate that value when discharging at high current. If I'm doing the calculation correctly a single start might consume less than 1% of battery capacity at full charge. It sounds as though your wiring is fine. I'll probably try turning the fan on high to see if the voltage reading changes. Right now I'm considering the INNOVA 3721 Battery and Charging System Monitor available on Amazon. I just measured my battery voltage 20 hours after disconnecting the charger/maintainer and it read 12.82 volts.
Reply by ●July 5, 20172017-07-05
On Wed, 05 Jul 2017 13:05:46 -0500, Peabody <waybackNO584SPAM44@yahoo.com> wrote:>Jim Thompson says... > > > There's a 'little' TC issue that must be met to ensure > > proper charge... > > > <http://www.analog-innovations.com/SED/AlternatorRegulat >orTC.pdf> > >Thanks very much. Well I don't see anything on your graphs >anywhere near Honda's 12.4V. It looks like you have an >absolute minimum of 13V even at high temps. And I suspect >if my Honda followed that, there would be no problem. > >Charging voltage aside, is the "off" voltage of a fully >charged battery also temperature dependent - assuming you >give it time to settle? So would the 12.6V I've been using >as a fully-charged voltage be lower at higher temps? >Is there a graph for that? >I've never actually measured that. The graphs show the drive voltage necessary to supply current TO the battery, so I suspect, but don't know absolutely that the battery should show voltage equivalent to that IF at the proper temperature. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I'm looking for work... see my website. Thinking outside the box... producing elegant solutions.
Reply by ●July 5, 20172017-07-05
On Wed, 5 Jul 2017 05:11:15 -0700 (PDT), pcdhobbs@gmail.com wrote:>>How does that help? �The voltage regulator is in charge of things. > >It is, assuming there's enough alternator output for it to be in regulation. Sounds like that's likely the problem.Doesn't to me. It seems the charging system is trying to be too cute to save .001MPG.
Reply by ●July 6, 20172017-07-06
Here is some information on adjusting battery charge voltage relative to temperature. http://www.trojanbattery.com/Tech-Support/FAQ/Temperature.aspx "For every 10 degrees above 80F, subtract .028 volt per cell from the charger voltage setting." "Example: A 12 volt battery at 90F. The recommended charging voltage (at 80F) is 14.60 volts. The adjusted charging voltage is 14.60 - (6 cells x .028vpc) = 14.43 volts." The next link mentions 12.4 volts as a key level to maintain battery life. https://www.optimabatteries.com/en-us/experience/2010/12/what-normal-parasitic-draw "The key to long life for any battery is to make sure battery voltage doesn't drop below 12.4 volts. The combination of a significant parasitic draw and long periods of non-use can easily cause voltage to drop below 12.4 volts. When that happens, sulfation begins to diminish both capacity and performance. That is why vehicles that only see weekend or occasional use (this includes boat owners) should have their batteries maintained with a quality battery tender or maintainer."
