Comment by D9u | Hacker News Reader

Comment by D9u | Hacker News Reader

Not an Apple consumer here, but my netbook battery only lasted about one year, and I attribute this rapid failure to my use of a cheap, (I live off-grid) modified sine wave, voltage inverter, but I have no valid proof of my assumption. As likely a cause for the battery failing to take a charge is the fact that I often ran the netbook until the battery charge depleted to the point of shutting the PC down.

When I bought my current, pure sine, inverter I noticed that my new battery lasted nearly twice as long, but since switching to FreeBSD last year my second battery quickly bit the dust...

I'm expecting the present battery to last somewhere between one and two years, but I'm not taking that expectation to the bank.

To confirm or disprove your idea, you could look at the output of the battery charger rather than the input to it.

In general, AC-DC converters are pretty insensitive to the harmonic content of the AC input because their role is to remove any harmonic content they do find. They do this with huge low-pass filters with corner frequencies well under 1Hz, whether the charger is either linear (unlikely) or switching (much more likely).

When AC becomes distorted, you start seeing harmonics (i.e. contributions at higher frequencies). Low pass filters are progressively more effective at higher frequencies. This is to say, I wouldn't be at all surprised if the efficiency of the charger itself suffered, but the output voltage was unaffected, meaning the laptop was unaffected.

Interesting, but does using a DC to AC inverter change anything?

I've noticed that cell phone batteries also failed prematurely when I had the modified sine inverter.

Do you mean that if my charger was operating with less efficiency due to modified sine wave input then my batteries were not likely to be affected?

It's more likely that you were simply cycling the batteries more aggressively due to the circumstances which led to you using a DC-AC inverter.

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