2017 v with 36K Playing around the other day, I hooked up my 1500 w converter to the 12 battery as a just in-case backup. I had the converter for 4 years and used it 3 times while camping on our '16v. It worked fine until the engine started then it faulted out. I originally thought the converter was bad and was going to replace it, but then I thought I would try it on out '08 with a 3yr old battery, it worked fine, even when the engine started. I checked the charging voltage on both cars and the '17 is charging at over 15v, thus triggering the converter to shut down as over voltage fault. The '08 is charging at a bit less than 15v so the converter still works. So 2 questions. Why is the charging rate higher than normal on the 17 (5yr old battery) ? Is it possible the 12v is on it's way out, (our '08 went 10 years on the OEM battery) or, is there an issue with the 12 charging rate that could be adjusted. ? Thanks in advance
The Gen 1 and Gen 2 charged at quite low rates, with the result that the battery was often chronically somewhat undercharged, unless you did a whole lot of driving. Gen 3 addressed that somewhat by boosting the charging voltage, and adding a battery-area temperature sensor so it can charge more aggressively when it's ok to do so. Still, I've never seen a Gen 3 charging voltage above 14.7 or so. Your Gen 4 has the battery moved out under the hood, with an elaborate battery state sensor assembly added (not just a temperature sensor), so it seems they have decided they can go to even slightly higher charge voltage when warranted. Your best bet might be to contact tech support for your inverter and ask if you can adjust the overvoltage alarm point slightly.
The inverter was not a top of the line unit. I might just do better by buying a new unit. The average max input voltage is around 15v, but I do see some higher end units go to 16.5v, designed for trucks and campers. Inverters designed for solar panels do have built in voltage can go much higher as the have built-in voltage limiters. Thanks for your input.
15.0V is maximum as far as my service info says, (per 2012 model year info that I have). Remove the inverter, check voltage again in READY. Inverter may be oversized is my suspicion. REVVL V+ 5G ?
Oh yeah, I saw the 2017, but didn't notice this was a v. Did v ever adopt the Gen-4-ish underhood battery placement, etc., or is a 2017 v still a Gen 3 at heart?
The Prius inverter's dc to dc charging algorithm will increase the voltage when the battery is discharged more. So a 15v charging voltage means the battery was significantly discharged. It would be useful to measure the 1500w inverter's 12v current under full load while noting battery voltage with the engine off in Ready. You may be drawing more current than the Prius dc to dc can provide, at least in the engine off Ready state. And / or the 12v battery is getting old and discharging too fast. A better external inverter with a higher input voltage is a solution, however if the load is discharging the vehicle's 12v battery you may be shortening the battery life. Which may be inevitable if the external inverter load is excessive. A preferred solution is a separate high capacity, deep discharge battery with a battery isolator.
As previously noted, a Gen3 can charge at a higher voltage and rate than does the Gen2, so this might be causing the overvoltage trip. Gen3 has multi-stage charging depending on battery state of charge, while if I remember right, Gen2 is fixed to a single lower-voltage stage. But Gen3s still tend to have undercharged 12V batteries. If you can get the 12V battery to a higher charge state, the Gen3 charging system won't step up to as high a charging voltage, and this might help in avoiding the overvoltage trip. Then run the inverter only with the car in Ready mode, so the battery doesn't deplete and kick the charging system back up to top voltage when the ignition is turned on. Even if this works, it might not banish all trips, just reduce them. And I can imagine this mechanism being a problem even if the 12V battery is not otherwise nearing its end of life. Also, don't ever plug in 1500 W of load, keep it under 1000 W.
