how do you compare batteries ?

[cishato]

I’m looking to buy a new laptop, and one has a 71wh 6 cell battery, and the other has a 80wh 3 cell battery. Both laptops have a 3070 8GB and the only main difference is in the CPU (i712700H vs i711800H respectively) 

Which laptop has better battery life ? 

[Kilrah]

By looking at reviews, battery alone (what matters for it is the Wh capacity) is meaningless without knowing how much the system draws.

[Gokul_P]

13 minutes ago, cishato said:

I’m looking to buy a new laptop, and one has a 71wh 6 cell battery, and the other has a 80wh 3 cell battery. Both laptops have a 3070 8GB and the only main difference is in the CPU (i712700H vs i711800H respectively) 

Which laptop has better battery life ? 

Both have 2 differant set of hardware so Wh isnt going to mean anything. and even with the same hardware manufactures use different power management so look reviews there is no point comparing Wh without Matching the hardware, softwere and every small thing that makes a laptop. 

[Eigenvektor]

Look at reviews as was suggested.

 

An 80 Wh battery will last roughly 1h with an 80W load (80W x 1h = 80 Wh). At max load either i7 will use somewhere around 45W (but can be configured by the manufacturer for 35W) and the 3070 will be 80–125W. So you could be looking at 125W + 45W = 170W. 80Wh / 170W = ~0.47 hours (a little under 30 minutes). It's hard to guess how long they will last while idle though, depends on how aggressively they try to minimize power usage.

[Spindel]

In theory more cells should be better than fewer when the battery starts to go bad if they are wired in parallel since you lose less capacity per cell going bad. 
 

In practice you have more points of failure and you have no idea of how the cells are wired. In your example the one with 6 cells may as well have 3 parallel banks with each bank having 2 cells in series effectivley making it the same as the other one. 
 

For a fresh new battery Wh is what matters. 

[cishato]

48 minutes ago, Spindel said:

In theory more cells should be better than fewer when the battery starts to go bad if they are wired in parallel since you lose less capacity per cell going bad. 
 

In practice you have more points of failure and you have no idea of how the cells are wired. In your example the one with 6 cells may as well have 3 parallel banks with each bank having 2 cells in series effectivley making it the same as the other one. 
 

For a fresh new battery Wh is what matters. 

this helps a lot, thanks ! 

[mr moose]

1 hour ago, Spindel said:

 

For a fresh new battery Wh is what matters. 

So long as you know the maximum power delivery and the system power draw.

 

Wh is power delivery over time, just like Amp hours is current delivery over time,  It is only a measure of total capacity.  You can have two 100wh batteries but if one is limited to 50watt delivery then even though both batteries will last the same time on a 50 watt load, the battery that can sustain the full 100 watt delivery might be better if the laptop can spool up for shorter but more intense loads.

 

So intended device capability and use along side powered delivery, then wh for estimating run time.

 

This is why device reviews are more important than specs by themselves.

 

 

[Spindel]

1 minute ago, mr moose said:

So long as you know the maximum power delivery and the system power draw.

 

Wh is power delivery over time, just like Amp hours is current delivery over time,  It is only a measure of total capacity.  You can have two 100wh batteries but if one is limited to 50watt delivery then even though both batteries will last the same time on a 50 watt load, the battery that can sustain the full 100 watt delivery might be better if the laptop can spool up for shorter but more intense loads.

 

So intended device capability and use along side powered delivery, then wh for estimating run time.

 

This is why device reviews are more important than specs by themselves.

 

 

You are correct. 
 

Also the reason in example Apple Silicon laptops perform the same on battery and connected to the wall compared to a lot of x86 laptops (AS sips power)

[Guest]

WH stands for "Watt hours." 

I forget the exact formula but it's something along the lines of supplying 1 watt for the number of hours listed. 

 

10WH = 10 Hours of 1 watt. 

 

If your hypothetical system draws 2 watts when powered on with a 10 WH battery, it should only last about 5 hours. 

 

 

This is if I remember the algorithms properly. 

This is theoretical and is often quite close mathematically...

 

but your laptop has:

CPU, GPU, RAM, HDD, Motherboard, screen, led lights, speakers, wifi module, mouse, trackpad, keyboard, etc. 

Not to mention potential "bloatware" that the manufacturer might install that runs extra processes. 

Reviews/tests show the real world.

Realistically, I see a laptop as a mobile all in one computer because I can't think of anywhere I wouldn't have power to plug in where I would use it.

If I'm in the car or plane I can play a 2d game so I can look away if I am getting motion sick but even then some modern cars have wall style plugs and airplanes have wall plugs too. 

 

Pack your charger, a surge protector, and a car cigarette lighter to wall adapter and you're set for basically anywhere. 

 

Most modern laptops can run the PowerPoint or word for significant enough time. 

I got a used laptop with a 1050 and I was able to program, compile, play dawn of war dark crusade, surf the web for at least 1-2 hours with a non full charge and still had battery left over. 

I even did a flash drive file transfer of a few GB of data to an HDD. 

Maybe my laptop is more power efficient, but I'm quite certain most modern laptops are good. 

This is my "alternative"answer since you already have solid answers that directly answer how to get your answer. 

[birdhuman]

16 hours ago, Spindel said:

In theory more cells should be better than fewer when the battery starts to go bad if they are wired in parallel since you lose less capacity per cell going bad. 
 

In practice you have more points of failure and you have no idea of how the cells are wired. In your example the one with 6 cells may as well have 3 parallel banks with each bank having 2 cells in series effectivley making it the same as the other one. 
 

For a fresh new battery Wh is what matters. 

Actually, the cells are connected in serial to get a higher voltage for example 12V or even 19~20V. A Li-ion cell is normally 3.7V to 4.2V. In order to make it suitable for the desired voltage, they are serial. So, less cell means lower failure rate.