Is my hybrid battery toast, or just in need of a charge?

I let my 2010 Prius sit for a year. I know; that was a terrible idea. I eventually replaced the 12v battery and have been using a trickle charger for the past few months, so at least it's still got a charge. HOWEVER when I get into the car now and hit the button, I get absolutely nothing, and a "check hybrid system" indication. Where do I go from here? I presume that the hybrid battery has dropped to some really low level. How to get it back? Can it be brought back at all? How can I tell?

 

Yes I am surely inclined to DIY this. Can you recommend hardware and software to do the diagnostic, and what I should be looking for? Thanks!

 

I assume you're referring to the risks of tinkering with a high-voltage battery. Thanks for the warning; if I decide to attempt to charge the battery I will surely take every precaution. I am not going to go as deep as replacing pieces of the battery; if I choose to get the Prolong charger and it doesn't revive it, the charger goes on sale here and the car gets donated to some organization. It's too bad; the car is otherwise in decent shape.

 

OK, I bought the Prolong charger and have gone through the setup process. I just powered up the charger as of 1:30PM EST today, and will see what transpires. The charger indicates 201 volts; I assume that is the current state of the battery, and hopefully suggests that it is not "too far gone". I understand that the process will take a few days. Attached here are some photos of the state of things right now. I skipped several pages of the installation guide - the ones that referred to how to install the charger permanently. That is not my plan; I will be selling this car if the process works, and giving it away to a charity if it does not. I don't want to invest a lot into a dealership repair, or even a DIY install of a new 3rd party battery; given the value of this 13 year old car. This is car #3 in a two-person household - I should have sold it ages ago.

The "green box" that connects to the fan, etc did not come with clear connection instructions, so I reached out to Prolong tech support for clarification. I sent a photo along of the state of things, and got the picture back with instructions for connecting it. It's included here. Hope this helps someone else going through this process.

Wish me luck. I should know in a few days. BTW if anyone is interested and lives within reasonable distance to Lewes, DE, please note that if this project works I can offer the car for $4500 WITH the Prolong charger included. My email is [email protected] (the info attached to my Priuschat account may be old).

 

After 3 hours or so it's up to 232 volts from the initial 202. This is faster than the "couple of days" I either read somewhere or heard here. In any event I am happy that the battery seems to be responding well to the charger. Re: the pack cover - thanks for the tip. I was not aware that that was the route that air from (or to?) the fan took. I will set it on (but not bolt it on) for the sake of airflow.

 

OK I guess the key part there is that the process you describe is ONLY in the situation I am in now, having disconnected the battery? I see there's some disagreement about this; time will tell.

 

I reinstalled the pack cover (just rested it on top) to keep the cool air in. I see that the fan blows air under the pack and it comes up through holes in the cells along the middle of the pack. I take it he pack cover directs the cool air over the tops of the cells.

After the re-reading the Prolong Hybrid Automotive Battery Charger User Guide | Hybrid Automotive, I see that the entire process should take just under 24 hours - and I am at that point now. The charger reads 238 volts, .359 amps. I will let it keep going for a just a little longer to see if the numbers fluctuate.

 

Here's what's happened since my last post. In early August I received the Prolong charger, installed it for temporary use, and over the course of a week ran it twice, for 24 hours each time, a few days apart. It brought the battery from 202 volts to about 239 volts. See the before-and-after pic. Then I had to let the project sit for almost a month, until today. At this point the 12v battery is freshly charged with the trickle charger and the hybrid battery was not checked. I installed Dr Prius and the recommended OBD2 device, the Veepeak. I started the car and got the "check hybrid system" message. Dr Prius presented me with its initial findings - see the screen grab.

Given this, how do you think I ought to proceed? Pay the money to Dr Prius to get more specific info? Run the Prolong charger again and try again tomorrow? From Dr Prius' findings it appears to me that at least a couple of modules need to be replaced. Is that a fair assessment?

Thanks for your input here. Being a newbie at all of this, I believe I can be counted on to do the right thing last, so any suggestions are appreciated.

 

OK thanks for that. Of course I was trying to get by on the cheap - apparently that's not working out. In your opinion, given the near-zero state of a couple of the modules, do you think it's possible that the patient can be brought back to life with the discharger's help? Or do they not all have to be perfect for the car to run again?