Should I buy a new battery

No you do not have to buy a new battery.
You can replace that bad cell.
But before replacing that cell, check for corrosion or damage to the connections on that cell. It may just be giving bad readings but is not actually bad.
While in there, check and test the rest of the cells and connections.
These batteries are very serviceable and are not that difficult to understand and work on.
In the case of going DIY on it, read up on it and follow the important safety steps and procedures before you begin.

 

module 5 is bad at 13v while the rest are near 15v. You can just replace that module if you're a DIY capable person. My cheap Prius has the same issue before where I just replaced 1 module and grid charge it. Replacement module can be bough online from a guy https://2ndlifebattery.com. Still works for a year now, it's my son's daily driver.

 

It is module pair 5 that has a low voltage. There are two modules measured in series and each module has 6 cells in series. You can't tell which of the two modules in module pair 5 has a bad cell until you measure each module voltage with a multimeter. Note that the replacement module should be a match for the remaining 27 good modules if you want your repair to be effective. It should have about the same capacity (amp-hours), effective internal resistance, and state of charge (voltage at rest). Do a lot of reading about the process used by experienced PCers to fix their hybrid batteries that has been reported here on PC.

JeffD

 

Hello and welcome to PriusChat!

Your High Voltage battery is made up of 28 modules connected in series. The battery ecu (computer) monitors the voltage of the modules in groups of 2 - so that's 14 battery "blocks".

On your report it shows block 5 with voltage of over 1V lower than others, so one of the two modules in that block has failed.

Can't really predict how long it can go "before it just stops". When the ecu sees a "minor" fault (voltage differences between any of the blocks), it will turn on the warning lights, overall performance and mpg will go down as the battery degrades.

Eventually the things get worse & the ecu sets more codes and "that's it" - it won't run.

Some people have a scantool that they use to clear any codes- this lets them drive for a few days or weeks longer before the battery fails completely (sometimes with a "bang" as a module explodes).

As the HV battery gets older, the modules lose capacity. That's OK as long as they do so EVENLY. If you "just" replace the failed module, it is very unlikely that the "new" module has the same capacity. When the ecu sees different voltages, that's when ot sets codes for the battery.

Getting a "refurbished" (rebuilt) battery is a crapshoot. These are used modules that might last a few years, or they might fail a couple months or weeks after installation.

If you go this route, understand all the details of your warranty, ad you will likely need it.

Posted via the PriusChat mobile app.

 

I believe member PriusCamper does battery work in your vicinity. (His location is "Pacific Northwest".) Perhaps send a PM and he can give you some advice. Be aware that refurbished batteries are still composed of old cells, and may not last very long. In this forum many of us do not recommend that people without some economic resources purchase these cars because while they are cheap to drive when they work, some of the repairs can be pricey. If you know somebody who can do the work for you for free a new OEM battery is around $2K (get a price from each local dealer - some sell well below the MSRP), and a ProjectLithium (https://projectlithium.com/) one about the same (but I think they are out of stock right now.) A new OEM battery would probably last another 10-15 years, but it might not make sense to spend that much if the car has other major problems. We don't know for sure how long the LFP batteries will last though as they have not been around as long as the OEM NiMH batteries. Again, PriusCamper can walk you through this.

(Assuming Portland is Oregon and not Maine.)

 

Buying a new battery vs. refurbished...depends.

I ran into this after my CAT got taken and I waited for the dealer to install a shield. My prius sat stone cold for a couple weeks and a single weak module caused a failing block.. Voila Red Triangle.

I have a spare car, so I had time and curiosity.

Putting a new module in "can work" in the immediate, is cheap, but won't last long (< 1 yr). In my case, I had one module fail, but ultimately had to replace three modules that were about to fail (just like replacing headlights).

Finding a module that matches assumes you can measure capacity, etc. There's the rub. Buying used modules, even from known refurbishers (vs. ebay) is a crap shoot. They are all using old modules by definition. If you want to do more than slam a module in, you need to buy a grid charger ($700ish) or buy some hobby chargers ($200 ea). Cycle time per module to safely recondition with hobby chargers is about 3-4 days per module, 2 runs ea, 12 hour runs. Disharge takes forever.

28 modules * 4 cycles * 12 hours = 56 days if you never stop. one quad hobby charger ($200) means at least a couple of weeks.

So...

1. All of these options start with taking out and handling a high voltage battery. Once you've done it, you've eliminated the largest cost - mechanic labor. If you remove the battery, replace bus bars, check HC ECU and cables for corrosion. Clean everything with rubbing alcohol.

2. Cheapest, fastest - Pull the battery out, measure the voltage on each module, wait 24-48 hours and measure again. This will give you "some" fast indication of weak modules. Buy 2x the pre-charged replacement modules that are weak to be safe, discharge the new modules to match the most common voltage on the other modules, re-assemble and get on the road.

3. Depending on how many weak modules, might be cheaper to buy a junker battery whole from a junkyard - same year and model you have. I did a pull-your-part for $300 and got 28 modules. That's the same price as about 8 ebay modules with shipping, etc.

4. Common experience in my area is purchased reconditioned batteries last 1-2 years, cost about $800-900 installed. New Toyota battery in my area is $1600. If I can scrounge up the cash, there's no comparison - new battery vs. reconditioned old battery,

5. The lithium option sounds great, but they are always out of stock for months and price does not include shipping - from the L.A. area, I believe. I couldn't wait that long. Also single, new (and innovative) supplier. Think replacement parts....

6. My rig is 4 quad chargers ($800) and 2007 and 2010 junker batteries to work with as cores. I have three hybrids (2 prius) so it's worth it for me to build and then maintain a couple of spares. At the lower amperage, low time method I use it still takes about 2 weeks per battery (of 28 modules). It's also a hobby. Not cheap, learning how to do it with all the opinions, not easy. Definately not fast.

If I needed to get back on the road fast and cheap, I would have done #2 (frankenbattery option). If I had some time, with a single car I would have done #4, it's a no brainer (although you have to give back the core). Removing the battery yourself is a no-brainer if you are careful (pull the plug, put it in your pocket and wait 5 min before touching anything, don't touch module terminals until the bus bars are off) and the maintenance you do can extend the life quite a bit (or so I'm told).

That being said, I'm happy with my results, got my capacities up > 6000mah and found some cells soon to fail. I spent about 2/3 of a new battery for a system and rig that I will be re-using and it's been a fun exploration. YMMV

 

I have two "hobby" chargers and they cost about $35 each, not $200. You are correct that the discharge cycle is slow due to the heat dissipation limit of the charger so it does take a couple of days to balance each of the 28 modules.

JeffD

 

The LKQ nearest to me never has any packs. Zero. I asked why and they said they have a deal where they sell them in bulk to one of the pack remanufacturers. (They wouldn't tell me which one, or how much they get for them, and they wouldn't let me buy one for more than that. The deal is that they all go.) I don't know how LKQ runs things, maybe they are all like that, or maybe they are independently owned, like a McDonald's franchise.

 

A grid charger is more like $300 from maxx volts. Price goes up based on features and if you get a built in discharge system. I believe prolong starts around $400.

 

$35 for a quad charger? do tell, please. If you mean single chargers, indeed, it can be scaled down but with two chargers you can double the time I quoted. If you have the time, it certainly works, it's all a matter of how much time you have, the chargers all do the same thing, more or less. <2a discharge is a real bummer for all of us

 

Last time I checked, Prolong with a discharger and the cables so you can leave the battery in place was about $700-800. They do have cheaper options if you don't want the discharger. However the discharger is much more than a lightbulb and switch. Some have reported the tapering discharge method really helps with capacity. I've not tried it.

The Prolong® Battery Discharger is an innovative new automated hybrid battery discharging device. It features 1.5A-200mA auto tapering NiMh Hybrid battery discharging, delivering 1.5A load to the battery pack while in the battery’s normal operating range. As the battery drains below the normal operating range the load is reduced first to 0.5A then again to 0.2A to protect the battery from damage during deep discharge. It has three user selectable discharge termination voltage options, allowing you to simply set the desired minimum voltage, press start, and walk away. It will safely drain the battery pack to the desired voltage then turn itself off and sound an audible alert when finished. The Prolong Battery Discharger has multiple safety systems including thermal protection and excess voltage protection to protect itself and your hybrid battery.

KEY FEATURES: 1.5A-200mA auto tapering NiMh Hybrid battery discharging

Three discharge termination options: Pack discharging to an average value of 0.8V/cell, 0.5V/cell, and 0.1V/cell

Audible alert when discharge finished (can be turned off if desired)

Compatible with all Prolong Battery Systems Discharge Ready Car Harnesses

 

FYI, I just got an email if you're considering lithium:

The highly anticipated Nexcell Lithium Version 2 AUGUST Shipment Pre Order begins NOW

Arrival and beginning of shipping slated for mid August. All pre orders will be fulfilled at a first placed first served basis.

July Pre Order was sold out in 3 days. We appreciate all your patience as we are ramping up production to our best capability. If you have any questions, please feel free to email us and visit us

That's Nexpower energy dotcom.

Prius Gen2, Gen3, CT200h Lithium upgrade pack V2 - 14 blocks
Sale price
$2,120.00
Regular price
$2,310.00
SALE
shipment delivery time depend on Los Angeles port efficiency
Pickup available at US - Warehouse

Usually ready in 24 hours

I have no affiliation, I do respect the innovation being done here and I am not selling anything.

 

Replacing a bad cell is just a temporary fix... Soon after you'll be relacing another bad cell