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Info on 12 volt power converter?

Discussion in 'Gen 2 Prius Technical Discussion' started by SteveWlf, Mar 25, 2014.

  1. SteveWlf

    SteveWlf Old-on-Hold

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    2007 Prius
    Model:
    II
    I have a 2007 with about 190,000 miles. Running great (with my Plug-in Supply 10K rechargeable pack)!
    Put a new Yellow Top Optima in just a year ago due to OEM dropping voltage to less than 12.4 volts and throwing a bunch of codes and the Red Triangle and other dash displays flashing. The now battery solved that problem for year and 20k miles now, the problem is back again.

    Each time I get the Red Triangle, etc. I still have the Ready indicator as long as I don't turn of the Power switch. Once I do, I have to try and clear a bunch of code and sometimes recharge the 12 volt battery before I can at least get the Red Triangle to go off. I still will have other ABS and VSC. etc.. These won't clear but sometime go away after driving some distance.

    Initially I thought this had to do with the cold weather and at times I would use the electric defrosters in the windshield duct and the rear defoggers along with the headlights. (too much power draw for the power converter. However, over the last couple days, the problem has continued and is almost daily, even after I charge the battery each time I return home. Now it is to the point I had to return directly home after about 15 miles after charging the battery.

    I have put a battery load tester on the Optima and it test normal. Just won't stay up, almost like it isn't getting a charge from the power converter.

    I have no idea of how to determine the charge voltage to the 12 volt battery.

    Any thoughts or experiences would be appreciated.

    Thanks,
    Steve
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    That is very simple. Measure the voltage across the 12V battery, when the Prius is READY. It should be ~13.8VDC.
     
  3. nh7o

    nh7o Off grid since 1980

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    You might have a bad connection to the ground, or the terminals themselves. Check that all is tight.

    You could put a voltmeter on the battery semi-permanently, and run the wires forward so that you can see what is happening. Or, use one of the monitoring tools (scangauge, torque...) to see what the car is actually setting the battery voltage at. You should see something like 14.2V initially, and 13.5-13.7 volts after the car has run for a while.

    The way that car people test a battery is to measure cranking amps on a short duration load, and that won't necessarily tell you how it performs in the Prius with a constant long term load.

    There seems to be a few stories about the Optima's not being everything they were hoped to be.
     
  4. dorunron

    dorunron Senior Member

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    I would do what Patrick suggested. Check the voltage at the battery posts when the Prius is in "Ready" mode. I would also confirm that all the connections are tight and that no corrosion is present as nh70 suggested. It has been suggested more than once to confirm the ground connection at the frame by several here on PC. I concur with that statement.

    If all of that looks good, I would then charge the "yellow top" with a desulfating type charger at a high voltage to see if you can raise the resting voltage.

    It would not surprise me if your battery has begun to sulfate. The battery in the Prius does not have a very large capacity, so it doesn't take much to make it weak. According to spec, the yellow top is rated at 38 amp/hours. With sulfation beginning to set in, surely the capacity is reduced. Hence the lower capability of "holding a charge". If that doesn't help then either the battery needs to be changed again or you need to do some checking on the Prius itself.

    It would not surprise me if you were to put in a new battery that your problem would go away just like it did last year when you put in the new yellow top.

    When you are charging the battery with your charger, are you using a charger that has AGM parameters on it AND is the AGM parameter selected?

    Refer to the following website for voltage and amperage utilized for optimum recharging of the "yellow top" battery.

    Support - Battery Care - Charging | OPTIMABATTERIES
     
  5. lopezjm2001

    lopezjm2001 Senior Member

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    I had the same problem of dying 12v batteries before. Like you I also have a PHEV kit and other added components which may be putting a small load on the 12v battery when the Prius is switched off, but a small current over a lot of time adds up to a lot of enegy used leading to a flat battery. I installed a 12v battery charger so that when you are charging your PIS PHEV kit you are also charging your 12v auxiliary battery. So I leave my PHEV kit plugged in all the time when not driving my Prius.
     
  6. SteveWlf

    SteveWlf Old-on-Hold

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    I appreciate all the responses and suggestions.
    I was able to finally clear the read triangle today but the Torque Pro program reads the battery voltage of 12.8 volts even after I have charged the battery with a final voltage at the terminals of 13.7 volts. However, I still had several dash indicators that hadn't cleared the display yet (ABS, VSC.)
    Strangely, Torques Pro never shows any codes so. So I had used a"Prius aware" OBDII scanner to clear the Read Triangle even though it wouldn't show any codes, I kept telling it to Erase Codes, confirm Erase Code and it finally cleared the Read Triangle and the other dash displayed warnings. I then connected Torque Pro again and was reading 14 volts on the 12 volt system while in Ready. Went and checked at the battery terminal and it was 13.4 volts.

    Regarding the suggestion of lopezjm2001 about keeping the Optima on trickle charge. That is what Robb at Plug-in Supply had suggested. I want to do that but my normal charging arrangement is from my Level 2 station at home or at public stations. The 12v charger being 120v AC I would have to run a second cord for the wall outlet or Level 1 hookup and with out a bumper connector that would have to be through the hatch or cracked window (something I have done on occasions for a small heater or charger). Maybe I will put a 120v connector in the bumper. I can't tap into the internal connection for the Level 2 since the charge station cable doesn't provide the neutral lead for 120 volts and if I try to sneak a connection to the Ground the charge station will go to Ground Fault (I would suspect, haven't really tried that yet.).

    Will see how far I can get tomorrow before the Red Triangle comes back on. In the mean time I will put a spare jumper battery in the back. That has been my insurance before when I had a questionable OEM 12v battery.

    Thanks for follow this thread.

    Steve
     
  7. Britprius

    Britprius Senior Member

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    Buy a UK battery charger 220/230 volts, or a charger with a switch mode power supply. These can use any voltage from around 80 volts to up to 260 volts without having to select the correct voltage. The output voltage is not in any way affected by the input voltage.

    John (Britprius)
     
  8. epoch_time

    epoch_time Active Member

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    Check your inverter/converter cooling pump. You should see waves/ripples in the inverter coolant reservoir when prius is in ready mode.
    You can also feel coolant pump vibrating due to its slightly unballanced internal rotor, when it's running.

    Also torque pro can light vsc and abs indicators if odbII communication protocoll is set to auto/search.
    Make sure odbii protocoll in torque's vehicle profile is set to iso 15765-4 can 11 bit 500k baud.

    The genII 12 volt converter that charges the 12 volt battery and runs the 12 volt accessories is rated at 90 amps.

    Also torque pro with usbseawolf's extended pid file can display hv battery module voltages. And module voltage differences.

    I believe either you have overheating inverter/converter or bad high voltage battery module.