Member Since: 31 May 2008
Location: Praha (Prague)
Posts: 2430
OK so me being a auto-eletric numpty ..........
can anybody explain why the alternator would change it's output?
I mean that as far as I'm concerned; when the engine is running the auxiliary belt that turns the alternator is still running regardless of alternator output, so what AND how does it changing output voltage effect the efficiency of the engine?
The belt tension is always going to be the same so the same load to spin alternator, or is there a fraction of a fraction of a fraction resistance due to magnetic fields pull on the internal components of the alternator as part of its internal process to create the the electrical output?
(if you say yes to that, how much difference does that actually make on the system/ fuel consumption)
confused..........Experience is a difficult teacher, because she gives the test first and then the lesson afterwards!!!!
13th Nov 2012 8:44 am
amazing
Member Since: 05 Mar 2011
Location: chengdu
Posts: 1542
Popelka
The effort to turn the alternater is proportional to load. So if low load easy to spin
Those who had a dynamo on their bikes and added extra lights will testify to the extra effort required.
50 W out needs 50 W plus losses in.
So yes the initial losses due to friction are the same when charging or not but when chqrging starts you need to put in what you get out +losses.
But keeping a battery at 100% isnt really needed. Also as we are stealing energy from the engine to convert into electricity we could choose to steal it when the engine is in a more efficient state..so not when on tickover..cold..or accelerating. So the clever little engineers build this feature into many new cars....without a thought for additional batteries added aftersales......but they should.
In the past many people would add a second alternator as old ones were not powerful enough for mens work. With current electrickery we may see seperate closed circuit alternator kits makng a comeback. some Jeep forums are already showing this as an option to avoid this smartcharge system
..but a piggy back charge fooling cpu seems more likely
but don't get carried away
It is better to have and not need it then need and not have it.
can anybody explain why the alternator would change it's output?
I mean that as far as I'm concerned; when the engine is running the auxiliary belt that turns the alternator is still running regardless of alternator output, so what AND how does it changing output voltage effect the efficiency of the engine?
The belt tension is always going to be the same so the same load to spin alternator, or is there a fraction of a fraction of a fraction resistance due to magnetic fields pull on the internal components of the alternator as part of its internal process to create the the electrical output?
(if you say yes to that, how much difference does that actually make on the system/ fuel consumption)
confused..........
The Alternator just puts out whatever charge the main ecu is requesting as the ecu controls it, that's why unless you have an expensive setup for testing the D3/D4 alternators you can't test them only on the car..
Flack
13th Nov 2012 10:27 am
DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
flack, how does the ECU check - would it think the battery needed charge if the Aux was at , say 10v, and the main was at 12v : or does it just assess what is being used on the main car circuits and charge that way. if so - if you had a low main battery would that mean it never charged properly.
i am hoping that if the two aux batteries are drained then the ECU will see a combined low voltage and kick out enough volts to bring them back up to normal ???Duncan
-----------------------------------------------------
If I'd known I was going to be so thirsty this morning I'd have drunk more beer last night.
FFRR Autobiography 4.4 SDV8 MY17
D4 HSE MY13 SOLD
FFRR 3.6 Vogue TDV8 SOLD
D4 HSE MY10 SOLD
D4 SE TECH MY15 SOLD
D4 XS MY12 SOLD
D4 HSE MY10 SOLD
D3 HSE MY06 - Re-Cycled Worldwide
13th Nov 2012 10:39 am
drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
Hi again Duncan and as I suggested, go for a drive and monitor your voltage.
The ECU controls the operating voltage, which in turn will effect the amount of current produced.
But if you have a low battery and the D4’s voltage drops to say 13v, you will still draw reasonable charging amps.
It’s when the battery is near fully charged that the charging can be a problem but there are still a number of factors that will make or break a dual battery set up.
Land Rover has programmed some pretty good smarts into their voltage operations and this makes them good at charging batteries, particularly if using lots of power when camped and then do some decent driving.
Popelka, amazing covered what happens pretty well.
The primary reason for all this messing around with a vehicles voltage levels is ultimately to reduce the vehicle’s exhaust emissions to meet ever more stringent anti pollution standards.2008 TDV8 RR Lux + 2009 D4 2.7
13th Nov 2012 11:43 am
DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
got a 200 mile journey for tomorrow so will monitor then Duncan
-----------------------------------------------------
If I'd known I was going to be so thirsty this morning I'd have drunk more beer last night.
FFRR Autobiography 4.4 SDV8 MY17
D4 HSE MY13 SOLD
FFRR 3.6 Vogue TDV8 SOLD
D4 HSE MY10 SOLD
D4 SE TECH MY15 SOLD
D4 XS MY12 SOLD
D4 HSE MY10 SOLD
D3 HSE MY06 - Re-Cycled Worldwide
13th Nov 2012 12:14 pm
Moo D3 Decade
Member Since: 13 Aug 2010
Location: Wiltshire
Posts: 13912
Simple solution....by a D3
13th Nov 2012 12:15 pm
DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
what, and use old technology
may as well buy series3 instead Duncan
-----------------------------------------------------
If I'd known I was going to be so thirsty this morning I'd have drunk more beer last night.
FFRR Autobiography 4.4 SDV8 MY17
D4 HSE MY13 SOLD
FFRR 3.6 Vogue TDV8 SOLD
D4 HSE MY10 SOLD
D4 SE TECH MY15 SOLD
D4 XS MY12 SOLD
D4 HSE MY10 SOLD
D3 HSE MY06 - Re-Cycled Worldwide
13th Nov 2012 12:42 pm
Moo D3 Decade
Member Since: 13 Aug 2010
Location: Wiltshire
Posts: 13912
Some things you just can't improve on....
13th Nov 2012 12:52 pm
Q86ARR
Member Since: 23 Feb 2010
Location: Jersey
Posts: 378
Hey Dunc,
I had a 12MY D4 that was converted for Ambulance use running split charge at work.
I had to download a modified CCF that had non BMS (battery monitoring system) selected.
13th Nov 2012 9:00 pm
DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
Oh,Oh looks like i might be buying a Faultmate MSV !!.......................................again !!Duncan
-----------------------------------------------------
If I'd known I was going to be so thirsty this morning I'd have drunk more beer last night.
FFRR Autobiography 4.4 SDV8 MY17
D4 HSE MY13 SOLD
FFRR 3.6 Vogue TDV8 SOLD
D4 HSE MY10 SOLD
D4 SE TECH MY15 SOLD
D4 XS MY12 SOLD
D4 HSE MY10 SOLD
D3 HSE MY06 - Re-Cycled Worldwide
13th Nov 2012 9:48 pm
drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
Hi Q86ARR, and first off what tipped you off that there needed to be a change and do you know what voltages your D4 now runs at now?2008 TDV8 RR Lux + 2009 D4 2.7
13th Nov 2012 9:52 pm
Russell
Member Since: 24 Aug 2007
Location: Kent
Posts: 10564
Popelka wrote:
OK so me being a auto-eletric numpty ..........
can anybody explain why the alternator would change it's output?
I mean that as far as I'm concerned; when the engine is running the auxiliary belt that turns the alternator is still running regardless of alternator output, so what AND how does it changing output voltage effect the efficiency of the engine?
The belt tension is always going to be the same so the same load to spin alternator, or is there a fraction of a fraction of a fraction resistance due to magnetic fields pull on the internal components of the alternator as part of its internal process to create the the electrical output?
(if you say yes to that, how much difference does that actually make on the system/ fuel consumption)
confused..........
Alternators need a charge or excitation to work, so the ecu will probablly use this as the signal to turn on and off the alternator e.g when the alternator is required the ECU sends a signal to charge/excite the alternator when not needed the ECU turns this signal/excitation off. The net result is the ECU's can control when the alternator charges or no and as such improve economy and emissions.
Someone on here worked at a site where they produced Police and HART emergency spec D4's, cannot remeber who, but do they know what are used with regards to dplit charging systems on these vehicles.MY17 D5 1st Edition Namib Orange
MY15 D4 HSE Kaikoura Stone
MY12 D4 HSE Nara Bronze Sold and gone
MY11 D4 HSE Stornaway Grey Sold and gone
D3 S spec Silver Sold and gone
Tow bar, full length roof bars, side steps, tow bar storage unit, surround camers.
D4 camera club
13th Nov 2012 9:56 pm
DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
wasnt that xtcDuncan
-----------------------------------------------------
If I'd known I was going to be so thirsty this morning I'd have drunk more beer last night.
FFRR Autobiography 4.4 SDV8 MY17
D4 HSE MY13 SOLD
FFRR 3.6 Vogue TDV8 SOLD
D4 HSE MY10 SOLD
D4 SE TECH MY15 SOLD
D4 XS MY12 SOLD
D4 HSE MY10 SOLD
D3 HSE MY06 - Re-Cycled Worldwide
13th Nov 2012 10:10 pm
Popelka
Member Since: 31 May 2008
Location: Praha (Prague)
Posts: 2430
thanks all for that well explained info especially 'Amazing' , I really didnt think there was that much of requirement for power when charge as opposed not charging.
did like the pics as well..... Experience is a difficult teacher, because she gives the test first and then the lesson afterwards!!!!
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