[Leafocaster]

Not had any low battery warnings and yes I have the battery maintenance switched on, I’ve checked the battery voltage a few times over the last week with a Fluke meter and it hovers around 12.17 volts, this morning 12.07 volts. That to me is a battery with only 60% of its nominal voltage of around 12.6 volts, I have no way of measuring the amps btw.

The car is a 2019 manufactured Ioniq EV and I’ve read of a few issues with dead auxiliary batteries from other owners.

I monitored my back then 4-year-old Leaf’s 12-volt battery and as soon as it dropped to 12.0 volts I replaced it, I started getting weird error messages on the dashboard and the new battery resolved it.

I’ve been on a few long trips of around 2 hours motoring in the Ioniq so would think the auxiliary battery would have been charged enough.

The Hyundai dealer I bought the car from is quite a journey for me and as there are no errors showing will just say nothing wrong with the battery. The battery is a Delkor and imho tiny for a medium sized car, if it’s just a duff battery I’ll order a Yuasa replacement and be done with it, I’ve had good service from Yuasa batteries in the past.

Thanks in advance for any suggestions or advice

 

[Hitstirrer]

Search the forum for dozens of threads on this subject. The simple, and pragmatic, solution is to buy a smart charger and attach it to the 12v DC battery for a lengthy period at least once a month whether it seems to need it or not. The programme can sometimes run for as long as twelve hours meaning that overnight is usually convenient.

Such chargers analyse the condition before instigating a specific programme of charging to rectify any problems such as sulphidation and then correctly charge in a phased way that a dumb charger will not do. Even a low power trickle charger will not perform as well to keep the 12v battery in good condition. I am pretty sure that you do not need a new battery, and it is highly likely that your earlier Leaf didn't either. They just need regular maintenance using a modern smarty.

I realise that this will be annoying. I know that it should not be necessary. Which is why I used the word 'pragmatic' at the start. Life is too short to stress over such a simple remedy that seems to be part of EV ownership for many. The issue is random, not car specific, and only affects a small number of each model. Trying to track down the cause has beaten many before now. Try to treat it as part of your monthly tyre kicking and screenwash bottle filling routine and all will be well.

 

[Leafocaster]

I am pretty sure that you do not need a new battery, and it is highly likely that your earlier Leaf didn't either. They just need regular maintenance using a modern smarty.

Thanks for your your response, yes I’m hopeful the battery is ok.

I bought a Ctek smart charger and ran the Leaf battery through the recondition mode twice, at first it looked promising but after a few days the weird dashboard errors started appearing again, a new battery however sorted it.

I'll let the Ctek do its stuff on the Ioniq battery

 

[Patteri]

We have a 02-2019 registered Ioniq EV with the original 12V battery, no problems. I have a lithium boosterpack in the glovebox and have never needed it. You could go our route and see if you ever have problems, more common that you won't.

 

[Leafocaster]

We have a 02-2019 registered Ioniq EV with the original 12V battery, no problems. I have a lithium boosterpack in the glovebox and have never needed it. You could go our route and see if you ever have problems, more common that you won't.

Thanks for your response, I bought a Lithium booster pack for the Leaf a few years back, I’ve not needed to use it other than to run it down and recharge it again a few times.

Looking into this a bit further, when you open the door to access the bonnet lever the car partially wakes up in readiness for use, so the battery is loaded down hence the lower voltage readings. And with just the bonnet open the car is again electronically active letting Bluelink know the bonnet is open.

I’ve come to the conclusion that it’s all normal

 

[HandyAndy]

Something drained the 12V in my 22 month old 38 kWh Ioniq last night! 8.6V this morning!! So it's going to get full checkup when serviced in Sept, also now has BM2 monitor to keep an eye on it. My LiPo battery-booster that I bought specially to recover from this problem failed to give enough boost to get the car going, so am rather disappointed with that. So I'm now fitting a 23 Ah auxiliary battery Exide AGM12-23 plus a beefy diode, and a beefy Mosfet gizmo. So this will be arranged that the new battery gets charged from the car, but cannot discharge back into the original Delkor 40 Ah battery, until I press a small button inside the car. In effect this connects the 12V +ves with a jumper-lead, so it's a beefier booster-pack if you like. Should do the trick. Total cost of parts around £80. Full info & pics in a few days time will be on ioniqforum.com .

 

[Hitstirrer]

Something drained the 12V in my 22 month old 38 kWh Ioniq last night! So I'm now fitting a 23 Ah auxiliary battery Exide AGM12-23 plus a beefy diode, and a beefy Mosfet gizmo. Full info & pics in a few days time will be on ioniqforum.com .

This will be the gizmo that I picked your brains about back in January when I had an idea to use a spare alarm battery in that way. An extra battery under the bonnet that could be charged by the system but not discharged until a switch was thrown. Your circuit drawing at the time was well beyond my ability to construct so the idea was put on the backburner. I had also thought of a way to engage the booster without having to enter the car if the 12v didn't open the doors by lodging a toggle pull string under the scuttle by the nearside wipers.

Once you have designed and built your device I would be very interested in commissioning another control unit from you with just simple leads to connect the two batteries as discussed, which I might be capable of carrying out without blowing myself up. I already have the spare battery of course. I would still like to have the operating switch as a pull on/off one such as in bathroom lights - with a string to where it can be accessed without going into the car.

I will watch your progress on this get out of jail gizmo over in the Ioniq forum. I had seen your name in there but assumed that it was a coincidence as that is much more US orientated.

 

[HandyAndy]

Ioniqforum's a lot more multinational, I'd say more European than USA maybe? But it's required reading I think for Ioniq owners!

Yup, the self-same circuit diag I pulled up! No reason it shouldn't have a puller-cord switch like a bathroom one, you'ld just need to remember to pull it again to turn it off. You'd want it left on a few moments while getting into car & starting up properly, but there's a risk you'll drive off leaving the battery engaged, forget all about it, and then drain both batteries when the next vampire hits!

I'm happy to just have internal button, as I can open Ioniq or Ampera door with the key blade even if battery is flat. Might be a different matter on a Tesla/EQ6/other vehicle with fancy foldaway powered handles.

I'm not keen on making a special kit for this, and offering it for sale. It's going to be hard to know what current-draw there might be, so I'm guessing 300A should be enough, also it's hard to calculate the heat losses through the semiconductors as a lot will depend on how flat the other battery is, what the internal resistance of your aux battery is, etc etc. So it's very much experimental suck-it-and-see at the moment. I need to overengineer it by quite a margin to be safe, the silicon's not too expensive fortunately. Also if I sold a kit, I would be liable if it went belly up & torched your car+house, but I might be persuaded by direct msg to lend a helping hand to someone else...

 

[Hitstirrer]

OK - I'll wait until you have burned your own car down a few times then.

But on this subject can I bounce another of my hair-brained ideas off you? It did occur to me that one way of keeping the standby battery charged but avoiding the danger of it being flattened alongside the main 12v DC battery would be to fit a 12v timer that broke the parallel positive connection most of the time but allowed connection for a limited time daily so that both 12v batteries would balance themselves off simply by being connected together. A cheap timer like this would isolate the two batteries completely except for 30 minutes a day when the emergency unit could be topped up. That would massively simplify the concept.

12V Power Timer Switch LCD Digital Microcomputer Control Time Relay Panel Mount | Wish}&guest=true&gclid=CjwKCAjwruSHBhAtEiwA_qCppkc0KHYaLUncUILoIt7vxSnyg4ybijjbY2bDn5QqLiInYBljrK163BoCjGQQAvD_BwE&share=web

And then a simple circuit to bypass the timer when needed - operated by your cabin push button or my bathroom light pull on/off switch.

 

[HandyAndy]

Sounds complicated to me. You have to think about the timer each day, how are you going to charge the aux battery if the 2 batteries are both isolated, restricted to 30 mins/day to recharge the aux battery? And if you couple them up for a decent period just when the vampire strikes, then both get drained. Can't see how this simplifies things tbh.

I've eyeballed how the Exide aux battery goes in. Dead easy, it's the same width & height as existing, and the width is slim enough that it goes right in front of the existing battery, with the base resting on the present battery clamp. I'll make up a flat support plate to distribute the weight, probably carve a piece of wood. Then I'll use my chunky reusable cable-ties to strap the 2 batteries together. Getting a wire to go into the cabin through the firewall looks tricky, so I'll simply put a toggle switch along with the electronics stuff, so it will be a bonnet-open job to activate when needed. Also easier to remove everyhing when it goes in for servicing. Mosfets have arrived, RS sold me diodes purporting to be 210A, was a typo on their site & only 10A !!! So got that fixed, and have reordered some 150A ones arriving tomorrow. There's a real shortage of these things - lots of diodes/Mosfets out of stock, back-order for November delivery!

I've chosen diodes with typical 1.3V drop. I've seen 14.2V from the car's charger on my voltage meter plugged into the Aux socket, and AGMs like to be held at 13.5V max for long-period float charging; much higher and they start to out-gas & make hydrogen & oxygen/whatever, and they don't like this as they can't vent. So you're told to not overcharge them. These diodes will limit the charging voltage to around 13.0V, should be ok I reckon.

 

[Hitstirrer]

Sounds complicated to me. You have to think about the timer each day...........,

Not at all. Such timers can be programmed to operate daily on/off at set times and will continue until you change the programme, so it would have minimal admin ongoing. Maybe not that particular cheapy model but one that is a bit more robust and offers the weekly program options.

Getting a wire to go into the cabin through the firewall looks tricky, so I'll simply put a toggle switch along with the electronics stuff, so it will be a bonnet-open job to activate when needed.

Access through the firewall was an anticipated problem which is why I looked at the pull switch option. I'm sure that a stringpull exiting under the nearside scuttle out of sight would work and not require access to the car and bonnet pull to energise the standby battery.

......... how are you going to charge the aux battery if the 2 batteries are both isolated, restricted to 30 mins/day to recharge the aux battery? And if you couple them up for a decent period just when the vampire strikes, then both get drained.

I can't have explained too well. The idea is to connect the two 12v batteries in parallel. Then break the positive connecting lead with the 12v timer unit connections that are 'switched' by the timer relay ( The 12 v timer itself being energised by direct connections to the main 12v battery)
Then, set the timer to only operate for 30 minutes a day so that both the 12v batteries are connected in parallel and power will flow to level the charge off in both of them. That way, the emergency battery will receive a charge daily for 30 minutes but most of the time is isolated from the car.

Then if the main 12v battery is flattened by a mystery event and the car doors won't open it would just require the string toggle to be pulled to bypass the timer and connect both 12v batteries again. That should provide enough energy to open the doors and start the car. At which time the toggle can be pulled again ready for the next emergency.

 

[HandyAndy]

Ok, so how does this scenario work out? Aux 23Ah bat is charged up, Main 40 Ah gets hit by vampire, drops it to 8.6V over a few hours. Timer kicks in & connects for 30 mins. Qn is, what's the final state of the Aux battery now? If Main was in tip-top nick, that drop to 8.6V must have sucked out say 30 Ah at least? So now after coupling up, assume they've balanced their voltages, what's the new voltage now? And what if the vampire is still draining away? I don't know whether it's a 3A for 10 hours or 30A for 1 hour type of thing, afaik. Then the timer finishes the 30 min balance, vampire is still draining the Main battery for quite a few more hours before you arrive to drive away? Main battery has been further flattened in the meantime, so now when you pull the switch the Aux is now partly drained, and you wanted it to be as powerful as poss.

I'm thinking about re-jigging my circuit a bit. At the moment when I operate the boost switch it's wiring the Aux battery in parallel, so is having to recharge the Main battery at the same instant that the car needs power. This is an extra load that the smaller Aux battery can well do without.

I'm going to think about installing another mosfet, maybe another diode, whatever, the idea being that when I operate the boost switch, the Main 12V battery that's drained gets removed from the circuit entirely, and the only battery connected to the car is the Aux battery. So this will take the Main battery charging load off the Aux while the car gets going. Something like this I hink:

So I think I need a 3-position switch:
Postiion 1: Usual state, Aux can be charged but cannot supply. Main can be charged & can supply.
Position 2: stage 1 of recovery: Aux can be charged, can supply car only. Main disconnected completely. This allows car to be started up normally, and driven if necessary.
Position 3: stage 2 of recovery, car now powered up ok: Aux can be charged, can supply. Main reconnected as normal, so gets charged by Aux as well as car's 400 -> 12V charger. In position 2 & 3 the Aux battery is vulnerable to vampire drain, so once car is up & running the switch is usually set back to position 1 which protects Aux from the vampire, and puts all the workload back onto the Main battery alone.

May sound a bit more complicated, but reduces load on the Aux battery, so a smaller & cheaper one may do fine. And it stops the Main 12V from shorting-out the Aux battery, who knows, plates may have buckled inside it/whatever.

 

[Hitstirrer]

OK, I get your disaster loaded on top of a catastrophe scenario where the 30-minute top-up period might just coincide with the same 30 minutes where the main 12v battery is being subjected to a huge and sudden vampire event. Leading to both the get out of jail battery and the main battery draining together. Could happen I suppose. But highly unlikely.

To avoid even that remote possibility I would suggest that the 30 minutes top-up of the emergency battery should be programmed to happen when the car is being used normally for a daily commute. Possibly even on the home trip as well. Two timer sessions from 8 - 8:30 am and another 5 - 5.30 pm, or to suit the drivers daily runs when the car is likely to be in motion. Perhaps avoid weekends. But then again my solution is cheap and cheerful, very basic and costing nothing. And might not actually work when needed for the reasons that you set out. And would need a monthly check of the voltage in the emergency battery to make sure that all was still well there.

The alternative to cover all bases is starting to look expensive.

 

[Peter Cittern]

Have you both ruled out the water in doors shorting out the electrics scenario which was my problem? Mine has been fine since the door electrics were waterproofed.

 

[Hitstirrer]

Have you both ruled out the water in doors shorting out the electrics scenario which was my problem? Mine has been fine since the door electrics were waterproofed.

Agreed. But the problem is that specific causes like that are just one of dozens of gremlins that seem to cause these issues and in many cases the cause remains elusive. Many people carry a booster around ready to provide some voltage if and when this happens. I am just musing about a way to have a semi-permanent solution that can be activated by a toggle pull if you are locked out by a flat 12v battery.

 

[Peter Cittern]

It looks like I got lucky (when the real cause was found after 4 visits to the dealer) as I was so p*****d off, I was about to part ex the car for something else.

 

[HandyAndy]

Deffo not a moisture problem! This vampire happened to me after I'd spent most of a day gently charging it on one of the hottest days this year! And it was fine before that, and has been fine since. So mine has to be either the battery at 2 years old (quite a few month spent sitting on dealer's forecourt I think, perhaps their demo car, had done 5k miles when I bought it 1 year old) has been tortured & is about to totally collapse, or it's some non-moisture thing - perhaps I didn't somehow shut the driver's door properly? But pretty darn sure I did, nothing looked out of place the next morning when it was flat.

 

[HandyAndy]

Ok Guys, I'm happy with my circuit diagram have bought some of the bits. Just got to build one & try it now!
More info here: Yet another 12V battery dies...

 

[Hitstirrer]

Can't wait. But the users manual might be a weighty tome with numerous flowcharts.

 

[HandyAndy]

User manual will be about 2 sides of A4 PDF. Any more, and my printing costs start to mount!!!
All parts ordered. It will fit in one of those outdoors 2-gang 13Aplug holders, so the front cover can be lifted to change the 100A fuse if necc! There will only be the 2 rocker switches to operate.