Battery State of Charge info poll

[drivesafe]

Hi folks, if any of the readers have the time, and has access to a digital multi meter, would you like to take part in a simple battery voltage test.

The idea of the poll is to see whether cranking batteries are not being charged above the 70% level that is proposed in quite a few articles or is it more like 90+% the state at which I find most vehicle’s cranking batteries to be at.

There are 10 basic questions and just answering the first will do, but if you have the time and info available, answers to any or all of the other nine would be very helpful in see just how alternator battery charging works in different vehicles.

The info can be from any vehicle, not just your 4x4 and please feel free to post any additional info you think may be related to the subject.

The first question will be more accurate the longer the vehicle's motor has been off, preferably 12 or more hours after the motor was last on.

1 ) Once the motor has been off for a few hours, preferably 12 or more, what is the voltage at the cranking battery’s terminals.

2 ) Type of vehicle.

3 ) What make & type of battery & Age ( a model number will do )

4 ) When was the last time the vehicle was driven.

5 ) How long was the last drive

6 ) Is this your day to day drive or a once a week vehicle

7 ) Alternator size

8 ) Is this your tow vehicle or other.

If you can, the following info would also be of interest.

9 ) What is the voltage at the cranking battery about 1 minute after you first start your vehicle ( cold start )

10 ) With the motor still running, what is the voltage at your cranking battery after a 30 minute drive.

The last two questions are for gaining a better idea of how different alternator operations. Alternator operation in most vehicles is now controlled by the vehicle’s Engine Management Computer. This independent control not only means that there will be differences in alternator operations between vehicle makes but even between same make and models.

I Had an 03, Mark III Range Rover, first version of the current model. It’s alternator went to 14.3v soon after the motor started and stayed there for as long as the motor was running.

I now have an 08 Mark III Range Rover, the latest version of the current model. The alternator in the 08 RR does not start generating power for about 30 to 50 seconds after the motor is first started and the initial voltage can then be anything from 14.2 to 14.9 volts and does not seem to be influenced by ambient temperatures.

Exactly 30 minutes after the first start, the voltage lowers and can be as low as 13.2v.

For anyone trying to get any form of alternator operations info, it is almost impossible to get any data form any of the manufacturers, so your input can be very helpful.

A suggestion to make the data entering easier to post, copy the ten questions and paste them in a word processor, add your data under each question and then copy and paste into a reply.

[+dj_hansen+]

Will do this for you tonight Tim.

[drivesafe]

Will do this for you tonight Tim.

Cheers mate.

[legs_11]

I'll take some measurements over the weekend and get back to you

[drivesafe]

No hurry legs, I reckon it will take a week or two before some people will get the time to do this but every bit helps.

Cheers.

[chimpboy]

Will do this for you tonight Tim.

I will too, at least with one of the cars.

But probably not today, it's raining again

Perhaps you should post a link in chit-chat or gen tech to get a bigger poll result.

[macca81]

Perhaps you should post a link in chit-chat or gen tech to get a bigger poll result.

agreed, or at least a post that links back to here.

ill do it 2nite. maybe even over the weekend as ill be up in the snow, just for comparisons sake. damn rain tho... grrr...

[drivesafe]

Thanks folks, that’s a good idea and done.

Cheers.

[+dj_hansen+]

1 ) What is the voltage at the battery’s terminals.
Main 12.57
Aux 12.69

2 ) Type of vehicle.
Toyota Landcruiser, 80 Series, Factory Turbo

3 ) What make & type of battery & Age ( a model number will do )
Main - Exide Orbital Blue Top, Feb 2008
Aux - Fullriver DC 100-12a, March 2009

4 ) When was the last time the vehicle was driven.
Monday afternoon

5 ) How long was the last drive
~ 20 mins there, stopped for 15, 20min drive home, fairly free flowing traffic so not stop start.


6 ) Is this your day to day drive or a once a week vehicle
Once a week at the moment

7 ) Alternator size
IIRC 130amp

8 ) Is this your tow vehicle or other.
Other, trip car now.

It is also cold outside atm ~10c, car has sat since last driven.

Will get the other info on the weekend when its not freezing and raining

[drivesafe]

Thanks DJ, some good info there.

Folks I have altered questions 1 and 9 for clarity.

DJ please note this does not effect your answers.

[legs_11]

Here you go:

1 ) Once the motor has been off for a few hours, preferably 12 or more, what is the voltage at the cranking battery’s terminals. 12.68

2 ) Type of vehicle. Toyota 1994 4Runner V6

3 ) What make & type of battery & Age ( a model number will do ) 3 month old century NS70

4 ) When was the last time the vehicle was driven. 7pm saturday night

5 ) How long was the last drive 45 minutes

6 ) Is this your day to day drive or a once a week vehicle Daily driver

7 ) Alternator size Whatever the standard one is for a V6 4Runner, I dont know

8 ) Is this your tow vehicle or other. Just my everyday car

If you can, the following info would also be of interest.

9 ) What is the voltage at the cranking battery about 1 minute after you first start your vehicle ( cold start ) 14.45V, on average, was floating either side of this mark by about 0.04V

10 ) With the motor still running, what is the voltage at your cranking battery after a 30 minute drive.14.45V, same as above

[drivesafe]

Thanks to those who took part in the poll and I am not going to post up any opinions on the results, people can come to their own conclusions.

Anyway here is the initial results from 52 replies of the Cranking Battery Voltage reading are as follows :-

95% ( 12.6 ) or higher = 25

90% ( 12.5 ) or higher = 13

80% ( 12.42 ) or higher = 4

70% ( 12.32 ) or higher = 2

Lower than 70% ( 12.32 ) = 8

There is a lot more data to be sorted yet but this was the main aim of the poll.

The Highest reading was 12.95v and the lowest was 11.83v

A small number of the reading were taken less than 12 hours from the last time the motor was run so I will have to do some calibrating.

Again Thank you to all those who contributed.

[drivesafe]

Some more info from the poll, and there are still replies coming in.

Most but not all replies included the operating voltage, of the info supplied, only 6 had 14.5v or higher, nearly half the vehicles ( 23 ) were between 14 and 14.4v but more interestingly though, 21 were under 14v but most had a cranking battery SoC of higher than 90%.

Some additional info, and this was to be expected, 6 of the vehicles with cranking battery SoC of less than 80% were pre 2001, 2 were 2001 Jeeps and these also had operating voltages of just 13.9 Max, 1 vehicle was 2003 and the last was 2006.

Of the vehicle with 90% or better cranking battery SoC, 14 were 2002 or later, but 13 were pre 1999 and of these 4 were pre 1990.

This well and truly makes a mockery of the myth that you can’t charge a cranking battery over 70-75% SoC and it shows that the alleged problem probably never existed.

BTW, could everybody add the make year of your vehicles when replying.

It’s been interesting to see how any older vehicles had good battery stats

Cheers.

[macca81]

1 ) Once the motor has been off for a few hours, preferably 12 or more, what is the voltage at the cranking battery’s terminals.
12.78

2 ) Type of vehicle.
93 Toyota Hilux Surf, 1KZ-TE engine

3 ) What make & type of battery & Age ( a model number will do )
Optima YellowTop, Model D35 YT, 650CCA, 48 AH. 2 in parallel with no isolator.

4 ) When was the last time the vehicle was driven.
24 hours prior to test

5 ) How long was the last drive
5 mins

6 ) Is this your day to day drive or a once a week vehicle
Daily

7 ) Alternator size
70amp AFAIK

8 ) Is this your tow vehicle or other.
Is used for towing on average once or twice a month, but primarily it is a daily drive

9 ) What is the voltage at the cranking battery about 1 minute after you first start your vehicle ( cold start )
13.1

10 ) With the motor still running, what is the voltage at your cranking battery after a 30 minute drive.
13.84


just as an extra bit of info.
on startup, the voltage dropped to 10.3, then inside the space of a second it had risen back up to 12.4.
alternator was putting out 14.01 at idle
after a 30 min drive, the voltage was 13.84 with engine running, then dropped to 13.10 with the engine off

[drivesafe]

Hi folks and the poll is now closed.

Thanks for all the replies, and while I had hoped to get 20 to 25 replies but there are some 61 replies and thats excellent.

Owing to some dubious one eyed comments made on a number of sites, the poll results are being compiled by someone else and once the results are available I’ll post them up.

The poll has been a very good chance to show many people just how bogus this 70% myth is and the fraudulent lengths some are prepared to go to to protect this myth.

Thanks again.

[chimpboy]

Owing to some dubious one eyed comments made on a number of sites, the poll results are being compiled by someone else and once the results are available I’ll post them up.

lol dear god, some people are farkheads aren't they. Good on you for doing this, it is shaping up to be very interesting.

[-Scott-]

Owing to some dubious one eyed comments made on a number of sites, the poll results are being compiled by someone else and once the results are available I’ll post them up.

lol dear god, some people are farkheads aren't they. Good on you for doing this, it is shaping up to be very interesting.

x2

I just had a browse through a few of these "other" forums, and some of the responses are simply unbelievable. What happended on Overlander?

But those caravanners are definitely from another planet. They worship their book writer, and won't hear that he could be wrong - blind ideology at its worst.

Good luck with the results. How will you post the results on Caravaners if they've locked the thread? But it probably doesn't matter: you can lead a horse to water, but you can't make it drink.

[macca81]

wow!

i just chased up a few of the other threads, and by christ there are some odd people out there! and i agree, the caravaners are from an entirely different planet

[drivesafe]

Yep, also not the most honest of moderation but it has been a very good exercise in that it has exposed the book writer for the utter fraud he really is.

As far as posting the results go, I won’t be wasting my time on the Caravaners forum because a number of members from there have already posted on other OPEN forums and as such, will get to see the results anyway. Some of them actually E-mailed me to let me know that they wanted to participate but opted to go to another forum to do it to save being attacked.

It’s a shame because Caravaners could be a good forum.

Overlanders was a surprise because I thought there would be some opposition there but they already seem to think the 70% is a myth and the one clown that did try his luck, his luck ran out and he was shown the door and that was the second forum he was banned from.

[presto]

i saw the overlander site, any chance of a link to these other forums? im just curious to see what their reasoning was.. id never heard of this myth before

[macca81]

i saw the overlander site, any chance of a link to these other forums? im just curious to see what their reasoning was.. id never heard of this myth before

how much time ya got?

read THIS

[-Scott-]

i saw the overlander site, any chance of a link to these other forums? im just curious to see what their reasoning was.. id never heard of this myth before

how much time ya got?

read THIS

I haven't read the whole debacle, but, from what I can see, the "in crowd" worship at the alter of the author, and (apparently) take as gospel a belief that 12.6V represents 70% SOC.

While I'm here, I'll state this again: for people such as those on the caravanner forum, who camp much more than they drive, I can accept that a standard alternator system is unlikely to charge significantly discharged batteries much beyond 70% in a few hours of driving.

Under certain circumstances, the 70% guideline is reasonable.

But to claim that an alternator system can NEVER charge beyond 70% (as at least one of the Caravaners has explicitly claimed) is simply wrong - as drivesafe has now proved (well, to all reasonably intelligent people...)

[drivesafe]

i im just curious to see what their reasoning was.. id never heard of this myth before

Hi presto, a little history on what lead up to the poll and the carrying on.

I’ve been working in automotive electrics and electronics, for just over 35 years, and I’ve specialised in dual battery systems for 20 years.

In the late 90s, I read an article by a guy in the USA about how it was unlikely that batteries in family sedans in the middle of a typical North American winters night, driving in bumper to bumper traffic, in the rain, with the windscreen wipers going headlights on, heater and air conditioning at full power and the sound system up, there was no wonder that these batteries would not reach much over 70% SoC.

This was about family sedan cranking batteries in North America and nothing to do with RV batteries or Australian conditions.

About 2002 I started reading similar stories here, usually in the form of advertising hype for some wonder battery charger or what ever, extolling their virtues while at the same time make statements like you can’t fully charge a battery from an alternator and the one I rally like and see a lot of now days and goes like this” Through what ever reason, vehicle makers deliberately make sure that the cranking battery is never charged over 70%” and so.

Another mob, pushing one of these wonder devices claims you could drive from Perth to Sydney and never charge your batteries.

This is all just total B/S and is nothing more than sales hype.

With all the above and more, in mind, I started questioning the validity of this crap on a number of forums where it wa being pushed by people who had absolutely no idea of what they were on about but had been sucked in by the advertising hype and by a book put out by THE book writer.

After some heated debates, THE book writer pops up on the Caravan & Motorhome forum and posts up a thread, to which the first link will take you.

http://forum.candm.com.au/showthread.php?t=2987

I had had enough of all the lies and decided to run a poll on that forum to see just what SoC most people’s cranking batteries were at. I already knew from all the years I had worked in this industry what the results would be, or there about, would be, but this seemed a good way to educate a lot of other people at the same time.

The next link takes you to the poll thread and the debates that went with it and this is why I then decided to run the poll on a number of site.

http://forum.candm.com.au/showthread.php?t=2955


To my surprise, the members of most site agreed with what I was saying and liked the idea of the poll, the rest WILL be history.

[presto]

hahaha yeah piss off drivespace.. wow those guys are sensitive! i usually dont have a dig at anyone but.. wow. some pretty silly accusations and responses. interesting to read tho i guess theyre a pretty close-nit bunch.

[drivesafe]

While I'm here, I'll state this again: for people such as those on the caravanner forum, who camp much more than they drive, I can accept that a standard alternator system is unlikely to charge significantly discharged batteries much beyond 70% in a few hours of driving.

Under certain circumstances, the 70% guideline is reasonable.

But to claim that an alternator system can NEVER charge beyond 70% (as at least one of the Caravaners has explicitly claimed) is simply wrong - as drivesafe has now proved (well, to all reasonably intelligent people...)

And I agree with this as well, mainly because, as you put it, it can’t be done in a few hours and there be the problem, most people NEVER drive long enough to fully charge their batteries, no matter what set up they have and this is where, in the vast majority of cases, an alternator can do a much better job than any of these wonder set ups can.

[drivesafe]

i guess theyre a pretty close-nit bunch.

And all butt kissers of THE book writer.

Did you like all his claims that battery manufacturers back his myth yet after asking him at least a dozen times for the name of these battery manufacturers, he never states which ( mythical ) battery manufacture.

[presto]

now i can see how the dual battery thread escalated.. i hope noone thought i was taking this view on things!

Did you like all his claims

yes, i enjoyed every post
still got about 30 pages to get through..

[drivesafe]

i hope noone thought i was taking this view on things!

Not at all, this is by far one of the better sites and people tend to be far more honest and intelligent

[chimpboy]

THIS

Hooooooooooooooooooooooooly shit. That is actually quite weird. And I'm only on page 4. I would not have lasted anywhere near that long if I were you Drivesafe.

For the record, and I don't want to seem like any kind of ass kisser (I don't really have any reason to kiss yours anyway), I've always thought that you do a very good job of NOT promoting your business at all here, and when it gets a mention it's pretty appropriate. Then again that is true of nearly all vendors who are on this forum come to think of it.

[drivesafe]

And the irony is that one of the clowns posted all the info about my company from ASIC on the site.

It was quickly removed by one of the moderators but as you will see they still kept posting my web address, to what aim I don’t know, but I have already had quite a few orders thanks to their postings.

The thread gets much worse and has very little educational value other than to show what lengths those clowns will go to to defend the indefensible.