Battery Voltage

[Road Stone]

Hi Folks,


I was just wondering what the correct battery voltage is when the car is not running. Read various threads which indicate mine may be a bit low.


I have no running/starting issues at the moment. Car had a new battery fitted in October before shipment to here.


Recorded on my Diagnostics device I have:


12.1v after a run
12.1v after car has sat for 5 days not used. But has been open and closed a couple of times.
Put my SCA "smart charger" on it last night and this morning 12.3v.


Can someone advise their experiences?


As stated I have no issues at this point and battery is new.


Cheers, Jerry

[Eevo]

simple answer

12.1 is about 50%
12.3 is about 75%
12.6 is about 100% :)

[Homestar]

Yeah, 12.6 to 12.7 is fully charged. 12.1 is quite low. What sort of voltage do you have while it's running? You should have around 13.8 to 14.0 on these.

[Road Stone]

Many thanks for the replies.


Okay, today when out for about an hours run, started the car a couple of times.


After being home for a couple of hours the reading is 12.5 -12.6v.


I started the car in the car port and it reads 13.5 to 13.7v.


Is there anything I should read into this?


Cheers, Jerry

[Homestar]

Charging system is fine - these vehicles do use power while sitting there doing nothing, and just unlocking them starts up systems that use more power, so I wouldn't be too concerned. If the battery does start to die, the car will start to throw fault codes during, or just after starting - things like EAS Fault or ABS fault. This is usually the first sign the battery is on the way out.

[Road Stone]

Yes, the charging does appear to be doing its job and yes, there is lots of whirring and puffing when the car is unlocked!


Carrying on with the observations, battery is down to 12.1-2v this morning, so it would suggest to me that my new battery is not holding the charge well.


I don't have a drain, as it maintains 12.1v over many days.


As stated I took it out yesterday after 4 days. 12.1v and indeed I got an EAS warning which cleared almost immediately.


Next move is to ask the guys who put the battery in a question or two!


Thank again.

[Eevo]

its as if its dropped a cell

[bee utey]

How about you compare the readout with an accurate volt meter? No sense panicking if the readings are wrong. It's like asking for a second opinion from a qualified health professional before diagnosing a prolapsed battery.

[Eevo]

How about you compare the readout with an accurate volt meter? No sense panicking if the readings are wrong. It's like asking for a second opinion from a qualified health professional before diagnosing a prolapsed battery.

good point.
use a multi meter across the battery.

[Road Stone]

Okay, understand that.


But are you saying the reading from the Diagnostics is not accurate?


Cheers, Jerry

[drivesafe]

I started the car in the car port and it reads 13.5 to 13.7v.

Hi Jerry and as above.

Get a voltage reading at your battery before you start your motor, then another one after the motor has been running for at least a minute.

If you actually have a low battery, then 13.5v to 13.7v seems a tad low.

[Eevo]

Okay, understand that.


But are you saying the reading from the Diagnostics is not accurate?


Cheers, Jerry

sometimes they are less than accurate due to wiring and voltage drop.

[Road Stone]

Well I don't have a multi meter which is the bad news and always relied on my diagnostic machine, when I had D2/3's.


The good news is I'm heading to Brisbane next week so can get one at Bunnings!


Any recommendations? I have no idea how to use one. The next google search!


Cheers, Jerry

[rar110]

Jerry,
Fluke is a premium brand which starts at about $600 from memory. Expensive but will last. Too much for me. I fried my last cheap MM testing amps on the 110. I wouldn't want to accidentally destroy a $600 tool.

I bought a US branded multimeter from Bunnings for about $40. I can't remember the brand name. Not their cheapest, but seemed reasonable quality. I like and use its back light feature so if working in low light I don't need to also to find and hold a torch.

You could also consider a clamp meter which is also a multi meter. Good for finding mystery power leakages. I think a reasonable one starts at about $160 when I was looking.

[Aaron IIA]

You could also consider a clamp meter which is also a multi meter. Good for finding mystery power leakages. I think a reasonable one starts at about $160 when I was looking.

If you have never owned a multmeter, a cheap clamp meter might be a good idea. They can be found for under $10

http://pages.ebay.com/link/?nav=item.view&id=381505076979&alt=web

Aaron

[DiscoMick]

Might be a silly question but have you checked the levels in the cells? If down it might be why its not holding charge.
My new Varta 800CCA easily holds 12.6-12.7 even when sitting for a couple of weeks. I replaced the 6 year old original Varta when it wouldn't start after sitting for 2 weeks.
Incidentally you can buy little plug in voltmeters for cigarette plugs for about $15 from Autobarn, Jaycar etc and then watch the readings while driving. Easy solution.
Mine shows the current from the alternator at 14 while driving dropping to 12.6-7 from the battery when stopped.

Sent from my SM-G900I using AULRO mobile app

[DoubleChevron]

Might be a silly question but have you checked the levels in the cells? If down it might be why its not holding charge.
My new Varta 800CCA easily holds 12.6-12.7 even when sitting for a couple of weeks. I replaced the 6 year old original Varta when it wouldn't start after sitting for 2 weeks.
Incidentally you can buy little plug in voltmeters for cigarette plugs for about $15 from Autobarn, Jaycar etc and then watch the readings while driving. Easy solution.
Mine shows the current from the alternator at 14 while driving dropping to 12.6-7 from the battery when stopped.

Sent from my SM-G900I using AULRO mobile app

I fitted two voltmeters to the old range rover ... one was attached to the battery (measuring the 2nd battery voltage), the other was fitted to the dash wiring. They often showed upto 2volts different with the headlights or fans on ..... There is some serious voltage drop in the wiring in these cars. It would probably pay to fit relays to the headlights and demister fans :)

seeya,
shane l.
PS: What I'm saying is I wouldn't necessarily trust a voltmeter plugged into the cigarette lighter.

[harlie]

Okay, understand that.


But are you saying the reading from the Diagnostics is not accurate?


Cheers, Jerry

If you are using diognostics to measure resting voltage you are really wasting your time. The car is consuming quite a bit of power to give the data feed you are reading (no doubt ignition is on...). IMO 13.6 while running is fine, once again the ECU readout will be down on what would be measured at the battery, especially if the AC is on.

The numbers quoted in post #2 in regard to a level of charge is only an indication when measured on a rested battery - at least 2hrs of no load or charge. In the L322 that means disconnected.

Multimeters don't need to cost much, I have a very good one in the garage, and a small jarcar ($30) unit that lives in the car.

[Homestar]

If you have never owned a multmeter, a cheap clamp meter might be a good idea. They can be found for under $10

http://pages.ebay.com/link/?nav=item.view&id=381505076979&alt=web

Aaron

Maybe lash out a bit more than this - it doesn't do DC current so useless on vehicles...

[DoubleChevron]

I'd like to get a reasonable analogue meter.... You can see voltage fluctuations that way. The cheaper ones these days seem to be complete junk though :(

something like this will probably do everything you really want for automotive work.... And when you fry it tinkering with the amperage setting it wont be the end of the world :)

Low Cost Digital Multimeter (DMM) | Digital | Multimeters | Test & Measurement | PRODUCTS | QM1500 | Jaycar Electronics (http://www.jaycar.com.au/Test-%26-Measurement/Multimeters/Digital/Low-Cost-Digital-Multimeter-(DMM)/p/QM1500)

at $10 bucks you could afford to leave one in each car.

seeya,
Shane L.

[Road Stone]

If you are using diognostics to measure resting voltage you are really wasting your time. The car is consuming quite a bit of power to give the data feed you are reading (no doubt ignition is on...). IMO 13.6 while running is fine, once again the ECU readout will be down on what would be measured at the battery, especially if the AC is on.

The numbers quoted in post #2 in regard to a level of charge is only an indication when measured on a rested battery - at least 2hrs of no load or charge. In the L322 that means disconnected.

Multimeters don't need to cost much, I have a very good one in the garage, and a small jarcar ($30) unit that lives in the car.


This is actually a very good point. Yes ignition is on as are tv screen/EAS and anything else whirring away.


There is more to buying a MM than I thought so next week Saturday I'll have a close look!


This is the battery:
https://www.aulro.com/afvb/images/imported/2016/01/514.jpg (http://s133.photobucket.com/user/roadstone/media/20160109_112007_resized.jpg.html)


Its sealed I think so how do I check each cell? The guys who fitted it are asking to do that.
The suggestion their end is that these batteries are very good and its more likely that my alternator is tired. 13.7v charging at idle is low.


Cheers and thanks,


Jerry

[Eevo]

The suggestion their end is that these batteries are very good and its more likely that my alternator is tired. 13.7v charging at idle is low.
[/FONT]

not sure i agree with that,13.7 isnt that low. depending on the car, 13.7 is normal

[drivesafe]

Hi Jerry, at this stage, until you get yourself a multi meter, don't worry about what voltages you are getting right now.

Also, don't get a cheap multi meter, try for around the $20 to $40 mark and you will be fine.

If you can, see if you can get one that turns itself off after 10 minutes. There is nothing worse than needing to get a voltage reading off something important and when you find your MM, you realise the last time you used it, 6 months ago, you left it on.:censored:

[Aaron IIA]

Maybe lash out a bit more than this - it doesn't do DC current so useless on vehicles...

Fair cop. I didn't read all of the fine print in the description. This one is an all round better meter.

http://pages.ebay.com/link/?nav=item.view&id=262190877141&alt=web

Aaron

[Homestar]

Fair cop. I didn't read all of the fine print in the description. This one is an all round bettet meter.

http://pages.ebay.com/link/?nav=item.view&id=262190877141&alt=web

Aaron

Yep. :)

[Road Stone]

Fair cop. I didn't read all of the fine print in the description. This one is an all round better meter.

http://pages.ebay.com/link/?nav=item.view&id=262190877141&alt=web

Aaron





Okay thanks for that. Plenty to learn!


So I have used the car frequently over the last few days and did the same test today.


This again is on the diagnostic tool:


Battery Voltage engine off: 12.3 (vehicle has sat for about 18 hours)
Battery voltage engine at idle: 14.2 -14.5 (left it longer this time to settle down).


I'll report back when I have the MM and learn how to use it.


Thanks Jerry

[drivesafe]

Hi again Jerry, and with 14.2+v, your alternator charge voltage is fine.

The 12.3v battery voltage ( around 70% SoC ) is not that low especially if, as you say, you have been using your RR ?frequently? over the last few days.

With that alternator voltage, if you had been driving for a decent amount of time, each time you drove, then I would expect to see a little higher voltage, say 12.4, 12.5V.

But, as I suspect, you have probably been doing short drives, of 20 minutes or less, and if so, then you are not only not allowing the alternator to fully charge your battery, you are actually using more energy to start your RR than you are replacing while driving.

If you have a multi stage battery charger, preferably no bigger than a 10 amp one, try giving your battery a few good soak ( conditioning ) chargers.

You do this by first allowing the battery charger to fully charge your battery, and this may take quite a few hours with a small charger, then once the charger goes into float mode, leave it on for around 8 to 10 hours, then remove the charger for at least 10 to 12 hours.

If you can, do this a few times, even if you have to use the RR between charge cycles, you may find the settled voltage of your battery will rise.

Continual short drive, the Shopping Trolley Syndrome, is probably worse for cranking batteries than leaving them unused for a week at a time.

[Piddler]

Maybe purchase a CTEK or something similar when you are in Brisbane if you don't have for battery maintenance.

Cheers

[Shirley]

Yeah, 12.6 to 12.7 is fully charged. 12.1 is quite low. What sort of voltage do you have while it's running? You should have around 13.8 to 14.0 on these.

With my L322 Vogue 2003 4.4L I seem to get the same or similar voltage when running and with ignition off.
13.8 - 14.1v at idle 750RPM and about 12.5v with power off.
Funny part is, the battery will go flat after about 7 days if the vehicle is not used at all.

New battery fitted a month ago (big sucker) as per specification made no difference.
Might need to check if the alternator is bleeding backwards, hey?
Oh the fun never stops....... :)

Cheers, Shirley.

[rar110]

Recently I went on a trip OS and the L322 didn't get driven for 3 weeks. The battery voltage was ok and started fine. I must be lucky.

[DiscoMick]

This is actually a very good point. Yes ignition is on as are tv screen/EAS and anything else whirring away.


There is more to buying a MM than I thought so next week Saturday I'll have a close look!


This is the battery:
https://www.aulro.com/afvb/images/imported/2016/01/514.jpg (http://s133.photobucket.com/user/roadstone/media/20160109_112007_resized.jpg.html)


Its sealed I think so how do I check each cell? The guys who fitted it are asking to do that.
The suggestion their end is that these batteries are very good and its more likely that my alternator is tired. 13.7v charging at idle is low.


Cheers and thanks,


Jerry

13.7 charging at idle is not low, it's normal.
As Drivesafe said, regularly give your battery a good session on a multi-stage charger and that might expand its storage ability a bit.

Sent from my SM-G900I using AULRO mobile app

[Road Stone]

Hi again Jerry, and with 14.2+v, your alternator charge voltage is fine.

The 12.3v battery voltage ( around 70% SoC ) is not that low especially if, as you say, you have been using your RR ?frequently? over the last few days.

With that alternator voltage, if you had been driving for a decent amount of time, each time you drove, then I would expect to see a little higher voltage, say 12.4, 12.5V.

But, as I suspect, you have probably been doing short drives, of 20 minutes or less, and if so, then you are not only not allowing the alternator to fully charge your battery, you are actually using more energy to start your RR than you are replacing while driving.

If you have a multi stage battery charger, preferably no bigger than a 10 amp one, try giving your battery a few good soak ( conditioning ) chargers.

You do this by first allowing the battery charger to fully charge your battery, and this may take quite a few hours with a small charger, then once the charger goes into float mode, leave it on for around 8 to 10 hours, then remove the charger for at least 10 to 12 hours.

If you can, do this a few times, even if you have to use the RR between charge cycles, you may find the settled voltage of your battery will rise.

Continual short drive, the Shopping Trolley Syndrome, is probably worse for cranking batteries than leaving them unused for a week at a time.



First off, thanks everyone for the input. Fantastic.


Drivesafe: You are correct trips here tend to be short distance but can take some time due to the appalling road system. Out of town is brilliant. First world roads across the savannah.


Yes I have been charging periodically, this is what I use!!
https://www.aulro.com/afvb/images/imported/2016/01/509.jpg (http://s133.photobucket.com/user/roadstone/media/Charger%20SCA.jpg.html)


So as Im coming to Brissie next weekend, is this okay or do I need to upgrade? If so light as possible as weight will be and issue.


Vehicle is charging at a solid 14.3 today, battery was at 12.3 again.


Thanks again. Jerry

[Piddler]

First off, thanks everyone for the input. Fantastic.


Drivesafe: You are correct trips here tend to be short distance but can take some time due to the appalling road system. Out of town is brilliant. First world roads across the savannah.


Yes I have been charging periodically, this is what I use!!
https://www.aulro.com/afvb/images/imported/2016/01/509.jpg (http://s133.photobucket.com/user/roadstone/media/Charger%20SCA.jpg.html)


So as Im coming to Brissie next weekend, is this okay or do I need to upgrade? If so light as possible as weight will be and issue.


Vehicle is charging at a solid 14.3 today, battery was at 12.3 again.


Thanks again. Jerry

I would buy a ctek

:)

Cheers

[drivesafe]

Hi Jerry and while that battery charger will take quite a long time to fully charge your battery, if you have the time available, it is actually going to be very good for your battery.

I wouldn't upgrade unless you have some other specific reason to do so.

[Graeme]

I didn't know that such low current battery charges existed but I suppose its really for a motor cycle battery or to keep a vehicle battery topped-up when unused for an extended period. 40 years ago trickle charges were at least 4A and that was when batteries were very small capacity compared with today's batteries.

[drivesafe]

Hi Graeme, you can get even smaller chargers, and they will still charge the battery. There is a well known brand that has a maximum of 750ma output, but as posted, it will take a long time to fully charge a battery.

I have lots of customers who use a 10w solar panel to maintain their batteries.

If the battery was low when they left the vehicle for some time, the 10w solar panel would, over a week or so, fully charge the battery, yet a 10w solar panel will only have a maximum output current of around 0.5 amps, and this is only while the sun is at it's peak.

BTW, if anybody wants to maintain their cranking battery with a solar panel, your can fit up to a 10w panel and you do not need a solar regulator.

You can increase the total solar wattage by 10w for each battery you have in your vehicle, and again, no regulator needed.

[Graeme]

For the OP's apparent vehicle usage pattern it seems to me that this very small charger is unlikely to ever get the battery up to a decent state of charge unless left connected for a few days without opening a door.

[drivesafe]

Hi again Graeme, even that small charger will work fine with an RR.

For every minute the doors are open, that charger will replace the energy used in fifteen minutes of charging time.

So say it take Jerry 10 minutes to unload groceries, with in 3 hours, that charger will have replaced the used energy and will continue to charge the battery.

So a continuos use overnight, every night, for a while, will bring the battery up to a fully charged state and will condition the battery to better hold that charge.

Using a bigger current capacity charge would not make all that much difference during the conditioning of the battery and this is where improvements need to be made, for the battery to get a better life span.

[Road Stone]

Hi Folks,


Returned from my lightning trip to Brisbane. Now with Multi Meter!


First up, car has sat for 10 days unused. Started on the button, I was stupid and did not take a reading first!


After a short run, the MM indicates battery at 12.8v. I started the car and it showed 13.7v.


From the helpful advice already given, this appears to be okay.


I'm going to monitor over the next few days and see what happens. I go away again next week for 11 days so WILL check on my return.


Prices have gone up in Brisbane!!


Cheers, Jerry

[harlie]

Completely agree with drivesafe - We have a tractor on a property with a 10w solar panel on the roof, no regulator. Battery voltage never gets too high, and the battery is kept charged.

When the engine is started the ampmeter shows about 15+ for a couple of minutes and slowly drops to about 5+ over roughly 10 minutes and then moves to 0 over a couple of minutes, which would be replacing the power used by the glow plugs and starter - if the battery was low it would be more than 30+ to begin with and then sit at 10-15 for a while. It sits for several weeks at a time and the 10w panel works a treat as Drivesafe mentions.

[DiscoMick]

Hi Folks,


Returned from my lightning trip to Brisbane. Now with Multi Meter!


First up, car has sat for 10 days unused. Started on the button, I was stupid and did not take a reading first!


After a short run, the MM indicates battery at 12.8v. I started the car and it showed 13.7v.


From the helpful advice already given, this appears to be okay.


I'm going to monitor over the next few days and see what happens. I go away again next week for 11 days so WILL check on my return.


Prices have gone up in Brisbane!!


Cheers, Jerry
As I understand electrickery, 12.8 is a fully charged battery so that's good. The 13.7 after starting would have been the amount of power the alternator was pushing around the system and that's also a good number. My Defender sits on 13.9-14.0.

[Road Stone]

So just and update:


After 10 days of sitting doing nothing, the wife elected not to use it whilst I was away, I took the battery reading before starting it.


MM read 12.4v which I guess is not bad?


On starting, it got a reading after a couple of minutes of just over 14v.


No I'm wondering if my alternator is on it way out!!


Cheers, Jerry

[Aaron IIA]

All sounds good there.

Aaron

[drivesafe]

The reading depends on where you sourced it and were you driving at the time.

I would have expected around 14.5+v for some time, while driving, and then settling back to around 13.8 to 14v, but this would be after at least 30 minutes of driving.

Except for the last of the L322s, their initial voltage boost will last for exactly 30 minutes and then settle back to the normal operating voltage, and the boost voltage can go as high as 14.9.

What year model is your RR?

[DiscoMick]

14 volts sounds normal to me, as others have said.

[Road Stone]

The reading depends on where you sourced it and were you driving at the time.

I would have expected around 14.5+v for some time, while driving, and then settling back to around 13.8 to 14v, but this would be after at least 30 minutes of driving.

Except for the last of the L322s, their initial voltage boost will last for exactly 30 minutes and then settle back to the normal operating voltage, and the boost voltage can go as high as 14.9.

What year model is your RR?


Thanks Guys,


Its a 2007 TDV8.


Yes Drivesafe, you are correct. On start up 14.4v and then after a while it drops to 13.5v these readings taken from my diagnostics machine (Hawkeye).


I took the multi meter readings from both the jump start point and direct from the battery terminals both read exactly the same.


I have decided to buy a recon alternator and keep here as a spare. Given where I am if something did happen I wont be off the road for a month! $400 for a 150amp 2 year warranty, valid here too believe it or not so feel its wise.


Cheers, Jerry

[drivesafe]

Those voltages are fine and it sounds like it is running OK.

BTW, they are fun ( NOT ) to change.

[DiscoMick]

Thanks Guys,


Its a 2007 TDV8.


Yes Drivesafe, you are correct. On start up 14.4v and then after a while it drops to 13.5v these readings taken from my diagnostics machine (Hawkeye).


I took the multi meter readings from both the jump start point and direct from the battery terminals both read exactly the same.


I have decided to buy a recon alternator and keep here as a spare. Given where I am if something did happen I wont be off the road for a month! $400 for a 150amp 2 year warranty, valid here too believe it or not so feel its wise.


Cheers, Jerry
I assume your TDV8 has a 'smart' alternator which is designed to vary the output depending on the demand i.e. raises it to start and recover the charge used for starting, then drops it depending on the load on the system, so that's normal.
My Defender isn't that smart - it just makes the same all the time.

[bsperka]

I assume your TDV8 has a 'smart' alternator which is designed to vary the output depending on the demand i.e. raises it to start and recover the charge used for starting, then drops it depending on the load on the system, so that's normal.
My Defender isn't that smart - it just makes the same all the time.

Btw: typically "smarter" than that. Won't charge at idle ( unless battery voltage indicates required), charges when decelerating, won't charge if high engine output required etc .

[Road Stone]

I assume your TDV8 has a 'smart' alternator which is designed to vary the output depending on the demand i.e. raises it to start and recover the charge used for starting, then drops it depending on the load on the system, so that's normal.
My Defender isn't that smart - it just makes the same all the time.



I have no idea if its smart or not! Hope so, smarter than me anyway. As long as it charges when in remote areas I don't care LoL!


I'm heading on safari mid week in the remote Western part of Uganda/DRC boarder so heres hoping!


Cheers, Jerry

[disco gazza]

Some pics of the area if possible please. :D
Sent from my SM-G900I using AULRO mobile app

[Road Stone]

Hi Disco Gazza, I will do indeed now I'm back.


Well after a 1100klm run A/C on most of the time battery is sitting at 12.6v after vehicle has stood for 24 hours.


Hopefully that is okay.


Cheers, Jerry

[DiscoMick]

Sounds better. Hope it holds the charge. How was the trip?

Sent from my GT-P5210 using AULRO mobile app

[drivesafe]

Hi Jerry and it looks like you had a great trip.

It also looks like the long drives not only charged your battery but it also improved it's condition, because at 12.6v after 24 hours, your battery is sitting at 95+% SoC, which is pretty good.

[Road Stone]

Sounds better. Hope it holds the charge. How was the trip?

Sent from my GT-P5210 using AULRO mobile app


All good thanks, have posted a few pics on a new thread.


Thanks Drive safe, hopefully it stays that way for a while.


Cheers, Jerry