iPhone X Teardown

Have you seen the tear down of the old MacBook power bricks? Check it out if you haven’t. There’s a lot of tech in there to improve efficiency (ie keep that tiny brick from melting)

Explanation as to why this isn't the case:

TL;DR - putting the cells in parallel without changing their C-rating does nothing for charging them faster. You're limited by the C-rating of the cells, which is usually determined by the quality of components and the anode/cathode design.

Putting batteries in parallel maintains the voltage of one cell but multiplies the current by the number of cells in the pack.

E.g. if you have two Lithium Polymer cells in parallel, the nominal voltage will be 3.8V. At 5W, the current would be ~1.3A

Putting batteries in series adds the cell voltages while keeping current the same for the pack.

e.g. if you have two Lithium Polymer cells in series, the nominal voltage of the pack would be 7.6V and at 5W the current would be ~0.66A. Notice compared to the parallel example: voltage is doubled, current is halved.

What you need to compare here is the so-called "C-rating" (capacity rating) of the cell. All the C-rating means is that if you provide this much current, the cell is full in an hour. A C.10 rating would be the current over 10 hours. C.20 current over 20 hours, etc.

e.g. you have a 3.8V LiPo cell that's 2000mAh. A C-rating of 1 means you charge or discharge at 2A and it's full/dead in an hour.

So, putting batteries in parallel keeps their voltage the same but "doubles" the current.

However this entire time we've been talking about current, when we should be talking about power.

If your 2000mAh battery has a C-rating of 1, meaning you can charge it at maximum at the capacity of the battery, then in parallel you have 4000mAh (2x2000mAh) at 3.8V, meaning you can safely charge it at 4000mAx3.8V = ~15W

Put the same two cells in series. Now you have 2000mAh at 7.6V. How fast can you charge it? 2000mAx7.6V = ~15W.

Consumer electronics don't need a high C-rating because the cells don't need to charge/discharge at extremely high rates (as they would in a quadcopter, for example).

The main benefit of putting cells in series is that you raise the voltage, which lowers the current and thus means you can use smaller (and cheaper) wires to carry the same power.

Putting the cells in parallel would increase the current for the same power, but it does not change the C-rating and thus the amount of power you can safely put into the cells.

The low end doesn’t understand why people pay so much more for fit and finish.

Except automobiles. Everyone seems to accept and even approve of the high end for cars.