Kona as a backup battery for home power outage?

Discussion in 'Hyundai Kona Electric' started by Jgood, Nov 5, 2019.

  1. Hmmm, I have one of those at our cabin with our solar system, a cheapie from Canadian Tire, but it does the job. Since we don't use it there in the winter, mayber I should bring it home and use it with my Kona if/when we get a power outage, which sometimes does happen here in late fall or winter.
  2. Ah, I get you now. I would definitely go with a quality 48v inverter, even if its single phase you could add something like the Outback power PSX-240 auto transformer and split your single phase into dual phase. I personally have outback 48 volt 3600 watt outback inverter. It provides a very reliable clean sine wave single phase phase 25 amp service from my 20 kWh( 10 kWh usable)lead acid battery bank - sixteen 220 ah 6v golf cart batteries series wired into 2 paralleled groups. The lead acid batteries are still the most economical power storage option at least 1/5 the cost of Tesla powerwalls. I have been running my setup for the past seven years, I am seriously thinking of upgrading to an outback 8000 watt radian series inverter at some point. Its basically the electronics of two inverters and transformer combined in one box. It can provide a 30 amp split phase 240 V service. Which can pretty much run anything in the house including central AC. My best advice with inverters is skip the cheap Chinese inverters. You will pay more upfront but eventually you will need to fixed failed electronics, the better inverters have field replaceable boards that are easily sourced. The Chinese inverter will be a throw away item.
  3. bwilson4web

    bwilson4web Well-Known Member Subscriber

    Just offering what we did in November 2005 with our first Prius:

    In April 2011 tornadoes wiped out the high power transmission lines in North Alabama. We had a 4 day, 6 hour power outage. Our Prius powered the house for lights, TV, and gas heater fan. Cooking and hot water came from the propane BBQ grill. We burned ~2 gal/day to campout in our house.

    It is very important to load test the system on a nice day in case something goes wrong. Use a resistance heater or high power, adjustable light(s) for load testing. When the 12V sags to 13V, that is the constant power limit.

    You will still have to deal with inrush and motor startup loads. This can best be handled by oversizing the inverter by 50% over the constant power limit. My experience is the 'surge' rating is useless. Your 12V battery can handle most surges.

    Bob Wilson
    milesian likes this.
  4. Thanks for the input. I will definitely take a look at the outback inverter. I currently have a Fronious 6000 watt grid-tie which works great for what it was designed for. I would replace it with a hybrid if they had a 48 volt version but they don't. I am also considering the Schneider Context Sw 4048 its a 4000 watt pure sine wave and split phase.

    Right now I am still researching all my options.


  5. Thanks for the link it is very detailed and helpful.
  6. FlbrkMike

    FlbrkMike Member

    I considered the tankless option but have chosen to go with the hybrid heat pump unit (not actually purchased or installed yet) because it's quite a bit more efficient. The tankless water heater is probably 93% to 95% efficient, whereas the heat pump is about three times as efficient as any electric resistance unit, due to the fact that it operates on a vapor compression cycle (like an air conditioner). Some heat will be lost from the storage tank, but not all that much.

    Besides that, it will actually blow cool air into my hot garage during the summer, whenever it's operating. Probably not enough to make a difference, but it's a nice thought.

    I will need to re-route a 240V circuit from my utility room about 15 feet out into the garage to make this possible. We don't need 240V in the utility room anymore because we recently replaced our electric clothes dryer with highly efficient heat pump unit, which only requires 120V (and no vent).
    Last edited: Nov 6, 2019
    ehatch likes this.
  7. I was due for a 12 V top up today (battery @12.10 volts) so I decided to try my inverter at the same time.
    It is this model here RDC 97100
    Note that the same model #RD 97100 (without the "c" for Canada) is listed at 100 W in the US
    I will use it for back up heat at my home (108 W starting and 72 W running fireplace insert wood burning for the fan motor)
    Last year 30+ hours of no power after a windstorm , the house was cool as the fireplace insert running without the motor running had a hard time keeping up, normally with the motor running I have to open windows as it gets too hot.
    So I ran it today for 3 hours no problem (through the 12 V accessory outlet in the cabin). The battery was constantly charging @ 14.8 V (in run mode)
    and the resting voltage now sits at 12.56 V.
    Not much I know but its a start, but during the next power outage I will just have to let the beer get warm as not strong enough for the fridge.:)
    ehatch and Francois like this.
  8. FlbrkMike

    FlbrkMike Member

    It seems like the stationary (home or commercial) battery market would be a good place to send the used cells from EV batteries once they ready for recycling, for the same reason mentioned above, that the stationary application doesn't require the high charge density that a EV does. Probably less energy and material intensive than trying to recycle the materials into new cells.

    I've been told that Tesla probably already puts cells that may not have passed the strict QA required for their EV batteries into their PowerWall units.

    My Sonnen Eco storage battery uses lithium iron phosphate cells instead of Li-ion. Supposedly more stable and less likely to spontaneously combust.
    eastpole likes this.

  9. Looks like from the video and the pictures they are using the chademo port on the Car which makes sense for a Mitsubishi. Which might leave all the CCS connectors out of luck. I would be curious as to what is included or the $10,000 price tag. Is it just the bidirectional charger or dose it include the wall battery as well.

    Will be interesting to see how it progress.
  10. milesian

    milesian New Member

    Great thought-provoking thread here, guys, thanks. It got me wondering if an "easy" backup solution might already exist for novices like myself who struggle to understand everything in this thread. For instance, maybe I can install a transfer switch that backs up a handful of circuits in my panel, then plug a so-called "power station" into it, like the Goal Zero Yeti unit. It supports concurrent charging while it discharges, and there's even a car charging kit that can hook right into the Kona's 12V battery that can presumably be supported by utility mode. See below links:




    Surely there are many obstacles that I'm unaware of, but one issue is that the typical power station maxes out at just 3000W surge, meaning it probably can't run my central AC/heat or anything like that. Do you guys know of any power stations with higher surge/sustain ratings that might make an "easy" backup solution a reality?

    Sent from my ONEPLUS A5000 using Tapatalk
  11. hobbit

    hobbit Active Member

    For completeness, here's another Goal Zero link. Nice product line,
    but has a few issues on integration. It is possible to charge at 350 watts
    via the mini-Anderson connection, as long as the source is north of 13.5
    volts or so. The Kona with its ridiculously high 12V rail has no problem
    with that...

    It's too bad that 95% of the "solutions" use the 12V, which has already
    been converted once, and convert that back up to 120V. An inverter
    with suitable high-voltage input range could run from the big battery,
    like the Prius "plug-out" solution [google it]. About the only way to
    conveniently access that, though, would be something crazy like wiring
    a spare CCS plug for output and convincing the HV junction box to
    turn the fast-charge relays on. Klunk, fzzzzzzz.

    milesian and Fastnf like this.

  12. Simple answer is yes the Goal zero will work with the items you show.

    You could install the transfer switch with a Interlock on the main breaker. Or have it installed by an electrician. You could charge it from of the Kona in utility mode. Note though that Kona will not keep up with the power usage at max on the Goal Zero. The input charge rate is 150 watts as limited by the Goal zero charger. The output is of the goal zero is 1500 watts or 10 times the input from the Kona so its not going to keep up. The key thing to remember is that your max continuous output is 1500 watts, or at 120 volts you have 12 amps available. It will run a small refrigerator and maybe your gas furnace and a few led lights. Its enough for night time (sleeping) house hold use but 12 amps is not a lot for a house when you consider typically you have 200 amp service from the grid. Great for an emergency.

    A simpler approach would be to have a transfer box installed and connect it to a 1000 watt inverter connected directly to the Kona battery. This would be more efficient than running the power trough Goal zero battery and charger.
    Last edited: Nov 11, 2019
    eastpole and milesian like this.
  13. eastpole

    eastpole Member

    Milesian, can you tell us more? Are you heating with electrical resistance? Running a heat pump? Or just sparking up a gas boiler and circulating some hot water? Different heating systems have vastly different electrical draws...

  14. Paul DeLeon

    Paul DeLeon Member

    My question is: how much power (current) can you draw from the battery?
    That is, at what rate will the Kona replace the battery charge?
    Without doing any damage to the Kona's electrics, of course.
  15. eastpole

    eastpole Member

    From earlier:
  16. Based on the test shown in the links previously posted test show about 1300watts. Watts equals volts times amps so dividing 1300 watts by 12 volts DC we get an output of around 108 amps being drawn from the DC to DC converter on the Kona. This is about the equivalent of a 100 amp alternator on an ICE or hybrid car. Bear in mind that run through an inverter that same 1300 watts gets divided by 120 volt AC and only gives about 10.amps
  17. 10 amps (at 120V) should be enough to power a freezer on and off as needed during a power outage. Also fire up the furnace in between. So it should be as good or better than using a small stinky, noisy generator that most people use for these situations.
    eastpole likes this.
  18. XtsKonaTrooper

    XtsKonaTrooper Active Member

    If i had an inverter, id id slap it on there and try but i would go directly off the 12v battery.
    Either gonna work or not.
    The EV system is gonna see 12v discharge and start charging the 12v battey.

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