Prius Battery with no codes but not optimal

1. The Prius state of charge gauge typically should reside in the 3 to 6 blue bar area, unless you have descended a relatively long mountainous road in which case it may rise to 7 or 8 green bars. It will drop down to the 1 to 2 red bar area when the air conditioner is in heavy use and the car is in stop and go driving.
2. You need to consider that the ambient air temperature in your area has risen from an average high in the 20's back in January, to the 60s in April. That may have an impact on the battery performance.
3. If you don't have any warning lights on, just drive and don't worry. Your worrying is not going to help the battery to do better.
4. If you insist upon worrying, figure out how you will fund an eventual traction battery replacement. Once you have that plan in mind, then worry no more.

 

I agree with not worrying too much about it. You have a chemical battery that's twelve years old and has seen many charge cycles. If you like this car and are willing to invest more in it, it may be wise to start a battery fund, in addition to looking at options as you're doing right now.

I was in this same situation about six years ago, and was able to replace my battery with one salvaged from low-mileage wreck for a net cost of $500 ($800 battery less $300 "core" sale), plus a couple hours of my time. But almost all salvage batteries will be in the nearly same shape yours is in now, or will be in a year or two. So I wouldn't go that route now because I want to keep my Prius for many more years.

Some are using Hybrid Automotive's Prolong Charger to keep the battery "conditioned." Options start around $400, and some report success.

Others are replacing individual modules as they fail, with some success, and some games of Whack-a-mole and plenty of service interruptions. Hobbyists might enjoy doing this.

One member here replaced the Gen2 modules with a full set of salvaged Gen3 modules. I would pursue this route personally, since I'm comfortable doing the work. and it would likely cost under $1000.

If you really like the car, the best option will be to get a new Toyota battery, for a minimum parts cost of $2100 plus labor. Most dealers will quote up to $4000 for the job, probably more than the market value of the car. Start shopping.

 

Look into getting a "grid charger" for HV battery maintenance.

Also, keep a close eye on oil levels/usage.

 

here's the prolong developer: @jeff652 you might be a prime candidate.

 

There are signs when the battery is weakening. They are subtle but visible if you know what to look for. Here is a guide that might help you assess your battery's condition:
How do I know if my hybrid battery is failing? - Hybrid Automotive

If you start to service and maintain the hybrid battery now, you can likely add several years to its life without having to replace it. If you wait until a red triangle is present, odds are a module or two will need to be replaced. Either way, our products are the lowest cost way to efficiently extend the life of the battery pack. We have sold thousands of systems all over the world. You can Search PriusChat on Prolong Battery Systems to read some reviews from other users of our systems.


Jeff