Its possible to replace the battery with a DC/DC adapter, I did it with a Samsung tablet. It does require a "beefy" power supply at a an odd voltage (4.2V or so) since batteries can provide more current than most power supplies. Also required a resistor to fool the tablet into thinking the battery was not drained.
It might be because of brief spikes in power draw that a battery usually "smoothes out" but USB power can't handle. For the same reason, some laptops cannot run without a battery (most can).
You're likely right. Some stable power feeder does need to exist, but could it skip the chemical energy storage parts?
The charge-discharge cycles needlessly put a lifespan on that component when I'd like to have it left on 24x7.
Same for always-powered laptops. With WFH, for 1+ year I've used my Thinkpad as a desktop, not bothering to unplug when fully charged, and now the battery doesn't hold charge for 10+ mins.
The answer is that phones really need a user setting to enable a charge limit.
About 4 months after COVID hit and I started to WFH, the battery in my Pixel 3 started to swell because I had allowed it to basically live on the charger all day, constantly at 100% battery. Also, by that point, a 100% battery would only give me about 2 hours of screen time.
A few months ago, I got a Pixel 6 Pro, and I'm basically just charging it from a weak 500 mA USB port a couple hours each day, keeping the battery between 50-80%. I'd really like to set an 80% charge limit and just forget about it.
AccuBattery gives an audible alert when a configurable charge level is reached (default is 80%). Not as nice as having the phone stop charging by itself, but at least I'm not frying my battery.
I don't think that's normal. I have an old cheap Lenovo from 2012 that sees 4-12 hours of active use daily. It's almost always plugged in without any limits on the battery charge (which as a result is always at 100%). The battery still has around ¾ of the original capacity (it ran for ~4 hrs of light use back in 2012, and gives around 3 hours now).
I don't think it can. UPS's store energy too, and stop holding charge after a while. It would be nice to bring back easily replaceable batteries, since they're basically a consumable these days.
> I don't think it can. UPS's store energy too, and stop holding charge after a while. It would be nice to bring back easily replaceable batteries, since they're basically a consumable these days.
I don't know anything about how much "oomph" a dashcam needs as opposed to a smart phone or an uninterruptible power supply but I kno0w one of the bullet points in the marketing of the dashcam on my car was it uses a small capacitor as opposed to a battery and therefore it is safer to use it in a hot car.
I had a dash cam years ago that had a capacitor, and all it really was for was to make sure the camera could finish a write operation and close the video file gracefully to avoid corrupting the last segment. Cameras with batteries often can support recording even while the car is off without draining the car's battery.
IMO, the solution to the battery-in-a-hot-car problem is to have the battery be an in-line part of the power cable that can be placed in the glove box, outside the direct sunlight, rather than building it into the camera itself.
On my OG Motorola Droid, I once tethered my laptop to it and downloaded a torrent.
In 15 minutes, I drained 25% of the battery. IIRC, it had a ~2,000 mAh battery. That meant I was pulling 2 amps from it. This was back in 2010, when most phone chargers and USB ports were still only 500 mA.
If I had relied on USB power, it wouldn't have been able to power it.
Oh, and yes, the phone got incredibly hot during this time. I thought I was going to burn my hand when I picked it up.
Probably some phones do work on direct power without battery.
But anyways in the general case the user wants the battery to charge when they connect their phone. Not allowing the phone to run without a battery will show more clearly that there is an issue with battery connection or battery itself, than if the phone would run when connected to power without battery.
> Not allowing the phone to run without a battery will show more clearly that there is an issue with battery connection
This is a non-issue since battery status (or lack thereof) is clearly shown in the UI. A more likely issue is that the battery is commonly relied on to deal with peaks in power draw, beyond what can be supplied via the USB port. This can even be an issue in many laptops.
I recall some older android devices with replaceable batteries did. If your battery was almost dead, you could plug it into a charger and swap out the battery for a fresh one.
The correct answer is simple: there is no profit in it and therefore no reason to do it. Any work or addition to the BOM of a phone for this purpose is therefore a waste.