will my 12v battery be alright?

Yes.

Is 12v battery still under warranty?

 

No.

your killing the hybrid battery too. If I were you I would sell your Prius ASAP while it still has a good hybrid battery because when it fails and it will cause your killing it then it becomes a real hassle to get it repaired or replaced.

hundreds of posts on here from covid killing the hybrid battery. It is the absolutely wrong car to let sit.

start reading.

 

If it is only 12.1 V after charging it, that's not good. You could try @edthefox5's headlight test.

I am actually stumped | PriusChat

 

Smart play is not to own an aged G2 in this covid times. There still selling very well now. Sell it.
G2 is only a good car if it has a good hybrid battery and you drive a lot everyday. If you don’t have those 2 it’s a cinder block hanging from your neck.

Buy a little Kia or Hyundai. No battery.

If I only drove 5 miles a week I would not own a car in covid I would doubke mask and take a Uber. Save a ton of money.
then finally Get your 2 shots go buy a car with the money you saved.

Covid will be a long time till we are all safe. It been 14 months of covid
My wife tries everyday to get a shot appt after 3 months of trying we got our first text back for her to get a shot next week.
Probably another few months till we both get a shot.

Or keep your g2 and drive it at least 5 highway miles everyday watching the battery charging behavior carefully. If you don’t it’s going to get you.....

 

The battery is a deep cycle agm from the factory. A direct replacement will also be a deep cycle agm. The rules and warnings for a normal lead acid are not the same for this agm.

You can be 95% assured it is fine by doing a couple of things. Install and drive it for thirty minutes now. The car will fast charge at much higher amps. Then check the voltage. Hopefully its 12.4v or better. I would then put a four stage low current charger on it (directly in the car) and let it further charge for 8 to 12 hours. Get to the point where it is at least 12.3v after sitting overnight without a charger. Then drive it two or three times a week.

You can have it load tested at most auto parts suppliers or mechanics. But that test is most accurate when fully charged. Don't be discouraged, many of us have deep discharged an agm and still got 7 years of life out of it. Worse case, you warrantee the battery.

 

Just to clarify, no 12v battery (new or used) in a Prius is going to last very long if you're only driving five (5) miles per week.

How would they know if it was discharged below 10.5 ?

On an unpleasant side note; if your catalytic converter hasn't already been nicked, you might consider that possibility as well.

 

Your much better charging it to a full charge now and then. If only to observe it’s charging behavior on the charger. Is it capable of turning the green full charge light on? How long does that take?
If it can’t that’s the first oh no sign....better start watching it.

Healthy Prius battery lives at 12.6 volts so I agree with RJ the cars charge voltage is fairly substantial. My yellowtop measures that every time I check it every few months.
But at lower charging current from a charger it takes forever to get to 13. Something volts.
My newer Citek mus 4.3 takes about 12 hours to go from 12.6 to 13.3 and turns on its full green light. The fuller it gets the less current it pulls.

The Citek charges my other car Crown Vic monster lead acid battery much much faster.

 

NO. 12.1 is not enough.
First, charge it longer.
If it won't go above 12.6 after sitting for a few hours with the charger off, shop for a new one.

AND if driving only 5 miles a week, you NEED to get a battery tender.

 

Maybe YOU should start reading.

Any posts that tend to look that way at first glance, almost always end up being very old vehicles and/or with very high mileage where sitting for a long time unused was just the last straw that finally broke a HV battery that was already on the way out.

I don't remember seeing even one single post about a long period of un-use "causing" a hybrid battery failure in a relatively new, low mileage vehicle.

The sky is not falling.

 

At which point, it stays at 13.3....which is the float charging voltage and NOT the voltage of the battery itself.

 

Jut editorial: it’s CTEK.

 

Oops your right. I bough5 because you liked it checked it out it’s pretty nice I like it.

 

Well don’t know your technical skills do you own a DVM?

 

Excellent.

what does the battery measure at the front jump point with the car off?