https://www.parts-people.com/index.php?action=category&id=141&subid=475&refine=battery

Here is the Amazon listing for the battery

https://www.amazon.com/SOLICE%C2%AE-Inspiron-15R-N3521-15R-N5521-15R-1528R/dp/B01HYUKEOU/ref=sr_1_4_sspa?dchild=1&hvadid=77996657376106&hvbmt=be&hvdev=c&hvqmt=e&keywords=dell+inspiron+3542+battery&qid=1600512306&sr=8-4-spons&tag=mh0b-20&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExMEFQQ0RSN1pGMlFDJmVuY3J5cHRlZElkPUEwNzQ3ODU2M0tYOEo5MlpCQko0WCZlbmNyeXB0ZWRBZElkPUEwMjM3NDE4M1QyUE40MTJUV1VJNyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

I am confused with the battery voltages. The battery that my laptop originally came with shows 40Whr 14.1V type XCMRD. Whereas the e-commerce websites show 65Whr 11.1V type MR90Y battery. They say that this battery (MR90Y) is compatible with Inspiron 15 3542. So should I buy the battery from those websites?

Thanks for the reply. But I still didn't get the answer for whether the 65Whr battery will be compatible with my laptop which originally had a 40Whr battery.

If you want the larger battery for better runtime, you can choose that.  The voltage is lower and the size of the battery is larger and it's heavier, so it will increase the size and weight of the system vs. the standard 4-cell battery.

The battery options are clearly listed on the parts-people.com website.

If you want Dell's official answer, you'll see that in the specifications manual here:

https://www.dell.com/support/home/en-us/product-support/product/inspiron-15-3542-laptop/docs

For any individual seller's offerings -- many of which will be non-OEM -- ask the seller.

I purchased the 65Wh MR90Y battery and fitted it in my laptop.

But now I am experiencing some weird issues. The laptop turns on for a while, bit it automatically gets switched off for no reason. When I power it on again, again the same thing happens. 

Also another issue is with the keyboard. Sometimes the keyboard works and sometimes it doesn't.

I started experiencing these problems after installing the new battery. Please help me.

@ejn63 

Remove the battery and run on AC only.  Does the same fault occur?

Yes:  likely an overheating or a mainboard power rail problem.

No:  check with the battery supplier for their warranty terms. 

When I run the laptop on AC, same problem occurs. The laptop runs for few minutes and then turns off without any warning/message. Is their any way to solve this problem?

@ejn63 

If it's overheating and has never been cleaned internally (including the replacement of the thermal pads/compound), it's overdue for that.

If it's not running abnormally warm and cuts out intermittently, run a full diagnostic (F12 at powerup).  If it cuts out during the diagnostic, it suggests a power problem -- the likely need is for a mainboard replacement.  If it does not cut out when running diagnostics, it suggests a Windows issue.  

I don't know if the issue is overheating or not. I checked the temps using HWMonitor. It showed CPU temperature at 50 - 62 degrees average at 50 degrees.

I also ran the Dell ePSA Diagnostics tool by hitting F12, and the test also passed successfully. There was no power failure during the test.

I was facing the same problem 5 months back when I was using the laptop without battery on AC.

Also, one thing to note is that I have never cleaned the internals of the laptop from the time I bought it (5 years ago).

@ejn63 

Yes the battery is charged nearly 75%. Even with the battery charged the laptop shuts down.

So what should I do now? Maybe cleaning the internals may help or would I have to buy a new motherboard (that would be costly too)?

@ejn63 

If the battery is charged, and it's still shutting down, it's a power problem on the board.

If the battery is absent, and the power plug or jack is loose, that would initiate a cutoff as well, but the battery should keep the system running.  Those temperatures are not high enough to cause a thermal cutoff.