Battery at 25%. How long does it have left?

since it is a 2011, i'd guess around 3 years or a percent of your current miles

 

The battery is as strong as it weakest element.

The car measures the voltage on them in pairs.

Typically, center modules go bad (AKA loose capacity) faster then ones on the sides.

If you take the battery out, remove the bus bars and recondition all 28 modules, you can
a) get some capacity back - I've reconditioned successfully modules from 1.5Ah to 4.5-5.0Ah. The original capacity is 6.5Ah.
b) identify modules that are bad - can no longer pass a load test or have significantly less capacity when comparing to the rest of them,

Once all good modules are reconditioned and bad ones replaced, the whole battery needs to be balanced. Put the modules in the housing that all negatives will be on one side, connect them with a wire, then connect all positives with another wire and leave the battery for 24-48 hours.

Just finished restoring my spouse's battery from her 2012 v: she used to run out it fairly fast on car washes (when you are required to put the car into Neutral).

Did the car wash today and lost only one bar (vs her previously got beeping and begging to put the car into Park ASAP and only a single bar left on the battery).

Module reconditioning takes time. It took me two weeks to get that 2012 v battery into good shape. Used an automotive 12V bulb as a disharge load (3.5Amps) + a cheap battery meter from Amazon and RC chargers to charge modules back.

If you have $2500-3000 in the budget, the best way is to buy a new battery from Toyota - you WILL get Gen 4 battery modules. I swapped the old battery for the new one under 3 hours - they only sell cells and the metal housing, all electronics and blower motor needs to be transferred from the old battery to the new one.