Service of the Jaguar Battery By Ronald Miller
EDITOR'S NOTE: Here is a small portion of a very detailed and exhaustively researched article on proper battery maintenance. I urge you to go to Ron Miller's site for the entire article, http://www.gearloose.com/jagbat.html, Mr. Miller has given us permission to use this article in our newsletter.
A note from the author, Ron Miller:
I admit that I'm a nut about maintenance. Maybe because, as a Navy Fighter Pilot for a full 30 year career, maintenance was what kept us alive. Did you see the movie "Top Gun?" I was the maintenance officer for the F4 Fleet Support squadron there. I had 60 aircraft, 600 men and 15 officers under me. I did all the "test" flights after major maintenance as well as giving F4 flight instruction.
Be sure to tell them that battery care is not as complicated as they will think at first glance. Boiled down it's: 1) Know YOUR battery's parameters using YOUR test gear. 2) Bring it back up to THOSE specs every month using a SMALL charger. 3) Get a new one BEFORE the old one fails.
THE COMPLETE JAGUAR BATTERY CARE PROGRAM
Updated December 22, 199
I am 67 years old. For some 56 of those years, I have been "into" batteries, and thought I knew just about all there was to know about them. Then, in 1995, I bought a 1992 Jaguar XJ-40 that was, and is, in mint condition. It is "Silver" with blue leather interior.
When I looked into the "owner’s packet," I found a large card stating: "CAUTION: To prevent a dead battery, disconnect prior to leaving the vehicle parked for extended periods. (2 to 3 weeks, depending on the state of charge at the time the vehicle is left)"
I said: "Whoa! That’s a pretty short time, and they’re talking DEAD battery!"
Then I read the "Owner’s Manual" and found the following three interesting statements:
First, "The service life of the battery is also dependent on its condition of charge."
Second, "It must always be sufficiently charged for the battery to last an optimum length of time."
Third, "Therefore, we recommend that the battery charge is checked frequently if the vehicle is used mostly for short distance trips, or if it is not used for long periods of time."
Then, when reading the technical information about the new XJ-8, I found this intriguing statement:
"Multiplexed electronics system modules have a "sleep" mode to
reduce battery drain."
AND, then I came across a Service Bulletin from Jaguar to it’s dealers warning them about customer problems from selling cars with undercharged batteries and explaining the need for frequent charges to keep them in shape.
SHAZAM! Said I, hand hitting forehead. That’s the reason I see so many "battery" problems on the JagLovers net.
OK, so what to do? Well, first, devise a "plan" that will neutralize this built-in problem, and, second, write it up so others can see what to do and why they should do it. So, here we go!
This paper is based on three premises:
First that there is absolutely nothing good about a poor battery. The basis for our car’s entire existence is electrical, and a failure may place us in physical and/or financial danger. Murphy’s Law will dictate that the failure will happen at the worst possible place. It may cost a tow or a meeting missed, and a new battery purchased on the road may well cost twice what it should IF one can be found. If we choose to "Jump" the battery, we place both our alternator and on-board computers in jeopardy. In short, living with a "bum" battery is risking a disaster.
Second, that the XJ-40 on-board electronic system can be pretty tough on batteries.
And, third, that we can, with just a little bit of intelligent effort, stay ahead of the Cat, and ensure that we NEVER (well, almost never) suffer a battery problem.
Equipment needed:
- Battery hydrometer (NA for sealed battery)
- Hand-held digital voltmeter
- Small (1/2 to one amp) non-automatic charger
DETAILS
(In the beginning - new battery, new car, or beginning this maintenance plan with an old one)
I. With the Battery on the bench - (if possible, in car less desirable)
A) Wash the battery case with soda water (teaspoon of baking soda in a glass of warm water), then rinse it and let it dry
B) Clean the battery terminals (bright and shiny clean!)
C) Document the characteristics of THIS battery
1) Charge slowly (2 amps max) until both voltage and specific gravity (SG) stabilize. (This could take several days)
Note: I am responsible for four batteries.
Their final, stabilized voltage on my ½ amp charger is 15.32, 15.38, 15.46 and 15.99. As you see, each one is unique.
2) Record the above values two ways:
On charge - A) Specific Gravity_________
B) Voltage________ Off charge - (a day or so later) - Voltage________(SG will be the same)
Note: This initial charging is absolutely vital to ensure that your battery gets started right.
I have confirmed that "new" batteries have been on the shelf for up to 6 months, may be more than half discharged, AND already sulfated.
In June, 1998, I found this battery condition in my Sister’s brand new SUV.
In November, 1999, I checked at least ten batteries at each of three stores and found: none fully charged, most between ¾ and ½ charged and one dead.
II. Install the battery in the car
A) Dip the cable ends in soda water to neutralize any acid on them, dry, make the connecting surfaces bright and shiny, then cover them with a light coating of non-metallic grease (Vaseline is fine). Connect the positive (+) cable first, then the negative (-) cable.
B) Calibrate the in-dash voltmeter by comparing with simultaneous readings at the battery with the digital voltmeter. Note and record any difference as a constant.
III. Test the battery/ alternator combination -
A) Start the car, wait until the voltmeter reaches it’s highest value, then, with the digital voltmeter, record the voltage at the battery_______. This is setting of the voltage regulator in your car. (It will be between 13.8 and 14.8, and is not adjustable)
B) Using the in-car voltmeter, test the load-carrying capacity of your alternator (so that later, you will be able to tell if something is going wrong)
1) After step A) above, note the voltage with the engine running slightly above idle (1,000 RPM is enough) and with all loads off.
2) Drop engine speed to idle and place transmission in a drive gear so the RPM is pulled down to 550-600 RPM. (The voltage should not change)
3) Turn on electrical loads one-at-a-time and observe the voltage change. (Add radio, headlights, low beam, high beam, heater blower to high, then rear window defroster) (The voltage will drop slightly as each load is added, but should stay above 13 until the rear window defroster is turned on - then it will probably slowly move down to near "battery" voltage - below 13)
4) Increase the engine speed (1,000 +-) and observe that the voltage rises to above 13.
5) Turn off the power consumers. Note: If the values on this first test are not close to the above, you may have a problem even now.
Several things should be noted about this test.
First, it shows that even a perfect alternator cannot carry the full load with the engine at a slow idle - so it is possible for the battery to be discharged while the engine is running.
Second, it’s normal for system voltage to go down when carrying a load.
Third, it shows you how your system operates when it is in good condition.
If you develop a system defect, such as a slipping belt or a failed diode in the alternator, the voltage will drop under a much smaller load, thereby alerting you to the problem - BUT ONLY IF you are paying attention.
Recently a friend called me after stalling away from home. I asked what her voltmeter was reading, and found that she didn’t know she had one, or what it should read.
The alternator had failed!
IV. Daily (See Para # IX)
1) Turn the key to "on" and note the voltage reading (light-load battery voltage)
2) Note the voltage reading while the starter is cranking the engine (Heavy-load battery voltage - if lower than usual it’s a sure sign of a battery problem)
3) Note the voltage rise after the engine starts (regulated, alternator produced voltage)
4) Occasionally check the voltage value. From it’s high, it will drop from .5 to 1.0 volts as the under-hood temp rises.
5) Check the voltage frequently as you drive. If it drops to or below "battery voltage" -- the number you had at step #1 above, you have had an alternator failure.
Here is where a "good" battery pays off -- turn off all power consumers, and it will carry you to safety.
A "bad" battery might stall you almost immediately.
V. Monthly (This procedure is your BEST ASSURANCE of maintaining a good battery)
1) Test the battery’s "Off charge" SG and/or voltage.
2) If not very close to the original values, charge slowly (with the same little charger as before) until the SG equals the original value and the "on charge" voltage peaks and stabilizes.
(But charge at least overnight once every month)
3) Check to see that corrosion is not appearing on the connectors, and that the battery top does not look "wet" (acid).
If "Yes" on either, correct it.
VI. Occasionally
1) Do the alternator "proof test" (para # III. B) to ensure that the charging system is healthy.
VII. Annually (In addition to the regular monthly service)
1) Check electrolyte level and carefully (with the hydrometer) add distilled water as needed. It should take only a small (1/3 hydrometer per cell) amount.
Do not "fill" the cells. High water usage is a major warning sign of trouble.
2) Unless the battery top appears totally dry, wipe it with a cloth dipped in the soda/water solution. If the area "fizzes," it had acid on it. (Acid will speed the loss of charge.)
3) Remove and clean (shiny) the connectors and renew the light coating of non-metallic grease. (Check radio security code and frequencies first)
VIII. When the battery reaches its "guaranteed life"
1) Watch for battery sales and BUY A NEW ONE (Remember - buy the best)
2) Bring the battery home and start "The Plan" over again. (Para I A) above )
It is likely that the specifics on the new battery will be somewhat different than for the old one.
3) Put the old one on the shelf and give it regular maintenance - just as if it was in the car.
4) Use this battery as a loaner, as a spare, or as the trade-in next time. (I take mine with me if I’m going out in the remote backwoods - just in case)
IX:. NORMAL OPERATION
Beginning with a good battery that is fully charged, the normal sequence of daily electrical events is:
A) Key on - ignition, brake boost pressure pump, heater fan and interior lights are all operating. The load on the battery will be less than 25 amps, so the voltage will be pulled down slightly from the basic "no load" value. (Which is about 12.8 when fully charged)
B) Cranking engine - in addition to the above loads, the starter will require some 200 to 300 amps, so the battery voltage will drop to the 9 to 10V range.
C) When the engine starts, the alternator begins to generate power. The voltage regulator will sense that the system voltage is down because of the power used in the starting operation, and produce a high amperage output. The voltage will quickly move up to a position just below the "running" voltage, then, in a matter of seconds, when the lost power is restored to the battery, the voltage will move up to it’s highest value.
D) As radio and lights are turned on, the voltage will drop ever so slightly as the alternator picks up this additional load.
E) Later, as you drive, the under-hood temperature rises, and the voltage will move down a small amount - between 0.5 and 1.0 volt.
GENERAL INFORMATION ABOUT BATTERIES
a) All brands of batteries are not alike in their characteristics. They vary by voltage, by ease of charge, by resistance to sulfation, by length of life, by capacity, etc.
b) Batteries can fail due to internal defects, but do so only rarely.
c) Properly cared for, every battery without said defects, CAN provide excellent service well beyond it’s guaranteed life, but that is truly "borrowing time," - not recommended.
d) There is never a "good" time for a battery to fail.
e) The modern battery/alternator setup is well engineered. Keep it at "spec" and it will serve you well
f) Batteries and electrical systems as a whole are not well understood by either mechanics or owners.
ADVICE ABOUT BATTERIES
p) The cost of a battery is pocket change compared to the cost of a failure at the wrong time. Batteries are cheaper now than at any time in the history of the automobile - well under a dollar per guaranteed month.
q) A new battery should always be slow-charged until it tests 100% full charge.
r) A battery that is discharged by accident (such as leaving the lights on) should be brought back to full charge with a battery charger.
DO NOT ask the alternator do it.
s) The difference in voltage between a fully charged battery and a fully discharged one is less than one volt. Therefore, only use a sensitive digital voltmeter to check voltage.
t) Always buy the BEST (big capacity and long guarantee) battery that will fit the car.
u) Given the choice, always buy a non-sealed battery. (Because you cannot test the electrolyte on a sealed battery)
v) Any water added to a battery cell should be distilled, de-ionized or rain water collected with non-metallic equipment.
DEAD BATTERY, BUT NOTHING WRONG!
During that "Mother of all snow storms" back in December of 1990, quite a few cars stalled in traffic because their batteries went dead. Ever wonder how a battery can go dead while the car is being driven?
Shouldn’t the alternator not only carry the electrical load, but recharge the battery as well?
The answer is "Yes, but."
"But" the alternator must be "sound," and it must be turned fast enough to carry the load. During that storm, drivers created a condition that we rarely see - prolonged idling with an unusually heavy electrical load.
Think about it! You are stopped in traffic, the engine is idling, the transmission is in "drive" your lights, heater fan and radio are on. Guess what? Unless your engine idle setting is on the high side, your alternator is producing less power than you are using, and you are discharging your battery.
Do it over a prolonged period, add a less-than-perfect (sulfated) battery, and she goes belly-up.
OK, so how to make sure it does not happen to you, and, how will you know it is happening?
Well, when you first get into your truck in the morning, turn the key to "On." (Don’t start the engine and be sure the lights, fan, radio, etc., are off). Look at the reading on the voltmeter gauge. That is your "no load" battery voltage. Any time the engine is running, the voltmeter MUST show a higher reading than
that, or the battery is being discharged, and you are heading for a breakdown.
So, if you find yourself in the situation described above, you can do one of two things.
First, you can raise the output of the alternator by increasing the engine speed slightly - usually just putting the transmission in "N" is enough.
Second, you can reduce the load on the alternator by switching to parking lights or a lower heater fan setting - but get that voltmeter up.
There are two mechanical problems that can only make things worse.
First, the alternator drive pulley is small, and, when under load, the alternator requires several horsepower to drive it.
Therefore, alternator drive belt tension must be just right, or it will slip, and that’s a sure fire recipe for trouble. (The new flat belts work better.)
Second, it is possible that the failure of a diode in the alternator will cut it’s output in half. You’ll never know it if you drive only in the daytime, but you won’t get far at night.
To test for these two problems, with the engine idling, turn the headlights on high beam, and set the heater fan to high speed.
Watch that voltmeter. If the alternator is good and the belt is tight, the voltage will stay up in it’s normal range.
MY BATTERY CHARACTERISTICS - January, 1998 (examples only)
Battery ___ Spec Grav (adj) Volts (@.5 amp) Volts (no)__Auto
Time
JAGUAR 1.270 15.38 12.71 14S
BIG BLUE 1.270 15.32 12.79 12S
DELCO Sealed 15.99 12.91 14S
WV VAN (NEW) 1.289 15.46 12.85 16S
BATTERY "A" 1.280 14.02 12.72 9S
BATTERY "B" 1.280 14.03 12.65 7S
- Voltage for full charge NOT on the charger
- Time in seconds between charging flashes on the automatic charger Note: Batteries "A and "B are deep-cycle batteries
(C) 2000 Richard Miller
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