Dead

The 12V battery was totally drained after two months of disuse.

Put a charger on the 12V battery, set to the 4A charging position. Let the battery charge overnight. Try to make the Prius READY tomorrow morning.

If the car will not become READY, replace the 12V battery.

 

and if it will become ready, learn how to test it to see if it will last or needs to be replaced. what kinda one year old battery won't last 2 months?

 

Would a model w/ SKS in the ON position under the steering column do this? Also assuming no dome light, map light, vanity light, and trunk light was left on.

 

Yup, 7 year pro-rated warranty (0-24 months 100% Toyota pays, 25-48 months 50% proration, 49-84 month 25% proration). Hopefully you have the original receipt or paid an arm/leg to have the battery dealer install the battery. If no receipt, but dealer installed, go back to the installing dealership for warranty replacement, as they will have the records of installing the battery in your car.

I would stop charging and take it to the dealer, tomorrow (if open). This battery is defective (as you indicated nothing to account for dischage: SKS off position and no interior/exterior lights ON), and it's useful life is now shortened by this unexplained self discharge. Unfortunately bad batteries happen.

EDIT:
Consider getting a charger to occasionally recharge the 12V battery, esp if you let it sit for prolonged periods, say more than one week. I like the CTEK line b/c of size, perfectly suited for AGM batteries, and it has the permanent battery pig tail attachment. I have the Schumacher SSC-1500A-CA, b/c it can charger AGM's too and has a higher amp charge setting for the conventional 12V wet cell batteries; just wish Schumacher had permanent pig tail attachments. Still a good idea to check the 12 battery compartment for water, due to the hatch cracks that Gen 2's suffer from.

 

If the OP does not charge the 12V battery, the car will not become READY. If the Prius does not become READY, he won't be able to take the car to the dealer unless he has it towed or removes the battery from the car and takes the battery using another vehicle.

Most Toyota dealer service departments are not going to be open on a Sunday, not to mention Easter Sunday.

The OP needs to decide whether it is more important that the Prius be given a reasonable chance of running on Monday, or if he is more concerned about trying to get a new 12V battery under warranty right now.

if the battery is actually damaged due to the storage period, the OP will have plenty of opportunity in the future to take advantage of the 12V battery warranty terms.

Even if the 12V battery is brought to the Toyota service department totally discharged, the first thing the service writer will do is hook up the battery to a charger to see if it will hold a charge. That will take most of a day.

If the battery holds a charge, then it will be returned to the OP after the battery was given plenty of time to recharge. He has nothing to lose by attempting to charge the battery himself - and his potential gain is that the 12V battery is restored, and therefore the car is ready for use by Monday morning.

Also, if it should turn out that the Prius has another problem unrelated to the 12V battery, the OP needs to figure that out sooner vs. later. To do that, he needs to make sure the 12V battery is in good condition, then he can see what other issues may or may not exist.

It is unlikely that a 12V battery installed in the Prius will withstand two months of disuse unless the battery was brand new and fully-charged immediately prior to storage:

0.02A quiescent current draw x 24 hours/day x 60 days = 29 Ah

Whether or not you turned off the Smart system, some electrical current drain is present. For example, the clock maintains correct time. The stereo system maintains preset station memory. The MFD unit, and trip odometers in the combination meter ECU keep track of elapsed miles since last reset. The fuel gauge circuitry in the combination meter ECU retains memory of fuel level. The immobilizer and body ECUs are in standby mode, ready to respond to a fob door opening signal. The skid control ECU is ready to respond to the driver's door being opened, to power the brake actuator pump.

The 12V AGM battery has a rating of ~40 Ah. If the battery was fully-charged before it was stored, the Prius might start after 60 days. It is unlikely that the battery actually commenced the period of storage, in that highly favorable condition.

More likely it started at a 50% or at best 75% charge level. So 29 Ah of discharge would bring the battery down to zero. Then the OP runs the car for 15 minutes and wonders why the battery is not back to normal.

The battery needs to be recharged at least overnight to have a chance of recovering.

 

So Gen III Prius does not have this "Onboard battery testing"; How to see if your 12v Auxiliary Battery is going bad

 

i think it does, iirc. pat, i agree about new and fully charged, but i have left 4 year old batteries for unto 6 weeks in a lot colder climate than california, and never had an issue.

measured mine this year, and it dropped from 12.7 to 12.4 over 5 weeks. i can see that a battery in the low to mid 12's might drop too low to fire up the car, but a one year old battery fully charged when installed should still be in pretty good shape in a mild climate after 8 weeks.

unfortunately, too many people assume you buy a battery and install it, without check the charge level first.

 

The recommended Schumacher charger should only be used at it's lowest charge rate of 3 amps (AGM) on the Prius battery. As stated on the top of the battery the maximum safe charge rate is only 4.5 amps. To attain full charge at 3 amps the battery would need to be charged for at least 18 hours.

John (Britprius)

 

don't you get a warranty sheet with the battery?

Merged

dontcha hate it, when one year turns out to be two?

 

that could be problematic. did you get any paperwork saying it was certified?

 

excellent.

 

Consider sharing your experience w/ the BAR (Bureau of Auto Repair) and Toyota. Hopefully they can stop this bad behavior.

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Granted, the Warranty was given, but only after your insistence b/c you happen to be in the know about the warranty terms. Imagine how many people they have willingly defrauded, to increase their profit margin.

Just out of curiosity, did the defective battery state the obvious like in this picture.

 

You assume that the battery was "perfectly good". In fact, it was likely in a partially discharged state all along, was barely able to start the Prius while you were driving the car, and the storage period killed it.

It is simple to avoid the problem, there are at least three alternatives that you can choose from:

1. put a 12V charger intended for AGM batteries, on the battery at least once per month, and leave the battery to charge at least overnight. Do not underestimate the time required to charge the battery.
2. use a 12V battery tender continuously connected to the battery.
3. fully-charge the 12V battery, then disconnect a battery cable for vehicle long-term storage. The rear hatch, which is electrically operated, will not open once the battery is disconnected. Therefore you need to either keep the hatch ajar or else be ready to crawl into the hatch from the rear seat, and find the mechanical latch release when the time comes to reconnect the battery.

A modification to #3 is to disconnect the positive cable at the dedicated jumpstart terminal in the main relay/fuse box near the inverter. Remove the 10 mm nut at that terminal and pull the cable off the stud using long-nose pliers. Replace the nut on the stud, close the red plastic cover, place the cable on top of the red cover, replace the relay/fuse box lid, close the hood and you are done. It is much easier to open the hood than the hatch, when the 12V power is off.