I've ordered (and kept spares) of brand new batteries so I could test this most of the time, but that was never the issue for me. Glad it was for you!
Mine too! I’ve never sent it back and all I had to do twice is take out the screen and clean the temperature sensor.
"Friends, Romans, countrymen, lend me your ears;. I come not to bury Grasshopper, but to praise him"
(yes, edited a bit from the original haha)
You may remember that after a year and change, my Ti GH finally stopped performing the way it did. It would still vape, but weakly and it no longer milked my can nor did the AVB look done.
So, I blew it out, I cleaned the threads, I sacrificed a virgin to the gods (and you just don't know how hard it is to find one of those these days), all to no avail.
I despaired of having to send it to Hopper and go through the RMA cha-cha with them.
But, I did think to order a new set of batteries first to eliminate any further possible causes. I had been using my second set of batteries, GHB-2s, and I religiously rotate and charge the four batteries I keep in the line up.
Now understand, it wasn't that I wasn't getting as many loads as before...it was that the vape was not running as hot as previously...by a long shot.
Got my batteries this past weekend, topped them off in a Nitecore charger, and ran it last night with a PFE in a stevenlmz79 FC-188, 14 mm, Mobius knockoff. The new ones are GHB-2 also, but with what appears to be a thicker sleeve on the outside.
MY GRASSHOPPER LIVES!!
Seriously, performance was back to brand new.
I did try different batteries out of the four when I was having issues, but since they were all rotated religiously they all had the same number of charge/discharge cycles and apparently they all got puny at the same time also.
So, if you are finding your GH running a bit cold, you may want to consider new batteries before RMA.
... or Psychology Today. 
I rotate all and then in about a year of use I buy new ones but discharge and charge all my old and pick the best ones
DISCLAIMER: I had not intended this to be so friggin' long. I really didn't mean this to be a treatise on the Revelations about Battery Performance over Time in the Real World. However, I think it's worthy of publication in either Science Today
@Baron23 that was really a helpful observation, thank you!
I have been going through this same saga with my Ti's.
I do exactly as you, with a 4-battery rotation in the Nicore.
This made me realize something I would like to share, hoping it's a "useful awareness".
• I'm on my second rotation of 4 batteries over the past full year (rough idea for purposes of my point).
• I consume about 3 modestly-filled chambers per day, and desire/expect a respectable ABV color. Point being that the hopper is used all day, several to many times a day. I hit once/twice, and lay it down. Lather, rinse, repeat.
Perhaps the #1 Frustration with the battery rituals is knowing when to swap batteries.
When I'd decided to swap out the first rotation of batteries 5-6 months after I began with them, it was a pain in the ASS, and now I understand why: I was too hung up on the life of the battery as a measure of the battery's 'health', and ignoring maybe the other factor: performance when fairly charged.
I'm sure someone out there can answer the question, "How many well-toasted chambers
will a fresh GBH2 produce on a single charge?" Perhaps that is a "gold standard" against which a mid-life battery could be measured. Because I think that after mid-life, the battery might LAST (roughly) as long as a new one, but actually underperform, making the hopper look like the problem. Upping the Temperature to T5 is always an option, I suppose, but when one is not used to doing that for the first "3 months", one tends to avoid breaking that habit for the "last 3 months". And still, that doesn't answer the question of whether the hopper is the problem.
Hence, my mind was blown: It's time to replace the batteries when I start really questioning whether I should do the RMA-dance. Throw a fresh battery in it. See what happens.
So that's what I did. And like yours, @Baron23 , my hopper jumped right back to top-shelf hitting.
Bottom line, for me, is, how much am I willing to put up with sub-standard performance? Pretty long, if I know it's not the Hopper, but just the battery getting tired.
They are supposed to but sometimes overworked
It would go straight to blue and not heat up. It happened twice since I’ve had it. However, once I gave it a really good cleaning the second time I haven’t had issues with it.
I'm done with this vape. I purchased and started using the PFE in June of this year. They claim it has nothing to do with my multiple failures.
If there is anyone in Canada who wants to cover shipping, you are welcome to my hopper/PFE...hmu
What has been an issue the entire time the GH has been out? That they're fixing all issues as they arise within their means? All that remains is the heater issue and that is a new problem.
No, that their product is very unreliable and as far as anyone can tell they haven't done much if anything to improve that problem. Still people over a year after releease having multiple warranty claims within a few months is kind of insane.
