According to previews, the battery lasts an entire day. I've had a phone with a 4000mAh battery, though it's nice it adds weight and bulk. LG emphasises on thin and light, that's what their whole G series was about (they were the first to do small bezels). Also, with Snapdragon 845 + Android O, battery life will be no problem. And let's not forget, they needed room for that sound chamber which I'm willing to trade battery life in for an outstanding speaker. Compare with a Samsung speaker, it's embarrassing. Do you guys forget that Apple iPhone 8 has only a 1800mAh battery but the battery lasts all day typically? Plus it's using LCD and it's proven that, despite what people think, AMOLED eats up more battery:
https://www.digitaltrends.com/computing/should-you-buy-oled-laptop/ ... I can also speak from experience, I've noticed IPS LCD phones do better with battery life than AMOLED.
Again, not trying to be a fanboy but speaking from experience, optimization and processor size/type make more of a difference than actual battery size. BTW the S7 Active (4000mAh) battery was mediocre, the S6 Active (3500mAh) battery life was terrible after 8 months in. The phones were thick and heavy as a brick. No thanks, I'll take 3000mAh.
I'll probably not get the G7 but I'd definitely pick it over HTC due to the lower price and tons of useful features. I'm still happy with my V20 which has been over 1.5 years now and I don't see myself getting a phone for a while because there's nothing enticing on the market today besides LG (Galaxy S9: too boring, nearly identical to the S8, Huawei: banned in the US, plus no headphone jack, OnePlus 6: also very boring and uninspiring, no micro SD, Chinese spyware, Motorola: come on now! I don't need to say anything).