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| ericvv Member Since: 02 Jun 2011 Location: Near the Jet d'Eau Posts: 5816   
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What should be the normal voltage that the alternator turns out when the Puma engine is running? I have a battery voltage meter which I can plug into the cigar lighter, and my Puma 2.4 is showing when running at any rpm about 14.3 to 14.4V. A friend of mine with a more recent Puma 2.2 in the same circumstances is showing 14.9V to 15.0V.
Then a second related question. When the engine is running and then turning on the lights, there is no voltage drop at all. When additionally turning on both the electric front window defroster and the rear window defroster the voltage drop is marginal, like it will be down 0.2V or so. But, when you turn on the ventilation fan to position 1 (and this without anything else turned on), the voltage drop is something like 0.3 to 0.4V (so in my case my voltage meter in the cigar lighter will then show 13.9 to 14.0V only). When turning the ventilation fan to position 3, the voltage drop is something like a solid 0.5V and stays there until you turn the fan off again, when voltage will immediately go back to 14.3/14.4V.... The same effect with the Puma 2.2 we tested this voltage meter on. With the fan at position 3, voltage drops from 14.9V to something like 14.5V. Are these ventilation fans so energy hungry then? More than lights, plus the front and rear window defrosters combined? Anyone in the know? Eric You never actually own a Defender. You merely look after it for the next generation. http://youtu.be/yVRlSsJwD0o https://youtu.be/vmPr3oTHndg https://www.youtube.com/watch?v=_GtzTT9Pdl0 https://www.youtube.com/watch?v=ABqKPz28e6A https://www.youtube.com/watch?v=rLZ49Jce_n0 https://www.youtube.com/watch?v=XvAsz_ilQYU https://www.youtube.com/watch?v=K8tMHiX9lSw https://m.youtube.com/watch?v=dxwjPuHIV7I https://vimeo.com/201482507 https://www.youtube.com/watch?v=ZSixqL0iyHw |
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28th Nov 2013 2:22pm |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610  
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My Puma is exactly the same as yours 14.3 - 14.4 volts. As for everything else why worry? I am an electrician and different loads will affect the charging voltage. The nominal voltage or Open Circuit Voltage of a single fully charged battery cell is 2.10 volts. As long as the charging voltage is sat around 13.5 plus volts you can forget everything else as the battery will charge. Don't overcomplicate your life and find something else to worry about.
 If you go through life with your head in the sand....all people will see is an ar5e!!
Treat every day as if it is your last....one day you will be right!! |
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28th Nov 2013 2:30pm |
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). If you are not suffering from a low battery or slow starting I don't think there's anything to worry about. Also try taking a reading directly off the battery terminals with and without the engine running and compare the results. The heater motor is quite power hungry - have you got air con?
| davew Member Since: 02 Jan 2012 Location: North Yorkshire Posts: 888  
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Most likely you are seeing an earth effect rather than a real reading. You'll probably find the heater blower and the cigar lighter use a common earth and what you are seeing is the effects of resistance in the earth lead back to the battery. Measure the voltage between the earth of the cigar lighter and the -ve battery terminal and you'll probably find your "missing" 0.5v
The best way to check is to measure the voltage at the battery. Bear in mind also that comparisons between different gauges is not useful unless they have both been calibrated properly. Many voltage gauges are only accurate to within around 1 volt. The charging voltage will depend on the type of alternator, many modern alternators are "intelligent" and will reduce their output as the battery reaches it's fully charged potential, some will maintain a fixed voltage above the battery voltage. As a result, depending on battery state and alternator type you can get anything between 13 and 14.5 volts. http://www.yorkshireoffroadclub.net/ |
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28th Nov 2013 2:39pm |
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| ericvv Member Since: 02 Jun 2011 Location: Near the Jet d'Eau Posts: 5816
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Thanks all replies. Mal, I am not worried about anything (I am not our friend C*t**h*m
 ), but I just was wondering why the big difference in voltage drop when the ventilation fan is turned on as opposed to all other mentioned voracious electricity consumers. I was thinking that that little fan must be pretty low wattage, so was wondering if I was missing something here. Anyway, my more than 5 year old original Varta battery is still going strong, never had any problem with it sofar, and there is still the 12S plug and the c-tek to top things up easily too this winter.
Eric You never actually own a Defender. You merely look after it for the next generation. http://youtu.be/yVRlSsJwD0o https://youtu.be/vmPr3oTHndg https://www.youtube.com/watch?v=_GtzTT9Pdl0 https://www.youtube.com/watch?v=ABqKPz28e6A https://www.youtube.com/watch?v=rLZ49Jce_n0 https://www.youtube.com/watch?v=XvAsz_ilQYU https://www.youtube.com/watch?v=K8tMHiX9lSw https://m.youtube.com/watch?v=dxwjPuHIV7I https://vimeo.com/201482507 https://www.youtube.com/watch?v=ZSixqL0iyHw |
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28th Nov 2013 3:20pm |
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| Lou Sparts Member Since: 15 Apr 2012 Location: Kent Posts: 1501 
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I had a Lancia many years ago which had a volt meter and the heater blower always gave the biggest drop when switched on so i guess it,s normal.
My understanding is an alternator should put out 13.6-14.4 volts. 2005 Td5 90 XS Steve |
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28th Nov 2013 3:33pm |
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| HardCharger Member Since: 03 Mar 2013 Location: Manila Posts: 737  
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Hi All!
Resurrecting. I notice these voltage variations as well but are voltage fluctuations in the neighborhood of 0.1V to 0.6V normal with steady loads and while idling with no loads? Didn't use to be like this until I had issues with my alternator. Replaced the clutch and the IC. Your input is greatly appreciated. Thanks! |
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14th Sep 2017 3:01am |
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| sandu Member Since: 30 Jan 2015 Location: Chisinau Posts: 11  
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I have a Defender TD5
I observed with my Nanocom that the battery voltage varies a lot even when idle. At idle: 11.8-13.2V On load: 12.5-13.7V On heavy load (3000rpm): it varies about 13.5-13.8V Do you think I should start thinking about alternator repair? It may also be a worn belt? LR DEF 110 TD5, 2000. LR DISCO-2 TD5, 2001. ARB Difflocks, front + rear. Ashcroft CV Joints + Halfshafts.. Transferbox 1.410 ratio. Warn M12000 + Warn 9.5xp Maxxis Creepy Crawler 255/85R16 |
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5th Jan 2018 4:15pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20371
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I would be inclined to check directly at the battery posts with a Multimeter for voltage.
The Nanocom could well be variable within the OBD system due to inherent draw and fluctuations. At rest as a close bench mark the battery voltage should be around 12.2v. Alternator changing current with motor running around 14.2v. I would say your Alternator is not working at full efficiency any more. I would say 0.3v fluctuations approximately are acceptable. (Or near). Keep all drain load loads off, whilst testing. $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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5th Jan 2018 5:34pm |
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| Alien Member Since: 18 Jan 2015 Location: Bacchus Marsh Posts: 230 
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Just thought I'd a little of what happened to our 2.2 with voltages that started reading up to 15 volts.
I have a duel battery controller that was picking up peak voltages over 14.8 and cutting out. As we know the ECM controls the alternator instead of a traditional regulator so it had me a little concerned. About 3 months later I found the start battery was flat after sitting the Defender for 2 weeks, a flick of the duel battery controller switch saw it start. This happened again after the rig was parked up for more than 2 weeks. The start battery was tested and replaced as it was at 60% of it's CCA when tested. Once fitted with a new battery voltages dropped back to previous levels. Somehow the system picked up the battery wasn't taking a proper charge and raised the input to compensate. Cheers, Kyle. |
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6th Jan 2018 11:07am |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20371
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Have you checked for any drain at rest I.e. Any parasitic loads?
A bit off on a tangent but never the less curious. $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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6th Jan 2018 11:15am |
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