Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
Hi viethson and do you know how much driving you had done before you left your D4 for around two weeks unused?
If your cranking battery was at 7.6v and the auxiliary battery was at 12.0v ( BTW this is the cut-out voltage level of the isolator, so it did it’s job ), with that low a cranking voltage and the auxiliary battery could still jump start your D4 then your cranking battery is most likely not damaged, just badly discharged.
As Robbie posted, it sounds like you have something in your D4 discharging your cranking battery, because even if your cranking battery was just in a low state, after just a two week break, it too should be no lower than 12.0v.
my main battery packed in and the traxide second batt would not start it...not even a click.
had to use second car to charge for about 15mins before it would start.
new battery fitted u.der warrenty andots of resetting by the tech
Hi amazing, and if your cranking battery is stuffed ( where it has a dropped cell ), then the only way to get an emergency jump start is from a donor vehicle, with it’s motor running at high idle.
Even if the auxiliary battery is in a fully charged state or if you tried to jump start using one of the many booster packs on the market, you can not get enough VOLTAGE to get over the near dead short situation the stuffed cranking battery causes.
Only a decent sized lithium battery equipped boost pack can successfully jump start over a stuffed ( dropped cell ) cranking battery.2008 TDV8 RR Lux + 2009 D4 2.7
14th Feb 2014 11:41 pm
amazing
Member Since: 05 Mar 2011
Location: chengdu
Posts: 1542
when the traxide switch did not allow start8ng I metered battery and saw it was stuffed.I then disconnected the second battery and used my other car 8ndeed on a high idle to get it go8ng...It is better to have and not need it then need and not have it.
How can a brand new 95aH AGM batt plus 55aH aux batt discharge like that in just under two weeks.........
viethson
I have to ask about batteries....OK I know its how lead-acid cells work technically & the do's & dont, that kills batteries...I have run fleets of forklifts & electric tugs that use lead acid...done properly batteries last for many years (well over ten in some cases if well used & looked after)
an AGM is all about taking a charge faster...it should battery for battery accept a charge far more rapidly than an equivalent sized Lead acid battery (or the non lead acid ones originally put into Discos's)
an AGM will discharge accordingly to what ever draws power from it (how can it do anything else ?)...so if you have an issue that draws power unseen & unknown it will discharge the AGM like any other battery.
AGM's a newish technology (for cars anyway) was the answer (before other technologies like Li-on) were scoped out....an answer to the development of stop-start systems that were intended to save fuel at the expense of having to restart your engine far more times than a non stop start vehicle in a given time or journey.
an AGM for a non stop start vehicle should be "better" if you have concerns about the vehicle/battery being used infrequently..start the car - short run then leave it for a whole bunch of time.
With a non AGM battery the battery (maybe) cant & won't receive sufficient "investments" of a charge that balance the "withdrawals" of starts & restarts...+ the withdrawals of things left on or working when the car switched off & parked (like is standard on a Disco).
thinking an AGM can somehow miraculously defy the laws of chemistry & physics just isn't possible...it will & indeed can discharge to the extent it won't start the car given a specific or collection discharges.
I thought my year old Disco AGM was cream-crackered when it wouldn't crank the engine after sitting engine off - radio on & about with the car for a couple or three hours. I always wondered why my disco switches on to radio / stereo low volume when I power of the engine & turns itself off after a time that is preset...its solely to save battery power. You dont realise the amount the HSE system uses (radio,nav,dvd,amps with 14 speakers etc).
My Jag XK does just the same....its a hard car to crank over....5.0 litres & its looking for sparks to ignite fuel as well..I have learnt the hard way...my CTEK lives with this vehicle to allow me to do what I have had to do when battery compromised charge wise.
also what I didn't realise was my size 5 CTEK isn't the one to recharge or top up / recharge / condition my AGM battery..I need a bigger one.
South Yorkshire Battery Services (Leeds) have been superb in supplying & advising me as the what AGM's are about....not rip off merchants...they persisted in not selling me a battery when I thought I had an issue....a three year old standard LR battery that did odd (to me) things....they explained the rules.
other outlets may have & just wanted to sell me a battery.
I have no connection with SYBS other than being a paying customer.BREXIT - done properly.
Right now ...We need Government - not Politics
Save the Dipstick Flagbearer-keep it simple, less likely to fail campaign-agenda items:Starting Handles, Acetylene Lamps.
Founder: Dipsticks-R-Us Inc
D3 HSE-perfectly formed, passenger friendly...has real DIPSTICK
Jag XK-but sadly no DIPSTICK...HUGE design fault
FL2 has DIPSTICK..."real comfort in rear seats"
VW Golf wondermobile (?)..has real DIPSTICK
Morris Minor..original DIPSTICK technology..and a real KEY.
15th Feb 2014 9:44 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Quite a difficult post to read but I think I know what you are saying. For accuracy the 'radio' itself does not draw that much power but when it is on the car is 'awake' and a whole host of systems are prevented from shutting down. All these systems added together pull a great deal from the battery.
The final factor (on the D3 only) is that it takes 30 min for the car to go to sleep. This can lead to the scenario where the car is started and driven no appreciable distance, stops for 30 min; hardly driven again, stops for 30 min, before being started again for a short run. After final parking (plus another 30 min) you go back to the car to get something out of the boot to add yet another 30 min. Even this short scenario of 3 starts plus being awake for another 120 mins can really challenge the battery on the next cold start.
Regarding the issue with the Ctek 5.0 and some AGMs - this appears to be fixed and the new 5 amp Ctek does not suffer from this. Incidentally the little Ctek 3.6 did not have this issue and I don't think it had anything to do with output current; batteries like low amperage charging. So if you have this problem with a 5.0 then get it exchanged.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 13 Jan 2009
Location: Bavaria
Posts: 136
@drivesafe. thank you. I did not drive a lot before I left the car. But I fitted a new battery just a few days earlier. That´s why I was a little amazed...
@BLFarrar. Thank you for your post. But I did of course not expect the battery to power the car for two weeks. I am aware that the AGM has some advantages over the wet cell type (thats why I fitted one) but I certainly did not expect it to do magic and hold the same amount of power as several wet cell batteries of the same size.
When I switch on the radio with the ignition off, will the car switch it off after some time or will it just keep running? Maybe that was the problem.
I have also made the cig lighters perm life so maybe that prevents the car from shutting itself down on its own after some time.Life in the slow lane
15th Feb 2014 3:40 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Depending on key position and door resets there is a 60 min and 10 min power-save time-out, plus a 12.3v check.
Having the 12v sockets perm-live will make no difference to the battery, unless you have something plugged in.Land Rover - Turning Drivers into Mechanics Since 1948
Quite a difficult post to read but I think I know what you are saying. For accuracy the 'radio' itself does not draw that much power but when it is on the car is 'awake' and a whole host of systems are prevented from shutting down. All these systems added together pull a great deal from the battery.
there may be a difference between:
having the keys out, car unlocked & radio on
as compared to:
keys in position 1 & radio on
Robbie wrote:
the issue with the Ctek 5.0 and some AGMs - this appears to be fixed and the new 5 amp Ctek does not suffer from this.
have you tried a new CTEK 5.0 on a large AGM ?
Robbie wrote:
if you have this problem with a 5.0 then get it exchanged...
I will mail CTEK & ask them
Robbie....I realise you have had to read through what I wrote....the detail about charge in & power out...is from the SYBS guy who explained the difference to me......
AGM fast.....faster take up of charge...same as any other battery if anything "on" drawing power...
logically this sounds OK.
thanks for the dataBREXIT - done properly.
Right now ...We need Government - not Politics
Save the Dipstick Flagbearer-keep it simple, less likely to fail campaign-agenda items:Starting Handles, Acetylene Lamps.
Founder: Dipsticks-R-Us Inc
D3 HSE-perfectly formed, passenger friendly...has real DIPSTICK
Jag XK-but sadly no DIPSTICK...HUGE design fault
FL2 has DIPSTICK..."real comfort in rear seats"
VW Golf wondermobile (?)..has real DIPSTICK
Morris Minor..original DIPSTICK technology..and a real KEY.
15th Feb 2014 8:36 pm
drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
Hi again viethson and you were probably the engineer of your own demise.
A new battery, while fully charged, does not reach it’s full capacity until the battery has been cycled 20 to 30 times.
So your new battery was most likely down on capacity when you installed it and your small amount of driving before you left the vehicle parked up meant the battery was in an even lower state.
The number of initial charge cycles needed to get a NEW battery up to it’s full capacity varies from one type and brand to another, BUT, there is a huge hole in the amount of info being supplied by many battery manufacturers, so it makes it very difficult to get the specific info needed.
The new AGMs used by LR have almost no useful info to be able to get an idea of what is the best operating conditions for these batteries.2008 TDV8 RR Lux + 2009 D4 2.7
15th Feb 2014 8:44 pm
viethson
Member Since: 13 Jan 2009
Location: Bavaria
Posts: 136
hi drivesafe and thank you for your post. Very interesting I did not have any trouble with the battery or starting the car since so you are probably right that the battery just needs some cycles before it reaches is full capacity.
I the meantime I have disabled the BMS with the faultmate (which now allowes a full 30min park heater cycle ).
I understand that the BMS normally signals the battery´s state of charge and the required voltage to the EMS which is then signaled to the voltage regulator inside the alternator to adjust the output voltage. If we set the BMS off in the CCF what tells the alternator the required voltage now. Does the EMS revert to its own internal charging strategy? Is this the way it worked in the D3?Life in the slow lane
20th Feb 2014 9:08 pm
drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
Hi again viethson and until there is some relevant info about these batteries, it really doesn’t matter what the D4 BMS does, because we don’t know if it’s operations are good or bad for these new AGM cranking batteries.
I personally never buy or recommend any brand of battery that does not have all the relevant specs available. It just doesn’t make sense if a battery is supposed to be good for a given chore, why don’t they list full specs for them.
I have searched the net and can not find any relevant info for these batteries about how they can be charged by an alternator.
So just be careful of how you use these batteries until the correct charging spec are made available.
Another alternative is to get a dealer to update your vehicle with the relevant software for the new AGMs and then all should be OK2008 TDV8 RR Lux + 2009 D4 2.7
21st Feb 2014 2:43 am
viethson
Member Since: 13 Jan 2009
Location: Bavaria
Posts: 136
yes strange. I thought AGM batteries are common these days in larger and more power hungry cars.
Also LR is fitting AGMs in new cars and as replacement. So at least they should know how to deal with them.
What I am really concernd about at the moment is, will the car stop charging the battery with over 14.6V when the battery is (at least nearly) full and can it do it without the BMS? Others have also turned off the BMS on their cars and should be able to report (AGM or not).Life in the slow lane
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about with the car for a couple or three hours. I always wondered why my disco switches on to radio / stereo low volume when I power of the engine & turns itself off after a time that is preset...its solely to save battery power. You dont realise the amount the HSE system uses (radio,nav,dvd,amps with 14 speakers etc).
).
