Speak EV - Electric Car Forums banner

21 - 40 of 50 Posts

Registered
Joined
4,865 Posts
Regrettably no, but is a route to ensure permanent damage if the battery has started sulphating.

Basically, manufacturers seem to be trying to 'save electricity' (more range) by deliberately (through ignorance) under-charging lead acid.

I think this is sheer ignorance from a digital-electronics generation because all the grey-beards have retired.

What happens is the hydrous lead sulphate turns to solidified lead sulphate and will not resolvate in the battery acid under charge.

Worse of all, get the charge just a little bit low but not much and you end up with one or two of the 6 cells sulphating.

Then you can't tell anything at all. The battery might, for example, look like 10V open circuit when in fact only 2 cells are badly discharged.

It's a nightmare to try to figure this out and the only way (short of old fashioned ways involving draining out battery acid and weighing it .. another post for that) is to give it a desulphation charge, this is a series of pulsed over-voltages which turn the solid sulphate back into spongy.

It is an absolute and total classic way to kill a lead acid by 'charging' it at less than 13.5V whilst it is also forming part of a circuit, which is precisely what some of these companies are doing.

In an ICE, batteries get a good blast of 14.4V for a long time after they have done their cranking business, to get them topped back up. This is a life saver for the battery and any that are routinely held up to 14.4V (and higher still for AGM) will last for years.

So, all of you, every one of you, just get a high quality desulphation charger and blast your battery with that cycle every so often over a weekend. You are then very unlikely to see a problem.

This is a problem purely of the manufacturer's own creation, because they got rid of engineers like me that know this stuff, as a false economy to try to save money (at their customer's expense, so all they end up with is lost business).

Lead acid chemistry is quite a black art. In fact, the commonly held ideas of how it even works (chemically speaking), like wikipedia might offer, are clearly wrong. It's a magical mystery!
Welcome back Donald, we need more posts from the grey beards馃榾
 

Registered
Joined
4,865 Posts
Regrettably no, but is a route to ensure permanent damage if the battery has started sulphating.

Basically, manufacturers seem to be trying to 'save electricity' (more range) by deliberately (through ignorance) under-charging lead acid.

I think this is sheer ignorance from a digital-electronics generation because all the grey-beards have retired.

What happens is the hydrous lead sulphate turns to solidified lead sulphate and will not resolvate in the battery acid under charge.

Worse of all, get the charge just a little bit low but not much and you end up with one or two of the 6 cells sulphating.

Then you can't tell anything at all. The battery might, for example, look like 10V open circuit when in fact only 2 cells are badly discharged.

It's a nightmare to try to figure this out and the only way (short of old fashioned ways involving draining out battery acid and weighing it .. another post for that) is to give it a desulphation charge, this is a series of pulsed over-voltages which turn the solid sulphate back into spongy.

It is an absolute and total classic way to kill a lead acid by 'charging' it at less than 13.5V whilst it is also forming part of a circuit, which is precisely what some of these companies are doing.

In an ICE, batteries get a good blast of 14.4V for a long time after they have done their cranking business, to get them topped back up. This is a life saver for the battery and any that are routinely held up to 14.4V (and higher still for AGM) will last for years.

So, all of you, every one of you, just get a high quality desulphation charger and blast your battery with that cycle every so often over a weekend. You are then very unlikely to see a problem.

This is a problem purely of the manufacturer's own creation, because they got rid of engineers like me that know this stuff, as a false economy to try to save money (at their customer's expense, so all they end up with is lost business).

Lead acid chemistry is quite a black art. In fact, the commonly held ideas of how it even works (chemically speaking), like wikipedia might offer, are clearly wrong. It's a magical mystery!
BMW started this trend on 5 series going back 6 years or so again. Managed Lead Acid charging, limiting the alternator output voltage to improve the emissions ratings and dead batteries everywhere.
 

Registered
Joined
16 Posts
Our 12V battery died today halfway through the school run, causing a knock on chain of delays that messed up my whole day. The AA guy tested it and found it was reading 4V.

After jumping with his larger battery device and getting the car started, it was drawing <0.5A with the incoming 13.4V or so not reflected by the 0.5A on the negative terminal. He says it's toast and needs replacing, and advised me to drive it straight to the dealer. He stayed there while I called Hyundai Nottingham and told me to ask them what the warranty on the 12V was.

Hyundai call centre gave me the earliest booking they had which is on Tuesday, where presumably they will replace the battery if they admit it is faulty. However this will leave us without a car for a whole bank holiday weekend so I am tempted just to replace it myself.

This happened once before about 18 months ago, when I'd left it on the drive with the heating running, though only for about 15 minutes. It's disappointing though that with a huge high voltage battery, and a small Li-ion jump battery, I wasn't able to start it myself!

I did find the kids left the internal lights on since yesterday, which is probably why it was so bad, but it's strange that I managed to start it, drive them to school, and stop once, and it was only on the third time I started the car that it failed!

It seems the 12V has not been charging properly, despite the regular trips all week and the maintenance setting that auto charges it regularly.
 

Registered
Joined
16 Posts
My sister and I actually had both had a DBPower one, and neither worked. They were both at 50% or less battery which might be why, but I left it sitting there for an hour or so and it made no difference. Not sure why. By the time the AA guy had got there, the electronics were completely dead.
 

Registered
Hyundai Ioniq 28
Joined
7,553 Posts
My sister and I actually had both had a DBPower one, and neither worked. They were both at 50% or less battery which might be why, but I left it sitting there for an hour or so and it made no difference. Not sure why. By the time the AA guy had got there, the electronics were completely dead.
Those are meant to be jump starters and only connected for 30 seconds or so to supply enough brief power to an EV to allow the main contactor to engage and start the car. At which time the normal DC to DC converter takes over to charge up the car's 12v battery. Leaving it connected for an hour or so to a totally flat battery would just drain the jumper unit down to the same very low level. Which is what happened, and what you reported.
 

Registered
EU base model with heat pump Sept '18
Joined
552 Posts
... so I am tempted just to replace it myself.
It might pay to start searching for one either way. It seems to be an odd size.
BMW started this trend ... Managed Lead Acid charging, limiting the alternator output voltage ...
I'd say it's been a common feature for over 10 years now. My 2009 Swift Sport was the first car I noticed had that. I think BMW though added the IBS sensor to the neg battery terminal.
 

Registered
Joined
16 Posts
Those are meant to be jump starters and only connected for 30 seconds or so to supply enough brief power to an EV to allow the main contactor to engage and start the car. At which time the normal DC to DC converter takes over to charge up the car's 12v battery. Leaving it connected for an hour or so to a totally flat battery would just drain the jumper unit down to the same very low level. Which is what happened, and what you reported.
Yes, I am aware of that. That's how I attempted to use it, but by the time I connected it (it wasn't in the car) the electronics weren't firing up at all, no lights, no , nothing. I left it for an hour in the hope it would put enough charge in to do the miminal amount required to get the traction battery turned on. The AA guy's battery was much larger, so perhaps it was just so low that the smaller unit couldn't handle it. To be honest though, these DBPower ones are a bit shoddy, a quick google shows me lots of complaints about them dying.

It seems the kids left the internal lights on, and a quick burst of too much heat without the "engine" turned on this morning may have been fatal. But the read the AA man got seemed like the battery may have been knackered up by too many short journeys over the last year, and not enough charging.
 

Registered
Kia E Niro 4
Joined
149 Posts
I have an E-Niro and there is a setting in the system whereby it tops up the 12V from the main traction battery. I've looked out on occasions to se the green charging light flashing whilst it is obviously topping up the 12v system. Does the Kona not have a similar option. With my old Mercedes I used to put it on charge every couple of months during lockdown to keep it maintained, and it was on the original 12 year old battery. All modern cars particularly EV's are never totally asleep as monitoring things and the alarm will be a constant drain, and EV 12v batteries are low capacity since they don't have to turn a motor hence less resilience.
 

Registered
Joined
16 Posts
Yes is does, and it is turned on. My wife remarked she's seen the high voltage light (which is yellowish) on the Hyundai logo turn on a few times in the last couple of weeks. So I think it's doing something. I will check the voltage with a mutlimeter again tomorrow after some charging.

Last time our 12V died, it had recently gone in for a service and that option was turned off in the menus. I haven't checked yet, but it went in for a service in February, so might have been reset I suppose. But given the battery reading of 4V earlier, I feel things must have got pretty bad in terms of charging.
 

Registered
Joined
30 Posts
If the battery saver option is still available in the settings menu on a Kona, then it has not had all of the battery management updates applied, or they have been applied incorrectly.
The BMS should be charging the 12 volt battery for 20 minutes every four hours.
 

Registered
Hyundai Ioniq 28
Joined
7,553 Posts
These bizarre events started to become reported frequently soon after I got my 2016 Leaf 24. They led to dozens of forum and social media threads as owners struggled to understand what was going on. As cars started to be flat bedded into dealers the usual response was to simply replace the 12v battery with a new one under warranty and send them back out there. I am aware of a few cars that had three batteries replaced with a dealer claim that they must have been from 'a bad batch'. No serious Nissan research was undertaken as it was far cheaper to just swap them out.

Better minds than mine delved into potential solutions and failed. Many and various theories were put forwards and numerous lengthy tests and trials were completed by owners. The problems persisted. Our own resident lead/acid battery expert in this forum declared that a pragmatic approach could save our sanity. In his expert opinion, he recommended that owners of all EVs should obtain a quality smart charger that had a de-sulphidisation programme and connect it overnight at least once a month to the 12v battery and let the programme of conditioning run its full cycle. He explained that such problems build up and eventually kill a battery unless such action is regularly taken.

He acknowledged that such action should not be necessary and that it was an early symptom of EV software that couldn't cope in all cases with the absence of a traditional alternator pumping in a large number of amps in an ICE. We all thought that the combined brains of all OEMs now making EVs would just adapt and overcome this issue. Until then a simple monthly preventative maintenance action would prevent us from being locked out of our cars and that life was too short to stress over trying to fight the problem. Unfortunately, this faith in the OEMs was once again misplaced and the problem persists.

All that I can say is that for six years since these weird events I have religiously connected my smart charger for as long as the programme runs until it shows on the screen that it has ended and displays the 'Full' message. And following my own bad experiences I have now been trouble-free amongst a sea of forum complaints. People still refuse to take this action on the grounds that it shouldn't be necessary in this day and age. They are correct. And in some cases, it will indeed be a duff battery that cannot be revived, and needs replacement. But who knows, what if that same battery had received regular maintenance? Would it still have failed catastrophically?

This is so clearly a case of the EV 12V battery management systems being deeply flawed and unable to cope with the constant drains from modern computer laden cars. It cannot be beyond the wit of man to solve these recurring issues. Especially when they have a massive power bank sat there to ensure that the 12V systems are kept up to speed at all times. Perhaps the answer is to bite the bullet and ditch that ancient lead/acid unit for a different tech unit that is better able to cope. Even a dumb observer like me knows that a normal small ICE battery that was designed to crank an engine over on a cold morning is not what is needed in an EV where only a tiny power surge is required to engage a contactor and switch a car on. After all, this is why the aftermarket boosters work.

Bottom line is that eventually, this issue will have to be seriously addressed by all OEMs ( other than Tesla who seem to have already solved it) and years from now we can all tell our kids about such early adopter problems.
 

I'm not crazy, the attack has begun.
Joined
29,503 Posts
I did find the kids left the internal lights on since yesterday, which is probably why it was so bad, but it's strange that I managed to start it, drive them to school, and stop once, and it was only on the third time I started the car that it failed!
These are effects of sulphation. The charge is present but cannot deliver the current through the solidified sulphate. The plates depolarise and you get the effect of negligible open circuit voltages.

This sort of thing was never much of an issue with ICE because as one approached problematic suphation, one performed a 'current draw' test every time one cranked one's engine.

It's almost the opposite in an ICE; very little charge needed but big current. For BEV one needs good charge capacity but little current.

So the whole nature of 'noticing effects' is wholly different.

A slow-cranking ICE gives a nice early warning of problems, often allowing months of prior notice before being left stranded. A BEV, being 'digital' so to speak, gives nothing away until it has stranded you.

Now, there is no such test so nothing to tell you in a BEV whether the battery has a current-delivery issue (different to a charge-capacity issue).

I would be pretty confident this battery is fully recoverable.

Your AA guy calling it toast was either the best advice to encourage you to act immediately to do something about it, or was under 60 years of age and has never been taught or learned of such issues.
 

Registered
Joined
1,020 Posts
I found the demonstration and explanation of a desulphation method in these two Youtube videos (by the same guy, one is from a few years ago, the other is more recent) to be very informative...

Older

More recent
 

Registered
Joined
16 Posts
These are effects of sulphation. The charge is present but cannot deliver the current through the solidified sulphate. The plates depolarise and you get the effect of negligible open circuit voltages.

This sort of thing was never much of an issue with ICE because as one approached problematic suphation, one performed a 'current draw' test every time one cranked one's engine.

It's almost the opposite in an ICE; very little charge needed but big current. For BEV one needs good charge capacity but little current.

So the whole nature of 'noticing effects' is wholly different.

A slow-cranking ICE gives a nice early warning of problems, often allowing months of prior notice before being left stranded. A BEV, being 'digital' so to speak, gives nothing away until it has stranded you.

Now, there is no such test so nothing to tell you in a BEV whether the battery has a current-delivery issue (different to a charge-capacity issue).

I would be pretty confident this battery is fully recoverable.

Your AA guy calling it toast was either the best advice to encourage you to act immediately to do something about it, or was under 60 years of age and has never been taught or learned of such issues.
Thanks, for all the useful advice. Indeed he was under 60. I took his advice mainly on the understanding that he'd probably seen a lot more lead acid batteries than I have.

It did appear to be taking charge last night, and after a few hours on the regular wallbox charger was reading 12.4V on a multimeter. I will take some more readings today. I don't think it's beyond recovery, but I currently only have a regular battery charger and not a de-sulphination type one. I will see if I can find one for a reasonable cost. No doubt it will be cheaper than a new battery anyway.
 

I'm not crazy, the attack has begun.
Joined
29,503 Posts
I found the demonstration and explanation of a desulphation method in these two Youtube videos (by the same guy, one is from a few years ago, the other is more recent) to be very informative...

Older

More recent
I had quick scan of these. I can't advocate what this guy did in the second video because the power input would be very high and might cause thermal damage.

Consider the sulphated battery as if it is a working battery and a 'sulphate' resistor in series (sitting on the plates); by applying 30V at 2A, basically 16V is being placed across the sulphate 'resistor' and 14V across the 'still good' battery.

So that'd be 16V x 2A^2 = 64W.

64W is a lot of power to be dumped across any resistor, let alone one that is only an 'accidental' resistor. Where does this heat go? Straight into the delicate lead/lead oxide electrode grille.

So, this is why a desulphation process is preferentially a long one, and consists of a series of 'over-voltage' cycles. A 'good' desulphation charger will take its time over this, at least 24 hours, usually around 48 hours, this avoids thermal damage to the plates. I think my RSC408 runs the desulphation cycle at around 18 to 20V, which is more than adequate. One only needs a few extra volts to shift the electropotential so the sulphate can resolvate in the water (of the acid mixture, making the mixture more acidic).
 

I'm not crazy, the attack has begun.
Joined
29,503 Posts
I was secretly hoping someone might have challenged me on my statement "Lead acid chemistry is quite a black art. In fact, the commonly held ideas of how it even works (chemically speaking), like wikipedia might offer, are clearly wrong", so I would have something to push back on. But in fact lead acid battery probably already looks 'black art' to you and no further explanation necessary!! ;)
 

Registered
Hyundai Ioniq 28
Joined
7,553 Posts
But in fact lead acid battery probably already looks 'black art' to you and no further explanation necessary.
Correct. But the main mystery to me is why OEMs persist with using this tech to energise a contactor to switch the main traction battery on. As demonstrated by the use of tiny booster gizmos for that function they actually require relatively low power but sufficient voltage to activate a relay.

In theory the 12v DC lead/acid battery could be replaced by a small booster type unit as long as once the car is 'on' the other car domestic systems run from a tapped off supply from the main traction battery. Leaving a simple DC to DC converter and regulator to keep that one function booster topped up, without any other power drains after that initial start-up zap.

Is there a good reason why the car's normal 12V systems can't be run from a 400V DC to 12V DC converter which will always have sufficient power as long as the car has power available.

There just has to be a way to ditch the lead/acid ICE type battery and avoid all of the black art bizarre events and requirements and a need to leap through dozens of hoops to keep it happy and available at all times to simply switch on an EV.
 

I'm not crazy, the attack has begun.
Joined
29,503 Posts
Correct. But the main mystery to me is why OEMs persist with using this tech to energise a contactor to switch the main traction battery on. As demonstrated by the use of tiny booster gizmos for that function they actually require relatively low power but sufficient voltage to activate a relay.

In theory the 12v DC lead/acid battery could be replaced by a small booster type unit as long as once the car is 'on' the other car domestic systems run from a tapped off supply from the main traction battery. Leaving a simple DC to DC converter and regulator to keep that one function booster topped up, without any other power drains after that initial start-up zap.

Is there a good reason why the car's normal 12V systems can't be run from a 400V DC to 12V DC converter which will always have sufficient power as long as the car has power available.

There just has to be a way to ditch the lead/acid ICE type battery and avoid all of the black art bizarre events and requirements and a need to leap through dozens of hoops to keep it happy and available at all times to simply switch on an EV.
Yes, there are good reasons.

lead acid are virtually immune to spike-, over- or under- voltage events on the 12V bus. Quite the opposite, they act as a very low resistance, in the milliOhm range, to 'soak up' all the Bad Stuff that you get on real-world electrical networks.

Closing that inductive contactor solenoid can generate a big spike. Yep, one can put all sorts of circuit protection in place to stop that, and indeed there is such protection there. What happens if the circuit protection fails and you have a li ion battery with clever electronics on it? Answer; not only could that clever battery fry up, but the whole of the 12V bus might fry too.

A lead acid pack helps mitigate, if not completely removes, the potential for single-point failure modes that can result in writing off the car in the next 'start-button' press after some load-dump protection failure.

Also, they are virtually immune from cack-handed recovering folk who have a standard approach to cars, namely whack on 12V onto the battery to get it started. Try that with a completely flattened 'clever' 12V li ion pack and see the sparks. An NiMH pack would cope but would not perform the former function I mentioned.
 

Registered
Joined
841 Posts
There are many of us I am sure that have never had this problem. My car was purchased in Sept 18 and I have never (fingers crossed!) had a problem with my 12v battery. I have a BM2 to monitor the system and I can see that it gets topped up roughly every 4hours. So I still consider these failures are due to something specific being wrong or different with some cars. if it was problems like those discussed above then I would expect every Kona EV to have this problem, and they don鈥檛.
 
21 - 40 of 50 Posts
Top