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The Ioniq EV has the default setting to periodically charge the 12 volt auxillary battery (under the hood) even while the car is turned off and parked idle. Occasionally, I look in the garage and see the centre blue dash light is flashing indicating this function is active. This also sometimes shows as a message when I first use the car after it has not been used for a day or two.

It tseems to me, the 12 volt battery is always kept in a good state of charge and rechargers automatically (using energy from the big Li-Po battery), as the voltage drops slightly from parasitic drain and self discharge while the car is idle. It therefore seems reasonable that by connecting an AC inverter of modest power capacity, say 500 watts, we would have a ready source 120 Volt, 60 Hz AC power for household power failures. And by doing so, the big battery in the car would keep the 12 volt auxillary battery alive and well for many many hours. It would sure beat burning gas in a portable AC generator.

Of course, ideally, such 120 volt AC power inverters should be designed into the stock workings of the car's power conversion system making available emergency power to owners when the need arises.

Something to consider, how much power can the automatic charging system deliver to the 12 volt battery with or without the car running.

Has anyone considered this idea and wants to offer comment.

Norm in Ottawa
 

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Thousands of Prius owner have been doing this for over 10 years.
 

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The Ioniq EV has the default setting to periodically charge the 12 volt auxillary battery (under the hood) even while the car is turned off and parked idle. Occasionally, I look in the garage and see the centre blue dash light is flashing indicating this function is active. This also sometimes shows as a message when I first use the car after it has not been used for a day or two.

It tseems to me, the 12 volt battery is always kept in a good state of charge and rechargers automatically (using energy from the big Li-Po battery), as the voltage drops slightly from parasitic drain and self discharge while the car is idle. It therefore seems reasonable that by connecting an AC inverter of modest power capacity, say 500 watts, we would have a ready source 120 Volt, 60 Hz AC power for household power failures. And by doing so, the big battery in the car would keep the 12 volt auxillary battery alive and well for many many hours. It would sure beat burning gas in a portable AC generator.

Of course, ideally, such 120 volt AC power inverters should be designed into the stock workings of the car's power conversion system making available emergency power to owners when the need arises.

Something to consider, how much power can the automatic charging system deliver to the 12 volt battery with or without the car running.

Has anyone considered this idea and wants to offer comment.

Norm in Ottawa
A good question.

I don't think the topping up battery system would cope with anything like a 500W drain on the 12V battery. That would require a charging current in excess of 40 Amps. I'd expect the charger to have a more modest capability of around 2 Amps - 24 Watts.
 

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I don't think the topping up battery system would cope with anything like a 500W drain on the 12V battery. That would require a charging current in excess of 40 Amps. I'd expect the charger to have a more modest capability of around 2 Amps - 24 Watts.
The DC-DC converter that maintains the 12V system has to have at least the capacity to run all of the 12V electronics. That includes power sockets, USB charge ports, full interior and exterior lighting, HVAC, heated seats, heated steering wheel, etc. (I don't see Hyundai running these systems directly off of the hazardous high voltage, that's too risky for the occupants in a collision.) That's going to be a lot more than 2A / 24W, although I don't know how close it is to 42A / 500W either, or whether the car would be willing to operate it's DC-DC converter continuously to prop up the 12V battery when the ignition is off. It probably needs the inverter coolant loop running to sustain that.
 

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If you want to tap the power from 12V battery, then you should keep the car "running" so that the 12V is maintained reliably.
 

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I work in my ioniq 2020 ev about ten hours a day with a laptop in one 12 volt socket and an extra monitor in the other. No problems so far after two months except the last couple of days noticing the inverters' lights blinking on and off. I've yet to confirm whether this is because I'm draining too much power through my appliances or it's a battery issue.
 

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Nobu, the 2017-2019 IONIQ electric's are only rated for 180W from the 12V sockets, which is pretty low, but should power a laptop and a screen. However, as mentioned above, the 12V battery on the BEV is TINY. If you're drawing power from the 12V sockets while you work, you should have the car "ON" so that the 12V battery continues to charge from the traction battery or it's likely to run down very quickly. You'll also stay comfy with the HVAC running.
 
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Hey @Ou Boet , I noticed that sometimes even when the car is "ON" the inverter will turn itself off with lights blinking and my current workaround is to turn on the HVAC, heat, to about anywhere from 22 to 24 degrees which seems to require enough power for the 12V battery to start drawing juice from the bigger Lithium battery. Then the inverter, laptop and screen are mostly fine. So perhaps it has a mechanism where if no HVAC is used, lights are turned off, etc regardless of if the car is "ON" it gets into a mode where it lets the 12V provide power until hitting a threshold when the Lithium battery starts to replenish. I don't know if that even makes sense and I'm just taking a wild guess here.
 

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Btw, if anyone knows where to get a robust totally silent inverter that could go into the 12V socket or a really good 12V extension cord, please let me know. I have this Stanley one (500w if attached to the 12V directly on normal cars, 140w through the 12v socket) that is pretty good but the fan like most others is quite noisy. I tried an extension cord for the 12V but the connection was poor so the power intermittent although being able to put the inverter in the back behind the driver seat cut down on the noise quite a bit from its current position on the passenger side front seat. I saw a better one on Amazon but like to buy things in a bricks-and-mortar store in case something goes wrong.
 

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Hey @Ou Boet , I noticed that sometimes even when the car is "ON" the inverter will turn itself off with lights blinking and my current workaround is to turn on the HVAC, heat, to about anywhere from 22 to 24 degrees which seems to require enough power for the 12V battery to start drawing juice from the bigger Lithium battery.
Perhaps you can install a bigger battery for more energy?
 

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I have a 180W inverter for such cases. I've not used it on the ioniq yet but I understand that putting the vehicle in utility mode (it's in the settings via the steering wheel menus) will power the 12V from the HV battery. It's intended for use whilst camping etc.
I'm not sure I'd risk drawing more than 400-500W from the car's 12V system though (and that would need to be directly connected to the battery)
The simple 180W inverter I have cost around £12, and is very useful if we get a power cut. I just run an extension lead from the car, and it's enough to power the TV, internet router, charge a phone/laptop and power a couple of LED lamps.
 
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It's intended for use whilst camping etc.
I'm not sure I'd risk drawing more than 400-500W from the car's 12V system though (and that would need to be directly connected to the battery)
Actually, the battery is where you don't want to connect a high power inverter in the IONIQ:

The DC-DC converter is quite robust as it has to deal with powering everything at once (interior and exterior lighting, HVAC fans, cooling fans, front and rear heated seats, heating steering wheel, power seats, power windows, power mirrors, power sunroof, computers, infotainment, 12V battery charging), while the 12V battery is intended only to keep the BMS, Bluelink, and keyless entry alive; then boot up enough computers to get the DC-DC converter running again.

The car actually monitors the amount of power heading towards the 12V battery, and if it exceeds the worst case charging loads it will cry foul and shut down. You want your AC inverter to be connected to the 12V bus, not the 12V battery.
 

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Actually, the battery is where you don't want to connect a high power inverter in the IONIQ:

The DC-DC converter is quite robust as it has to deal with powering everything at once (interior and exterior lighting, HVAC fans, cooling fans, front and rear heated seats, heating steering wheel, power seats, power windows, power mirrors, power sunroof, computers, infotainment, 12V battery charging), while the 12V battery is intended only to keep the BMS, Bluelink, and keyless entry alive; then boot up enough computers to get the DC-DC converter running again.

The car actually monitors the amount of power heading towards the 12V battery, and if it exceeds the worst case charging loads it will cry foul and shut down. You want your AC inverter to be connected to the 12V bus, not the 12V battery.
Will that not achieve the same result though? I was coming from the point that you wouldn't want to connect anything that exceeds the 180w limit on the cigar socket points. How would you connect it to the 12V bus?
 

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Will that not achieve the same result though? I was coming from the point that you wouldn't want to connect anything that exceeds the 180w limit on the cigar socket points. How would you connect it to the 12V bus?
You'd have to go into one or the other fuse box and piggy back off of something beefier than a 15A breaker. There was a related thread where somebody had a beefy inverter they'd used to keep a refrigerator running during a blackout, that's where a limit on the charge current back into the 12V battery was mentioned. I can only assume they spliced into one of the large fusible links to pull that trick off, which would of course be a warranty voiding move. Individual needs and risk tolerances will of course vary. :)
 

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The powermonitoring is placed in the return-line to the 12V battery. When power is drawn from the battery itself, power monitoring registers charging current to the battery (and this is limited).

A large load should be connected to its own fuse from the 12V bus (or battery). The return line to the car chassis (not the 12V battery itself)
 

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The powermonitoring is placed in the return-line to the 12V battery. When power is drawn from the battery itself, power monitoring registers charging current to the battery (and this is limited).

A large load should be connected to its own fuse from the 12V bus (or battery). The return line to the car chassis (not the 12V battery itself)
Thanks for the clarification! I'm actually drawing up to 50A in this exact configuration, positive from battery+ through own fuse, negative to chassis ground. Seems to work so far. Been monitoring voltage quite closely out of habit, and see no difference in 12V charging behaviour. BTW, the load is resistive, not sure I'd dare to put a heavy inductive load or heavy power inverter on it.
 

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Thanks for the clarification! I'm actually drawing up to 50A in this exact configuration, positive from battery+ through own fuse, negative to chassis ground. Seems to work so far. Been monitoring voltage quite closely out of habit, and see no difference in 12V charging behaviour. BTW, the load is resistive, not sure I'd dare to put a heavy inductive load or heavy power inverter on it.
Hi, can you share some schematic drawings and photos to give me an idea on how to do this?
I keep blowing out my 12V sockets using inverters to power my laptop.
 

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Actually, the battery is where you don't want to connect a high power inverter in the IONIQ:

The DC-DC converter is quite robust as it has to deal with powering everything at once (interior and exterior lighting, HVAC fans, cooling fans, front and rear heated seats, heating steering wheel, power seats, power windows, power mirrors, power sunroof, computers, infotainment, 12V battery charging), while the 12V battery is intended only to keep the BMS, Bluelink, and keyless entry alive; then boot up enough computers to get the DC-DC converter running again.

The car actually monitors the amount of power heading towards the 12V battery, and if it exceeds the worst case charging loads it will cry foul and shut down. You want your AC inverter to be connected to the 12V bus, not the 12V battery.
You mean I can't take the alligator clips that come with most inverters and just connect it to the battery with the hood open and extension cord running from the inverter to my laptop? I wanted to do this with the 400w pure sine wave Motomaster inverter from Canadian Tire.
 

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Btw, does this void the warranty? The tech lead at my dealership, really helpful guy, said it might. But he's willing to install one for me or even walk me through it if I buy all the supplies he recommended.
He said he'd help me get the wires through to the cabin, mentioned some grommets for the firewall.
-8 gauge wire with inline fuse holder and suitable fuse
I also have a car audio installer willing to do this.
 

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I assume it's like this but what a crappy diagram in the owner's manual:

34611


I can't tell where that loopy negative chassis ground is.
 
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