Long term charging of 2014 Plug in Prius

Negative my EV mile record setting forum friend. 85.0 is theoretical full charge, although I generally see 84.3-84.7 if the charge has completed more than a few hours prior.

 

The most common advice about lithium-ion cells is to charge them to about 40-50% nominal SOC for long term storage. This is low enough to keep the long-term calendar degradation of the battery from being worsened by a high state of charge and it is high enough to leave a large buffer against any eventual slow self-discharge.

 

My owner manual states exactly as bisco said: leave a small amount of SOC before storage. So small PiP changes from EV to HV mode.

However, another chapter states, that you have to READY your PiP once every two to three months. If charge drops enough ICE will come on after about 10 seconds. If so, leave it running until ICE is done recharging battery. Then power back off your PiP.

And of course, owner manual also advises to maintain your 12V battery charge, add at least 20 litres (5 US gal) of fuel every 6 months, disconnect charger from the wall, after 14 days Smart Entry & Start might not work (you can switch it off manually)...

 

sounds like the best advice is to keep driving it. my father wanted to buy one, but 6 months here and 6 months in florida, i advised against it. it's just to much to worry about.

 

OP, is your PiP still under warranty? (bumper-to-bumper or battery-only - CARB, etc) Due to the limited age of any PiP, I would assume this is the case.

If so, it is my opinion that you'd be a fool to do anything other than what the manual recommends. If your battery fails while you're following the instructions, it is Toyota's problem. (And honestly, I'd gladly trade the inconvenience of having to bring the car in for service for a new battery anyday.) The unlucky gentleman in the other thread referenced earlier is only SOL because he imported a grey-market car from one country to another, which is by its nature a huge risk.

Don't over-think this, and don't assume that anyone knows better than Toyota regarding what's best for your car.

 

All of the devices containing LiIon batteries that I have had had some sort of parasitic load from the device; with all the "smart" controls in devices these days, "off" isn't necessarily completely "off"; it's really "standby". But the traction battery in the PiP is completely disconnected when not READY; only the 12V battery has parasitic loads from the various equipment in standby mode. According to Elevating Self-discharge - Battery University , the self-discharge rate for LiIon batteries at 77°F with 40-60% SOC is about 4%/month. It goes up with higher temperatures and higher SOC. So given the Toyota recommendation to store the PiP with the battery discharged to HV level (about 23% SOC), I can see why they say that you really need to run it every couple of months.