Member Since: 26 Apr 2011
Location: Sheffield
Posts: 2990
Robbie wrote:
sean 471 wrote:
I presume the d3 is just a straight swap for the battery?
Hi Sean,
For the D3 a regular wet cell battery works just fine and with the Exide one so cheap and so good it is an obvious choice for many so few will need to adjust the CCF. We did have problems with our armoured D3s in very hot and high conditions so we installed AGMs together with a software tweak. These outlasted the vehicles(!).
Thanks I got the Exide from Tanya. Will fit today, it was flat has a fart when I returned from Scotland so time for a change.
30th Jun 2015 7:45 am
drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
Robbie wrote:
- A D4 with wet cell logic set on the CCF will top-out at a regulated 14.0v (float @ 13.1v)
- A D4 with AGM logic set on the CCF will top-out at a regulated 14.1v (float @ 13.1v)
Furthermore Robbie, these are the MINIMUM operating voltage levels, not the MANDATORY operating voltage levels.2008 TDV8 RR Lux + 2009 D4 2.7
30th Jun 2015 7:50 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
sean 471 wrote:
Thanks I got the Exide from Tanya. Will fit today, it was flat has a fart when I returned from Scotland so time for a change.
The Tayna price is really good and takes the sting out of a battery swap. If you need to confirm if your charging system and current drain are ok I'm happy to test it for you.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 25 Sep 2013
Location: Saddleworth
Posts: 26
Decided to invest in a new battery... Opted for the Bosch S5 AGM & now all our troubles have gone away
6th Jul 2015 9:29 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
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Glad all is well and your vehicle will have been optimised for AGM charging logic at the factory but it should have a BMS reset. Just remember when you charge it to do it via the vehicle wiring or with the charging lead connected to body ground rather than direct to the neg post so that the BMS can recognise the charge.
It is worth giving the new AGM a conditioning charge or 2 to get the most out of it. The D4 system will only look to charge up to 75% state of charge and will only go above this if there is 'free' regenerative energy available, or by use of a battery charger.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 25 Sep 2013
Location: Saddleworth
Posts: 26
thanks for the info Robbie
23rd Jul 2015 4:12 pm
Dudleydisco
Member Since: 20 Jun 2014
Location: York
Posts: 853
Robbie wrote:
The D4 system will only look to charge up to 75% state of charge and will only go above this if there is 'free' regenerative energy available, or by use of a battery charger.
I do wonder why they chose this strategy. I'm sure we'd all have less battery related problems if it would look to charge up to a higher SoC !D4 MY14 XXV - RLD/IID BT
D4 MY13 HSE Lux - RLD/IID BT
P38 RR - Sad parting
110 - Even sadder parting
S3 88" - Still going strong after 23 years of ownership
23rd Jul 2015 4:21 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
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I see where you are coming from but there is method in JLR's madness and whilst it took them far too long to get it right (arguably from MY12 onwards, with lots of revisions for earlier D4s) it is now a pretty good system. As you know, the methodology is all about saving drag on the accessory side of the engine to save fuel and emissions.
The idea behind the 75% SoC is that the alternator will behave a bit like a regular alternator should the SoC drop below this figure. For example, you start the car on a sunny day and the engine grabs 130 amps or so, pulling the battery below 75%. After a few seconds the alternator ramps up the current to rapidly feed the battery with say 60 amps for a while. You then drive around and the current is allowed to drop as it approaches 75% and then it maintains this with a low current level (say around 2 amps). At this level the alternator is providing very little drag on the engine.
The system still looks to increase the SoC if the journey allows by using regenerative energy when slowing down. The alternator is helping to provide engine braking and dumping as much free energy as it can into the battery without busting any limits (temperature, current, voltage, time etc). Given enough opportunity the battery will increase its SoC towards its maximum.
A bit wordy and I've simplified things a little but I think it is a pretty good way of saving fuel. It is not uncommon to see D3 batteries at around 70% SoC anyway and as a quick snapshot my D4 battery is at 88% today.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
And it the best way to shorten a battery’s life span.
Robbie, the very fact your own battery is at 88% is because the alternator is trying to fully charge the battery.
To maintain a battery a battery at a 70% SoC level, the alternator would have to run at 12.3v CONTINUOSLY.
If the alternator ran at any voltage level above 12.3v, the battery would continue to charge, WHICH IT DOES IN ANY D4.
Furthermore, if your “Theory†was correct, no one with a D4 could charge any other battery in the vehicle, or in any camper trailer or caravan connected to the D4.2008 TDV8 RR Lux + 2009 D4 2.7
23rd Jul 2015 9:27 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
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Looks like I left the door unlocked again.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
Robbie wrote:
The idea behind the 75% SoC is that the alternator will behave a bit like a regular alternator should the SoC drop below this figure. For example, you start the car on a sunny day and the engine grabs 130 amps or so, pulling the battery below 75%. After a few seconds the alternator ramps up the current to rapidly feed the battery with say 60 amps for a while. You then drive around and the current is allowed to drop as it approaches 75% and then it maintains this with a low current level (say around 2 amps). At this level the alternator is providing very little drag on the engine.
No you didn’t leave the door open, it is obvious you totally misunderstood the LR info.
You have the cart before the horse.
They do not DELIBERATELY maintain the battery at 75% SoC.
The alternator’s operation is to maintain the battery in the highest possible SoC but to achieve this when the normal loads on the engine are at their lowest, to help maintain the lowest possible emissions.
The 75% SoC is the minimum tolerance the battery is allowed to drop to, and still try to maintain the lowest possible emissions.
If the battery drops to or below 75% SoC, at that point the the priority becomes charging the battery not maintaining lowest possible emissions.
Again, you yourself stated that your own battery was at 88%, so you contradicted your own THEORY.
get as cocky as you like, it does alter the fact you misunderstood what you were reading.2008 TDV8 RR Lux + 2009 D4 2.7
23rd Jul 2015 10:43 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Ah the selective quoting trick. Glad you now agree that the charging strategy changes at 75% to a mainly regenerative methodology and a more convention strategy below this figure.
Robbie wrote:
The system still looks to increase the SoC if the journey allows by using regenerative energy when slowing down. The alternator is helping to provide engine braking and dumping as much free energy as it can into the battery without busting any limits (temperature, current, voltage, time etc). Given enough opportunity the battery will increase its SoC towards its maximum.
You really haven't mastered the art of being nice to people.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50978
You are both well respected on technical views but it would be nice if you could give up the squabbling ......lets have constructive rather than destructive debate please chaps.
The funny thing is when you read the technical bumf there is no reference to "regeneration" ...only that the modules will make best opportunity to draw from the engine at times of less demand. If I have read it all wrong ...can someone point me in the direction of how this "regeneration" is taking place.
Regading the 75% ...the only reference I can find to this is
Quote:
BMS Control Module Self Calibration
Periodically the BMS control module will initiate a self-calibration routine. To self calibrate, the battery monitoring system first charges the battery to its full condition.
NOTE: If the vehicle is only driven for short periods the charging process could take a number of days to complete.
Once the battery is fully charged, the BMS control module will discharge the battery to approximately 75% of its full state of charge, but never lower than 12.2 V. The time taken to complete this part of the routine is dependent on the electrical load on the vehicle.
When the second part of the routine has been successfully completed, the BMS control module will return the battery to its optimum level of charge. The optimum level of charge will be between 12.6 V and 15 V, depending on battery condition, temperature and loading.
The BMS control module also monitors the primary battery condition with the engine switched off. If a low voltage condition is detected the BMS control module can request the infotainment system is switched off to protect battery voltage
So I read this as the system will take the battery down to 75% when going through a periodical self calibration .....not consistently21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
Last edited by DG on 24th Jul 2015 8:05 am. Edited 1 time in total
24th Jul 2015 7:20 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Thanks DG.
Thankfully the D4 does not 'consistently' take the battery down to 75%, in routine use it's just the point where it looks to increase the SoC further by energy recovery and not through traditional charging (although there are a few exception to this, including after start as previously mentioned).
You can almost think of the remaining 25% as an extra tank to make use of the energy available through engine braking. If the alternator ran in the traditional way and filled the battery towards 100% it would have no capacity spare to store the 'free' energy when it became available. The Topix extract you have quoted is how the BMS learns the charging and discharging characteristics of the installed battery between 75 and 100%. It also learns the individual quiescent current drain so it can aim for a SoC that assures good battery performance.
It's pretty nifty stuff and works well.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50978
What I can't understand is why engine braking has anything to do with it ...and this isn't stated anywhere in the description of operation. The generator spins at 3 times engine speed and as I understand it the engine offers a constant to the generator ......it is the module which regulates the required draw at any time. How is the action of engine braking making any difference in the scenario. Other than the belts between the engine and the generator there is no other mechanical interaction apparent.
So in a nutshell there are belts between the engine and the generator ...the generator spins at 3 times whatever the engine speed is whether it is accelerating, braking or idling ... a module decide when it's best to take that draw and at what level ....What am I missing? 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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