Alternator Voltage

[Dazandtrace]

Hi all

I dont think i have a problem but just thought I'd ask the question. I dont suffer with bad starting or a flat battery.

All it is i thought I would check the battery and the voltage just to see what i get going into the battery when engine is running. Well i get 13.5v . Is this right i always thought an alternator gave out around 14 to 14.4v. Is my alternator running abit low

My car is a 2006 2.8crd voyager

Thanks Daz

[andyb2000]

Hi Daz,

 

This is quite a complex question actually! These things have a temperature sensor right below the battery (when you take battery out you'll see a round plastic fitting, that's the battery temperature sensor, and underneath it is a twin-core wire going to the wiring harness) which senses the temperature. It will vary the output of the charge circuitry depending on what temperature the battery and ambient is at, the idea is to prolong the life of the battery.

 

Various people (myself included) did a lot of tinkering with this to test what voltages it changes to. If the sensor is a little faulty or it was warm when you tested it may just have been reducing the voltage itself. If it's like that on a cold morning at first start it may be the alternator starting to dip a little.

 

Over on that other forum (which most of us also inhabit!) search for ButtonMod by Leedsman for more info from various people on it.

[QinteQ]

14.4 used to be the old[er] charge rate. The current thinking of 13.8 is generally accepted battery charge rate. To me that's too low, A cell on our lead acid starts to charge @ 2.25 x by our 6 cells is 13.8 in most/many cases that's gonna take one hell of a long time to replace just one winters morning. The ButtonMod Andy speaks of is easy, 10 minutes, safe as houses costs less than a quid and delivers 14,2[ish] well inside the 14.5 gassing safety and a much reduced re-charge time.

[Dazandtrace]

Hi all thanks for all the comments and advice. Ill take a look at this mod. And see what i can do .

Thanks again

[matgriff]

After getting fed up of the constant state of near battery flatness on my 2007 Grand Voyager CRD I finally decided to get it sorted...

Its not that my battery was going completely flat, but it's always just on the edge, in the mornings it just has enough to start the car, but it's never fully charged. I have no excuses as I work in R&D with power electronics :-)

Step 1 - check the charging voltage... it was 13.5v both unloaded and with everything switched on, it was regulating correctly, but in my experience this is a bit low. My LR Discovery regulates at 14.4v and my neighboursMondeo at 14.5-14.6v

Step 2- Unplug and measure the battery temperature sensor. It was reading about 12K ohms at 15C.

Step 3- I warmed the sensor up with a hot air gun until it was pretty hot, resistance dropped to around 3K ohms.

Step 4- Popped it in the freezer for half n hour, it went to 29K ohms

Step 5- made up a little wiring loom with a 22K ohm 1/2 watt resistor, plugged in in instead of the temperature sensor.

Step 6- checked the regulated voltage with the engine running, both unloaded and loaded, it's now 14.3v-14.4v

Step 7- shut the bonnet and bask in the smugness of a simple job well done :-)


To be honest I think the battery temperature sensor is an unnecessary gadget, I use a simple lead acid gel battery from Euro Car Parts, I got the biggest one that would fit, it cost £45 with a 4year guarantee, I'm happy to change it every 4 years for that price.

As I've used a fixed resistor it will always charge at 14.3v regardless, which isn't a problem.

I did this 4 weeks ago and it's been much better ever since, spins over great in a morning now.

[johngee]

i did the same mod with the resistor but i also had a parrasitic drain of 1.6amps on the battery ,i eventually found it to be the audio amp ,so removed the fuse and wired in an isolation switch on the dash for the amp ,easy peasy and up till now no more flat battery ,happy days

[Caspian]

This is what I use to check voltage:
When engine is not running, it shows current battery voltage. (useful to check how worn is battery)
When engine is running, it shows the current voltage, the alternator is charging the battery.

I fitted this on the far left side of the windscreen, so one look and I can see.

 

[jasonleah1]

Exactly how do you do the mod?? I tried and my car still only charges at 13.6 or so volts?? I must have not done it right, Do you just fit a resistor inline and be done with it??

[QinteQ]

- 33K Ω @ 1/2 watt gave me the 13.9

- 22K Ω @ 1/2 watt gave me the 14.4 I wanted, Back to 'happy days' old school charging rates

- 09p from Maplins

- snip the black wire that comes from the 'battery button sensor'

- insert a 22K Ω @ 1/2 watt resistor back into that wire - sorted

- 5 minutes

- greets to 'matgriff', hadn't spotted that post

 

 http://i.imgur.com/DKa3lr6.png

[jasonleah1]

Did the mod this morning, Cut brown wire from sensor under battery stripped both sides and put these into both ends of connector block, fitted resistor into connector block the same way and plugged back in. Drove car and tested while running and was returning 14.15v after an hours drive on a brand new battery tested again and was only giving 13.6v loaded and unloaded. Left car until about 10 mins ago and battery was showing 12.4v , when I turned it off this morning it was showing 12.6 surely it couldn't have lost .2 v in just a few hours of leaving it or do I have a problem. I don't know if the charging voltage is correct but it just doesn't seem enough. The old battery on the car used to show 12.1v while on the car but I took it off and replaced with a Bosch S4. Tested old battery a few hours later and it was showing 12.5v?? either my tester is duff or I'm loosing power as soon as I connect my battery to the car.

Edited November 26, 2016 by jasonleah1

[QinteQ]

The S5/4/6/ is just how long your warranty runs for jasonleah1, it tells us nothing about your new battery. For example I have a spare Bosch S5 that is an actual 12V 85Ah 800CCA Type 110 S5010. The 800 cold cranking amps is the most important bit the 85aH is less important for starting and just means the time it takes to empty and the S just stands for their 'silver line of batteries'.

 

I don't understand what's wrong, apart from myself at least seven others have done this exact MOD and using the same resistor which is non-directional and though we all vary slightly we are all ≈ [ish]. I will guarantee that you have not used a type 110 because they will not fit our GV's without cutting and pruning the battery compartment to fit a type 110, so what is your actual new battery number ? I've long advocated 80 / 800 for our GV's they draw a flaky IOD of .025 to .030aH at rest after the 16 minute sleep command and have a lot of electrical toys, add to that the big 3 litre lump of a UK ± °C cold compression engine and you have some big needs. The only obvious thoughts are (1) cut wrong wire (2) not reading the voltage from an in cabin gizmo at 1500+ RPM.

[jasonleah1]

Hi cheers, The battery on the car now is a Bosch 096r with 74Ah and 680cca If this means anything to you, The battery that came off is a Numark 70Ah 640cca, that has been in my shed for over a day and is still holding 12.5. I have just been out to test my battery and it has not got down to 12.05v from about tea time when it had 12.3v I tested it using a normal handheld sinometer M-830B. The car is now charging at 14.35v. I'm sure there is a drain on the battery so how do I go about and find it?? I will remove battery tomorrow and have another go at the resistor mod but I think the drain on the car is far more than it should be even with the 16 minute sleep command on it.. I'm also using a maplin solar charger / maintainer  when the car is not in use

[QinteQ]

Hi cheers, The battery on the car now is a Bosch 096r with 74Ah and 680cca If this means anything to you, The battery that came off is a Numark 70Ah 640cca, that has been in my shed for over a day and is still holding 12.5. I have just been out to test my battery and it has not got down to 12.05v from about tea time when it had 12.3v I tested it using a normal handheld sinometer M-830B. The car is now charging at 14.35v. I'm sure there is a drain on the battery so how do I go about and find it?? I will remove battery tomorrow and have another go at the resistor mod but I think the drain on the car is far more than it should be even with the 16 minute sleep command on it.. I'm also using a maplin solar charger / maintainer  when the car is not in use

I think you have done the MOD correctly and your new battery will be charging at 14.3 or .5 where I think you have confusion is the method of reading the average value over the REV range.I'll dig out an old post / thread of mine for you to read that covers much of your concerns.

 

IOD draw is an absolute pig to chase down, unless someone has'bodged' wiring especially aftermarket radios its a possible but unlikely culprit. Solar battery maintainers - anything short of £100 good quality panel and controller is unlikely in the winter ever to replace the 1/2 watt minimum needs of a GV IOD. I'll get back to you after the Arsenal match.

[QinteQ]

- get one of these for your RHS [not left] cigarette lighter socket, not very accurate but a good indication of 'live average data' while driving

- read this from a year ago, covers most of the batteryMOD

- read this on solar maintainer part 1, part 2 is in this very thread

 

Put your excessive IOD draw theories on the back burner for now. Get this battery and the solar maintainer / lifestyle right for starters my friend. I think you will find that you are now charging at 14.4 [ish] average volts with the 22K Ω @ 1/2 watt and yes you used the correct colour brown wire. Telling me how often on average you use the car [(1) lifestyle - frequent use - winter starts - duration [50 miles every other day] of recharge from the alternator - no intervention needed] .. .. [(2) lifestyle - infrequent use - winter starts - duration 30 minutes once a week you will always have problems. I started with a 4W Maplins panel good for the summer months absolutely pointless in the winter I looked at the actual IOD draw, mounting winter-sun-position of the panel and quality of the panel and soon realised I was going to have to do it right and forget the cheepo Maplins stuff.

[jasonleah1]

Hi, Thanks for the info, The car is used probably twice a day to do school run, school is about 3 miles each way at most, also used for the odd meeting for our foster children similar distance, The problem is elec doors being used, that damn heater which never seems to be off, and obv in the winter months lights wipers etc. My solar panel probably isn't up to the job of anything either as it is only a 12v 2.4w cheap jobbie. I have read the above links too, still cant get my head around the charging voltages though lol. I have done your air dam mod this afternoon and I have the Renault thermostat on order from local motor factors just in case I have to do the thermostat mod too. On a quick side note, I took the car on the M5 very late last night as I couldn't sleep and did about 100 miles only had radio on, I got back and tested the voltage in the battery engine off, it steadied out at 12.75v resting. I took out the IOD fuse locked all doors and went to bed. this morning at 10am I tested the battery again and it hadn't lost a single .1 of a volt still showing 12.75, took the car for a half hour or so drive and it was charging at 14.15 again from starting the car but when I got home and the car was warm the voltage was 13.95. I know I have a big hang up of these numbers but I want the car to charge at 14+v all of the time as it still seems to be dropping voltage like it should without the battery mod??  Your post said you were getting 14+ all the time or is it because I'm using a 33k resistor and not a 22k??

Sorry to be a pain.

[QinteQ]

Hi, Thanks for the info, The car is used probably twice a day to do school run, school is about 3 miles each way at most, also used for the odd meeting for our foster children similar distance, The problem is elec doors being used, that damn heater which never seems to be off, and obv in the winter months lights wipers etc. My solar panel probably isn't up to the job of anything either as it is only a 12v 2.4w cheap jobbie. I have read the above links too, still cant get my head around the charging voltages though lol. I have done your air dam mod this afternoon and I have the Renault thermostat on order from local motor factors just in case I have to do the thermostat mod too. On a quick side note, I took the car on the M5 very late last night as I couldn't sleep and did about 100 miles only had radio on, I got back and tested the voltage in the battery engine off, it steadied out at 12.75v resting. I took out the IOD fuse locked all doors and went to bed. this morning at 10am I tested the battery again and it hadn't lost a single .1 of a volt still showing 12.75, took the car for a half hour or so drive and it was charging at 14.15 again from starting the car but when I got home and the car was warm the voltage was 13.95. I know I have a big hang up of these numbers but I want the car to charge at 14+v all of the time as it still seems to be dropping voltage like it should without the battery mod??  Your post said you were getting 14+ all the time or is it because I'm using a 33k resistor and not a 22k??

Sorry to be a pain.

 

Stop reading the battery terminal voltage with the alternator / engine off it serves no purpose to this debate jasonleah1, and in the scheme of things confuses you, it tells us nothing at all about your issues. You need to tell me what its charging at while driving along @ 1500+ RPM [#11] and as stated several times can only be done from your own observation inside the car while you are driving. I have one of the Ring RBA3 voltmeters, but there are many available from a couple of quid.

[QinteQ]

Get one of these, put it on your old battery and leave it switched on forever and ever. 80% of batteries we scrap & replace are actually still good just 'sulfed', we scrap them by the million but they are mostly ok. Battery manufacturers worlwide rub their hands together, melt them down, then sell us back our own expensive lead as 'grey lead' % in new lead batteries. This charger will even repair sulphated batteries.

Edited November 27, 2016 by QinteQ

[QinteQ]

is it because I'm using a 33k resistor and not a 22k??

 

 

Yes I clearly said in #9

 

- 33K Ω @ 1/2 watt gave me the 13.9

- 22K Ω @ 1/2 watt gave me the 14.4 I wanted, Back to 'happy days' old school charging rates

 

 

The answers to some of your other questions are :

 

Battery choice on a GV, like choosing a wife, provokes different opinions on what is beautiful. The issue however are simple. You should be looking for about 800CCA over 80aH, this is a physical size that will not fit the CRD battery tray, so get a big one and modify the tray, or get a smaller one and take your UK winter chances. There is a~n~other UK issue of lifestyle, its a use it or lose it condition. If like me you do 2000 miles per annum with two 15 minutes trips once a week you will regardless of battery size / cost never keep that battery charged, the BUS [over 7 or so days] at resting will use more than the 30 minutes the alternator was able to replace.

 

Different people have success with different batteries, I'm sure the UK users will come to your aid with their suggestions, particularly the Scottish contingent who have an even colder climate than I. For myself I originally had a Banner Uni Bull 690 / 70, it was useless, my replacement was a Bosch S5 Type 96 at 800 over 80.

 

Bad GV Lifestyle = two 15 minutes trips once a week.

 

The  higher  the  voltage  applied, the  faster the battery will charge, charging at too  high a voltage WILL  damage  your  battery. A simple 100Ah open lead acid  battery and a 180A charger connected to the battery discharged to 50% :

 

- @ 50% full @ 13.2V current was 35A

- @ 50% full @ 14,8V current was 160A [improvement of 457%]

- @ 75% full @ 13.2V current was 1A

- @ 75% full @ 14.8V current was 60A [improvement of 6000%]

 

- two 15 minute periods @ 13.2V is 2 x 15 minute @ 21Ah, compared to ;

- two 15 minute periods @ 14.4V is 2 x 15 minute @ 60Ah, is an improvement  of  about  300%

 

The temperature sensor under the battery will drop [ temperature compensator's on modern alternators will compensate] the voltage output from about 14.0V to about 13.2V. The problem I have with this is the engine compartment soon reaches temp and the battery assumes its fully charged.

 

- 13.20 volts is about what you would expect from [split diode - does not apply to Voyagers, and] this vehicle with a temp sensor & alternator compensator

- 14.00 volts  is about what you would expect from any typical alternator without a vehicle temp sensor & alternator compensator

- 14.40 volts is what you would expect from a sealed lead acid to prevent [they tend to gas @ 50ºC] excessive gassing

- 14.80 volts is what you can risk pushing it to with an open lead acid to prevent damage to other equipment connected to the battery at the same time

 

NOTE01 : I wouldn't buy one smaller than 80 / 800, but in the interests of even handed-ness a spiral-redtop will do the job - make sure you get the right 'posts' for your type !

NOTE03 : There are IOD 7 functions that are 'live' when you think your car and battery are asleep, they pull a combined minimum of 0.025 ampere draw

 

IGNITION-OFF DRAW TEST - reproduced from the workshop manual !

 

The term Ignition-Off Draw (IOD) identifies a normal condition where power is being drained from the battery with the ignition switch in the Off position. A normal vehicle electrical system will draw from fifteen to twenty five milliamperes (0.015 to 0.025 ampere) with the ignition switch in the Off position, and all non-ignition controlled circuits in proper working order. Up to twenty-five milliamperes are needed to enable the memory functions for the Powertrain Control Module (PCM), digital clock, electronically tuned radio, and other modules which may vary with the vehicle equipment. A vehicle that has not been operated for approximately twenty one days, may discharge the battery to an inadequate level. When a vehicle will not be used for twenty one days or more (stored), remove the IOD fuse from the Integrated Power Module (IPM). This will reduce battery discharging. Excessive IOD can be caused by:

 

• Electrical items left on.

• Faulty or improperly adjusted switches.

• Faulty or shorted electronic modules and components.

• An internally shorted generator.

• Intermittent shorts in the wiring

 

[jasonleah1]

I will stop reading my voltage lol. I have ordered the ring intelligent charger, but can not find the voltage display you also showed me, Where would I find one of these?? got some 22k resistors on order too, As soon as I get everything I need will post back with my findings so you can fathom them out for me lol. I really appreciate the help you are giving me too as it was starting to met on my nerves a little, We will get there in the end!

[QinteQ]

still cant get my head around the charging voltages - #15

 

Its pointless reading a battery for at least 12/24 hours, it needs to be read at rest. Reading in less than at least that time will only ever give you a subjective lie. When you test a still actively exited battery it will return an artificially high state number. You mentioned your disappointment that it read 12.7 in an earlier thread - 12.7v (2.1 per cell x 6 cells) 12.7v  is in fact a 100% full . . . but now you know that would be an [exited state] lie, 12-24 hours later [rested state] would be a true honest real reflection of your 'actual state of charge'.

 

State of charge. What we all really want to know about our batteries is what is our actual CCA, 99% of people can never know, including clever mechanics in garages. I've got a Solar BA7, most garages have a cheepo 1940's designed £15 drop tester which are useless for telling you how many working CCA's you battery still has available to start your car at any point in time. For example a very good S5 800/80 when brand new might only be a 750/80 after 2 years - 700/80 after 4 years if you see what I mean.

 

______________________

29th Nov EDIT:

 

The solar maintainer

 

The nearest 'ready made' economically sensible panel in the UK that will return to your car the minimum IOD loss in winter sun is this exact one, if you are tempted to save £20/30 quid by getting a Chinese cheepo panel I can't vouch for it. If you have 'off street' parking you could mount it on the GV roof [cable into side opening window or upper boot lid or even screwed to the car port / house wall etc]

 

if your limited 'on street parking' and to having to place it on the horizontal shelf in front of the steering wheel in a 'through glass' situation you should still eek out the 0.25mA IOD on most 2 hour only days in the winter, but the 20x21" size means it will stick out a little more than the depth of the GV binnacle / info-bar.

 

Ring Intelligent 8 Stage Charger - £30 .. .. additional comment

 

Be sure- very sure, to use the MODE button set your battery type when you put a battery on charge, NORMAL GEL and AGM charge very differently. Your S5 is a NORMAL sealed wet cell.

Edited November 29, 2016 by QinteQ

[QinteQ]

#19 Where would I find one of these??

 

You don't need an expensive Ring brand, one of these will do you even the £2 Chinese ones will be within 1/2V accurate, more than good enough to get within the 14.4 your looking for. I take it you do have x2 cigarette lighters in the front of your car ?

[jasonleah1]

I kind of understand now. There are 2 charge points in the front of the car and a few more in the rear and boot I think. I have the charger and voltage reader on order. I do think though like a few people have already said because I just use the car for school run and on cold mornings with everything that can be on switched on then the little time the car is in use the battery is never going to fully recoup. On a plus point though your air dam mod seems to more than half the engine warm up time for the car which is great. Just wait for the mpg increase now and I'll be happy