Thanks for the reply AverageJoe, I agree, they're silent most of the time, and pretty quiet when charging on solar. I went ahead and bought a couple of Bluetti 2400's, very happy with them - thank you Will Prowse, Hobotech, and Martin Johnson YouTube reviews! The loudest fan noise is from the AC power brick wall chargers, not the Bluetti units themselves - and you can put them in a remote location when charging, so not a big deal.
The Bluetti is silent when powering an appliance, except the internal fan kicks in when the unit exceeds 400 watts of draw. For us this means only momentarily, as we use them to run a small upright kitchen fridge and a chest freezer, and they only draw above that for the startup surge.
For those wondering, the Bluetti 2400 will run typical small kitchen fridges and chest freezers (9 cu-ft AC fridge, 7 cu-ft AC chest freezer). I was worried about the 1200 watt surge/startup limit on the Bluetti inverter, but they have been handling these appliance loads just fine. We ran both appliances for a day and a half during a recent power outage, and had plenty of charge left for another day or two, longer if you connect them to the appliances through timers.
