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AGM Battery

64K views 20 replies 11 participants last post by  graigchq 
#1 ·
Morning folks- I’ll apologise for the long post! :)

Been away for a while but just recently bought another R56 Cooper D (57 plate 1.6 with the PSA engine) :biggrin:

This Cooper D has the stop/ start system which my other cooper D didn’t. I am completely familiar how the system works and all the conditions/ parameter required for the system to work properly as my other car a BMW my 1 series has the same system.

Despite the cold weather recently the temperature has been above 3c during the day on some occasions, engine fully warmed up, low electrical load etc. etc. but no stop start?? Thinking the AGM battery is on its way out???

When my 1 series stopped stop/starting- while the engine would still start perfectly well in the mornings, the battery wasn’t deemed in good enough for the stop start system to work.

Battery was replaced under warranty but I was told that the new battery needed to be coded to the car so the stop/ start system “learned” the new battery. Apparently if it isn’t then the new battery can be over charged??? :confused:

After searching the forum over the last few days there doesn’t seem to be that many people on here changing out battery’s as there are in other BMW forums- either the battery’s in the MINI’s are ok or people just don’t bother if the system stops working! :)

Anyway- Finally the question! :D

Have people changed out their battery’s and if I change the battery out for another AGM battery in the MINI does it need coded like the BMW’s?

Cheers
 
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#2 ·
#4 ·
Hi, could you please let me know how you went on with this.
I have just renewed my battery on my 90 Cooper D and it has not helped at all. The new battery is a Platinum AGM battery.
I have never heard of a battery being `coded` to the car.
Can you please shed some light on this.
Thanks in anticipation.
 
#6 · (Edited)
Just my two pennies worth on the subject.

A relative owns a 2007 Mini Cooper from new. She said the stop/start system only ever worked in the summer since new. The car is mostly used for short runs. With winter rapidly approaching, we thought it might be a good idea to replace the battery as a precaution.

After recovering from the shock of the BMW stealer quote to replace the battery, I discovered this thread, and indeed a Varta E39 or Bosch S6001 equivalent is far less expensive exact replacement for the original Varta 70Ah (760CCA) 'black coloured' AGM battery fitted to the Mini (11868-20 DE, S: 61 21 7 757 388).


Using an accurate multimeter to check the voltage across the terminals of the 6 years old battery, the reading didn't look good after the car had been left standing overnight. 12.25v to as low as 11.98v when outdoor temperature was less than 5C. The car still starts just fine.

For time being, we decided to use my old CTEK smart battery charger to top up the battery. The crocodile clip leads supplied with the CTEK weren't really long enough to reach the two connection points recommended for jump starting the Mini, so I just hooked it up direct to the battery terminals. I charged up the battery for 5 hours before prematurely halting it when it started to get dark and rain outside. The following day, the stop/start system started operating when returning from a shopping run.


Eventually the battery will need to be replaced and my research into this so-called 'battery registration' raises some queries.

On BMW forums, comments are posted about higher charging current being applied to older batteries from the alternator, and if you don't register the new 'identical' replacement battery, it could continue to overcharge and damage the new battery. My question is how does the alternator know to apply a greater charge for an older battery?

The alternator and voltage regulator pack on the Mini doesn't look any different to that fitted to any other make of car on brief inspection. The ECU doesn't look like it is wired to the alternator so it can't tell the alternator what to do. ie. surely whatever the alternator can deliver is what the electrical systems and battery receives.

On more expensive BMWs, there are posted comments about ECU switching off various electrical systems to save power (and reduce battery drain). There are some references to i-drive computer system. Switching off systems would presumably mean more electrical power from the alternator could be diverted to charging the battery in those cars, and I suppose that is where the risk of overcharging could occur. It looks like battery registration is therefore used to reset the aggressive power saving which the ECU may have adopted for the battery as it ages.

So is the electrical systems in the Mini really as sophisticated like more expensive BMWs where systems can be switched off by the ECU to reduce power consumption?

Additional research:

Comments posted on other forums seem to suggest that if you replace the AGM battery, like for like, there is no need for battery registration. If the rating of the new battery is different, then recoding is necessary.

I also read a comment that suggested that Stop/Start will not work for first 6 hours after reconnecting a battery (replacement or flat battery?). I suspect only extra benefit of battery registration is it resets this time delay to 0 hours so Stop/Start can be used almost immediately.
 
#7 · (Edited)
Update (August 2014):

The original battery continued to be topped up using CTEK charger once a month. The voltage measured at the terminals prior to charging varied from a low of 12.05v in March, to as high as 12.40v in recent weeks due to hotter weather. The readings (in the morning before starting the engine for first time in the day) never looked healthy but the car always started just fine. Stop/Start was deliberately switched off most of the time to reduce battery drain as the car is only used for short runs.

As the original battery is now 7 years old, we decided to buy a new Varta Silver Dynamic AGM E39 (570 901 076) from Battery Megastore for £99 (£110 less 10% discount code for installing their google play app. Comes with 4 years warranty). We are not bothering with battery registration as the new battery has the same ratings as the original and so I'm not convinced battery recoding is required from what I've researched. The new E39 battery looks identical to the Varta made OEM battery apart for the colour of the battery casing.

(The Bosch S6001 costs around £130 and only benefit is it comes with a 5 year guarantee. Halfords also stock an 096AGM battery with 4 years warranty - £149. From a warranty perspective, it is probably far easier to take a battery back to a local Halfords store, than to returning a battery to an online retailer. )

The new battery installed without problems. The only fiddly part was removing and refitting the plastic trim. I used the battery replacement guide found on the northamericanmotoring dot com website which has photographs for a left hand drive R56. Note that a 10mm socket is required, not 13mm socket. There is also a push-fit vent pipe connected to the side of the battery.

The voltage at the terminals of the newly installed battery measured a healthy 12.63v before starting the engine. The clock and radio stations required programming.

The Stop-Start system kicked in on a trip to the local shops the following morning.

The starter motor also used to make a slight metallic clank noise when disengaging after successfully starting the cold engine in the mornings. The noise has not returned since replacing the battery.


Update June 2015: Halfords 096AGM battery is currently priced at £99.99. It is manufactured by Yuasa UK.


Pictures of original Varta and replacement Varta Silver Dynamic AGM E39 (570 901 076) shown below:
 

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#18 ·
decided to buy a new Varta Silver Dynamic AGM E39 (570 901 076) from Battery Megastore for £99 (£110 less 10% discount code for installing their google play app. Comes with 4 years warranty).
hi bob8, old thread so not too hopefull of an answer. re the varta agm E39, is this battery vented? my R56 MCS (petrol) has vents on the current battery, connected on the left hand side as you're facing the bonnet. would this battery be ok? i ask because i think you may have been changing a diesel R56, just wondered if it's different ie no vents. from what i've read the vents are required on mine due to location of the battery, but may be this isn't the case for agm. sorry, i'm a bit clueless! although i have conlcuded that i don't have IBS, thankfully
 
#8 ·
... bob8 ....

many thanks for this very informative posting - Time was that you could bang any bit of lead/acid into a car... progress I suppose!

I was going to buy a:
Bosch S5 Battery 096 5 Year Guarantee - Amp Hours: (Ah): 77Ah - Cold Cranking Amp: (CCA): 780CCA @£97.20

as against the E39 Varta Start-Stop Plus AGM Car Battery 12v 70Ah (570901076) CCA = 760A @ £109.95 on the grounds that the extra Ah and CCA would be beneficial - however I think I'll just stick with the Varta on the basis that if things start going wrong after replacing with a Bosch MINI are likely to blame the battery and charge accordingly!!!

I've also read that any different amperage/CCA can cause problems because the battery will be undercharged by the complex electronics of the MINI

any comments would be appreciated
 
#11 ·
I don't have stop/start and don't want it or trust it. Great posts by bob8 though, just what makes this forum so useful.
 
#12 ·
Hi.I ve just bougth a used Coubtryman S All4 2010 with the start and stop system but i think i have to change the battery cause even if i tried to recharge it with my recharger the signal o f low battery doesnt go away.The original new battery costs 304 euros instead of an AGM VArta wich has the same charateristics and price of 175 euros.
Accordingly to bob8 i ll not have any poblems if i install the normal Varta and not the original one(with the start/stop system etc).Anyone else had tried to do this?
 
#19 ·
yes, there are holes on both sides of the battery. My earlier post quotes having to fit the push-fit vent pipe to the new battery.

The car is a petrol R56 Cooper (not S) with 'Stop/Start'.

I think I read some R56 without Stop/Start are not fitted with 'AGM' batteries, but don't quote me. Google the excellent 'r56 blog' who fitted an E44 battery to their very early R56. I can just about read the part number on the factory fitted OE battery - 61 21 7 570 679.
 
#20 · (Edited)
Another 7 years has elapsed. Started seeing this yellow car on ramp/lift symbol every time key was inserted for first time without pressing Start button.

Automotive lighting Automotive tail & brake light Rectangle Motor vehicle Bumper


Apart from the usual red handbrake symbol, there was no other warning symbol or message displayed on the dashboard.

Checked the SETINFO menu and could not find any service item that was overdue.

After a bit of googling, apparently if this symbol appears on its own, it is usually an indication there is a problem with the battery (or alternator).

On one occasion, the following battery symbol did appear on its own to confirm suspicion it was battery related.

Brown Amber Rectangle Wood Flooring


I hooked up a CTEK charger to the car, but it made no difference, the yellow car on ramp symbol still appeared the following morning. The yellow battery symbol once again appeared on its own.

Yesterday, replaced the 7 year old Varta E39 battery and fitted new Exide EK700 battery. Not yet seen either symbol appear today, so hopefully problem is fixed....
 
#21 ·
Hi bob, finally I’ve found something on this forum I can repay and help someone with!
I too started seeing that same car on stilts, which is basically saying take it to dealer. Also because of a dying battery, my car was sat not being used regularly and jump started once a fortnight as the battery would be flat. Eventually that intermittent car on stilts turned into erratic electronic control of lights and windows.
The culprit is the footwell module, which contains some sort of factory fault where it can only ‘reset’ a few times before some fails safe kicks in and disables it. Sent it off to a chap on eBay who returned it three days later and along with a new battery everything working just fine.

my personal experience was swapping out the agm, and putting standard pb battery in, and the coding is definitely required to tell computer that it’s lead acid and not agm, as well as the capacity, and it’s age, for the charging profile.
this can be done via Carly which is a great tool to have and worth the outlay. Obdii over Bluetooth and you reset using the app on your phone.

I would not recommend to anyone in this thread to swap out the agm, if stop start is used at all. Mine was mapped out with a tune and other upgrades, so I know it’s not a problem. agm batteries are designed for that repeated high impact discharge for starter motors, and often have a higher resting voltage and relative capacity. Generally they’re better batteries, but more expensive, and more susceptible to death on being allowed torun completely flat.

to anyone still wondering, there is no dark electronic connection or wizardry requiring this recoding,ut simply the car knowing what it has so it can treat it accordingly. In theory this means if you connect a much higher ah battery, it would never fully get charged, as the car would stop when it thought it was full, conversely, if you install a battery with a significantly lower ah rating, the car will very likely kill it by overcharging.
 
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