Hahahaha.

Also, yes, I put in a new battery after jazz band rehearsal (did I forget to mention that I'm a musician, too - irrelevant, to be sure). Right away, got the EPB calibration prompt. Reset all the memory stuff, and drove a couple miles home. Battery read 12.72v after shutting down. After knocking down the surface charge, it was 12.51v, so - a typical "new" battery.

After running a battery diagnostic and testing the charging system, the charging voltage came up to 13.8, but it was low - at 12.4v before that - don't know if that's relevant, but it's data. I like data.

I'm charging the battery right now. When it's charged, I'll rerun the tests, drive it around and measure the voltage again. If I get that ridiculous leak-down after turning off the engine, then I'll know it's a big quiescent drain eating my lunch.

Bad news, though, since I warranty-swapped the battery I got the same battery again from AutoZone. Hey, it was free to swap, so a completely rational test given a supposedly new battery. Later in the summer, assuming this battery is fine and holds out, I'll replace it with something more reputable, and relegate this one to UPS/standby power service.

More later, maybe even tonight.

Ken

 

I can be very persuasive. I went in with my data, and ready to even show them the video I took while driving to work the other day with the jumper run into the cabin. The guy didn't even put up a fight, offered a straight-across exchange. At least their customer service was good. My thinking is, "Hey, it's free. Since I'm still actually troubleshooting, being able to rule out the battery FOR FREE is awesome."

I'm going to start running OBD logs on my phone for every drive to monitor the voltage, if it's not evident that the new battery has fixed the problems.

How embarrassing would it be to be caught red-handed after a liquor store robbery because your emeffing EPB faulted and you couldn't move the car after re-starting? That's what you get for choosing an S-Type for your getaway car.

Ken

 

Because I'm a huge nerd, and I have lots of nerdy gear, I hooked up a battery pack to a Raspbery Pi, and a camera, and left it in my trunk streaming a live view of the charger. Don't have to take my delicate **** out into the rain to check how it's charging

 

And the verdict is?...

Kinda nervous since we haven't heard anything from you all day. Then I realized you were probably busy trying to get ahold of a sculptor to make a statue in my honor. Did you decide on marble or granite? Pros and cons for each, but both are good.

 

Busy day, but things are looking hopeful. Drove my son and his gf into Seattle to the Flight Museum. About the same drive as work.

Start:. 12.81v
Arrive:. 12.72v
4h later:. 12.68v
After short drive: 12.78v
After dinner: 12.62v
Arrive Home: 12.78v

Bypassed the EPB each time I stopped so I wouldn't have to hotwire it if it faulted. Battery is not on charger tonight, so we'll see in the morning.

Marble, for sure.

Ken

 

Not good news.

Start: 12.49v (EPB fault present)
Arrive/shutdown: 12.7v

Time for a more thorough quiescent drain test.

Sigh...

 

Okay, maybe not granite or marble, more like soap...

I've been thinking about the mythical 12.6v limit bandied about on the forum. My '02 doesn't have that pesky EPB, so I can't test my theory in person.

My hunch is the 12.6v itself isn't the fault/no fault determinant. Under the heavy load of the starter, it's perfectly normal for battery voltage to drop somewhat. Let's say 11.0v is normal with the starter engaged. (Making up numbers for illustration purposes.) The kind engineers at Jaguar factored in a reserve for the EPB system to power up normally, with down to 10.5v being satisfactory. Below that limit, you get the fault.

So let's say with a known good battery of proper capacity, if it can keep voltage above 10.5v under the load of the starter (no EPB fault), what would the unloaded, prestart voltage read? I'm thinking you should see at least 12.6v. Does that make any sense? My thoughts are the not-so-critical unloaded voltage is predictive of the critical loaded value.

However, this relationship between the two values could be dependent on the quality and condition of the battery. What if this relationship was reliant on a top quality battery? Perhaps the many successful examples in the forum were based on premium brand batteries. Maybe your WillItLast battery just isn't up to snuff. Remember, you never had this fault before installing a WillItLast battery. The newest replacement didn't fix it, either, but maybe that's because all you did was substitute a brand new mediocre battery in place of a year-old mediocre battery.

It's not going to hurt rerunning the quiescent drain test, but that still wouldn't explain the liquor store robbery scenario. Even with a fairly substantial drain (headlights left on, for example), that shouldn't cause so much trouble at restart only a few minutes later.

I also wonder if heat within the battery could be a factor. With the alternator charging away, the thin plates in a mediocre battery might warp or something like that. Meanwhile, a top quality battery might hold up better. That could help explain the liquor store robbery situation.

 

Here's an interesting data point: when shut off, the battery will drift down to 12.4-ish volts, and hang out there. I got home yesterday, shut down and measured voltage - 12.72v. About 4 hours later, I checked it again: 12.48v. I checked it this morning: 12.44v

Not sure what to make of that.

 

It's down to about 60% of charge.

 

Right. I find it interesting that, if there were some wort of quiescent drain, it apparently "shuts off" at some point and the battery voltage stabilizes and doesn't drop much afterward...

 

Anybody have any thoughts on my mediocre battery theory? Even if new, I've got to wonder if your Autozone special is simply not up to the job at hand.

 

Well, there is still a drain present that is out of the ordinary. I rigged a heavy-gauge jumper between Bat+ and the + battery clamp, and snaked it out the trunk so I could use my amp clamp and take readings:

Doors Locked: 2.7A
+ 5minutes: .82A
+10minutes: .79A
+15minutes: .78A
+20minutes: .77A
+25minutes: .77A
+30minutes: .06A (60mA)

From there it stays constant. So, in that first 25 minutes there is less than 1 amp draw. Yes, the 60mA quiescent current is too high (I've seen some literature that states 20mA is normal), but 60mA for 8 hours is only 480mAH. That's nothing, and the battery shouldn't even notice. Also, less than 1 Amp for 25 minutes should also be no big deal for a 95AH battery.

I went through the electrical system documentation (fantastic docs, BTW), and - based on some previous tests - have determined that I need to check the Primary Junction Fuse Box for drains. After disabling the trunk lights, the only drain I found was coming through F1, a big 40A fuse that feeds a bunch of stuff through the PJFB. My culprit will be found there. I also need to get a logic probe, since the working theory from the UK board is that degraded insulation on logic input wires in the presence of moisture and a nearby ground, can send those logic inputs to ground, keeping the module from going to sleep. Once I've figured out the module, I'll probably remove it and bench test it, then probe for ground faults.

However - BEFORE ANY OF THAT - I'm going to drop in a battery I have on hand. It's an Optima Yellowtop. Isn't quite the right size, but it should be up to the task for testing purposes. We'll see how the charging system does with this battery and whether it can hold the charge above 12.6v. I'll do that, probably, tomorrow evening.

Ken

 

How old is this battery? I'll be very interested to hear the results of this test.

 

Ken, my TheoryDuJour™ is you have two active faults, and they sort of overlap.

1) As you have already noted, a relatively small drain (under 1 amp) should have very little effect at restart on a good, fully charged battery within a short window, such as your valet or liquor store scenario. That is what makes me think your brand new Autozone battery just isn't up to the job.

2) You also seem to have a quiescent drain that would indeed do a number on your battery if the car sat for several days at a time, but that doesn't appear to really be the root cause FOR YOU based on your driving pattern. So yeah, find and fix the drain, but I'm still not sure that's going to take care of everything.

For measuring those small drains, did you see this method from another recent thread?:


https://www.jaguarforums.com/forum/s...2/#post1828594


It worked slicker than penguin snot on an iceberg, and didn't require any special access or breaking the circuit under test.

 

Yes, I use the voltage drop method. I didn't know about that video, but I have an electronics hobbyist background, so it seemed the natural thing The only difficulty with that is fooling the car into thinking the door/hood/trunk are all closed so that it'll eventually go to sleep so you can measure what you need to. I figured that out too. I was originally fooled into thinking there was very little draw because I didn't realize the Bat+ cable split right after the post terminal. Once I realized that - again, thanks to the electrical diagrams - I quickly homed in on F1 as being the feeder of the circuits which are "on". Fig.01.3 in the electrical diagram depicts everything that I will eventually need to test.

However...

At this point, I'm 97.2% sure that the battery is inadequate for my car. Before I go shell out $$$ on a battery, though, I'm going to swap in a known good battery and do a little static testing. If it a) accepts a charge, b) does so under heavy electrical load, c) and doesn't leak down like the current battery, then I'll know what my next step is. Finding the drain(s) has taken a backseat to proving categorically that the battery is or isn't a problem.

Ken

 

The amp readings you listed in post #72: Are those still valid, or did they not include the circuits powered after the cable split?

I don't know what "good" values are before the car goes to sleep, but under an amp within 5 minutes seems okay to me. The 60mA after 30 minutes is still high (30mA max), but that wouldn't even be part of the equation when restarted within a few minutes.

 

I rigged a long jumper that I connected between the battery and the + battery cable clamp. I ran that jumper out between the trunk seal and lid and back in, forming a loop which I can measure with the amp clamp. So, yes, I was measuring the entire current drain on the battery.

And, yes, 60mA should be meaningless even over the course of a workday. 480mAh is inconsequential.

In other news, my Jag-specific scan tool came in! I was able to pull codes from ALL the electronics modules. Guess what? Every module that does a voltage check had multiple Low Voltage or Low Battery Voltage errors set.

+1 for low power-up voltage.

Tomorrow, I swap in my test battery and find out for sure if the "WillItLast" battery is inadequate (HINT: It's inadequate, I'm just being scientific)

Ken
Test jumper

 

What scan tool did you get? I only have a generic scanner and am thinking of upgrading.

 

I think it was British Diagnostics Jaguar & Land Rover Diagnostics Equipment

 

No, I looked into IDS (and may still get one), but I bought a Foxwell NT510. I have other cars that have special diagnostics requirements, so it's nice to be able to swap out the software as needed.

Ken