@Unhappy Canadian  I haven't delved into diagnostics when it comes to batteries, but I suspect they would only really be able to check how the battery's current max charge retention compares to its max charge retention when it was new.  Those figures are reported separately by batteries and therefore give an indication of general wear.  But if those figures aren't very far apart, then I would once again wonder if there might be something specific to your Windows environment that is resulting in higher resource utilization and therefore faster battery drain -- which is why I suggested the clean install and controlled benchmark test earlier.

@jphughan  Thank you for such a quick reply!  I wasn't asking specifically about just battery diagnostics.  Maybe the battery is fine...actually that is our main worry, that the battery is fine, but that there is some other underlying issue which Dell does not want to deal with.

So, the question is really...and forgive me for not being very clear before...how reliable are the remote diagnostics in general?

Our computer was supposedly checked in toto...not just the battery...and they did not find anything.

Yet before, the old battery WAS bad, and they did not find anything wrong at that time as well.

So how can Dell assert so strongly that there is nothing wrong at all with our system, or even insist, despite everything, that even the old battery was good?

Can a battery be obviously bad (extremely swollen) and still give "excellent" figures for max charge retention?

And, if this battery health is the same excellent for both old and new batteries, why does the new one last twice as long (all things else being the same)?

While we have not yet tried the clean install...still a little bit hesitant about that...we have done the other things you suggested, such as removing the third party AV of Bitdefender and Malwarebytes, as well as other things.

Almost the only things left are what Dell provided us with.  The main added thing we use is the Firefox browser.

Thank you again for all your help.  ALL of your posts contain, if not definitive solutions, at least nuggets of wisdom that definitely add to our understanding and which very well may be helpful to us in the future!

@Unhappy Canadian  Happy to do what I can to help here, but unfortunately I can't speak to the quality of the remote diagnostics.  I've never used them because I'm an IT professional, and therefore I typically just run the local diagnostics on my own if Dell insists on making me do so before approving a part dispatch to address an issue.  But in fairness, I've never attempted to get a replacement for a suspected problematic battery, so I can't speak to that experience in general either.  Sorry!

@jphughan  Thank you nonetheless.  It was sort of a silly question anyways.  Of course no diagnostics, remote or otherwise are perfect.  Just because the Dell AR agent thinks that they are does not make it so.

Again, our worry is that something other than the battery is causing us problems...we do not want a second new battery.

If the remote diagnostics do not detect anything, that does not mean nothing is there.

Yes, perhaps the windows environment is at fault, but we have almost nothing on our system other than what Dell provided us.

Should customers have to do clean installs on Dell computers in order to get the promised performance?

That itself does not seem right.  I myself am very hesitant, though your instructions appear very simple...but what about those customers to whom this would be an impossibility?  

Dell claiming perfection for its remote diagnostics (or at least this from one person in AR) seems suspiciously as an excuse for Dell to minimize any further responsibility for their products.

Correct me if I am wrong, but there seems one relevant tidbit that I may have gleaned from your message.  Namely, that Dell much prefers their own diagnostic confirmation of some issue before approving any remedy.  Which means that denial of these issues may be the usual protocol in the absence of any such confirmation.  That may be good for their bottom line but extremely frustrating for those of us who may fall through the cracks.

Don't be sorry, we never thought you carried a magic wand!

@Unhappy Canadian  I didn't say everyone should be expected to perform a clean install to experience Dell's battery life claims.  But you've said you have "almost nothing" installed beyond the factory state.  The most important word in that sentence is...."almost".  It only takes one application -- or possibly one adverse interaction between multiple applications -- to trigger high resource consumption and therefore low battery life.  So while it's true that diagnostics can't identify everything, it is ALSO true that the software environment is a huge confounding variable in this scenario.  And therefore it's a variable that due diligence would demand ruling out.  For people who can't perform clean installs, Dell has factory restore tools, but I haven't used those myself either.

I also never said Dell claimed that their diagnostics were perfect or that they were the sole determining factor in whether a replacement is approved.  It is possible to get replacement parts even when diagnostics don't show anything -- as it sounds you've already found from your own personal experience.  But to look at this from Dell's side, would it make sense to continue approving hardware replacements despite lack of any diagnostics indicating a hardware problem AND before possible software causes of the undesired behavior have been conclusively ruled out?  I wouldn't think so.

@jphughan  Hi, I hope you did not take those things I said as representing your positions on the matter.  And your points are well taken.  Here is my response.

I really do understand your reasoning regarding the software environment.  Much of that environment, which the clean install would eliminate, are Dell products.  The rest are very common stuff.  Fairly minimal and I doubt very much some unusual combination which might cause an rare and adverse interaction.  

But granted, sure enough, this is a possibility, however remote.

But here are the things which make me suspicious and think there is something else involved, something for which Dell is likely responsible, and certainly something that Dell should not make it so difficult to determine.  

1.  The Dell diagnostics DID NOT identify the old bad battery as bad.  It WAS bad.  Unless a battery swollen to twice its original size can somehow be in "excellent" health.  It is confounding that Mr. Narenrdra R. of AR so stubbornly will not even admit this.

2.  And of course it wasn't you who claimed that the diagnostics were perfect, but rather that Mr. Narenrdra R. did so.  He has only repeated again and again that our system was performing "as per design", that the old bad battery was in fact good, and that he would be happy to sell us an extended warranty if we were worried about some other underlying condition that caused these problems in the first place.  Otherwise he has stated again and again that there was nothing else that they could do and that there was no way we could escalate this beyond his office.

3. And, by the way, we were never demanding "hardware replacements", certainly not before everything else had been ruled out.  When we got the replacement battery our expectation and hope was that everything would be fine.  Unfortunately it was not.  So, instead of working with us...like you have here, gratis!...to determine what was going on, they have shrugged their shoulders and basically told us to take a hike.  Messages and emails ignored, countless promises of callbacks never happen.  

4.  We are still very disturbed by the contrast between the "incredibly long battery life" which Dell promises and the uniform assertions from Dell Tech Support that 2 hours is "normal" battery life (20 - 30 minutes per cell, according to Mr. Narenrdra R.).  

If we have somehow inadvertently introduced into our system a malignant software environment that has severely shortened the battery life, why the necessity of so stubbornly insisting on this?

We have never received any answer to this, no matter how often and how directly we have asked.  Always there is some attempt at avoiding the question.  First the tech people claim ignorance of the promotions.  Then they claim the promotions are for some different computer, not the XPS 13.  Then they say it is for the XPS 13 but for some upgraded battery, not the 4-cell.  Then, when verified that a 4-cell is the only battery possible...well, maybe a callback from a supervisor or AR...which rarely, if ever happens, and never anything resolved, not just for our personal situation, but for why the contradicting claims.  Is it "incredibly long" or is it 2 hours? It cannot really be both.

Of course we understand the reasoning behind any protocols behind how customer's issues are handled.  But the customer should be treated as a valuable partner, not assumed to either some useless dummy or a potential scam artist.  We have now spent nearly two months and countless hours on this issue.  Less stubbornness and more flexibility on Dell's part could and should have resulted in a satisfactory resolution long ago.

As always, thank you for your attention, your care and your good will.  It is always, always appreciated.

@jphughan  Let me boil things down even more and get to the essence of our experience.

We have suffered issues which result in quite low battery life. We would like these issues addressed. But it seems that Dell does not even consider these issue are real, that we are just imagining things, because, for them, 2 hours battery life is "normal".

Yes, they have done some diagnostics.  I do not know how deep or comprehensive they were.  They have done updates and tweaks to the system.  Again, I am not able to judge how thorough these were.

But when our problems have persisted, all they say is that "2 hours is normal" and that our system is therefore working "as per design".

No one has suggested, not one, that we may have a software issue or proposed a clean install or anything else.

Even when confronted directly with the promises or boasts from Dell of "incredibly long battery life" they do all they can to avoid or redirect...it is for a different computer, a different battery...and so on.

And when there is no other excuse left, they promise a callback.

And then they don't.

No matter what side you look at this from, it cannot be right...

Perhaps I should ask you a practical question.  Aside from software interactions, what hardware issues might result in the low battery life we experience?  What tests should we make sure Dell technicians perform which may detect any of these issues?

We were always willing to work with Dell, we are not unreasonable.  We just feel that they should be just as willing and reasonable on their part.

Thanks again.  I know we must be trying your patience.  And it really should be Dell agents who show all the kindness, concern, and valuable assistance that you have so amply demonstrated here.

@Unhappy Canadian  I haven't encountered any hardware issues other than the battery itself that might cause severely shortened battery life, and thinking about it, I can't immediately think of a plausible hardware issue other than the battery that COULD cause that.  Sorry I can't offer any more than that here, and I do sympathize with the bizarre and frustrating experience you had with Dell Support, particularly given that it happened with ARS, which is normally quite good.  I've never been in a situation where they said something that was flatly implausible and completely at odds with Dell's marketing, and for them to say, "2 hours is normal, in spite of what we advertise" and NOT to suggest something being amiss with the software environment as a way to account for how their marketing and your individual experience could both be accurate is very uncharacteristic of them based on my experience.  That would have been the first thing I checked, even before replacing the battery itself if the diagnostics passed.  (Well, maybe I would have gone for a battery replacement as a goodwill gesture even if I didn't expect it to solve the issue, but after that I definitely would have wanted to rule out software variables by resetting to the factory default configuration.)

@Unhappy Canadian Unfortunately I don't have any back channel that would be useful in this particular case.  But if you have to continue pushing back against ARS in order to hopefully achieve something (as opposed to just on principle, which don't get me wrong would be quite understandable in your position!), then I would point out to them that multiple independent reviews of that system have also shown markedly better battery life.  Finding such reviews should not be difficult given that the XPS 13 is a very popular laptop due to having won "Laptop of the Year" from many publications for the last several years.  So even if ARS maintains that Dell simply doesn't believe in anything even remotely resembling "truth in advertising" when it comes to their own battery life claims, they would still then have to account for how so many reviewers have had such a different experience.  Good luck!