Electric Vehicle 12V Battery Failures

What is the problem with the common automotive 12V lead acid battery, or is the problem poor software systems that won’t black start?

https://www.fleetnews.co.uk/news/electric-van-12-volt-battery-issues-persist-says-afp

“The fundamental problem here is that when an electric van is left unused for a couple of weeks, the 12-volt battery charges down and it becomes impossible to start or recharge the vehicle,” explained Paul Hollick, AFP chair.

“There is no choice but to return it to the franchise dealer and even then, it can often take weeks to resolve the problem.”

I am not aware of IC engine vehicles, even the most modern and complex suffering from these problems.

I know that ‘maintenance free’ lead acid batteries are prone to sudden failures rather than the graceful degradation of older style where cold morning starting would get more difficult but this appears to be to much standing load, possibly from the support systems for the main EV battery.

Parents
  • There seem to be two problems, one that there is a steady load on the battery in the off condition. Modern but conventional  cars with radio keys etc have this problem to an extent, but it is all designed to 'sleep' except for a few milliseconds every second and then wake up if activity is detected. It is not clear to me why the 12V battery cannot be charged from the traction batteries but there seems no appetite to do this. And as there is no electric cranking to be done, the 12V battery is a relatively undersized.

    The second part of the problem is the amount of 'stuff' in the EV in way of settings that are held only in RAM. It could be made in a way that saves this system-critical data to something non-volatile as a last act when the battery dips below some lower limit like 11.9V then disconnecting totally. Such low voltage battery saving cut -off is in military kit that spends a lot of time parked up, but never in normal cars or EVs as far as I can see.

    Rather like tow charging for EVs, which would be easy enough to design in - the braking is regenerative after all, so charging the battery by pulling it along ought to be a thing, it seems to have been overlooked in favour of an attitude of "design only for success" when " design to cover every possible failure" is a better maxim, in my book at least.

    Mike.

  • I have previously posted on immobilized EVs,

    https://engx.theiet.org/f/discussions/28694/evs-immobilised-by-flat-batteries-or-breakdowns

    The situation doesn’t seem to get any better. Is the problem that EVs are seen more as software than mechanical systems and too much is in the hands of software engineers, who don’t generally have reputation for producing robust software. It is possible, but difficult and expensive, to produce reliable software. The railway and aviation industries have been doing it for a long time (although Boeing seems to have taken it’s eyes off the ball. Someone on here, possibly Andy M, said that for a reliable system it must be either simple enough that every failure mode can be checked or complicated enough that every failure can be detected.

    As an aside I recently went to pick up a relatively new Suzuki S Cross as a hire car. It was still wet from the cleaning both and I could open the doors with the remote key. We loaded our luggage and I went to start the engine, everything went dark. The hire company said ‘battery failure’, gave us another car and managed to get the tailgate on the first one open so we could get our luggage out. By the time we had transferred to the new car and were ready to go a mechanic had already changed the failed battery in the first car and got it started. No complicated reprogramming required.

Reply
  • I have previously posted on immobilized EVs,

    https://engx.theiet.org/f/discussions/28694/evs-immobilised-by-flat-batteries-or-breakdowns

    The situation doesn’t seem to get any better. Is the problem that EVs are seen more as software than mechanical systems and too much is in the hands of software engineers, who don’t generally have reputation for producing robust software. It is possible, but difficult and expensive, to produce reliable software. The railway and aviation industries have been doing it for a long time (although Boeing seems to have taken it’s eyes off the ball. Someone on here, possibly Andy M, said that for a reliable system it must be either simple enough that every failure mode can be checked or complicated enough that every failure can be detected.

    As an aside I recently went to pick up a relatively new Suzuki S Cross as a hire car. It was still wet from the cleaning both and I could open the doors with the remote key. We loaded our luggage and I went to start the engine, everything went dark. The hire company said ‘battery failure’, gave us another car and managed to get the tailgate on the first one open so we could get our luggage out. By the time we had transferred to the new car and were ready to go a mechanic had already changed the failed battery in the first car and got it started. No complicated reprogramming required.

Children
  • "difficult and expensive, to produce reliable software"

    I would argue that it is potentially more expensive not to. The cost of stopping a manufacturing line or a vehicle recall can easily outweigh profit. Let alone reputation damage. How many people are avoiding flying Boeing now?

    It is the same as the justification for doing proper systems engineering, for a complex project (and a modern car surely is), you will save yourself lifetime costs against not doing it. However, given we don't have parallel universes to check the alternative in, its not always easy to sell.

  • Hello Mark:

    "Difficult and expensive" also applies to the maintenance and repair of cars.

    System complexity is becoming a major problem for the smaller car repair shops here in the US.

    Even when handheld portable code readers are available, they sometimes do not provide adequate information to help repair the car.

    To a certain extent this also applies to the brand name car dealer's maintenance shops, who's prices have gone sky high.

    Based on what i have read a large number of car mechanics working for the smaller car shops have simply given up.

    Peter Brooks

    Palm Bay 

  • I would expect that pushing users to only use official dealers is an intent. Something I would expect to see more of, especially given the concept of monetarising the features which seems to becoming more common.

    In a competitive environment, you make less profit on the product itself and you need to recoup more of that profit by selling services to your existing customers.

  • Except that in some circles in the UK at least, lock-in to the dealer has  been seen as a bad thing, and a mix of pattern parts and hobbyist car bashers keep cars going long beyond the point where the dealer will be happy to touch it. - I've been driving since the 1980s,  and have never felt the urge to buy a new vehicle, although I now tend to buy at the 8-10 years point rather than older as I would have done years ago.

    Now that may not be typical , and I am aware I keep odd company, but I know a lot of folk who are quite happy to invest time to avoid paying over the odds for repairs etc. I'm not sure what maintaining a 10 to 20 year old EV will be like, but I guess in another 5-10 years we will find out. (as right now I'm driving a machine from 2010 ;-) )

    Mike

  • Ah, one of my former colleagues has a collection of older cars and bikes - and by that I mean at least 20 years old and going back to post-WW2. These are all self-serviced. The only thing he can't do is issue his own MOT certificate.

    As an aside, its interesting to be  driven in a car that doesn't have seatbelts, or indicators, or a roof but will still happily belt along at 40/50 mph. But at least has a spade on the side if you get into trouble.

    But the real issue will be that modern vehicle electronics is based upon modern mobile phone technology. Shrinking the lithography also shrinks the lifetime of the silicon. It isn't cost-effective to keep alive the older fabs that support the older processes just for spare parts.

    So I suspect you are not going to see the equivalent of a 40 year old Volvo 240 still on the road in the future.

  • Mike:

    Have you priced cars recently?

     As of 6 months ago, second hand cars ( 3 years old)  here in the US where only about $2,000 less than new cars. With new cars going for a little under $30,000.

    The car market is now going south due to the high interest rates and the companies that sell second hand are taking a blood bath. Companies like Ford are in trouble with their F-150 trucks sales as they were overpriced and their dealer inventory has sky rocketed.

    The trouble with older cars is the degrading of the plastic parts like door handles . The dealer wanted $180 for one, while parts supply chains were selling good copies for $30. 

    Peter Brooks

    Palm Bay 

      

  • Hello Mark:

    According to what I read recently the proposed new Semiconductor Fab in India will be concentrated on trailing edge technology.

    I assume that cars older that 1975 ,that are still running, you have to have additives (lead) added to the fuel.

    The other problem is getting the correct air-conditioning fluids (if you have never had A/C forget this).

    Having worked for an IC manufacturer who made parts for cars, I have many stories, that I can not tell!

    Peter Brooks

    Palm Bay