[yticolev]

I appreciate your concern, but there is nothing in the warranty that says you can't temporarily connect an external device to the car battery. It's the same as connecting jumper cables and starting a friend's car. Every circuit is fused and protected. The only thing the manual warns against is replacing a fuse with a larger one, which would void the warranty.

This is not a normal use or operation of a car. Thus you will not win in court should a warranty claim be denied. There are a lot of things the manual doesn't explicitly say you shouldn't do. Driving off a cliff for example. Using the car as a snow plow. Even with 800 pages in the manual, there simply isn't enough room to cover all the things the car was not designed to do.

While more power to you if you make it work with no downside, I can only imagine your 12 volt battery will be killed in short order with a longer test. It simply isn't made for it, nor was the DC/DC converter. Far better to connect an inverter directly to the traction battery and take out the stuff in the middle of your circuit. I believe that is how Prius owners hook up to house power.

 

[Greg Elmassian]

Utility mode is supported in the car. It is for things like "camping"... I'd be happy to go to court on that one.

Also during utility mode, there's no draw on the 12v battery, as proved by actual measurements on other forums.

6 amps is nothing.

Greg

 

[yticolev]

Are we talking about the BEV here? How can you be in utility mode with the head unit on not drawing any 12 volt power? Does utility mode, turning on the car without pressing on the brake, mean something different in the BEV than the other models?

 

[aginzu]

The head unit draws 12V power but it continually gets recharged from the main battery via the DC-DC converter. When I was running my tests the voltage at the battery terminals was a steady 14.3V, indicating that it was being fed from the DC-DC converter. It's like an ICE car with the engine idling and the 12V system being fed from the alternator.

 

[yticolev]

How long was it at 14.3 volts? I've seen a number of graphs that show only intermittent charging. In any case, Greg said no draw in utility mode, which should mean no charging either.

 

[Greg Elmassian]

OK, please read carefully, and yes this is the Niro EV forum, not the other models.

I did not say no 12v was being used, I said no power drawn from the 12v battery. Big difference.

When in utility mode, the car activates the 12v "charger", and supplies 14.7 volts.... this means the charger voltage exceeds the 12v battery voltage thus no current is drawn from the 12v battery, like I said. This has been verified by several people, and if you noticed there is a current measuring device on the negative side of th 12v battery so this can be monitored/measured.

the 12v battery will become fully charged if it was not before of course.

Hopefully that makes it clear. If not, please read the discussions on the other, more frequented Niro forums.

By the way, the alternator in an ICE car likewise puts out more volts than the 12v battery, usually 14.x volts so most of the time the car battery is not being drained.

Greg

 

[yticolev]

I reread the thread and think I'm going to have to yield to the experts. Pretty confusing why utility mode can provide a continuous 14.x volts, but the DC/DC is not supplying 14.x volts continuously while driving. If it did, there would be no issue with failing 12 volt batteries (absent excess vampire current when off).

 

[Greg Elmassian]

I think the extensive threads are on Speak EV... If I remembered right away I would have produced links.

And it is 14.7 volts just to be picky, which is a bit high to apply to a lead acid battery (although ours are technically a lead calcium)

There are devices that can record the battery voltage directly, and the people on the thread went to the trouble to make sure the voltage calibration was accurate.

Remember this thread title is about powering the house, and the op talked about powering a fridge. Nothing to do with operating the car while doing so, therefor, plugging into the cigar lighter and drawing your 6 amps for your fridge would be fine (but I suspect that 6 amps was not at 12 volts.. if that 6 amps quoted was at 220v, then need to think again, but that must be wrong too, since it was stated there was a 60 amp surge...)

The charging of the battery while driving is similar but different, and so is the periodic charging in "battery saver mode", and also what happens during charging.... all different situations with slightly different operation of the onboard "12v charger"... which is more than a simple inverter, clearly.

Suffice it to say it does not overcharge the battery, as designed.

Greg

 

[aginzu]

The fridge pulls 6.5 amps at 120v which translates into 65 amps at 12v. When I tested the inverter it had no problem powering a 1.7kw tea pot pulling 170 amps at 12v. I don't know what the maximum 12v current the Niro DC-DC converter can deliver. It seems to be at least 170 amps but I don't plan to push it that far on a regular basis. I believe that 1kw, around 85 amps, should not be a problem.

 

[aginzu]

How long was it at 14.3 volts? I've seen a number of graphs that show only intermittent charging. In any case, Greg said no draw in utility mode, which should mean no charging either.

It was at 14.3 volts the entire time I was running it, even when I was not pulling lots of current. That's probably because it was recharging the battery which was at about 12.6v and not fully charged when the car was turned off.

 

[yticolev]

How long was that?

 

[aginzu]

About 30 minutes.

 

[Greg Elmassian]

I'd definitely do the research to find the operating limits of the charger/inverter, it's purpose was the 12v consumers in the car, and also to support the "utility mode".

I don't remember the power limits being in the manual.

A couple of questions, you clearly connected a 12v to 110v inverter to the 12v battery, right? Did you have a way to measure the DC current?

(I forgot to check what country you were from, thus the 220v comments earlier)

Greg

 

[aginzu]

I did measure the DC current with a DC clamp meter. I can't find the Niro DC-DC converter limits anywhere but numbers I have seen indicate that Tesla's is 2.2KW, Nissan Leaf is 1.8KW, and the Chevy Bolt is 1.6KW. That's why I'm pretty confident that the 1KW I plan to use in emergencies should not be a problem for the Niro EV.

 

[Greg Elmassian]

Sounds reasonable to me, nice emergency solution. How big is the fridge (cu foot capacity total)

Greg

 

[aginzu]

This one is our second fridge in the garage and is 14 cu ft. However our main fridge in the kitchen is 21 cu ft and is also rated at the same 6.5 amps. That one is built in, however, making it difficult to get to the power plug. I'm thinking of plugging it in via an extension cord that would be accessible in case of an emergency.

 

[Greg Elmassian]

Yes, I would consider that, and perhaps both could run at the same time, but probably not, the starting surge current would probably trip the inverter.

You might be able to add a short extension cord to the normal plug wire and position that "junction" behind the vent panel.

Greg

 

[aginzu]

The inverter has a 4kw surge rating so it may be able to handle starting both fridges starting at the same time. There is no way to know until I try it.

 

[Greg Elmassian]

I was talking the "inverter" in the Kia...

 

[aginzu]

That one shouldn't be a problem because the surge current can come from the battery.