On Wednesday, July 19, 2017 at 10:33:35 AM UTC-7, Steve Wilson wrote:> You can read about it in the Battery University article, "BU-403: Charging > Lead Acid".Thanks for the information on constant current, constant voltage and float charging. The section that really interested me was the discussion on the choice of cell voltage. The range 2.30-2.35 volts per cell (13.8-14.1 volts) indicated maximum service life. The range 2.40-2.45 volts per cell (14.4-14.7 volts) offered higher capacity and less sulfation but problems with temperature and the need to add water. This suggests that 13.8-14.1 volts should still charge the battery more than adequately and result in longer service life. The other issue is that the car alternator does not charge with constant current followed by constant voltage. In addition, it's not clear if a given charging system switches to the proper float voltage if the battery becomes fully charged. I connected my Black & Decker 2 amp charger/maintainer recently in part because the car had not been driven. It looks as though my battery loses about 3 Amp-Hours per week to parasitic current and self discharge. In reality, I should be able to go quite a long time if starting with a fully charged battery. Even though the charger/maintainer may not be doing the three phase saturation charge described on the website, the specific gravity has risen to 1.295 which is actually above the thresholds normally mentioned for full charge. I've heard that a lead-acid battery can still be fully charged at lower current but it will take longer.
Automotive electronics - Honda charging system
Started by ●December 7, 2016
Reply by ●July 20, 20172017-07-20
Reply by ●July 20, 20172017-07-20
kt77 <kawill70@gmail.com> wrote:> On Wednesday, July 19, 2017 at 10:33:35 AM UTC-7, Steve Wilson wrote:>> You can read about it in the Battery University article, "BU-403: >> Chargin g Lead Acid".> Thanks for the information on constant current, constant voltage and > float charging. The section that really interested me was the discussion > on the choice of cell voltage.> The range 2.30-2.35 volts per cell (13.8-14.1 volts) indicated maximum > service life. The range 2.40-2.45 volts per cell (14.4-14.7 volts) > offered higher capacity and less sulfation but problems with temperature > and the need to add water.The point is to charge at constant current until you reach the set point, then switch to constant voltage. The current will decay to near zero. This means very little temperature increase. For example, P = E * I = 14.5 * 0.05 = 0.725 Watt. That is negligible. When the curent is near zero, there is very little gassing and no need to add water. I checked the water level in the battery fairly often and never needed to add water. So there was little or no gassing. However, at lower voltages there is the risk of sulfation. This can destroy the battery's ability to accept a charge.> This suggests that 13.8-14.1 volts should still charge the battery more > than adequately and result in longer service life.I lost three batteries in a row at 13.8-14.1 volts due to sulfation. That cost $450, plus $500 to change the alternator. The new alternator did the same thing as the old one.> The other issue is that the car alternator does not charge with constant > current followed by constant voltage. In addition, it's not clear if a > given charging system switches to the proper float voltage if the > battery becomes fully charged.If you can fix the alternator voltage to 14.5V, the battery will quickly reach full charge and the current will drop to near zero. This means you can keep the battery at full charge even on short trips. I never bothered with changing the voltage to float voltage. Since the current was already near zero, there was little point.> I connected my Black & Decker 2 amp charger/maintainer recently in part > because the car had not been driven. It looks as though my battery loses > about 3 Amp-Hours per week to parasitic current and self discharge. In > reality, I should be able to go quite a long time if starting with a > fully charged battery.You want to keep the battery at full charge. This is mentioned in the Battery University articles.> Even though the charger/maintainer may not be doing the three phase > saturation charge described on the website, the specific gravity has > risen to 1.295 which is actually above the thresholds normally mentioned > for full charge. I've heard that a lead-acid battery can still be fully > charged at lower current but it will take longer.I am a bit surprised by your reading. I'd try to compare with a known accurate hydrometer. Your voltage reading seems high also. So there is something strange going on with your charger and battery. B&D gives very little information on the operation of their appliances. I'd get a simple multimeter and check the operation. Verify the charging current and the maintaining voltage. There is very little you can do to change the operation of the B&D, but you can get 15V, 3A supplies real cheap on eBay. Search for 15v 3a dc power supply. Here are two at US $3.98 http://cgi.ebay.com/282331589635 http://cgi.ebay.com/311796300225 All you have to do is find the voltage setting resistor and drop it to 14.5V. eBay also has conventional power supplies with variable voltage and current at higher prices. If you don't have one already, you can get an inexpensive dvm. The DT830 is an excellent unit. I usually buy 3 or 4 at a time. Here's one for US $2.83: http://cgi.ebay.com/292064771224 I really like saturation charging. It is quick, it brings the battery to a known full charge, and you can easily monitor the process to verify the condition of the battery. All we need to do now is command the alternator to put out the correct voltage and keep it there.
Reply by ●July 21, 20172017-07-21
On Thursday, July 20, 2017 at 3:19:21 PM UTC-7, Steve Wilson wrote:> Black & Decker gives very little information.The Black & Decker 2 amp charger/maintainer does charge at 2 amps as measured by my VOM. The voltage varies depending on state of charge and surface charge. After going into maintain mode, my DVM typically sees 13.60-13.68 volts. I've seen the charge voltage drop and then rise which may be their method for detecting full charge. A portable radio placed near the charger indicates that a switcher is in use. Black & Decker also sells a nice looking charger with meter which includes a battery recondition mode. My voltage and specific gravity readings do seem a bit high but may just be the upper end of normal. The battery is essentially new with less than 900 miles on the car. The accuracy of my INNOVA DVM is stated to be 0.8% which could have a 12 volt reading off by 0.1 volts. My hydrometer is more than 50 years old and readings with other batteries was typically 1.265-1.285 which is normal for full charge. Readings do vary with temperature and also electrolyte level. It turns out you can check a DVM against a fresh unused battery. Alkaline 1.58V, CR2032 Lithium 3.3V, Carbon Zinc Heavy Duty 1.62V. My DVM is very close on all three. Several online sites discuss an Equalizing Charge which can lengthen the life of a lead acid battery. That process could be a help when the charging system does not keep a battery at full charge. An Equalizing Charge can reverse stratification within the electrolyte and help remove sulfate crystals.
Reply by ●July 23, 20172017-07-23
On Tuesday, July 18, 2017 at 7:54:19 PM UTC-7, kevin93 wrote: "Battery recharging in modern cars is complicated by the fact that in the effort to reduce weight, cost and maintenance the battery can't tolerate the high sustained voltage that older flooded cell batteries could. If the voltage is too high it will lose water and need topping up, which isn't easy with a maintenance-free battery or the thin grid will corrode excessively. Too low and the effects that have been described here become noticeable - so it's a compromise." Does this apply only to maintenance-free batteries? Many cars still have batteries with removable caps for adding distilled water. My 2016 Toyota battery has removable caps and was manufactured by Johnson Controls. They have a very good reputation and supply batteries to Sears and several other brands. The Reserve Capacity marked on my battery is 125 minutes. I didn't realize it but you can calculate Amp-Hours by multiplying the Reserve Capacity by 0.4167 which in my case is 52 Amp-Hours.
Reply by ●July 23, 20172017-07-23
On Sun, 23 Jul 2017 13:58:49 -0700 (PDT), kt77 <kawill70@gmail.com> wrote:>On Tuesday, July 18, 2017 at 7:54:19 PM UTC-7, kevin93 wrote: > >"Battery recharging in modern cars is complicated by the fact that in the effort to reduce weight, cost and maintenance the battery can't tolerate the high sustained voltage that older flooded cell batteries could. If the voltage is too high it will lose water and need topping up, which isn't easy with a maintenance-free battery or the thin grid will corrode excessively. Too low and the effects that have been described here become noticeable - so it's a compromise." > >Does this apply only to maintenance-free batteries? Many cars still have batteries with removable caps for adding distilled water.The chemistry is very similar.>My 2016 Toyota battery has removable caps and was manufactured by Johnson Controls. They have a very good reputation and supply batteries to Sears and several other brands.I haven't seen one for years. Not one where the consumer is supposed to add water, anyway. Many have panels that can be pried off to add water but I haven't seen an automotive battery with real filler ports for decades.>The Reserve Capacity marked on my battery is 125 minutes. I didn't realize it but you can calculate Amp-Hours by multiplying the Reserve Capacity by 0.4167 which in my case is 52 Amp-Hours."Reserve capacity" is defined as the time the battery will deliver 25A so, of course AH can be derived from it. AH, at 25A, anyway. At another current, the numbers will be different.
Reply by ●July 24, 20172017-07-24
On 2017-07-23, krw@notreal.com <krw@notreal.com> wrote:> On Sun, 23 Jul 2017 13:58:49 -0700 (PDT), kt77 <kawill70@gmail.com> > wrote: > >>On Tuesday, July 18, 2017 at 7:54:19 PM UTC-7, kevin93 wrote: >> >>"Battery recharging in modern cars is complicated by the fact that in the effort to reduce weight, cost and maintenance the battery can't tolerate the high sustained voltage that older flooded cell batteries could. If the voltage is too high it will lose water and need topping up, which isn't easy with a maintenance-free battery or the thin grid will corrode excessively. Too low and the effects that have been described here become noticeable - so it's a compromise." >> >>Does this apply only to maintenance-free batteries? Many cars still have batteries with removable caps for adding distilled water. > > The chemistry is very similar. > >>My 2016 Toyota battery has removable caps and was manufactured by Johnson Controls. They have a very good reputation and supply batteries to Sears and several other brands. > > I haven't seen one for years. Not one where the consumer is supposed > to add water, anyway. Many have panels that can be pried off to add > water but I haven't seen an automotive battery with real filler ports > for decades.I guess the market in your area doesn't trust customers with handling "chemicals" responsibly. I've got two batteries here, an aftermarket Yuasa with integrated "Magic Eye" (tm) hydrometer, flush screw-in filler caps with "coin" slots, and a factory new battery (Suzuki) marked with an FB logo on one side, (possibly Furukawa Battery) it has a translucent case with fill level marked and knob-type filler caps, the label on the top has Japanese writing. -- This email has not been checked by half-arsed antivirus software
Reply by ●July 24, 20172017-07-24
On 24 Jul 2017 09:59:43 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:>On 2017-07-23, krw@notreal.com <krw@notreal.com> wrote: >> On Sun, 23 Jul 2017 13:58:49 -0700 (PDT), kt77 <kawill70@gmail.com> >> wrote: >> >>>On Tuesday, July 18, 2017 at 7:54:19 PM UTC-7, kevin93 wrote: >>> >>>"Battery recharging in modern cars is complicated by the fact that in the effort to reduce weight, cost and maintenance the battery can't tolerate the high sustained voltage that older flooded cell batteries could. If the voltage is too high it will lose water and need topping up, which isn't easy with a maintenance-free battery or the thin grid will corrode excessively. Too low and the effects that have been described here become noticeable - so it's a compromise." >>> >>>Does this apply only to maintenance-free batteries? Many cars still have batteries with removable caps for adding distilled water. >> >> The chemistry is very similar. >> >>>My 2016 Toyota battery has removable caps and was manufactured by Johnson Controls. They have a very good reputation and supply batteries to Sears and several other brands. >> >> I haven't seen one for years. Not one where the consumer is supposed >> to add water, anyway. Many have panels that can be pried off to add >> water but I haven't seen an automotive battery with real filler ports >> for decades. > >I guess the market in your area doesn't trust customers with handling >"chemicals" responsibly.No, they haven't been needed in decades. Maybe they are, now, since the EPA is forcing such stupid rules.>I've got two batteries here, an aftermarket Yuasa with integrated "Magic >Eye" (tm) hydrometer, flush screw-in filler caps with "coin" slots, >and a factory new battery (Suzuki) marked with an FB logo on one side, >(possibly Furukawa Battery) it has a translucent case with fill level >marked and knob-type filler caps, the label on the top has Japanese writing.
Reply by ●July 25, 20172017-07-25
The removable caps I mentioned are the three-wide vent caps that you see on many batteries. The Sears website shows those caps on quite a few Diehard batteries described as Maintenance Free. That suggests that water might not need to be added over the life of the battery if operated under normal conditions and not overcharged. In looking at the vent caps, I see a single slit that must be the vent for all three cells. My impression is that these caps trap at least some of the water vapor which eventually returns to the cells as water. I've had several Sears Diehard batteries with these three-wide vent caps and did add small amounts of water on a fairly infrequent basis. The batteries generally lost more water during the summer months. I had a feeling that my 2016 Toyota Battery was made by Johnson Controls based on the vent caps. They are the same vent caps I had on several Diehard batteries and also a NAPA Legend battery purchased fairly recently.
Reply by ●July 31, 20172017-07-31
I've been considering getting a Conductance Battery Tester and ran across an exceptional video that I thought might be of interest. These devices inject an AC Current into the battery and do some analysis. You enter the CCA rating of your battery and the device tells you the actual capacity. Battery Clinic - Part 3 https://www.youtube.com/watch?v=Oi8sUE9XCgA This video provides a wealth of information and also shows the use of a 100 amp load tester and hydrometer. The complete battery clinic consists of four videos. One of the videos discusses smart chargers and shows the results after using the recondition mode to remove sulfate deposits. One surprise is that several batteries measured over 13 volts presumably after dissipation of all surface charge. It was also mentioned that charging should be done at 7 amps or less. Battery Clinic - Part 1 https://www.youtube.com/watch?v=uqs0FCJpjXU Battery Clinic - Part 2 https://www.youtube.com/watch?v=KKSwwgY86D4 Battery Clinic - Part 4 https://www.youtube.com/watch?v=4PAyHIhK8g4 Many other videos are available from the same shop. One set shows how to replace the battery in a late model Mercedes without losing computer memory.
Reply by ●August 15, 20172017-08-15
Here is an update on my battery. I bought a Solar BA5 Conductance Tester which provides an estimated CCA rating. The tester is showing 655 CCA for my battery which is nominally rated at 582 CCA. The high reading does not entirely surprise me based on the high specific gravity and 12.85 V open circuit voltage. The battery is marked Toyota but made by Johnson Controls which is the supplier for Diehard and Interstate. The mileage on the car is currently less than 900 miles. I'd be interested if anyone else has tried one of these Conductance Testers. I'm also attaching a chart showing my battery voltage versus time with a constant current charge of 2 amps. The battery was close to full charge at the start of the test. https://postimg.org/image/p50uhjdwz/ You can see the battery voltage rise starting at 12.75 volts with the constant current charge. The battery voltage levels off a little above 14.2 volts. The battery is accumulating surface charge as the voltage rises which effectively increases the battery voltage. When the charger is disconnected, the voltage starts declining from the same elevated voltage and takes many hours to fully dissipate the surface charge. Is this chart actually showing the sharp voltage threshold that Steve has mentioned when connecting a power supply to a battery? The chart seems to suggest that I would need a little over 14.2 volts if I wanted to charge at 2 amps after surface charge has reached equilibrium. The battery would represent a very low impedance load so the current would rise sharply whenever the power supply voltage exceeded the battery voltage plus surface charge and the voltage drop across internal resistance. Steve wanted a higher charge current so the voltage threshold would be higher for that case and is apparently around 14.5 volts. I believe the situation is different before the surface charge has reached equilibrium. In a vehicle, the battery is charged with a relatively constant voltage so the charge current would vary quite a bit. The charge current would likely be the highest right after starting the engine with no surface charge on the battery plates. Note that if the charger had been constant voltage, the current would have declined as surface charge built up on the battery plates.
