I can connect to the vehicle & most things work. But I can't connect to the battery or inverter? Does anyone know of an adapter that works with the battery & inverter?
There isn't an ECU inside a gen 2 inverter. It's all run by wires from the HV control ECU inside the cabin. What is it you're trying to do or connect to or see?
The OEM adapter / passthrough adapter is called a mongoose. The cheap knockoffs are called mini VCI adapters. Some work in older Prius, I guess since you're saying yours doesn't. My advice, keep looking for another that says it will do what you want and send it back if it doesn't.
Officially, Techstream should work with any adapter that meets the SAE J2534 standard. There are a lot of adapters like that. The "Mongoose" was a specific product of Drew Technologies (now Opus IVS), and the "Mini VCI" was a specific product of a company called XHorse. There are others too. Tactrix makes one. VXDiag makes one. More whose names I don't know. What's special about the Mongoose is that's the one Toyota tests with and supports; if you buy one of their hw/sw bundles, a Mongoose-Plus Toyota3 is the adapter they send you, and if you have trouble using it they'll answer your calls. If you're using some other J2534 adapter you need to solve your own problems. What's special about the Mini VCI is that counterfeiters swarmed all over it and now the marketplace is full of "XHorse" "Mini VCI"s that XHorse didn't make at all, and they're all super cheap, which is a great deal when they work, which is sometimes. If you're very determined, sometimes you can find an actual Mini VCI that XHorse made. It won't be as cheap as the counterfeits, and it's not very easy to tell, because of course that's what the counterfeits all claim to be. Tactrix and VXDiag are also options. Tactrix is a US company that I hope will not be smothered by counterfeiters the way XHorse was. If you buy their adapter straight from their web store it's around $169 (last I checked) and you know it's not a counterfeit. If you find "it" online for less, you're finding a counterfeit. If that's what you want, I'd rather you buy a counterfeit Mini VCI instead, 'cause that damage has already been done, and at least we can give Tactrix a chance to stay in business selling their own real product.