Dead 12V Battery/Rhythmic Clicking & Beeping

is the battery fully charged?
it take hours to recharge a fully dead battery

 

If the battery is old and really dead, then 2 amps is probably not high enough to charge the battery. You might need a 6 amp or higher charger to charge your battery enough so that you can then use the trickle charger.

If the battery is old, you probably should just buy a new battery.

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Try the 6A setting, but it may still not work.

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Read the label on the battery. It will likely list the maximum safe charge rate. IIRC the Toyota Truest arts are 4.3Amp.

If OP's charger is a smart charger w/ an AGM setting, he should just make the correct selection and let the charger recharge automatically. But, it seems likely his charger is not a smart AGM capable charger.

 

5 hours on 2a trickle on stone dead battery will do nothing really. Its probably not even at 8 volts. That battery is totaled.

Be careful as you do not know what your doing and this is the quickest way to seriously damage a Prius.

Carefully replace that battery.

 

Not enough power to work properly in the car.
Clicking could be relays trying to pull in but unable to hold.
It's never good to underpower electronics.

Deal with battery issue fully before attempting to start it again.

 

Glad to see that your tin foil hat is still working .........and that you can still diagnose things given only a text message with absolute certainty.

 

The first statement is not true?

That 12 weeks may have depleted it beyond recovery, but hard to tell. I'd suspect you're using an old-school charger? Try a 4 amp smart charger, one that monitors the battery as it's charging, goes through a multi-stage regimen.

Then, if-and-when it dubs it done, at the least assess at-rest voltage with a digital multimeter. Preferably after turning on the headlights for a minute, to scrub off surface charge. And post the result.

For a better picture: have it assessed with an electronic load tester; there's one reasonably priced diy version if your pockets are deep enough: Solar BA5.

 

This is based on OP saying he charged the battery.

 

Since the Prius has a near-constant draw on the 12V system (for the clock, anti-theft, and occasional brake actuator activity), I am almost certain that the battery is toast. Discharging any lead-acid battery to zero is not a best practice- even deep-cycle marine batteries recommend no more than a 50% discharge if u want it to last. These batteries are not meant for deep discharge; my OEM battery was severely discharged approx. 10-15 times by the simple act of accidentally leaving the manually-operated interior light on for less than a day and would need to be charged. I really noticed the deterioration when, after sitting overnight, the battery would have a minimum enough charge to start the car, but the red triangle was lit and a message on the touch screen telling me to put the car in park on a level surface (or something like this; can't remember exactly LOL. I promptly replaced my 12V battery using the information here and on youTube with an Optima yellow top. About $165 on Amazon with 2-day prime delivery. You can trickle-charge it after removing from car (or at least disconnecting the negative cable of battery)- then use a voltmeter across the terminals while the charger is still connected and plugged in to assess the voltage. Then unplug the charger and assess voltage (needs to be at least 12.1V or so; 12.8V is desired), then again 12 hours later. If it drops to < 11V replace the 12V battery.

It may seem counterintuitive, but using a partially charged battery on delicate electronics generates much more heat than does a fully charged one; Components are designed to operate optimally at a certain voltage. When the voltage is subpar, the components will draw more amps in order to make up for the lack of voltage (to a point). The increased heat can fry delicate wiring and components over time, and it's just common sense that the Prius is one machine where this condition should be avoided. I'm sure that baby boomers remember jump-starting cars back in the 70's and 80's and the cables becoming so hot that the insulation melted (a crude illustration of the above); this scene was so common back then, esp. with some Chrysler cars with those Carter carbs. Geez, I hated that sound LOL! Our next door neighbor had a 1972 New Yorker that served as my alarm clock as he struggled to get it running during the week, sometimes taking 10-15 minutes (I learned most of the popular curse words from this couple LOL). These kids nowadays have NO IDEA just how much they have it made, as they casually twist their keys and 100's of horsepower (within a couple seconds) roars to life-- no spitting, sputtering, dying out, jump-starting, swearing/cursing, or multiple cranking attempts!!!

 

I should have mentioned that I could be wrong.
I've been wrong before, and will certainly be wrong again in the future.

 

ericbecky, something tells me you are 100% right with this issue. Mine acted like the OP's issues right before I ordered the battery from Amazon. I quit driving the car and pulled the 12V battery out and waited the 2 days it took for delivery of the new Optima replacement. I trickle charged this battery with an automatic charger for 20 hours and the voltage dropped down to < 9V after 5 hours. I caught a ride with a coworker to my job during this time. The OEM Prius 12V battery (in my opinion) is underpowered and has too little reserve capacity to sit unused for three months, let alone having to endure a constant tiny discharge due to the anti-theft system. Not good for the hybrid battery to sit for three months, according to some of the posts on this forum.

 

I was wrong once a long time ago.(didn't buy apple stock at $59).. I never thought people would pay $299 for a cell phone, boy was I wrong.. now apple x goes for a grand and fools wait in line for days to get one..

 

With automatic smart chargers, sometimes they need to ne tricked into working on a deeply discharged battery. I have 2 automatics that will not initiate the charging sequence on a deeply discharged battery; one will show an error code indicating an internal "fault" and advises battery replacement; my newer automatic senses the voltage incorrectly and thinks the discharged 12V is actually a 6V and delivers insufficient current. My work-around: I have an extra 12V battery (nearly new; came out of his wrecked Honda) I picked up from my neighbor's garage sale a year ago ($5) that I use for my 12V tire pump. I top it off every couple of weeks. I take the discharged battery, connect the charger, then connect it to the Honda battery with jumper cables (parallel- NOT in series). Then I plug the charger in and set it on the AGM setting to 2 amps. After 10-30 minutes (depending on how dead the discharged battery is), disconnect jumper cables to hot battery. Presto! This works for a severely discharged battery, but NOT one with an internal short.

 

Beachbummm... Do like I did; I bought my iPhone 5S ($150) from my sister when she upgraded to a 6S. She kept it in a case and didn't have a scratch. I'm the oldest of 4 kids; I've always gotten seconds LOL! BUT.... I didn't have to wait in line! And it still works perfect.

 

Well...if you have been on this site as long as I have and seen this hundreds of times with a newb dicking around with a stone dead battery and blowing the car up maybe you would understand and not attack every person on this site who is trying to help a poster.

The safe play and guaranteed remedy is to treat that stone dead battery like a bomb and replace it carefully and get on with your life. Cause the op can charge that battery till the cows come home but its done.
Don't need a tin foil hat for that one.

 

OP just needs to get a new battery and a modern Smart 12V Battery charger that has an AGM setting. If OP will be gone for a prolonged period again, can attach the charger prior to leaving, to prevent a discharged 12V battery again.

READ Is my inverter coolant pump slowly failing? | PriusChat

Post #5- How to read 12V battery SOC (State Of Charge) after applying a load.
Post #8- SOC chart and three Smart AGM compatible chargers.​

IF OP's location is correct, Ft Lauderdale, FL, he should just swing by Pep Boys and get a Bosch AGM battery. Superior (45Amp Hr vs 38Amp Hr) and cheaper ($143 vs $238), than overrated Optima. He can always try to get a Toyota True Start, that has an 8yr pro-rated warranty, but hard to get dealers to come down in price like I did. OP can search "Toyota OEM parts Florida" to find Toyota dealers who have an online site and cheaper parts pricing; ask if your local Toyota parts manager if he/she can match/beat a Florida Toyota Dealer's Online Price.
Clermont Toytoa, $186.14; 2007 Toyota Prius Base Parts like 00544-21171-325


Remember, CCA is meaningless for the Prius; there is NO traditional 12V starter. AmpHour is the meaningful measurement of 12V battery for the Prius.
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