12v Battery ?'s

Yesterday I installed the SIR-TOY/SCC modules in my 2007 Prius (original 12v battery). This involved leaving the doors open for ~30 minutes (dome lights on) and turning the radio on/off several times to test. Then leaving the radio on for 10 minutes to receive the signal from Sirius.

After it was all installed and buttoned up, I went for a test drive. It was dark out by then.

This morning when I went to start the car and go to work, it powered up like normal but the red triangle with the "!" came on too - I had never seen that before! I checked my 12v battery voltage, as explained here and I get 12.1v at standing and 11.4v in accessory. When the ignition on, I get 13.6v or so.

Does this mean its time for a new 12v battery?

 

Replaced the battery with an Optima yellow top today. The old one started dying FAST. As a matter of fact, after I removed the OEM battery (original with sticker "0307" on it) the resting volts were 10.1v. Yikes.

The new Optima Yellowtop had a resting voltage of 12.2v, I had the guy at AAP test it on the spot before I took delivery of it. I thought new batteries should have at least 12.4v, no? The parts counter guy said it was the only one they had and it had been sitting on the shelf since March 2012.

Anyway, the battery has a 3 year warranty. I plan on monitoring it closely and as always, made a copy of the receipt, put it in a ziplock baggie and put it next to the battery in the trunk. I also filed the original receipt away. If I lose one receipt for warranty or the print fades on the original, Ill always have the other

 

Can I hook the battery charger to the battery while its connected to the car? Or should I remove the battery from the car completely and charge the battery?

I have a boat with AGM's and have a smart charger, so I could let it do its thing overnight (bulk, float, blah blah blah) but I dont want to hook it up with it being connected to the car and find out I blew a fuse or something crazy and not be able to get to work tomorrow!

 

Thanks for replying.

The battery charger has three selections for AGM batteries: 2a, 8a and 12a. I selected 8a for about 1/2 hour and then 2a for the other half before I installed it. So you think I should select the 8a and let it go overnight?

Edit: I just went out and hooked up the charger on 8a. Its indicating a 'sulfated' battery and is doing the 4 or 5 step, whatever it is, to desulfate and recondition the battery... its not looking good for this battery. I think Im going to have to return it and get a new, unflawed, one.

 

Patrick - in my case, would you return the battery for a new one?

Problem is, I took the only one they had in stock. The one I replaced is dead. They'd have to pre-order me one, wait for it to get in, then do the exchange because if i brought it back in I'd have no battery at all..lol. Anyways, Im not sure they do things that way. I think they want the battery back FIRST before they order another one.

OTOH, I reduced the battery charger to 2amp for the night - My "smart" charger was charging that little battery at 15.8v at 8amps (desulfation) and that made me nervous; I dont want to wake up to the charred remains of what used to be my beloved Prius tomorrow morning...lol

 

So I go to AAP today to exchange the battery. The same manager that told me 11.9v is "normal" also ordered me the wrong battery!!

I had to wait 30 mins while they went and retrieved a battery from another store. The date code on that Optima was 6/12, not much better than the 3/12 date code of the original low voltage Optima, but they tested it and resting volts was 12.75. Satisfactory in my book. Installed it in the parking lot, now I feel a little better about the $149 I spent! Not to mention more confident on the batterys future.

In other news, Im an expert and removing/installing 12v batteries on the Prius now!! lol