Can anyone help with Dr. Prius app?

Discussion in 'Gen 2 Prius Technical Discussion' started by ecut1, Jul 19, 2021.

  1. ecut1

    ecut1 New Member

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    Hi everyone,

    I have an 05 prius with 140k miles. I bought it with a bad gas motor which I replaced. The problem is... it sat for about three years. After replacing the engine, I pulled the hybrid battery and using a volt meter and a hobby charger I replaced two bad cells. Now after about 500 miles or so it's back to the red triangle. I downloaded the Dr prius app to try to figure out how many cells to order before pulling the battery. The full battery test on the app gives me different readings every time from "congrats, no problem" to "high side unbalanced" and on just about every pack. So I'm thinking maybe just the battery monitor on the app will give me the info need? How do I read this app? I'll upload a screenshot.
     

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  2. mr_guy_mann

    mr_guy_mann Active Member

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    Hello and welcome to Priuschat. What codes are you getting with DrPrius? The battery computer compares the voltages of all 14 blocks. If difference between the lowest and the highest is too large for too long it will set a code for the lowest block "becoming weak"- the greater the difference, the less time it takes to code. If the modules that you installed are much stronger than all the existing ones then the NEXT lowest block will set a code. Repeat the whole process again as needed- it's known as "whack a mole" on the forum.

    You (or a passenger) can watch the battery monitor screen while you are driving- you're looking for any block that is consistently lower than others (0.4V or more) while accelerating or goes higher than the others when decelerating. You can also watch voltages while sitting at "ready" with the A/C and lights on to discharge the HV battery. The app does have a logging function, but it saves as a .csv excel file- clumsy to interpret the data. Another option for android is the Hybrid Assistant app- logs data and displays as great looking charts.

    There is a HUGE thread somewhere on the forum about DIY battery refurbishing. Short form; you can use hobby chargers to cycle each module 3-6 times (or more) to try and get even capacity (measured on discharge cycle). Can take many weeks to "do it right" . Next option- replace all modules with a used set from a junkyard. Next- get a rebuilt or refurbished battery- generally only a short term solution, lasts a few months to a couple years (better understand the warranty terms). Last is to get a NEW set of modules from Toyota (or Newpriusbatteries.com) -should last for 10+ years (but highest cost).

    Posted via the PriusChat mobile app.
     
  3. PriusCamper

    PriusCamper Senior Member

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    Dr. Prius app is good place to start.. Then...

    --Hook a 12v 50w bulb to each module and record voltage drop in 2 minutes and add it to spreadsheet (load test)

    --Deep cycle each module and recharge, first down to 5v, then 3v, then 1v (reconditioning)

    --Make sure to not recharge all at once on deepest discharge, use a powerful cooling fan, also a thermal camera to find overheating cells.

    --Once deep cycling is done put on a high voltage trickle charger overnight to balance all modules to same voltage

    --After three days check self-discharge voltage numbers

    --Do load test of all modules again

    --Study spreadsheet and replace the weakest modules

    --Do balancing of all modules again

    --Start up car and be happy your warning lights are gone for 3 months to 3 years
     
  4. mr_guy_mann

    mr_guy_mann Active Member

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    What's your pass/fail limits for voltage differences during your load test?

    Don't forget mentioning to keep the modules properly clamped during the entire procedure so they don't swell.
    Posted via the PriusChat mobile app.
     
  5. PriusCamper

    PriusCamper Senior Member

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    My pass fail process is relative to the numbers of that particular pack rather than hard set numbers. Basically I add the self-discharge numbers, the load test numbers, the initial voltage numbers, etc on a spread sheet and mark the worst 3 to 6 modules with an X. Then I look at the whole spread sheet and eliminate modules that have the most X over time.
     
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