New owner of '05 with only 200 miles

It's indicative of a bad battery that the bar display swing wildly from low to full charge and back. The better the battery the longer both the charge and discharge times will be for a given rate of charge in amps. A higher capacity battery will hold more charge, and take longer to discharge it. There are other possibilities within the battery that may cause the MFD readings to show incorrectly, but these would normally issue a fault code.
If a sense wire is broken or the is corrosion in the plug at the HV battery ECU the ecu will give faulty readings. Each wire reports back the voltage for 2 modules "a block pair" around 16 volts. A broken or badly corroded wire usually where it joins it's module can report anything it likes between zero, and 16 volts. These voltages are added to give the total battery voltage. this cold be up to16 volts lower than the actual voltage from the battery.
Many here will know a sense wire being broken is not unusual. A simple volt meter across the HV battery terminal with the car in ready mode to add some load, but engine not running will give a good indication of it,s level of charge. There are enough graphs on PC to give a good indication of level of charge against voltage, and the number of bars that should be showing for that voltage.

John

 

When mine is warmed up, I could do that if I wanted to, but choose not to as I don't want to put that stress from cycling on the battery.

Maybe it is driving styles?

Also, it is a very common thing for noobs to want to force EV, even though it is bad for the battery long term.

The OP also said that if it wasn't for the display staying at 1 bar, he wouldn't think there was anything wrong with the car.

 

You claim to be a diesel mechanic, but you don't seem to be able to follow the logic of what has been suggested to you.

That would be correct, but you have driven some hundreds of miles now and let's just assume for the moment the battery is good, but the display is not giving the true data, then disconnecting the 12 V may reset the battery calibration. However you mention the car with exclamation mark appearing in the display. This is the Hybrid system warning, so clearly the car is not happy about something. You need to get hold of a hybrid capable code reader, or pay the Toyota dealer to do it and see if there are any codes.

Further, there could be corrosion or broken sense wires within the battery that might just need cleaning or fixing up.

The fact you can drive the car like normal, seems to indicate the battery is not totally knackered.

But if you are not willing to answer our questions accurately, there is not much that we can say and you will keep getting the WAGs you're getting.

We are all trying to work that out too, you truly have a unique case here and it's really intriguing. While the consensus might agree with the dealer, your car is not really exhibiting the usual symptoms of a dead HV battery.

Never heard of this, but @Britprius or @strawbrad can possibly say whether this is feasible or just a urban myth.

I don't know what the competitive situation is in NJ, but battery retails from online US$2075-22xx + taxes over the counter, they don't usually deliver. YMMV. It will take you 4-6 hours (or more) the first time. People who do the Dorman/Greentec thing have got it down to 1.5-2 hours, but there is more to doing OEM swap.

Yes, you can do it yourself, but you need to take proper precautions because you will be dealing with HV DC current which will kill you.

There is a video on the net that was made by one of the battery "rebuilder" outfits, that shows how to replace the HV batt with one of theirs (Don't use a rebuilt btw). I'll see if I can find the link, but a search here should turn it up as it has been posted here several times.

In the early stages, you will get to the stage where you can measure the open voltage.

Of course, with techstream, you can do it with out dismantling anything.

Post back if you have any further questions.

 

Here's the video:

HV Battery Installation

hope this helps

 

Then what are you going to do with it? I personally wouldn't spend my own money for a new HV battery just to maintain someone else's museum piece and drive it around the block every now and then.

 

Keep in mind the pip lines on the battery graphic do not necessarily reflect the same amount of charging for each line. I suppose if you are really low it might take more time to get the charge up.

 

post vin number. Since you dont no andody with a smart phone to post pic for you how rare smart phones just as prius 2005 with 200 miles

Post vin number to see what tell the from is true

 

If you're a DIY sort, it is MUCH easier to get these readings along with much more information from the white OBD port underneath the left dash just to the right of the steering wheel. Using an OBD cable hooked to an older winPC laptop that has Toyota's Techstream software loaded on it will reveal tons of information about the car.

Or you can take it to any Toyota dealer or hybrid specialist shop and let them do it (for a diagnostic fee of course). The greater NJ area should have tons of choices.

 

"The HV battery was disconnected from the vehicle via a latch/lever type connector in the rear, we knew about that because the owner had left a note in the car saying what was done to disconnect the power and where all the spare parts were stored. Every car had similar notes placed in large envelopes left in each vehicle. I think he actually figured he'd eventually be using the cars again at some point, but he never recovered and passed away 12 years later."

It sounds like to me that the orange safety plug is not completely installed correctly. What I would like for you to do (for my own peace of mind) is have you check the orange service plug to ensure it is properly inserted. This will seem elementary but please review this document in detail (page 21-118 is what applies). Pls pay specific attention to step 9. (c) on page 21-118. Many people (including qualified technicians) tend to forget this step. Pls verify the plug is installed correctly IAW this doc.

 

You cannot get a voltage reading at the safety plug. This basically splits the battery in near half when removed., and without the car in ready mode the other ends of the battery are disconnected, and cannot be connected until the safety plug is correctly in position.

John

 

Please don't go poking around. It's 300+ voltage.

Here's what I used: Amazon.com: Fotga Newest V8.00.034 MINI VCI for TOYOTA TIS Techstream Diagnostic Cable & Software Model: ZB031 Car/Vehicle Accessories/Parts: Cell Phones & Accessories plug into OBD port and USB port on laptop.

 

I agree with your safety point on the voltage, but it is 201.6 volts nominal.

 

No

 

DOH! Brainfart. I should have remember that since I use a gridcharger every month that only goes to 235v.

 

One other thing to note with the Prius system the batteries both the 12volt and the HV battery cannot look after themselves when the car is in neutral.
The HV battery cannot charge in neutral no matter how long you leave it. When it becomes discharged it can no longer charge the 12 volt battery.
If the engine is running when you change to neutral it will stay running, but if it is not running the engine cannot start. The battery will continue to discharge.

John

 

I know what you mean, but I have a Lexus GS450H and that only goes a little over 300 Volts.