Strange behaviour in battery on a brand new IPad

Could you clarify the situation further? How many hours you get?

Check brightness and display. Is that a pro or air or just a regular iPad? Did you do a restart?

I have a few ideas that might help improve your battery life. It's not a fix for whatever is going on with your iPad necessarily, but it should at least help give you more screen time with your current battery.
1. First, go to settings, general and completely disable background app refresh. That is one of the biggest battery drains on iOS/iPadOS. While it may be convenient, there really is absolutely no reason apps that are not running in the app switcher, should still be running in the background.
2. Go to settings, privacy, location, and make sure there is nothing in there that is set to always allow. This is also another battery drain.
3. Go to settings, accessibility, display, and enable reduce white point. This is a setting that helps to prevent pixels from reaching their absolute maximum bright point, which in turn improves battery life.
4. One more time go to settings, accessibility, and then go to motion. Enable reduce motion here. This just alters the visual effects your display performs when doing things like switching screens, opening or closing apps, opening or closing the notification or control center, etc. Also helps with battery life.

HTH.

The slider goes from 25 to 100% I believe. I’m assuming that when it’s at 100, less pixels are on, and 25% is closer to off (0%). Am I correct in my assumption?

That is a good question. I want to say that the higher number percentage refers to how much is actually turned on. In other words, if you have it at 80%, then you have 80% of white point capability. Though I could be absolutely backwards here. I currently have mindset to 50%. So, maybe take a screenshot with it a different settings, and check it would Be My Eyes?

I certainly don't think I'd ever disable background updates unless I was really desperate for battery - I think you'd find a lot of stuff would stop working that you wouldn't expect. If you're somewhere it'd be hard to charge it, maybe consider switching on low power mode which does that and a bunch of other stuff but will turn itself off when it has enough power.

Definitely make sure your screen brightness is something sane, and make sure you haven't accidentally turned off screen curtain. Other than that, the thing I'd check is battery under settings, specifically the section where it shows which apps are using the most battery. A lot of games use a lot, and I've definitely seen Safari use a lot if a particular tab is open and doing something weird. If you suspect an app is using more than it should, often force quitting it in the tab switcher and restarting it is enough to make it behave.

Other things to watch might be leaving it on the home screen with a bunch of widgets, since they do update particularly when you're focussed on them.

I guess the real question is, are you doing different things and using different apps when you're using it without a keyboard and is this making the difference? Just a few things to think about.

Battery life on the iPad is not that great anyways.

I had done so and does not affect anything.

Hello all:
I have an iPhone and am thinking about purchasing an iPad. Do I need both products? Sorry if this isn't the right place for my question. Also, any recommendations? Thanks.

Here are some reasons why you may want to consider disabling background app refresh.
https://www.macrumors.com/2019/05/28/background-refresh-apps-sending-data/#:~:text=When%20Background%20App%20Refresh%20is%20enabled%2C%20some,the%20relationship%20between%20apps%20and%20tracking%20companies

https://discussions.apple.com/thread/254963561?sortBy=rank

Note that the second link has a little bit of misleading information regarding notifications. You do not need background app refresh running, in order for notifications to work. Otherwise, I would never get a notification for anything. Ever.