What are the warning signs,that the hybrid battery will fail soon?

short, fast discharge and recharge cycles - while driving. Change your MFD, so you can see the current pathways and battery status.

Hope this helps....

 

Well in Vermont and being in a generation too even the last of those in '09 you would be at the point right now or you would be thinking about just what you're thinking about You're very close to due generally speakin. There are a few that have made super high mileage on the original battery whether they worked on them during that time or not I am not sure people get flaky when they're describing things sometimes leave things out don't remember etc. But going from the extreme heat or very warm to very cold for 13 to 15 years I would say be ready and the other post about going very quickly from blue to magenta to green to blue to magenta very quickly 10 minutes 8 minutes things like that is a definite sign that things are getting ready to take a dump.

 

When my HV battery failed I had noticed that fuel consumption went down from 42-44 mpg to 38-39 mpg a few months before the triangle of death. Also, many mornings when I started the car the HV battery meter went from half full to empty within 1-2 minutes.

Anyway, on year 14, (I bought the Prius brand new) I had the battery professionally rebuilt with 4 new modules for about $550 and today 3.5 years later still runs strong.

 

Same here I guess I'll get to find out how this really goes I have a very professionally rebuilt battery and a generation 3 that's about sitting right at a year now doing well with the air conditioner and on it comes down about like it always did My wife is one of them people that runs the air a lot without the car on so you know battery hovers around pretty low pretty good fashion but it charges right back up but what you describe is perfectly normal in my personal '09 when it came time I just bought a new battery the local refurbishers didn't seem like what I needed to be doing then I found the hybrid doctor up in Virginia and he set up like you're supposed to be to do this work.

 

if you hear a pop sound from the back, pull over and get out!

 

That may just be the illegal fireworks in his trunk..... Sorry, 4 of July humor......

 

if the rate at which it is doing that has quickened, your capacity has dropped, and your best bet is a swiss clinic for the terminally ill.

 

If it can’t make it through a traffic light without turning on the engine it’s getting bad bad

 

SORRY; watch out for the grim reaper - there's a red triangle waiting for you in the near future. Start researching replacement/rebuilt packs NOW; if your planing on keeping the car. You can sell it, for a halfway decent price - if the red triangle doesn't pop-up on the test drive.

 

I think as long as you are getting in the green and have multiple blue bars then you have some capacity left, 50% possibly, but it only takes one cell failure. If you can clean you Hybrid fan, and you could trickle charge your 12v battery up to full periodically, I have noticed that has helped my HV battery from dropping down to 1 bar when sitting in the driveway.

 

The symptom which worried me most about our 2007 was that the voltage would collapse rapidly and then the engine would start in stop and go traffic at night (headlights on). There is a Trader Joe's we visit pretty often which has a high school tutoring outfit near the exit from the parking lot. If one has the misfortune of trying to leave the lot when the kids are getting out of class it takes at least 4 minutes to do so, and the car only inches up a car length at a time. Our old battery really did not do well under those conditions. Never had a red triangle from it though.

 

The battery can get weaker than normal at low charge when worn. This can cause the engine on behavior and can reduce power for low speed acceleration that you had with a good hv battery at low charge. Sometimes oil burning will have created excessive carbon in the cylinder and combined with low hv battery power can cause engine pinging when accelerating from a stop.

 

That's the symptom of at least one or more dying cell. The other cells, in series, around it, needs to pickup the slack; ergo rapid charge and discharge cycles. Eventually that weak cell will either die completely or short-out, that's when you'll get the red triangle. In the meantime, your really working the cells around that weak cell - the rapid recharge and discharge cycles overheat the formerly good cells around the bad cell(s) - causing a cascade failure. Cleaning your battery cooler vents will help a little bit, along with running your AC - but your AC draws power, so the benefits are questionable.This is why most people play wack-a-mole, while replacing only a few bad cells in a pack. "Well the car's running and I don't have a red triangle - I'll just keep driving it."

IMHO; if you catch the issue early and replace that bad cell right away, your less likely to take-out the rest of the pack and play wack-a-mole.

Hope this helps.....

 

Cycling between blue and green in stop and go traffic sounds normal to me. I knew my battery was going bad as when leaving my house in the morning, with battery on green, it would hit purple by the top of the hill exiting my neighborhood.

 

Exactly. Or the car is in the low blue bars, it stops at a light, the motor turns off, when the motor turns back on the SOC immediately drops down to two purple bars, but after driving it for no more than 30 seconds it is back up to something like 60% SOC. That is, large SOC changes not easily explained by electrical discharge or charging currents.

 

You can't replace cells in a Prius. Cells are grouped in batches of 6 encased in a module. These modules are not serviceable at a cell level so the best you can do is replace a module when you see a module has one or more bad cells. Typically a bad cell is revealed by module voltage being 1.0-1.2 V (or more) lower than its peers.

 

Sorry, let me clarify. What I meant individual batteries. I thought it was obvious that no-one would crack open the plastic case of a battery and deal with the mess; much less try to rehabilitate the individual chemical plates within.

When you mentioned "modules", are you speaking about the pair of batteries (grouping id by diagnostic software) or individual battery?

 

Yes, I mean the individual battery modules of which there are 28 in a Prius hybrid vehicle (HV) battery. The paired modules that are monitored are called blocks. It is not me who came up with the names, it is what Toyota calls them.