Graham Butcher

Oh dear, you seem to think I'm anti you when I'm not. We all need to remember that there could well be people who don't have access to OBD2 devices at all, or others who don't know how to reset alarms etc. They are the ones that could easily be confused and make mistakes following poorly thought out but extremely well intentioned advice. Thanks

You are missing the point, I know all about batteries and how to charge them but if you knew anything about modern day batteries, you ought to have realised that unless you have an exceptional old battery, these instructions in the manual are actually referring to earlier style of battery. It mentions about vent plugs, I have not had a battery in a car with vent plugs for over 20 years now, it also mentions about having the acid level checked, how do you check that when the battery is completely sealed? In all the cars for the last 20+ years, I have had, there has been no way to see inside the battery to either physically see the acid level or measure its strength using a hydrometer. As is often the way with technical manuals, they are not written by the engineers but proper writers and will very often cut and past certain bits from other manuals and very often these are not picked by the proofreaders. So very often you will spot these issues mistakes if you actually know what to look out for. I don't know why you keep saying that people would not have loads of warning lights and error messages, modern equipment store a certain amount of energy in capacitors to keep memories etc retained while changing a battery over, but after a while this charge slowly becomes used up and the control units will suffer from energy starvation and forget their settings. For the uninitiated this spells trouble.

Thanks, I was 65 in that photo. To be completely fair to all concerned, you were trying to help me but in a manner that came across as you knew what you were talking about and with an apparent conviction that what you were saying was gospel, and it wasn't. It was just misguided and if someone had followed your advice and removed the battery and gave it a slow charge and then refitted it they could have been faced loads of warning lights and error messages and not known how to reset everything and had to get their local dealer / service dept involved at great cost. Its a classic example of just how a little knowledge can be a dangerous thing, no matter well-intentioned the advice was. I think that the trolls, as you call them, are really trying to tell you that maybe you are trying to sound far more knowledgable than you are and that can be dangerous at times. I enjoyed our chats all the same and found it interesting that your wife has driven a Bristol MW bus, personally I preferred the RE's with semi-automatic gearboxes.

No the battery is not original, it is 3 years old and yes the car is stop/start. The original battery lasted 6 years and I dare say that it might have lasted a bit longer if it wasn't for the fact of the alternator belt tensioner failed and shredded the belt and I had to call out the RAC because the battery gave out whilst limping into a dealer in Cambridge for repairs 3 years ago. It did get me from RAF Lakenheath to Bottisham on the A14 before it lost total power and the system shut down, knackering the battery completely. The RAC took a long time to get to me and by the time they arrived the dealers had shut and I had to get back to Chelmsford. They took my battery off the car and put it on charge in their van, fitted a spare battery to my car and escorted me back to Bishops Stortford, where they swapped the battery over to my original again so I could limp back home and to my dealer who repaired the car again, the following day. The unpleasant stuff, well I didn't think it was that bad really, but the others members do have a point, and I know that nta16 was trying to be really helpful, but it is dangerous when you appear to be relying on what others have claimed without any real knowledge of the subject. Like I said earlier, I know all about batteries and charging etc, I'm fully qualified, and basic battery theory has not changed, but has changed since I was last fully active in auto electrical field is the all the computer technology being employed in cars these days, hence why I was seeking advice here in the first instance, as there is now a massive extra layer of complexity involved in the controls these days.

Well maybe J.R. has a point, and please don't take this the wrong way. I have no doubt that you are trying to be helpful when you post replies here but I have to tell you that your knowledge of batteries is incorrect. Have you actually taken onboard that I'm an electrical engineer by trade and started out in the industry working for what was then the National Bus Company as an auto electrical engineer. There were zero college courses back then for that trade, the nearest being just electrical engineering, for which I did many courses over an 8 year period finishing up with HNC in electrical engineering as a qualification, similar to that of a consulting engineer. I only asked here for help because, the systems have become much more complicated since I was last active as an auto electrician. For the last 40 years I have been more active in the technical sales side and design side of electrical engineering and enjoyed companies cars which I never had to maintain, so have not bothered to keep upto date with systems, but battery behaviour remains constant. With modern batteries there really is zero need to trickle charge a battery in a car that is used frequently, if the electrical system is in good order, it will keep the battery charged under normal conditions. Cars these days have alternators which can deliver a high charge if required with the engine just ticking over, no longer is it necessary to have high engine revs or have to drive for a long time / distance to replace the power extracted to start the engine, just a few minutes running time is enough. Unless there is a damaged wiring loom or a faulty switch holding a circuit active which is drawing more current than your battery charger can supply, is there any need to ever remove the battery from the car in order to charge it. In fact if there was a damaged wiring loom then that will make itself known in so many ways besides running the battery down, the worst case scenario would be a fire with the likely outcome being a total loss of the car, especially if some amateur electrician has been bypassing the fuses or replacing them with wire etc. Yes you do see and hear of people who have cars in storage fitting a trickle charger to their car as a permanent fitment. The reason for that is that with modern cars and this is even worse with the larger more upmarket cars with extra bells and whistles, is because of the many control units that constantly talk to each other via the databus, draining the battery. Its no fun storing your fun summer car, or the car that you might keep for special occasions, that refuses to start after its been sat in the garage for 6 months, and once you get it started, the dashboard lights up like a Christmas tree because the battery voltage has dropped to such a low value that the control units have lost all the stored data and require resetting etc. Modern cars do not like having the battery being removed and then refitted, as some parts of the management systems will have their memories erased and will need to be reset etc. This is why it is dangerous to try and come over to others in these forums as if you are something of an expert, which is precisely how you portray yourself, even though you have this "Please note - I am not a mechanic or expert in anything." as part of your signature. For the record, I'm now 73 years and electronics is my hobby.

OBD2 devices are cheaper than the £100 you seem to think they are, and there is then either a monthly or yearly subscription fee. I use one called Carista https://caristaapp.com/adapter and there is a list of things it can do with a smartphone, depending on the make and model of your car. Trust me, if a EFB battery lasted 8 years it would be a fluke. You put of faith in charging your battery off the car, this is not scientifically proven. A car that is working correctly and driven regularly and is not stopped and started every 2 minutes is all the battery requires. The cars charging system will take care of the battery without any intervention from you, fact.

No it doesn't have that capability, it is accessed via a smartphone but its functions are very much limited to the various options built into the cars memory when it was built, things like auto locking of the doors when going faster than 10mph, running lights on/off, folding mirrors type of thing. It does not change the way the system interacts with the ECU's for instance as that is very strictly for the trained professionals rather than the informed amateur. I mentioned the EFB battery because you said "The AGM battery on my wife's car should well outlast the car then, going on what I've read on this site IIRC EFB batteries (on lesser cars than yours of course) have lasted longer than 8 years, depends on the user's use and abuse. " If that happened, it would be a fluke result. And no, I've not been a union rep, or manager etc

There is no way I'm spending hundreds of £ on a tool that I simply don't need, my scan tool is one that is recommended on this forum and is only 2 years old and is updated each time I log on. I really doubt that a EFB battery will outlast a AGM when all the experts say that AGM one's outlast EFB typical by 3 to 5 times.

Yes, my car does indeed have loads of extras, Enhanced stereo system with added power output power, DVD player and TV tuner with surround system, all seats heated, front seats are cooled, electric seat adjustment and memory function, also electric mirrors, also tied in to the memory system, automatic wipers, headlights, Xenon headlights which are also linked to the steering wheel angle, cornering fog / spotlights, heated windscreen, back window, washer jets, headlight washers and mirrors, auto dimming interior and door mirrors, cat vision interior lighting, footwell lighting, puddle lights, every door has door open red lights for traffic approaching from behind, electric radiator cooling fan and also A/C cooling fan, electrical steering and oodles of control units, all talking to each other. So yes, there are loads of extra draw on the battery. I already have a scan tool that can loads of things with the car but not at that kind of level you're talking about, in fact I expect that a tool capable of such advanced functionality is going to be restricted to dealers anyway, or mega expensive and thus not really a viable proposition. As to getting 8 years from a battery, this is something I have not managed to do, the old one did last 7 years, but if you google you find that can done with AGM batteries, also typical last 2 to 3 times longer than an EFB one.

Fact of the matter is that the type of battery EFB or AGM is dictated by the size of the car. If you are driving a small or mid-sized car then you are more likely to have a EFB, if you have a large, or premium car than you more likely have a AGM type because of the loading being applied is therefore more likely to be far greater with all the power hungry extras gizmo's fitted to them. My car falls in the latter category and so was fitted as standard with an AGM battery, which lasts typically for anything from 5 to 8 years and has a far larger capacity and can be recharged upto 5 times faster than an EFB. https://www.batteriesplus.com/blog/power/efb-and-agm-batteries https://batteryworld.varta-automotive.com/en-gb/efb-or-agm-which-battery-do-i-need Most places these days use your registration number to determine the make, type, engine size etc of your car. Once your registration plate has been inputted, the system will then automatically select the nearest equivalent item for your car, and this also extended to the cars battery.

Quick update, car was serviced, brake fluid replaced and also DSG oil changed and MOT done. Charging was briefly tested and confirmed to be working OK according to their tests, However, I raised the question about if a new battery is fitted, that I believe the car's system needs to be programmed with that fact and the battery details inputted. I was then told, yes that is the case if the battery is a AGM type, which is of course the type fitted to start/stop cars. The dealer is going to look into this very soon and see what difference this makes, as some models have a self learning capabilities and don't need it. More on this as it happens.

Thanks, so that's all good then, its not that I couldn't undo it if I had to, it was that I didn't want to undo it first by trial and error and risk damaging it when the car is in the garage for all of its servicing and MOT first thing Monday morning, that would be a totally insane thing to do.

Yep, the Bristol MW is a much lower HP engine than the one I quoted, its a 5 cylinder, 7litre of just 85HP, most cars can beat that for power, but they can't match get anywhere near it for sheer pulling power. It has a long stroke of 6" with a bore of 4.25" and max power is generated at 1,700rpm, but its that sheer grunt that the long stroke gives it that makes it so powerful. The 2 double deckers in these pictures show the type of bus I was talking, the batteries are kept under the stairs in the hand baggage locker area. The coach is my favourite, engine at the rear, slung beneath the chassis like the MW, and those coaches rode on airbags for a super smooth ride with tall gearing, they could really get a move on, 70mph with ease.

No, you clearly don't have the first clue about buses and how they operate. They are used on relatively short runs from one side of town to the other, maybe 4 or 5 miles with a stop at each end of about 10 to 15 minutes with the engine off but with the vehicle lights and the interior lights always on at nighttime and the destination boards or blinds always switched on as well. This means that their usage is even harder on batteries than a car is, and those engines really do take a massive amount of grunt to start. They are typically 10.5 litres, 150HP, yep that's correct with a really massive compression ratio compared to say a petrol car engine. Add in the fact that a typical bus is doing that for 10 hours a day and if it is a 30 minutes schedule, that makes the number of starts in an hour 3 at least. And for something like a white van doing home deliveries, many times more than that, remember it is illegal to leave a engine running on the road without a drive in the driver's seat. Using the analogy that use, there must come a point in a day that the van just will not start, with many bouts of actual driving being no more than a hundred yards or so.😏 Yes that is the type of plug I have on my car, and man oh man, that battery and engine bay is so filthy and with a battery in that state, that muck and bullets is actually conductive on the battery and will certainly drain a battery, so come on battery man, clean that battery at least if not the rest of your wifes engine bay 😆

I never did the test of disconnecting that plug, I undid the locking mechanism but was unable to extract the actual plug, as I'm not aware of the precise way to disconnect it, I decided not to force it as I need the car to be working and it's going in the garage on Monday anyway.

Well, I'd love to see just how you would have stood the test of time in my shoes, as already mentioned, I'm a retired auto electrical engineer and as such at one time, I was looking after over 200 buses and coaches and hardly ever had any battery issues with them, and they were never ever put on charge. I had a dozen huge 6V batteries in my workshop with a large industrial battery charger which got switched on about 4 times a year to just top up those batteries in case they were called upon. I do recall having to go out to rescue a bus however on one occasion that the conductor said was causing his eyes to stream and also some of the passengers. On that particular type of bus, the batteries were housed under the staircase, inside the bus, and boy the conductor was not exaggerating, it stung my eyes as well when I walked into the bus to see what was happening. The 24V alternator was overcharging them and the cells were boiling hot. I had to open all the windows and doors on the bus and then wait for the wind blowing through to dispel the fumes and cool the batteries down enough so that I could then start the engine and disconnect a battery without risk of them blowing up in my face if the spark drawn ignited the hydrogen gas, and drive the bus back to the garage for repairs and a new set of batteries fitted along with a replacement alternator. That's an advantage with diesels, once started they didn't really on having battery power to keep them running.

I watch all of their videos, and if you subscribe to the channel, you'll get to see what happens when a car battery gets so low that the ECU's cease talking to each other, when a new battery is installed the entire dash lights up like a Christmas tree, and sometimes it takes many attempts to clear all the error codes, and there are some that won’t clear until the car has been driven a few miles.

Well, my last one lasted 2 months short of 7 years, and it never saw a battery charger, the only charge it got was from the alternator and in reality that should be all it ever requires, unless the car has been allowed to sit for a long period without being started or driven.

@varooom I'll try that out later after I get back from a trip I need to make.

If you really want pain, watch this video about a Bentley (the ECU's are all VW/Audi) as you will see it is like my car where everything runs through ECU's everywhere, I'm even surprised that the umbrella in the door doesn't have a control module for it 😅 https://www.youtube.com/watch?v=-K1W4Bb2s-M

Well the one currently fitted has a makers 4 year warranty, so they must believe that it will last at least that long, it cost an arm and a leg,

Thanks, a 140A alternator is pretty big for a car. The VW computer programs is a real pain, especially on my particular model with just about everything being controlled via the canbus and the entire car is peppered with control units, in the doors, under the seats, in the boot and loads under the bonnet. This car is fully loaded with almost everything you could think of, Xenon headlights which are also controlled by the steering and speed of the car which will alter the alignment of the lamps, there is a TV tuner in the boot etc etc. The car is so complicated that I had fitted to the car when I ordered it, a solar sunroof designed to power the air circulation fan from solar power so that when parked up in the sunlight, the fan would be driven directly from the roof panel and lower the inside temperature by around 5C. That stopped working 3 years ago when the alternator belt snapped and nobody knows how to fix it and everyone I speak to in Skoda dealerships and indeed even Audi so called master techs even know about that such things exist. As to the potential Prime Minister, well lets just say, either way, we're screwed.

No, I did not say your logic was faulty. Looking at the workshop manual, there is another possibility for cars with the start/stop system, the battery monitor module which is part of the negative terminal. There is a 2 pin plug coming away from it and one lead connects to the starter solenoid, the other to the alternator. Now, if this is playing up, it will have an impact on both the charging and the starting. Modern cars are just so complicated, that it is almost impossible to repair them yourself with access to loads of expensive equipment.

Charging the battery is not really an option for me as I cannot get my car into my garage, garage too small for such a big car😉 and running leads out from the house to the kerbside is strictly frowned upon and should someone trip of the lead, then I become liable ☹️ A voltage of just 12.4V will only trickle charge a battery and is ideal to keep a car's battery fully topped up if it is not being driven on a daily basis, which my car is . And also if a car requires having its battery being regularly topped up when the alternator has an output of a 140A smacks of a charging issue and needs to sorted ASAP. Edit. Added text. Maybe I should have pointed out that I'm a retired auto electrician and as such I understand the battery is a storage vessel, or as you put it, a bank account. With an alternator capable of outputting upto 140A, there should be a need to charge a car battery unless that car has not been used for a few weeks, but not a car that is in use daily, even for short trips of a couple of miles is enough to keep the battery well charged. This, however, was not the case a few years when most cars only had dynamos, especially if that car was spending a lot of time crawling along in heavy traffic and sitting at traffic lights. Dynamos do not produce much power, sometimes none at all when in such conditions, due to the low engine revs, they need engine revs to be a lot higher to produce reasonable power. An alternator is capable and is designed to produce loads of power at even at tick over speeds. This link might help. https://en.wikipedia.org/wiki/Alternator_(automotive)

The battery spec for the car and indeed for the battery now fitted is an AGM type with a CCA rating of 760A and has a capacity of 70AH, so there is no on earth that just having the radio on for an hour could drain a battery of that size to a point where it is incapable of cranking the car.