Automotive electronics - Honda charging system

Den onsdag den 19. juli 2017 kl. 03.51.06 UTC+2 skrev Jim Thompson:

unless of course result is that the ECU tells you that something is wrong with the charging and you to get to service

Unless you know what you are doing ;-) ...Jim Thompson

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| 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  | 
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That is wierd. What is the voltage with the headlights off?

Maybe the battery contacts have corroded. Have you cleaned them with a wire brush? I found that a thin coating of vaseline helps improve the connection and reduce corrosion from the sulphuric acid.

Den onsdag den 19. juli 2017 kl. 04.24.25 UTC+2 skrev Jim Thompson:

it is not the 80's

On Tuesday, July 18, 2017 at 7:29:34 PM UTC-7, Steve Wilson wrote: ..

re

on

I have a GM service manual describing the charging protocol and "Headlight mode" is one of the 6 voltage regulation modes where it will be regulated b etween 13.9 and 14.5v depending upon temperature.

There is also a "Battery Sulfation" mode where it regulates the voltage bet ween 13.9 and 15.5 for about 5 minutes if the battery has been below 13.2v for 30 minutes.

Battery recharging in modern cars is complicated by the fact that in the ef fort to reduce weight, cost and maintenance the battery can't tolerate the high sustained voltage that older flooded cell batteries could. If the vol tage is too high it will lose water and need topping up, which isn't easy w ith a maintenance-free battery or the thin grid will corrode excessively. T oo low and the effects that have been described here become noticeable - so its a compromise.

This page on Battery University describes the situation

. For maximum ba ttery life around 13.8v to 14.4 is recommended.

kevin

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 think the car will be fine if driven several times per week. As you may r ecall, the battery read 12.85 volts last week the morning after driving the car.

In thinking about the power supply test you mentioned, the narrow 0.1-0.2 v olt band where the current increased sharply will likely vary quite a bit d epending on the state of the battery.

If you repeated that test with your current battery at 12.2 volts, the band would be in the low 12 volt region initially and then rise as surface char ge builds up. If you had a fully charged battery plus a full surface charge , the band would likely be in the low to mid 14 volt range.

I see you have no experience tricking an ECU ?;-) ...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 & economic solutions.

Then you should never try having the hood latch ripping loose from the body, the left hinge pulling loose, the hood smashing the reservoir on the master cylinder, and damaging the carburetor so you can't slow down in afternoon rush hour traffic on I-75 in Cincinnati.

The hood twisted 180 degrees, and caught on the wiper post, so I couldn't see, I had no brakes, and the engine was running wide open.

The shuttle bus I used to ride from Ft. Greeley to Fairbanks back in the '70s went over the side of the mountain, a few weeks after I got out of the Army. Friends of mine were on it. The ended up in the hospital, but only because it was caught in some trees, rather than falling all the way to the ground.

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They don't get mad. 

They don't get even. 

They go for over unity! ;-)

Your method charging will put charge into the battery. However, it does not fully charge the battery, which means you won't get the performance and long life it could have.

The only way to fully charge the battery is to use saturation charging.

This charges at a constant current until the set voltage is reached, when it switches to constant voltage mode. The current then decays to almost zero. The charger is a cccv, for constnt current, constant voltage, and is the kind I use. My set point is 14.5V. As I have mentioned before, just a few tenths of a volt less that 14.5V means very little current flows into the battery and it will not do saturation charging.

You can read about it in the Battery University article, "BU-403: Charging Lead Acid", at

See figure 1.

There are a number of other articles on lead acid batteries listed that you may wish to read.

g

Thanks for the information on constant current, constant voltage and float charging. The section that really interested me was the discussion on the c hoice of cell voltage.

The range 2.30-2.35 volts per cell (13.8-14.1 volts) indicated maximum serv ice life. The range 2.40-2.45 volts per cell (14.4-14.7 volts) offered hig her 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 tha n adequately and result in longer service life.

The other issue is that the car alternator does not charge with constant cu rrent 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 bec ause 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 saturat ion charge described on the website, the specific gravity has risen to 1.29

5 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 c urrent but it will take longer.

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.

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.

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.

You want to keep the battery at full charge. This is mentioned in the Battery University articles.

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

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:

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.

The Black & Decker 2 amp charger/maintainer does charge at 2 amps as measur ed 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 v olts. I've seen the charge voltage drop and then rise which may be their me thod for detecting full charge. A portable radio placed near the charger in dicates 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 90

0 miles on the car. The accuracy of my INNOVA DVM is stated to be 0.8% whi ch could have a 12 volt reading off by 0.1 volts. My hydrometer is more th an 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 als o 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 clo se on all three.

Several online sites discuss an Equalizing Charge which can lengthen the li fe of a lead acid battery. That process could be a help when the charging s ystem does not keep a battery at full charge. An Equalizing Charge can reve rse stratification within the electrolyte and help remove sulfate crystals.

"Battery recharging in modern cars is complicated by the fact that in the e ffort to reduce weight, cost and maintenance the battery can't tolerate the high sustained voltage that older flooded cell batteries could. If the vo ltage 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 - s o it's a compromise."

Does this apply only to maintenance-free batteries? Many cars still have ba tteries with removable caps for adding distilled water.

My 2016 Toyota battery has removable caps and was manufactured by Johnson C ontrols. 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.

The chemistry is very similar.

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.

"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.

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.

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No, they haven't been needed in decades. Maybe they are, now, since the EPA is forcing such stupid rules.

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 con ditions 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 an d did add small amounts of water on a fairly infrequent basis. The batterie s generally lost more water during the summer months.

I had a feeling that my 2016 Toyota Battery was made by Johnson Controls ba sed 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.

I've been considering getting a Conductance Battery Tester and ran across a n exceptional video that I thought might be of interest. These devices inje ct an AC Current into the battery and do some analysis. You enter the CCA r ating of your battery and the device tells you the actual capacity.

Battery Clinic - Part 3

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 disc usses smart chargers and shows the results after using the recondition mode to remove sulfate deposits. One surprise is that several batteries measure d 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

Battery Clinic - Part 2

Battery Clinic - Part 4

Many other videos are available from the same shop. One set shows how to re place the battery in a late model Mercedes without losing computer memory.

Here is an update on my battery. I bought a Solar BA5 Conductance Tester wh ich 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 enti rely surprise me based on the high specific gravity and 12.85 V open circui t 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 curre ntly 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 co nstant current charge of 2 amps. The battery was close to full charge at th e start of the test.

You can see the battery voltage rise starting at 12.75 volts with the const ant current charge. The battery voltage levels off a little above 14.2 volt s. The battery is accumulating surface charge as the voltage rises which ef fectively 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 m entioned when connecting a power supply to a battery? The chart seems to su ggest 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 repre sent a very low impedance load so the current would rise sharply whenever t he power supply voltage exceeded the battery voltage plus surface charge an d the voltage drop across internal resistance.

Steve wanted a higher charge current so the voltage threshold would be high er 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 constan t 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.