I've searched the forum but couldn't find my exact question answered. Since I only drive my 23 Prius once a week, I disconnect the battery in between uses and I use Ready mode every week to charge the battery, which is a near new battery purchased from AAA. However, the voltage produced by the Ready mode varies a lot. For example, yesterday I used Ready for almost three hours but the voltage didn't rise much over 12v. A week ago, Ready produced voltage near 13v in less than half the time. Is there a right way and wrong way to use Ready mode that explains this discrepancy? Thanks, Lloyd
The 12 volt charging is set up to minimize the power consumption and maximize vehicle efficiency. On my car it quickly drops down to about 12.8 volts if it senses that the battery has enough charge but it tends to leave the battery only about 50% charged. If you want it to always charge at 14.4 volts you can unplug the sensor on the negative battery terminal connector. This will not cause any warning lights or other issues. There’s another thread discussing this.
I'm curious how you disconnect the battery and if you are seeing any issues after reconnecting (initializing)?
Ready mode will recharge the 12 volt battery correctly only if the temperature is below zero Celsius. Above zero Celsius, it will recharge it for a few minutes and then it will only maintain it even if it is not completely charged. As recommended by others, if you have access to a 120-volt outlet, plug a smart charger into your 12-volt battery to recharge it. If no power outlet nearby, unplug the plug near the negative terminal of the 12-volt battery so that the DC-DC converter always charges to maximum when in ready mode.
