Graham Butcher

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.

Surely disconnecting the battery is not a good thing to do for the time it takes to carry out a low level charge, all the control units on the car will complain that they have been lost power and the dash will awash with error lights and error messages on the dot matrix display. The current battery is the 2nd in the car's life. The first lasted almost 7 years before it gave up the ghost and went to battery heaven after the alternator belt snapped, and the battery died while trying to limp the car into a Skoda dealer one day in Cambridge and failed to make it, dying completely at the side of the A14. The battery has a 4-year warranty and was purchased 19/9/19 so is still under warranty, I'll get that tested for problems when the car goes in for service next week.

After letting the car stand for almost 20 hours, I tested the battery voltage, and it is 12.12V and started the engine a few times with no problem what so ever and just after starting the voltage reads 14.7V as the alternator tries to replace the energy that the starting took out of the battery. Then driving it a few minutes later around the City and the Start/Stop system was kicking almost from the start, just as it does normally in heavy city traffic. I think that is a sign of a bad battery, surely not?

Doesn't the battery monitor the battery and instruct the Ecu to disconnect the item, in this case the radio. I know the system does switch things off if you leave anything ON after a few minutes to prevent problems.

Thanks, I never knew that, just tried it and it worked as long as I put my foot on the brake pedal. 👍

If it was the battery failing or failed, I'd have expected to display these kinds of symptoms often, but since the jump start 3 days ago the car has been fine, and I have been to Southend and North Weald again since then as well shopping which are short journeys in town with lots of stop/starts with no hint of any problems. I'm going out again in few minutes on some short local trips and I'll measure the battery voltage again then, before I start the engine and after.