Battery Resting Voltage

[ThorneGator]

Hello all,

My starter battery is about 4 years old now, and its resting voltage (when I go to start her up in the morning) is around 12.3-12.5V. Any one have any suggestions on what this should tell me about life left in the battery? Or is it a, "too many variables to tell" type of question?.....Just looking for general idea.

Thanks

[drivesafe]

Hi ThoreGator, and yes there are many “variables” but you actually need to know them.


First off, they are not bad voltages, 12.3v equals an SoC of 70% and 12.5 equals an SoC of 90%.


Next, some of the variables will be, how often do you drive your machine.


When you drive, how long is each drive ( average ).


How long do you leave it between drives.


Just some but these can be the main influence on your battery’s SoC.

[DiscoMick]

Also, what drains are on your battery while sitting?

[ThorneGator]

Thanks for the response and information,

To answer those questions, my average (daily) drive is 20km over 30mins. While sitting the vehicle has no additional draw on the battery, but while running a sub-woofer, and UHF are consistently drawing from it.

The reason I have posed this question now, is that I am heading off on a trip for two weeks and just wanting to handle anything I can proactively.

Thanks again for the help!

[DiscoMick]

Seems a bit low then, I think. Mine is usually higher.
You might be surprised at what is draining it.

[steveG]

I'd be reasonably comfortable with those voltages, but depends on what you're doing and where you're going on your trip.
Also whether its your only battery.
If its your only battery and you're planning to beat the heck out of it by draining it heavily with a fridge etc or heading off remotely by yourself I'd look at things differently.

Steve

[vnx205]

I fitted Supercharge Allrounder MRV70 in May 2011, almost 6 years ago.

I recently bought one of those very cheap accessory socket voltage, ammeter, temperature, USB charging devices; a bit over $3 I think. I was mainly interested in knowing how much a couple of nights of running LED lights in the camper took out of the battery.

I have no idea how accurate it is, but it shows 12.6V after an overnight rest and 13.7 to 13.9 as soon as the engine starts.

On a recent trip with the camper running LED interior lights and a 12 V water pump, it showed 12.5 or 12.6 after a one night stop and 12.4 after a two night stop.

I don't know what those figures would have been 5 years ago.

I also wonder if those figures are likely to gradually drop over the next few years in a linear fashion or if there will be some sort of acceleration of the deterioration over the next few years.

[rgty_kmj]

Hi,

My 110 will be 5 years old in 1 weeks time. I have had an ultra gauge fitted since I bought it in 4 years 8 months ago.

Back when I bought it the battery voltage was 14.77 with the engine running and nothing else on. Now the battery voltage is 14.28 with engine running.
The car sits in the garage all week and mainly does longer trips on the weekend. I've had no problems starting it.
I too am starting to wonder if the battery is heading down hill. Winter is only a couple of months away so I've chucked a jump starter in the back just it case.

Kerry

[ThorneGator]

I'd be reasonably comfortable with those voltages, but depends on what you're doing and where you're going on your trip.
Also whether its your only battery.
If its your only battery and you're planning to beat the heck out of it by draining it heavily with a fridge etc or heading off remotely by yourself I'd look at things differently.

Steve

Thanks Steve,

Off to Tazzy for two weeks, but no heavy draws on the battery. Only using12V LED lights around camp at night (1.6Amp/hour draw) so am hoping that I'm just being cautious. It is my only battery, but I'm not running a fridge or anything similar.

Cheers,
Taylor

[MountainD]

Are you taking the voltage reading directly off the battery? Since your alternator has such a strong voltage, I would expect a higher voltage. It could be drain during the night or the battery may be sulfated or just old. A good batter charger, such as CTEK (i use the 7002) has a battery reconditioning function and for me it really brought an older battery back to life. It won't cure an old battery, but it can cure a sulfated one.

If it is a battery drain, there are ways to trace those too---it involves removing fuse by fuse and taking an amp reading across the terminals with the car turned off and seeing first what circuit is draining it. You will have some drain for things like radio memory and such, but if you find more than there should be then you need to track that down... Usually not hard, just time consuming...