worker

what's your battery voltage after sitting over night?

I don't want any guessing or what the voltage should be. My battery sits around 12.4V despite it's being a new battery. I plug in the battery tender and it goes up to 12.8V but when left sitting it go back down to 12.4V. I think the battery should sit at 12.7V Something inside the car might be keeping it at 12.4V and wondering if everyone else cars does the same.

thanks.

KJSmitty

I just replaced my battery this past weekend. New battery sits at 12.6ish. I was checking for a draw thus took measurements both at night then next morning a few times etc.. Started out at 12.73 at 6PM and read 12.62 this morning.

Edit: 12.78 after fully charged/driving on the freeway for over two hours. So between 12.8 and 12.6 with my new battery. But each battery will/can be different. 12.4 isn't bad..

What type/brand is your battery and how old? My previous would charge to 12.8 and immediately start the car yet if left overnight would drop to 10volts... Had a bad/shorted cell.

worker

aw sux, I just went outside to check and my battery down to 12.28V. The battery tender wasn't getting power due to the stupid plug not making good contact. Plug it in now and it's charging up the battery. I'll verify later see what voltage it sits this time.

XxGoKoUxX

what battery are you using?

worker

RedTop battery.

Just went outside to check, the battery tender been plugged in all night. Verify and the tender was still working. Check the voltage and it was 12.48V. Turn on the headlight and it went down to 12.03V but the tender was still plugged in so it slowly crawl to 12.07V. Waited for about 10mins and still at 12.07V.

Seem like the HID never switch to low power. Oh well... turn off the light and 12.38V slowly going up. This voltage seem too low.

KJSmitty

I assume you are talking an Optima battery?

I utilized them in my ski boat and wasnt overly impressed. They are known to be finicky. I remember mine being less than 12.5 as well. Is your battery new as in are you just realizing these parameters or has it been giving you issues of some sort?

worker

Yes, it's Optima. They are the only going by the name RedTop and YellowTop. Just realizing this parameters. If the battery is weak than the alternator have to work extra, which I believe is the cause of my alternator died in the pass.

KJSmitty

Yep, thats the type of complaints I have read about them as well. Not necessarily that they are
weak, rather they can cause the alternator to charge more than it should. I used "blue tops" in the boat. They are a tad different as in more of a deep cycle yet acted as you describe as well.. They never left me stranded yet always gave me a bit of concern given the "gauge" indications..

I no longer spend that much on car batteries. I look for the most appropriate/cost effective one with at least a 3yr full replacement warranty. Optima has the 3yr yet at two if not three times the cost. For the right application maybe, but for an everyday commute vehicle a Maxx battery from Walmart is one of the best bangs for the buck - and are made by the same folks as Optima.

Cheers

burny

Bingo, running one right now in the GS300

XxGoKoUxX

I have an optima yellow on mine's. i'm at 12.3-12.4 after playing with it a ton. I'm pretty sure 12v is normal for the car being off, isn't it?

Edit: Here's a link from Optima, if your car battery falls below those parameters, you should really get it checked.

http://www.optimabatteries.com/us/en...e-and-storage/

" When possible, store your battery in a cool, dry location. Check the battery voltage every six months and charge if it falls below 12.4 volts. "

dpmac

Your battery should be 12.6-12.8 volts when fully charged. A car battery has very little drain on it and should always be in this range unless the lights have been left on! Take your battery back!

coppens1

Dear Forum Members, I have found an interim solution to my problem of a draining battery, that has plagued me since July of 2023. I left my car with an Auto Electric shop with multitudes of diagnostic equipment for several days and they could not find the problem.

I went online and bought a Battery Isolator for $4, which disconnects the battery from the electrical system, when the car is parked. You only have to turn a **** on the device, installed on your battery, to disconnect.

I have used it for 2 weeks, with NO DEAD BATTERY. Eventually, when whatever is causing the problem fails, I will get it fixed. JC