Long ago, I docked my iPod Touch with 30-pin connector onto a cheap ghetto blaster. I cranked the volume over an extended period. Shortly thereafter, the battery of the iPod Touch could not retain a charge. I am guessing that cranking the ghetto blaster caused damaging electrical noise to spike into the iPod Touch. These days, I only connect media devices to the ghetto blaster via an old audio cable.
Now I own an iPhone SE, which I'm still paying off. I am experiencing the low charge life that iPhones are known for. If I charge it with the car's 12V source (older cars use to have cigarette lighters in the socket but mine only has a cover), I won't get caught running out of juice when I'm on the road and needing to navigate or look things up.
But I am concerned about noise damaging my much more expensive iPhone. After all, it is a car, and the power sources probably weren't designed to be steady and quiet. Heck, I imagine starting the motor causes really causes fluctuations in the 12V, and maybe when the A/C kicks in.
I can pick up a USB power adapter to plug into the 12V socket, and I always carry a USB-to-Lightning cable (expensive buggers). The USB power adapter is only a few bucks at a car accessories shop, but $20 at a national electronics store chain (for a brand that isn't exactly high end). The price difference is approximately 5-fold. And generally, one gets what one pays for.
I will go for the much cheaper alternative if the risk to my iPhone is minimal. That depends on the sensitivity of the iPhone SE to gross noise on Lightning port. I won't even say on the powering lines, as I don't know exactly how Lightning is designed, and even if there were dedicated powering lines, the adapter may inject noise on all lines.
My decision should also depend on how easy and typical it is to filter or block such gross noise. I suspect that we've been charging all manner of electronics in the car for a while now. If the technology is a commodity technology, then even cheap adapters can be expected to filter/block gross noise. There's no way to be sure without lab-testing each product; it's more a risk assessment based on what is likely.
I can boil the above down into two questions:
(1) Is the iPhone SE known to be sensitive to damage from gross noise along the Lightning port?
(2) How commoditized is the technology to block such noise in USB adapters for the 12V socket of a car?
Truly answering this requires a comprehensive study which is probably unaffordable to most. I am only seeking information that can narrow down my complete lack of familiarity with the topic of either question, and enable a judgement call to be made.
Now that I've actually taken the time to describe the problem, I can't even say that the cost difference is the motivating factor. It's more the fact that I would feel far more gratified in having made a rational decision rather than just going for higher cost, which might make no difference in quality. And if the information exists with which make a decision rather than a wild guess perhaps this might help others.
Best Answer
I'm not sure how well this answers your question, but it seems the whole basis for your post is an assumption you've made about the experience you had a long time ago with an iPod Touch:
As you indicate, this is just a guess and there's no way to know what the actual cause of the iPod Touch battery no longer maintaining a charge was.
My experience
What I can tell you is that during the past 11 years:
In all of that experience, the only damage we've noticed is that cheaper adapters and cables end up failing sooner rather than later (i.e. sometimes they just don't work, or they blow a fuse in the vehicle). However, all iPhones, iPads, iPods and Apple Watches have survived without any damage whatsoever.
Finally, as all of these devices have internal batteries, they're less likely to suffer damage as a result of electrical noise or spikes.