My car wouldn't start this morning. I've had that happen with a few previous Priuses when I went away for more than a week. My last one had to get a new battery when I was gone for 6 weeks, even though my neighbor drove it once in a while. With the Covid 19 lockdown I haven't driven for 2 weeks. I figured that with an EV I would be able to get by without the 12-volt battery needed to start the engine. Even so, I started the car the other day, put it in HV mode, revved the engine while in park, and let the engine run a few minutes until it shut off on its own. This morning I had to move my car. It was dark, the temperature the low 50s. All I got was a warning that the 12-volt battery was low and it wouldn't move, even in EV mode, even with the headlights switched off. So I jump-started it (I have a portable one for just this reason), put it in HV mode, and drove around for awhile. Ten minutes later I had to move the car back, and it started fine but there were a few warning lights on the display. I will take it on a longer drive on the highway today or tomorrow, and be sure to drive it around at least once a week.
I had a similar situation shortly after I had my 2018 Prime. The 12V was low so I put it on a maintainer for 24 hrs and it's been fine since. I did purchase and keep in the trunk a LiIon jump starter just in case. If you search the forums you'll find others in similar situations. I'm a little surprised the situation continues even with your 2019. I "think" I might have left my car in other than off or READY so it may have been my own fault but I'm not convinced. I also keep a voltage monitor that I plug into the lighter/accessory port and keep an on on the 12V that way. J
amazing how many of these posts we're getting with the shelter in place orders. might be worth investing in a maintainer, or at least disconnecting the 12v negative. much easier in gen 4. i believe you can also shut off sks from the fob?
The only plug-ins that I know of that maintains the 12volt battery while not plugged in are Teslas. I don't know what the Prime does with it while plugged it. The 12v is needed to boot up the computer and flip the switches to the big battery for the Prius to start up. Once the car is on, it is charged by the big battery. The engine doesn't need to be running as long as that battery has juice for charging the starter battery. Charging up a 'dead' battery will take longer than a short drive though. A battery maintainer will take a long time to fully charge the battery, it, as the name implies, is meant for keeping the battery from discharging while sitting. That time may not be a problem in this situation. For more money, there are battery chargers that will automatically switch to a maintenance charge when done. IIRC, the one I have from HF was $40. Deep discharges aren't good for a lead acid battery. The battery protection circuit on modern cars are meant to keep it from going too deep, but you might get less life out of this battery than expected now. Of course, less could be counted in months.
A battery charger/maintainer is absolutely a worthwhile investment for vehicles not be in continual use. We went bonkers with the battery states on our (seldom used) summer cars until using charger/maintainers and are now assured they will fire up whenever a "tops down" day arrives.
Just put the Camry on the charger. I first picked one up because I was hypermiling non-hybrids with frequent shut downs on the commute. I'd top off the battery at least once a month with charger. @Kedavis I recall you had issues with getting a charger for your Prime. Will running a cord out for a battery maintainer be an issue. These should be left on 24/7, and will be to even hope it fully charges up a battery to 100%. There are solar powered maintainers. No clue how effective they are at maintaining a battery(I would only use one once I knew the battery was already charged up), but they might be an option.
I ended up getting a 50-foot heavy duty extension cord to charge, and run it from my condo to the parking lot. I have to leave my front door open, so I can't use it when it's really cold pr hot. I don't use it at night as I worry about someone coming inside my condo, or unplugging the car. We actually had a homeless person break into our utility box to charge his phone out there recently. Luckily, there are dozens of public car chargers close by, so I use those more often. Now that I'm aware of the battery issue on the Prime, I'll just take it for a long drive a least once a week, and have someone do that for me if I go away for longer. Thanks everyone for the advice.
Or this, $18 dollars & piece of mind. www.ebay.com/itm/12V-10W-Watt-Solar-Panel-Controller-Battery-Charger-Kit-Semi-Flexible-A0V7/132558663387?epid=23022764765&hash=item1edd1caedb:g:vaIAAOSw7VtbyU3C Rob43
The 12 volt battery does not start the engine. It starts the computer systems and then closes a switch that enables the high voltage traction battery to start the engine using MG1. The 12 volt battery is needed to get the car in READY mode but it does not start the engine.
***EDIT, Fixed*** I posted that seller because that's where my solar panel came from, they must have recently changed that. Luckily there are many other sellers of that same solar panel that ship to the USA, then just trim it with scissors like mine. Rob43
Unfortunately, you are not charging the 12V battery when you are plugged-in to the wall outlet whether from your condo or a public charger. This only charges the Traction Battery. The only way to charge the 12V is when the car is in READY mode or if you attach a 12V battery trickle charger/maintainer directly to the 12V charge points under the hood!
The long rides should help with that. It is best to charge the battery through a charger once it has died, as that is the best way to ensure it gets fully charged.
Partly true. The EVSE will lightly charge the 12V while it is actively charging the traction battery. The rest of the time, it just sits there doing nothing but using wall electricity to keep its LEDs lit. For some reason, folks get the idea that driving a car for a few minutes will replace the energy used in running the various systems that are always running while the car is off, plus what's used in powering up the car. You can't expect the car to put the same energy into the 12V battery as a dedicated charger does in a fraction of the time the charger needs. Edit to add: I just thought of something. The fact that the charger is only charging the 12V while it's charging the traction battery means that an L1 EVSE, since it takes more than twice as long as L2, should do a little better job of maintaining the 12V than an L2 EVSE.
On my 2017 Prime I plugged the car charger in but it was not charging. I checked the 12 volt battery voltage. Then I started the car charger using the button on the steering wheel. I again checked the 12 volt battery and the voltage was the same. It is my understanding that charging the Prime traction battery also charges the 12 volt battery only when the charge in the 12 volt battery is below an unspecified voltage (low). The Plug-in Prius was different as charging the traction battery charged the 12 volt just like when the Ready light was on.
It may be that your 12V was charged enough that the traction charger didn't need to charge it? Not sure if it has that capability, but my experience seems to point that way. If you plugged in right away and started charging right after a drive, I could see that happening. But I do know that when I tried the same test after the car sat overnight, the voltage on the 12V went from about 12.4 to about 13.1V when the charger started. Within a minute or two, it started to taper off to a much slower charge rate. I don't remember the numbers exactly since it was almost a year ago. On my PiP it was more like 13.8 volts.
Thanks for all the advice. I won't be getting a battery maintainer or trickle charger or anything else, because in 15 years of diving hybrids I never have this problem except in extraordinary circumstances such as a national lockdown or a 6-week hospital stay. Today, 2 days after I jump-started & drove around the block for 10 min., I thought I’d take a long drive to charge the battery, The door wouldn’t even unlock. I opened it manually, jump-started it again, and drive for an hour, mostly on the highway. The check engine light was still on when I finished. I’ll try it again tomorrow, and wait till the lockdown is over to take it to the dealer (I have 15 months left of free maintenance). No sense fixing it now if things aren’t back to normal. The virus broke my car
Keeping a smart charger hooked up will prevent such problems, if practical. If not practical, disconnect the negative connection. Just repeating what's been said above, fwiw.
