During shelter-in-place

Depending on where you live, shelter in residence doesn't mean lockdown.

Take your Prius for a drive at least once every other week just to exercise the batteries a bit.

We own a Prime and I do not store the pack fully charged while we are in this period of time. Something to consider.

 

It doesn't mean that regardless of where you live.

You should drive it at least (put in your favorite number here) 10 minutes to get the oil up to temp and give the 12 V battery a good
shot of charge. IF you don't have a legitimate reason to make a "critical" stop for food, medicine, gas or a doctor's appt. then start and end your trip at home. I think once a week is plenty.

A better idea is to have a tender-type battery charger to connect and then just LEAVE IT SIT.

 

I've been running to the grocery, etc. off and on for the last two weeks. I decided to check the 12V battery in all three of our vehicles yesterday. They were all hovering around 55-65 % so I charged them. These are not old batteries, and they are all garaged. Two are hybrids and on is not. They've all been driven some, but not as much as usual. We're also coming out of colder weather to warmer temps so there was some residual cold temp effects there as well. Hybrids are frequently doing stuff in the background which will draw down the 12V battery over time.

Check and or charge your 12V battery in all your vehicles. It's the smart thing to do with this reduced travel.

 

+1 to Sam's advice with caveats......

When I was punching holes in the ocean we used to have to leave our cars for up to 90 days at a time....or even longer if your relieving boat went Tango-Uniform.

That was OK for my married shipmates, but the single guys all tried various ideas to keep their cars from being welded to the parking lot.
Some of the more OCD even rented U-Store-it stalls and put their cars on jack stands and squirted oil into the cylinder bores.
One person almost got their car sold out from underneath them when the payment for the U-Store-It stall was late due to an extended patrol...BUT - fortunately - the owner was a retired squid.

Anyway....Priuses are NOT that fragile otherwise they would be unfit for daily transportation, and I would not own one.
OK.....
I already don't own one.....but that's another story.

As mentioned above - just take it for a lap around your neighborhood, town, whatever.
It will take anywhere from 10-20 minutes for the charging circuit to restore your 12-v battery, and while you're driving you will be exercising not only the motors but the braking, steering, [sic] ttransaxle, tires, springs, and all the other systems in your car that get cranky after forced hibernation.

WADR to Mr Spade, cities, states, and any other entity ending in "dot.gov" have very broad powers under the USC and history provides a few examples where curfews were rigorously enforced. A city sometimes called Los Angeles and another city sometimes known as New Orleans offer recent examples.
Not so recent examples can be found in the Lincoln, Wilson, and Roosevelt administrations, and very long time residents of a little territory I like to call 'Hawaii' probably know what the terms "military script" and "blackout" mean.
Remember...."curfew" doesn't HAVE to mean "dusk to dawn"

....but enough of that.
The REASON that you SHOULD be driving your car at least every week is that when you really need it, and you poke the Power Button.....you WANT IT to boot up and run properly.
You want a full bag of gas, and a bug-out kit, and a plan.........just like they do in Hurricane country.

Don't over think this.
Just take it for a short drive.
Every two weeks should be fine.....but I always run mine weekly.
If your car cannot be parked for 2 weeks without any special attention then you should immediately sell it and get a more reliable car.

As mentioned above a battery TENDER (NOT a "trickle" charger) can be used to keep the 12v (aux) battery topped off.

Good Luck!

 

Yeah helps to have a smart charger. Ours has been hooked up steady for the last week. That's close to "situation normal" for us: even in normal times it'll typically sit 2~3 days, so not much of a stretch.

A once a week spin is good, for the brakes, engine, hybrid battery. And your sanity.

 

Hi Mendel and Raytheeagle,
I live in Bay Area, CA... so I'm Sheltering-In-Place. Attached is Page 437 from "2010 Prius Owner's Manual US-Canada Edition.PDF". It says, "If recharging with the 12 volt battery installed on the vehicle, be sure to disconnect the ground cable".

I have a Deltran Battery Tender 3 Amp Charger (Costco Item 996821). Do I really need to disconnect the ground cable before recharging?

Thanks,
-jlim888

 

Nothing wrong with taking the car out for a drive. In fact I find it to be therapeutic.

 

I don't think anyone but the most OCD follows that recommendation. The reason it's there, though, has nothing to do with protecting the car or battery. It's there because of that potential for hydrogen gas. If it's escaping from the battery at just the right rate to produce a flammable mixture with the air, it could explode if you make a spark disconnecting the cables.

The proper connection sequence is to connect the positive first and then connect the negative to the chassis or body away from the battery. In a gen 2 or 3 Prius, there isn't a good ground at a good distance. But, if it's a charger and you're energizing it AFTER you connect it to the battery as you should, you should not get a spark.

In spite of all the dire, lawyer-inspired warnings in the manual, I've made countless sparks around my batteries in my 40-45 years of driving. Never saw the slightest "poof." Remember that hydrogen is much lighter than air. It won't just lay around waiting for you to get your cables ready once you open the hatch and give it a place to go.

 

Where in the Bay Area are you located ?

I wouldn't worry about the cable disconnection like @jerrymildred points out.

I'd go for a drive and avoid stopping anywhere .

Did that last Sunday just to give our Prime a workout since it's sat in the garage for almost a week .

You can just run the Prius in place too, but why not just go for a drive since it'll be sunny and you won't interact with anyone .

 

Owners manuals are NOT written by Engineers......for the most part.......and some old outdated conventions sometimes carry over from other models that the writers use as a starting point.
This is one of them.
An AGM battery does not release gasses except under the most extreme conditions.
So......not to worry as long as you are using a small charger.

 

@jlim888 I don't disconnect anything when charging. For convenience I installed a quick connect at the under-the-hood fuse box. @NutzAboutBolts has a video on where that connection is. There's a thread with links including that video, pinned at top of 3rd gen maintenance forum. The quick connect I have was supplied with my charger.

 

I live in Fremont. Yes, I took my Prius out last night, driving ~20 miles round trip. I didn't stop anywhere...

I have already used the quick connector for my van, because we hardly drive it. We use our Prius everyday for commuting... If it isn't Shelter-In-Place, I wouldn't need to recharge the 12V battery at all.

FYI, my Prius still has the original Yuasa battery! A few years ago, I bought a Jump Starter, just in case I need to jump start the Prius. I do check and recharge the Jump Starter once a month.

Yes, I also found it therapeutic... In fact, 4x therapeutic, because we have 4 vehicles in our family

Correct. On page 439, it says, "Only perform a slow charge (4.2 A or less)".

 

I just got back from taking the Corvette out for a spin and some gas on a sunny day. Ended up waving at two others that I saw while I was out.

 

That would make it about 9 years old.......and at least one year PAST it's max. expected good life.
Unless you enjoy tempting fate, I suggest that it should be replaced now.

P.S. Those cautions about the charging rate refer to the actual current going into the battery and NOT to the total capacity of the charger.

In most cases, you can connect a "10 amp" charger and still have less than 4 amps going in, especially if you wait a few minutes.

The rest of those cautions really do not apply to an AGM battery and are left-overs from previous warnings about wet cell ones.

 

I usually use the Battery Tender with a Kill-A-Watt meter, so that I could monitor the AC currents at the 120VAC input.

Kill-A-Watt would initially display AC current of 0.01A, then the currents increase slowly. The AC currents would hover around 0.60A to 0.70A while charging; it would slowly decrease to 0.40A, 0.30A, and eventually back to 0.01A when the 12V battery is fully charged.

Yesterday, I attempted to charge my Prius with Battery Tender at the 12V terminal under the hood. While the Battery Tender was showing the 12V battery is being charged, the AC current as displayed on Kill-A-Watt meter never gone past 0.02A. In a nutshell, Battery Tender couldn't initiate the proper charging cycle... I removed the Battery Tender and took the Prius out for drive...

 

Interesting test.
I think you would have seen similar evidence if you had just monitored the charging voltage at the battery during the same time period.
How LONG did you leave it connected before you concluded that it wasn't going to work ?
Did you plug in the AC before or after connecting to the battery ?
One of my "tenders", not a Tender brand, says to plug in the AC last and I have found that in some cases it makes a difference.

 

Amperage into the charger at 120VAC is way different than amperage out of it at 12-13VDC.

0.3 A at 120 volts would equate to 48 volt amps. That equates to 3.69 A at 13 volts minus the power lost to heat by the charger. 0.7 A at 120 would be 6.46 A at 13 volts minus the heat loss.

Since the charger is some unknown power factor under 1.0, the DC amps are only approximate. If it was a pf of 0.85, for example, that 48 VA would convert to 40.8 watts.

Still, it's interesting to see how it changes with time.

 

So rule of thumb, stick with the rating of the charger?