Kona as a backup battery for home power outage?

^^^^good points R.P.
I will have to read further but I think 1500watts might be a sweet spot, as it will just be a temporary solution especially in the winter time.

 

Good point. That is the proper way. I would do it if I would have a frequently recurring requirement. So far, once in 8 years, and I am getting lazy.

 

I don't know what your plans are, but if you are thinking of pulling 1500 watts from a Kona's 12V battery then the battery and the DC-DC charging system is not going to last very long.

I have an 1800 watt pure sine wave inverter in my caravan and a 360 amp-hour lithium battery pack to support it. When we run our small coffee machine and milk frother, between the two of them they pull 160 amps out of the battery pack. Your Kona won't cope with that.

You may not want to run a coffee machine, but unless you have some system to prevent a number of appliances all deciding to run simultaneously you could easily approach a 1500 watt total which I think will fry your car.

At a guess I think the max amps you should pull from the 12V battery is 30, so that's 360 watts. Not much to run a house with.

If you're talking about an EV with V2L (eg Ioniq 5), which would not be a Kona, different story.

 

The DC to DC converter on the Kona has been tested up to 120 amps at which point it blows the fuse in the car. There are other threads that discuss this. I set up my inverter with a 100 amp dc circuit breaker and have used it during power outages up to 8 hours to run my refrigerator, wifi, lights and computer. with no problems.

 

Wow, that's equivalent to an alternator in a large 4WD. Somewhat surprising in a small car.

 

Yes but everything on the Kona runs off of electricity. Heating, AC, Power steering, E-brake ,heated seats, cooling pumps, fans, heated steering wheel etc....So there is a higher 12 volt electric demand on an EV than an ice car where accessories are run by belts and pulleys or waste heat for heating

 

This is 120 amps at 12V? I many watts at 120V AC were you pulling?

 

Yes it was 120 amps on the 12 volt side. AC side would be 12 amps 120 volt. When I use the inverter on the house I typically run between 6 and 8 amps on the ac side. Watts are the same either side 1440 watts max. I limit my inverter to 1200 watts

 

AC and cabin heating runs from the HV battery.
I've yet to see a spec for the Kona DC-DC converter output current rating, I'd guess somewhere between 50 and 100A

 

The LDC is fused to the battery and rest of the car at 150A. Running 120 steady-state might make it a bit
warm, but probably won't pop it. However, sustained high loads can weaken fuses over time and lower
their effective break current.

_H*

 

I’d be surprised if the LDC can’t manage itself by current limiting. In any case the fuse is not easily accessible and looks to be intended as a last line of defence rather than to protect against inadvertent overloading.

 

Ah, now that you made me look, it's not in the HV junction box where I thought. And of course it wouldn't be because it's 12V, not HV.
Under the hood:

 

Sorry to bring an older thread...this setup looks cool, but where do you put the inverter? Is there enuf room to close the hood.

 

As it is a plug in setup, it is easy to connect/disconnect. My inverter fits nicely, securely under the hood over the black plastic cover in the centre. While stationary! Definitely not a solution for driving around with the inverter connected.

I never even tried to close the hood over it. For me there is no need.

 

I recall an earlier forum on the ability of the DC/DC charger in the Kona as being able to provide 1300w, so it's possible to draw 108 amps steady state without discharging the 12v battery. This is using the Utility setting.

 

We had power out for 4 days a couple of weeks back and all I could do with the Kona was charge another 12V car battery which I used to keep my (fibre) internet working. I don’t have an inverter and am not sure I could be bothered with the practicalities. I’d rather just trade up to an EV with V2L. I have a generator for the rainwater pumps but it’s too thirsty and noisy to use all the time.

 

I agree even though I have a nice inverter set up for my Kona, now that I have my F 150 lightning ⚡️ with 9.6kw built in I don’t see myself using the Kona setup again.

Also both Emporia and Enphase are coming out with v2h bidirectional chargers in the coming year.