New Battery Capacity Question

Hi oldturkey03 and thank you.

First of all, I appreciate your reply.

I just added 2 more pictures because when I initially installed the battery it was as stated, low and a few days later it showed both capacity and ability to hold the charge at 76000 however, within a couple days the charge capacity went down to 72109 where is has remained.

When looking at the pictures I just uploaded you will see this and the last was 8-14 however, this block of data points does not show on the initial report I posted. This too seemed odd to me because you can see the dates on both sides of it.

Regarding the BIOS, I do not have is set for a reduced full charge capacity as I do on other laptops because I wanted to see it stable at full capacity first.

Typically, the batteries I replace hold over the design capacity but only show the maximum design capacity and then depending on the charge cycles will slowly reduce. I have never installed a new battery that shows below design capacity when new.

Thank you again

oldturkey03

One more thing.

This laptop is used on a limited basis and during the time that it showed Design capacity and Charge Maximum at 76000 and the time that the Charge Maximum dropped to 72109 the laptop was not used other than periodic brief booting to confirm no issues because I also replaced the Wi-Fi card.

When I turned it on yesterday, I ran the test expecting to see 76000 because I was planning to change the maximum charge limit within the BIOS as I have done on my other Dell laptops.

Seeing that it was now 72109 I was and remain surprised.

Takes care,

William.

@williamk61042 this does makes sense and could very well be the BMS itself. It often just defaults to reporting the factory-programmed "Design Capacity" (76,000 mWh) to Windows because it doesn't know any better yet.

Over those next few days, even with just brief booting and the laptop sitting as you described, the battery does experience natural self-discharge and the BMS is now "learning" to take real voltage readings. It realized the actual ceiling of this specific pack isn't the theoretical 76,000, but rather the 72,109 mWh it's currently reporting. It is correcting its programmed value to the real world values of this specific battery pack. I would try to calibrate the BMS to the battery.

Give this a try. Charge the laptop to 100% and leave it plugged in for an extra hour or two so that all the cells will be completely saturated. Then unplug the AC adapter and use the laptop until the battery completely dies and the system shuts itself off. Plug it back in and let it charge all the way back to 100% without turning it on or interrupting the cycle. Check your capacity report after doing that. Whatever number it settles on is the true physical capacity of your cells. If it stays around that 72,000 number and the laptop power on just fine under load etc, the battery is okay and is operating according to manufacturing tolerances.

I do understand your concerns and know how it feels to have doubts because of what you expected from the new battery. If your gut feeling is that it will be better to replace the battery and since the iFixit team offered a refund or to replace your battery, consider doing so. It will only cost you the labor to do this. It is always very difficult to gain that initially lost trust. It is absolutely possible that you will always have doubts about this battery :-) Replacing it will offer you a peace of mind and that is priceless.

Thank you, oldturkey03.

It is to some degree the act of acquiring peace of mind. Your thoughts as shared mirror mine in as much as they are pragmatic and not emotional.

I do appreciate and respect the ifixit Team's no BS willingness to refund or replace the battery as it makes clear that they are founded in and remain committed to the customer being happy.

Having shared that, certainly I can swap the battery but that was not and is not my knee jerk reaction and I told them this.

I will do as you suggested and recalibrate or maybe better put let the system find its charge retention and ceiling using the process descibed.

I will share my decision once made.

Thank you again for engaging and sharing your thoughts.

Takes care,

William

@williamk61042 of course. Gut Feelings are my favorite guide to fixing things and I respect anybody that says they are going to do X,Y or Z based on that. I'd do the same thing and that is definitely not being emotional. It's a fixers instinct! Do let us know how it does turn out.