My Prius not charging main hybrid battery.

Sitting months is a problem I didn't even look to see where you were I'm assuming it's all been in the heat and when you do try to start the car like get in it slot the remote push the button put it in reverse and you go to back up within a few feet after sitting like this for a while the engine should start right up if it's capable I would think it would have enough charge to spend the motor over and if everything else is right with the world and the engine it would start right up and run and probably run for 5 minutes or more just sitting there with your foot on the brake in reverse is this not the case or if this is the case is the engine running really badly?

 

You vot to scan the vehicle, to retrieve trouble codes.

 

is the inverter pump working?

 

If you have a bluetooth ODBII reader apps like ODB Fusion and Doctor Prius can read a lot of the battery codes.

Another option is to get a get a TechStream clone cable and hook your computer up to your car's ODBII port. There's a VM Image of Windows XP with Techstream preinstalled if you google it. Techstream can be a real PITA to get working on modern OSes. Techstream will let you get all the trouble codes, and subcodes. Subcodes are extra bits of information that help you further localize the problem. There's clone Techstream cables on Amazon for pretty cheap.

Regardless of how you get them, the better you can get your trouble codes the easier time you'll have finding the problem.

Based on the behavior, and in my limited experience with mine and my wife's car, even without the trouble codes I'd check the the hybrid battery fan connection for corrosion. I'd also check the battery cell voltage sensors. Make sure the wires are okay, the terminal loops are snuggle attached, and connected to the wires and clean any corrosion, on the voltage sensor loop terminals, and bus bars. Also on the battery computer there's a big orange plug where the voltage sensor terminals plug in, unplug it to make sure it isn't burnt out or corroded.

 

Also based on my own self inflicted Duh! moment. Make sure the orange safety plug in the battery is properly in.

Push it in till the handle starts to go up, flip the handle up, and the part I forgot: push the handle down. If you don't do the last step you'll get some pretty nasty looking battery errors.

 

Then it would seem like the HV computer back in the battery could be corroded the plug etc or the inverter is literally not putting out enough voltage to charge the battery to fill up the battery gauge on the MFD I mean it seems like really only basically two places to be looking or the generator in the transmission motor generator is not supplying power to the inverter so it can get to the HV battery and there should be individual tests to break that down so you know exactly what's not working by following a flowchart.