Charging System Service Now

[FordTechOne]

Well, the aftermarket brake light is disengaged while the top is up, so that is the same as being disconnected. It does not get energized/lit, so the system should not be aware of it, right? Maybe I will drop the top tomorrow to verify the LED brake light still functions properly.

How is the brake lamp wired up? I'm guessing you tapped into one of the factory circuits, perhaps with quick splices? addle: If so, the Body Control Module (BCM) will detect the circuit fault, which will cause it to set a lighting DTC (B-code). From there, things roll right down hill.

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[paul123]

How is the brake lamp wired up?

it appears that the Charge System message started happening after the battery got run all the way down, and then charged back up

 

[davekro]

Did you try disconnecting the battery for a few hours, then reconnect? Maybe something needs a hard reset.

yes, I did exactly this several days ago.No change.

OP, next stop, your nearest auto parts, or auto repair, and get the battery load tested under an engine start. Any weakness in the battery will show up as too much voltage drop.

Good suggestion. I'll put that on my 'to do' list. Thanks Paul.

How is the brake lamp wired up? I'm guessing you tapped into one of the factory circuits, perhaps with quick splices? addle: If so, the Body Control Module (BCM) will detect the circuit fault, which will cause it to set a lighting DTC (B-code). From there, things roll right down hill.

I do confess to being lazy and using the (normally avoided) quick splice clips.
In my defense of laziness ;) it was for an extremely low current draw LED not stereo amp. (but chastizement duly accepted non the less.

it appears that the Charge System message started happening after the battery got run all the way down, and then charged back up

This does seem the most salient point as to options for cause and effect. Now just need to take the time get down to Napa, AutoZone or O'Reilly's for a load test.

 

[davekro]

Mixed Load test results

For an accurate load test, some web sites say battery must be at full charge, some say 85% full is OK for load test. So I do not know if my battery was full enough for an accurate reading.

I went to three auto parts stores for a battery load test. Battery spec is 590 CC Amps, which all stores entered into their testers.
Napa result: Replace battery. (Tester showed only 493 CCA)
Autozone & O'reilly's both had the exact same tester (Napa had a different tester).
Result: OK, battery just needs a charge.
None of the testers showed voltage under load which needs to be above 9.6 volts to be OK.

I am fully charging (disconnected) battery now. Water levels were all above lead plates but a few were below the tube ends so I added distilled water to those cells. After fully charged, I'll wait 30 mins and note voltage. Then I'll wait more than 12 hours (tomorrow morning) and note disconnected battery's voltage. A desulfate cycle is probably in order, but I'll complete this baseline testing first including reconnecting the battery and leaving car alone a day or two and monitor if it loses significant charge.

Light on top of battery has looked all dull orange recently. Just after pulled off charger, it shows a small bright green and small bright orange light. The owners manual does not even list battery in contents or index. Only found a short ref to battery on pg 218.

Not sure, but I may have a faulty power seat switch. Inquiring about that in a separate thread.
http://www.mustang6g.com/forums/showthread.php?p=985214#post985214

 

[paul123]

they load test your battery during an engine start? That is maximum current pull, and maximum voltage drop.

I wouldn't mess around, just buy a new battery. $100

 

[GT Pony]

they load test your battery during an engine start? That is maximum current pull, and maximum voltage drop.

The battery load test machines put a heavy load on the battery like it was in the car starting the engine.

 

[paul123]

their testing may be valid, but it would require a heavy duty machine to sink that much current. Testing under engine start condition is better


you could get something like this if you want to experiment:

http://www.amazon.com/BA7-100-1200-Electronic-Battery-System/dp/B0015PI7A4/

 

[GT Pony]

their testing may be valid, but it would require a heavy duty machine to sink that much current. Testing under engine start condition is better.

I'd think the battery testers in the automotive parts stores put a pretty heavy load on the battery - probably much more than the starter does on the car. Not hard to absorb lots of current for a short duration.

See section 6, item 1 in the link below.
http://autorepair.about.com/library/weekly/aa101604c.htm

 

[davekro]

their testing may be valid, but it would require a heavy duty machine to sink that much current. Testing under engine start condition is better


you could get something like this if you want to experiment:

http://www.amazon.com/BA7-100-1200-Electronic-Battery-System/dp/B0015PI7A4/

Both load testers were a more commercial looking version of your link. My multi meter does not have a min/max but if I can borrow a friend's, I can see what the voltage drop for an actual start is. I read that if it drops below 9.6V, replace the battery. I'll do this test tomorrow hopefully. But before replacing a 9 month old battery (6,000 mi.), I really would like to find out what caused an early battery failure. (seat switch or other battery drain).

Before a new battery, which may only mask an issue, I will do a desulfate cycle to see if that makes: 1) the dash warning go away or 2) Napa's load tester to say battery OK.

 

[GT Pony]

For an accurate load test, some web sites say battery must be at full charge, some say 85% full is OK for load test. So I do not know if my battery was full enough for an accurate reading.

I went to three auto parts stores for a battery load test. Battery spec is 590 CC Amps, which all stores entered into their testers.
Napa result: Replace battery. (Tester showed only 493 CCA)
Autozone & O'reilly's both had the exact same tester (Napa had a different tester).
Result: OK, battery just needs a charge.
None of the testers showed voltage under load which needs to be above 9.6 volts to be OK.

Did you go have the tests done in the order listed above? Did you recharge the battery after each load test?

 

[davekro]

Did you go have the tests done in the order listed above? Did you recharge the battery after each load test?

I did not recharge after each load test.
1st test Autozone, Result: OK
Drove 1/3 mile to Napa Result: Replace battery.
Drove 1 mile to O'Reilly's Result: OK, but needs a charge.
Alternator was charging +/- 14.5 volts as driven, but not distances/time were very short between tests.

I'm guessing that for some reason, this battery is having a current draw more than normal (maybe intermittantly?). I would kind of like to know the batteries state of charge after sitting 12 hours + disconnected, but the impatience in my would like to start the ≈24 hour desulfate process now because I think I'll start the desulfate tomorrow anyway. :doh:

 

[GT Pony]

I'm guessing that for some reason, this battery is having a current draw more than normal (maybe intermittantly?).

When it's back in the car you could measure the current draw when the car is sitting with everything off. Most modern cars draw 20 milliamps or less when nothing is on and all computers have went to "sleep".

 

[paul123]

When it's back in the car you could measure the current draw when the car is sitting with everything off. Most modern cars draw 20 milliamps or less when nothing is on and all computers have went to "sleep".

^ this

I tested my console light. Turned it on, and returned to the car after 15 minutes, and it was off. So I think you have something else pulling the battery down. You should investigate that before buying a new battery.

 

[davekro]

When it's back in the car you could measure the current draw when the car is sitting with everything off. Most modern cars draw 20 milliamps or less when nothing is on and all computers have went to "sleep".

Good, my meter does have a 10 amp mode to start the 'sleeping car' parasitic draw test. What is the time it takes for all systems to be sure to be asleep? I'll be sure to keep the key fobs in tin foil so as to not wake the car. I'll need to find the door pin switch to manually keep closed if I need to go inside to pull fuses from passenger foot well box. I'll hook the meter in series between neg cable & neg batt terminal and see what amp draw I get. If > 20 - 50 ma, start pulling fuse looking for the offending circuit.

 

[FordTechOne]

Good, my meter does have a 10 amp mode to start the 'sleeping car' parasitic draw test. What is the time it takes for all systems to be sure to be asleep? I'll be sure to keep the key fobs in tin foil so as to not wake the car. I'll need to find the door pin switch to manually keep closed if I need to go inside to pull fuses from passenger foot well box. I'll hook the meter in series between neg cable & neg batt terminal and see what amp draw I get. If > 20 - 50 ma, start pulling fuse looking for the offending circuit.

Minimum of 40 minutes for all modules to be in a sleep state.

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