Best way to do Long Term Storage?

The advice is to drive the car from time to time. Use electricity or gas. You have that choice with the HV/EV button. At home, plug in randomly rather than every night.

We have been patronizing local business. They are still working to provide food services and they still need money. So, it's out to get something to eat. The improvised curb-side delivery has been working great too. There's the drive-thru for the local coffee shop too. Eventually, you'll run out of some supply (toilet paper), so you'll need to run an errand for retail anyway.

 

We travel frequently for 1-2 months at a time. I make sure the gas tank is full, EV battery is at 50% charge, unplug it from the charger, and put a battery tender on the 12v battery. If possible I’ll have a friend come over 1 per month and drive it with gasoline, but there are many times I just have it sitting in my garage. Make sure you use a quality battery tender; they’re not very expensive. If I’m only gone for less than 2 weeks I don’t use the tender. In your case it’s pretty easy to just drive it around a bit, both in EV and Gasoline once a week and just manage the charge.

 

For long periods without use, apparently the best is keep the charge to HV level (no more than the 20% HV charge). Read that here somewhere.

Give it a bit of charge now and again to keep from draining the battery too low. Probably by driving it a bit, best for tires too.

 

Most shelter-in-place orders allow some essential travels such as grocery shopping and a visit to health care facilities. Unless you are completely locked in and can not drive at all for a prolonged period like over a month, you will have plenty of chances to drive the car albeit less frequently. I usually drive ~40 miles/day, 6 days a week regularly. Since I started working at home 10 days ago, I have driven my car a total of ~70 miles. Twice to take the trash to transfer station (30 miles round trip) and once to drop the package at the post office (10 miles round trip). I used HV and EV mixed to work both the engine and battery when I drive. I have not charged every day to replenish the battery to full now, only charge occasionally (once a week) when the battery is depleted and if I plan to drive the car following day after battery being full.

 

Incorrect. You have any recollection where you read that? It's helpful to find out the source of new misconceptions.

Think about it. Toyota's hybrid system has strived to maintain about 65% since for longevity since the very beginning, over 2 decades ago. That balance has proven itself well for a wide variety of uses & conditions, even with different chemistries. So out of the blue reading that HV level is better makes no sense, especially since that is below 14%.

Keep in mind that there's a lot of anecdotal comments passed along on the internet, some never confronted by critical-thinking, just accepted as fact. Don't be afraid to ask for links or detail to support a claim.

 

Good to get the facts, we may need to research a bit. Here's the post:

Leaving a Low Level Charge? | PriusChat

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The large or traction battery should already be electrically disconnected by the car's safety design. Don't further mess with it.

 

When doing that research, the comment posted is revealed to actually be part of a question... someone looking for confirmation of that being a valid suggestion. It's a good example of how hearsay gets passed along and later ends up becoming assumed fact.

In this case, it is easy to see a red-flag about the supposed advice, because the second sentence doesn't make any sense: "After confirming that EV mode has switched to HV mode, turn the power switch off." It's an illogical step. EV mode is always default. Switching to HV just prior to powering off achieves nothing. There is no point stated for doing that either.

The first sentence tells us more about the circumstance of the post though: "Leave a low level of charge in the hybrid battery (traction battery) when leaving the vehicle undriven for a long period of time." What was stated as the "hybrid battery" has been misunderstood to only represent the HV quantity, not including the EV quantity. t doesn't state whether that "low" represents the usable portion of the pack or the entire capacity either. So, you end up with a confusing mess of numbers the reader must interpret on their own.

This is why I share those driving videos with the ODB-II data added. That extra information provides insight to nudge people's brains for desiring a closer look. You discover there's more at play than a simple value being stated at any particular time. It's a complex system Toyota worked hard to create a "for dummies" interface.

 

I can understand your criticism, but the sentences quoted are a direct copy of the PRIME owner's manual. You should send your video to Toyota HQ.

 

@Robert N Lute just how infrequently are you driving? For example, are doing a once a week toot to the grocery store? Or less?

Just assuming you're situation is not crazy extreme, you're driving maybe once a week (say 10 miles at least), I'd recommend to get a smart charger for the 12 volt battery, that's about it. Those chargers can typically be left on indefinitely.

That's our current scenario, with our 2010.

 

I had a conversation with the woman who oversees Toyota University training materials. She was well aware of what I do. We discussed the content I provide as a consumer, having no connection to Toyota other than having purchased their product. Her feedback is why I am taking so much time to research Prime prior to creating a User-Guide for it. I also wanted this particular document to span the technology, rather than a single vehicle. So, it could be quite timely for RAV4 Prime rollout... especially with me working from home now, no longer spending time driving the daily commute.

 

As others have interpreted in the Leaving a Low Level Charge? | PriusChat thread, I understood Toyota is recommending to exhaust the EV range of traction battery to 0% during long storage to minimize the battery capacity reduction over time. Does your suggestion differ in this regard?

 

I found this one interesting toward minimizing capacity reduction:

●Use the charging timer function as much as possible in order to fully charge the hybrid battery (traction battery) immediately before starting off. (P. 157)

So, don't leave a full charge in the battery. Charge it to use it, not to let it sit around.

 

Ya know, you could get banned from all car forums for reading the owner's manual.

That makes a lot of sense, John, when you compare it to the non-plug in battery. So did Toyota screw up when writing the Prime manual? I've always been careful to use the departure schedule to avoid letting it sit long term or even repeated overnights because of what the manual says. In fact, mine has been sitting for two days with 50% range left and I'm feeling like I need to find a reason to go someplace to lower that SOC. Not stressed, but it's in the back of my mind.

 

Teacher, I learned something. Can I go home now?
More seriously, I was not aware that they were so specifically differentiated chemically. Thanks, Tide.

 

...and the gen-1 Prius PHV. For 5 years of ownership, that was the advice we shared. It made sense too, since all of the rest of the industry was in agreement. The same thing carried over to Prime. I never once heard otherwise from any other type of plug-in owner.

We know the owner's manual is intentionally generic. So, it's nice to know when we stumble across a new specific. For example, different advice can come about from different usage patterns.

Where exactly does this information about changed chemistry or lessons-learned come from?

 

I think I'd really like to read up on that, so some more info would be nice. I'm not a chemist, but some info on what's different about it should be interesting.