The charger is fine to use, but less convenient than external charging IMO.
If you have had a GH charger since mid May, it has an older inferior board in it, which may stop working at some point. The new one has a more powerful micro-controller and a simpler overall design which should improve reliability.
I killed my older style by plugging it into what must have been a non-UL listed USB adapter (a car adapter I found without packaging, so quite likely). It made some crazy techno noises and then it stopped working, but after some time it worked sporadically. When it worked, it was fine.
The one HL replaced it with (same older board design I think) didn't work at all, and would cause solid red LEDs when twisted to a certain position.
HL were confused by this, and incidentally (heat sensor issues) have my hopper and charger now, so hopefully they can learn about this other problem.
I just received a message back regarding priority postage, but my hopper has been with their warranty department for nearly a week now (longer than others with just a sensor issue) - so hopefully they can send it back soon
@Churrucaman if the hopper is working properly, it should be giving different ABV results per temp level, as per their official ABV video.
When mine had a broken heat sensor, it was giving fluctuating performance.
If the performance is consistent, it could be material or the environment, or a calibration issue.
Keep using it for a while, test with different types of bud and if it continues to perform as is or inconsistently, write HL.
FWIW I had more luck getting darker ABV with direct draw over water pipe usage, so maybe test that out too. (waterpipes cause more airflow, which is fine for convection heating but no good for internal conduction of material as it doesn't get time to heat soak. Something along those lines is my guess anyway. Either way, after you've had a couple of hits at 5 through a bong, hit it again direct and observe the difference vs the third hit through a bong)