2004 Prius fan kicked on and not charging warning

You are not having an issue.
This is normal behavior of all Prii.

When the Prius in neutral, the HV battery pack is not charging.

So if you stay in neutral long enough, the battery get lower and lower.
At some point the car is going to remind you that you are not charging.

 

lots of reports about dead batteries after a neutral car wash. you go in with the battery level low, the a/c and radio on, and come out with a lower battery level.

 

IMO....with a healthy HV battery that is at a normal or good state of charge?

A drive through car wash should NOT be a problem. I use them regularly, and I enter with the vehicle showing a higher state of charge and I'm fine.
If you enter with the vehicle in a low state of charge...or potentially with a bad battery, then you may have a problem.

My opinion in this case, is that assuming the battery wasn't low when entering, if it showed that warning in just the time it takes to go through a drive through car wash. I would be suspect of the "new"-used battery that was installed. It should be able to hold the charge well enough to get through a 2-5 minute drive through car wash.

Did your wife take note of how charged the battery was before putting it in neutral?
If it is low when you put it in neutral that message will appear. The message itself is "normal" from the perspective that it's just telling you the HV battery needs to be charged and it will not charge it in neutral.
Which is kind of why you never want to enter a car wash with the battery in a low state of charge.

 

But what if there's a line of cars in front of you. As you creep forward, you're probably using just EV and draining off charge. After a couple of minutes waiting to get to the front of the line, you enter the wash and shift to neutral. Now you're pulling amperage and the HV is in a low SOC. Yeah, I can see some lights coming on.

 

All I can say is that I've never had that problem. Even when waiting in a line. Of course my Prius is newer, with a newer battery, PLUS I do pay attention to my state of charge as I'm going to the car wash. I never arrive with it in a low state of charge.

My Prius seems to like to stay at about 2/3rds to a little above 2/3rds charged, I've entered with that state of charge, or even a "little" lower and never had a problem.
I think the key, is just making sure your not shifting into neutral with the battery at a dangerously low level.

I've never had a problem, but I suppose if you are eyeing a slow enough moving line just to get to the car wash? You might want to pass.
Some people don't use drive through car wash's just to avoid this potential problem.

I guess what I wanted the OP to know, is the message itself isn't a problem, it's a legitimate warning the vehicle will give IF the battery is low, and it is in neutral.
Whether it was low because the used battery is defective or not up to par? I don't know. Under "normal" circumstances, IMO...a drive through car wash SHOULD be easily doable.

But I would be curious as to how low the battery may of been before The Prius was shifted into neutral.

 

I want to reiterate that getting this warning IS NOT the sign of a bad battery.
As everyone has said, this is a legitimate reminder to the driver, since most people (including the OP) do not realize that the car will not charge the HV battery while in neutral.
Even a brand new Toyota Prius can make this warning message come up quite easily.

Perhaps the 60-day warranty battery is a good battery and will run the car just fine, but it simply has lower capacity than say a 3 year warranty battery. You get what you pay for.

Please identify the name of the supplier of the battery.
(I hope you do not say Elite Auto) Elite Auto - Beware. Craigslist hybrid battery ads should make you leery | PriusChat

 

many owners will not use the 'neutral' car washes.