“Short version,” writes an iPad owner who calls himself “batzgam” in the Apple (AAPL) discussion topic iPad ‘not auto-connecting’ solved! “Raise the screen brightness above the minimum setting — wifi reappears!”

Like many early adopters, batzgam had a complaint about how his new iPad was communicating with his local Wi-Fi network.

How widespread these problems are is hard to say. As of Wednesday morning the most heavily tafficked complaint thread on Apple’s discussion board — Weak wifi — had drawn more than 300 messages and 37,000 reads.

Batzgam’s problem was a relatively minor one — but frustrating nonetheless. Every time his iPad went to sleep, it forgot what Wi-Fi network it was using and had to be painstakingly reconnected. Apple took the complaint seriously enough to post several suggested fixes. But it was batzgam who seems to have nailed it. It turned out he had lowered his iPad’s screen brightness setting. When he turned it back up, his Wi-Fi issue disappeared.

“Dude, you sir are a genius,” wrote of the many users who said his trick solved their problem. “That is the weirdest thing I’ve ever seen. But thank you!”

The iPad’s other Wi-Fi issues may not go away so easily. The chief complaints: dropped connections, weak signals, forgotten passwords and sluggish downloads.

“Count me in as someone who’s having iPad Wifi issues,” wrote TechCrunch editor Michael Arrington, one of the Silicon Valley’s most influential bloggers, who set the tech press in motion with a post Monday entitled Trouble in Paradise. “The device works fine near the router, but on the other side of the house, nada.”

“My understanding of Wifi issues,” he wrote, “particularly cramped devices like the Macbook Air and iPad, is that it’s usually a hardware/design issue and something that can’t be fixed via a software patch. I hope that’s not the case with the iPad, because faulty Wifi would make this a very unattractive device.”

We’ve generally been impressed with the zippiness of our iPad and have had no dropped signal problems yet (knock on wood). But a side-by-side comparison using Speedtest.net (a free app) revealed that its throughput was about half that of our MacBook Pro (22.8 Mbit/s vs. 10.94 Mbit/s).

An Apple employee has posted an iPad Wi-Fi FAQ with pointers to several articles on dealing with Wi-Fi issues (one suggestion: move your device closer to the router).

But the complaints are piling up and getting a lot of traction in the media. As one popular Apple discussion thread (1,132 reads) puts it: No one goes home tonight until the WiFi issue is fixed.

[Follow Philip Elmer-DeWitt on Twitter @philiped]