New Optima 12V Battery - Necessary to Charge First?

I'm about to replace the original 12V battery on my 2008 Prius. I've purchased an Optima Yellow Top DS46B24R and am hoping to get this done in the next day or two.

My question is in relation to the initial resting voltage on the battery, prior to installation. The voltage on the Optima as it sits on my garage workbench is presently 12.6V (tested with my Fluke MM). I've read posts here where it is recommended to charge these batteries to full before installing them. My understanding (and this could be wrong) is that a fully charged battery of this type should read around 12.9V or 13.0V at rest. If true, that would indicate that my battery is not presently charged to full.

So I guess my main question is - how important is it that this be done? From posts that I've read here, 12.6V is still adequate (even "normal") voltage to power up the car, and if the Prius works as designed, the battery will be charged to full as I drive it over time.

To put this another way, in the real world, is 12.6V sufficient for me to install the battery as it is? I'd honestly prefer to avoid the hassle of charging it, but if necessary I will have to go out and purchase a float charger. I've seen that Harbor Freight sells one for about $10 that looks like it would do the job. If I were to go this route, what voltage would have to be applied to the battery to charge it? And at what amperage that is safe for the battery? Would I be looking for something like a 13.8V, 2A max charger?

-Kizzy

 

I should also mention that my Optima battery has a mfg. sticker on the side showing a date of 8/17. So it is new within the last month or so. I got it at my local Pep Boys, who are running a $55.50 off promotion right now on this battery. Drops the regular price of $184.99 down to $129.49. After adding CA sales tax and core charge it was $159.86 out the door, but I'll get $15 of that back when I return my old battery. So $144.86 final cost.

 

Yes I was glad to see that promotion. Cheapest by far I've seen, including Amazon and other online e-tailers.

 

Can you explain why you think this would happen? Doesn't the Prius charge the 12V battery while in the Ready Mode? I've read dozens of posts claiming that, over time, the Prius has a system for charging the 12V battery while driving, or idling in Ready.

Fair enough. Can you recommend one to me in that price range?

-Kizzy

 

Assuming, for a moment, for the sake of argument, that it merely maintains the battery at 12.6V, why is that necessarily a bad thing? So long as it is sufficient to operate the car, why is that extra 0.3V so important? Not trying to be contrarian, just trying to understand the importance of it.

My 2008, which I purchased in December 2007, has been running fine on its original 12V battery for nearly 10 years. This weekend was the very first time in those 10 years that I ever had to do a jump start, or noticed anything at all wrong with the car or its accessories. I know for a fact that it hasn't been at 12.9V all this time, and it has lasted far past the bell curve. So, what are the benefits, and the evidence of those benefits, of keeping the battery charged at 12.9V?

Also, couldn't I just leave the car in Ready mode overnight, with the car in Park and the parking brake engaged? Would not this achieve the same thing as topping off the charge on an external charger?

-Kizzy

 

Following up on my earlier post. Thought I'd do a little research into low-cost battery chargers/maintainers. The Pep Boys near me has these two in stock. Both are about 30% off with Promotion Code. Would either or both of these be suitable for charging the Optima before installing it?

Black & Decker 6V and 12V Battery Charger & Maintainer
Black & Decker 6V and 12V Battery Charger and Maintainer | 664372 | Pep Boys

Schumacher Speedcharge Charger/Maintainer 6V/12V 1.5Amp
Schumacher SpeedCharge Charger/Maintainer, 6/12V, 1.5 Amp | 50274 | Pep Boys

-Kizzy

 

Thanks, I see now what you meant. As for the two chargers, that Schumacher model will actually not work as a CHARGER for the YellowTop, only as a maintainer. It is only designed to charge smaller batteries, like the kinds used in motorcycles. It says so in the manual. The Black & Decker apparently will work. Still not really convinced I need to do this. I can see how it would be preferable however.

 

I respect your opinion, but am going to have to politely disagree. The manual for that specific model charger plainly states that it is not to be used to charge a battery the size of the Optima YellowTop, based on its CCA rating of 450. I'm not home now so I can't post direct quotes from it, but if you download a copy you will see what I mean. It is only designed to maintain a battery that is already charged to full, unless it's a very small motorcycle battery or similar type. Otherwise, you risk undercharging it (as it has a 12-hour cutoff), which can apparently diminish its capacity. There are, however, slightly larger and more expensive Schumacher chargers that will work for both charging and maintaining this battery.

 

Yeah I'm not too impressed with the B&D model.

This one looks like it would do the trick. It's the next higher model Schumacher charger.

Schumacher SpeedCharge Bench Charger, 6/12V, 6 to 2 Amp, Portable | 63777 | Pep Boys

At this point I'm thinking to just install the battery as it is. If needed, I can always purchase a charger later and charge the battery while it's in the car.

-Kizzy

 

Thanks for your response. I do see where you are coming from, and I'm re-thinking this. I'll look into getting a charger to test the battery's ability to reach and maintain the 13.2V range before installing it.