Using I Miev for backup power unit

[vh2q]

Absent a 60hz "Powerbox" (and I am told by the mfg that the US cars lack the software in any case), how much power (in Watts) can you draw from the 12V battery using an inverter, under 2 scenarios
1. Short bursts (limited by the wiring/fusing I suppose)
2. Long term average (limited by the dc to dc converter I suppose)

I understand the car has to be turned on to ACC in order to avoid flattening the 12V battery. I read someplace the dc to dc converter is rated 80A at 14V which is around 1000W. But the manual also shows fusible links that may not support the full 80A.

 

[PV1]

Yeah. I wish Mitsubishi would sell the Powerbox in the US.

If the car has 80 amp fuses, I would limit current to 70 amps or less. The car must be showing READY on the dash for the converter to be active.

To be safe, I wouldn't use any more than 800 watts.

 

[bennelson]

I think an Open Source Vehicle to Grid project is something just waiting to be tackled.

Especially if it was designed so it could be used by iMiEVs, LEAFs, and all the most popular electric cars.

Not that I'm an electronics guy, but it seems like it would have to be through the quick-charge port, as that goes straight to the battery (instead of through the charger.) After that, the communications pins would need to be spoofed, but some folks have been working on DIY Chademo lately, so I think that's worked out too.

After that, there needed to be some high-power DC to DC conversion and the inversion to 60 hz AC power.

None of that actually sounds terrible complicated, but I'm not sure what the costs would be either.

 

[vh2q]

Mitsubishi says they are working on a US version of the powerbox, or at least trying to figure out whether there is any demand for it. Meanwhile I am going to try to draw up to 1000W through the 12V circuit (hook up to the 12V battery) and see how well that works.

 

[Don]

The problem with the 'Powerbox' is . . . . Mitsu would want upwards of $2500 for it

Second problem would be . . . . if you're thinking of charging at night (when juice is cheap or even free some places) and then selling it back to the power company during the day would be that your iMiEV battery has maybe a couple thousand cycles in it and then you'd need a new battery pack. If you get your night time juice for FREE and you were somehow able to sell them 14Kw @ ten cents ($1.40 each 'cycle') and you did manage to get 2,000 cycles before your battery was shot, you'd have $2,800 for your effort - About the cost of the 'Powerbox' . . . . but far, far less than the cost of a new battery pack

I think the reason there's so little demand for the Powerbox is that it's only practical to use a few times per year in an emergency and it's do cheap (relatively speaking) to just buy a 5 Kw gas generator to keep your freezer frozen during a storm when the power goes out

Don

 

[vh2q]

Using this in Bahamas for backup only... the power goes out a lot and I need to keep fridge, TV, water pump and some lights (all on a separate emergency panel) on for up to five days ... and you can't sell power back to the grid in that country so no point in gearing up for that. At some point I would like to be able to charge my car from solar panels and run my emergency panel from the vehicle all the time, as electricity is v. expensive circa 50c per kwh. Then I would only need the grid for A/C in the summer as I already use solar for hot water. But I am waiting for solar panels to get cheaper and more efficient. Seems like they are around 20% efficient and cost around $2 per watt at the moment. 25% and $1 would be a more attractive formula. You need at least 1000W peak to charge the car and then you can get around 4 hours of charging time every day. So $1000 worth of panels plus the associated boxes (another $1000) and wiring. Powerbox doesn't seem that expensive in comparison.

 

[Don]

Maybe it's expensive to ship panels to the Bahamas? I bought a pair of 160 watt panels on eBay last month for my boat and the cost was less than $300, and that included shipping

A Honda EU2000i would do what you need when the power goes out - Especially if it's going to be out for several days. While it would be capable of doing what you envision, cycling your car battery in this manner would be very expensive in the long run - Much more than the cost of a small genset

Don

 

[jray3]

Some updated info on the Mitsu PowerBox today on the Seattle EV list. At current exchange rates, it sells for $1400 along with the car, but Mitsu won't sell them as standalone units. The instructions say that a software update may be required of the car for proper function. Nevertheless, here's a site listing 'em for sale.

When one considers that a 3D printed copycat CHAdeMO cable and handle runs $900, http://www.emotorwerks.com/index.php/store-juicebox-ev-charging-stations/dc-charging-systems/111-new-chademo-tm-compatible-cable-plug-for-emotorwerks-dc-chargers/category_pathway-17
the PowerBox would seem a bargain, even though it only offers 1500 Watts.

What'll it take to convince somebody to produce a vehicle-to-home PowerBox for the US market? If CHAdeMO protocol has varied enough to prevent plug-n-play solutions, then it may be too much to ask a third party.

 

[JKO]

Everybody talks about to charge with high power.
I want to charge with very low power directly from my sun panels.
So can I connect this Cable to my dc-dc converter (35v > 350V) an charge my car by using CHAdeMo port?
http://www.emotorwerks.com/index.php/store-juicebox-ev-charging-stations/dc-charging-systems/111-new-chademo-tm-compatible-cable-plug-for-emotorwerks-dc-chargers/category_pathway-17

 

[pbui19]

vh2q,

your biggest advantage in the Bahamas is the abundance of solar insolation, you ought to be able to get way more than 4 hrs per day. You can get an idea of sun hours here by entering your coordinates, though am not 100% sure it'll work for the Bahamas:

http://www.sunearthtools.com/dp/tools/pos_sun.php?lang=en

so you don't really need a large array. A forum member here, Aerowatt, has a really nice set up using an external 12-v battery bank. The idea is to "trickle charge" the external 12-v bank, using the iMiev 12-v source and the PV. The external bank acts as a buffer for the high demand while constant getting small feed, sort of like the water tower in the old days. Obviously you can also charge the iMiev via a 12vdc->120vac converter using the level 1 charger. You can size the external bank accordingly for peak load while tapping the iMiev 15kwh pack capacity slowly.

Given there is about 1kw/m^2 at 0 latitude, the Bahamas at 25 lat, gets cos(25) ~> 0.9 kw/m^2, loads of power ! but you have to mitigate hurricane wind force...

sorry, i get carried away, sounds like a fun project.

 

[vh2q]

I figure as long as I stay below the current limit on the on-board DC converter (I believe it's 80A), I can tap the car's 12V battery to power emergency circuits in the house. This yields about 1000W I think. Small surges should be possible as the battery will support several hundred amp load for short periods of time.

Adding a solar array and some additional batteries in parallel with the car's battery will make this whole thing more robust and uprate the average load to maybe 2000W and the surge as well.

The "hump" to get over is the water pressure pump that pulls water from the cistern. That's a bit of a hog at 3/4hp but it only runs for about 20 seconds at a time. The problem is the inrush current.

 

[jray3]

If using the i-MiEV as backup power through a 12V inverter, I'd consider attaching the inverter to a much larger 12V battery for a buffer and jumper the i-MiEV to it, which further reduces the stress on the system. BUT, there's not much concern, as I've used the i-MiEV to charge a big dual-battery diesel that tends to go below 10V after extended storage. After over an hour of boost-charging, the only overheated component is the jumper cables!

 

[Aerowhatt]

I figure as long as I stay below the current limit on the on-board DC converter (I believe it's 80A), I can tap the car's 12V battery to power emergency circuits in the house. This yields about 1000W I think. Small surges should be possible as the battery will support several hundred amp load for short periods of time.

Adding a solar array and some additional batteries in parallel with the car's battery will make this whole thing more robust and uprate the average load to maybe 2000W and the surge as well.

The "hump" to get over is the water pressure pump that pulls water from the cistern. That's a bit of a hog at 3/4hp but it only runs for about 20 seconds at a time. The problem is the inrush current.

The fuseable link to the cable going back to the DC to DC converter is right at the battery terminal. If memory serves it was a 60 amp and looked to be a slow blow variety but did not say that. To keep from adding problems during an outage stick with a 60 amp or less maximum draw from the car 12 volt system. Like others have suggested having an external battery bank that the car is connected to solves a number of issues. For high surge currents you need to have a properly sized inverter and often (with a smallish battery bank) a capacitor bank set up between the battery and inverter. The biggest issue with high start surge items is usually the supply battery voltage being pulled low enough, long enough to trip the low battery shut down on the inverter. A capacitor bank can prop the voltage up long enough to prevent this without adding a bunch more battery capacity.

Aerowhatt

 

[vh2q]

My inverter will support 3000W continuous, 9000W for 20 seconds. It is also a solar controller so I could do the solar trickle thing (which would also recharge the IMieV 12v battery if the ignition was off) but realistically that only makes sense if you are using solar power all the time. Using the grid to charge up after an outage is the easier solution, but that does limit the duration of the backup supply to 16 hours at 1000 Watts, so about 4 days if you are very careful and only use the power for a few hours a night.

I am thinking that the 12V battery voltage should not dip too much with the main battery "backing it up", ie with the ignition on. I just don't know how hard you can push it and for how long before the fuse blows. And I am pretty sure the fuse is 80A.

 

[Aerowhatt]

I am thinking that the 12V battery voltage should not dip too much with the main battery "backing it up", ie with the ignition on. I just don't know how hard you can push it and for how long before the fuse blows. And I am pretty sure the fuse is 80A.

Yes according to the Schematics it's an 80 amp fuse, thanks for the correction.

The surge loads you mentioned are going to require some serious battery capacity to hold through without tripping the low voltage threshold on the inverter(s). I'm thinking about 500Ah, "trickle" charged by the iMiev through a 50 or 60 amp resettable DC circuit breaker. I've seen way to many backup systems that are pushed to close to upper limits and then when needed most, something fails. Leaving no power at all until repairs are made and expensive components replaced. Not much of a backup system if it fails when you need it most!!

For longer outages you simply must have some solar input to the batteries as well. Generators just bring your neighbors to your front door . . . extension cords in hand :roll:

Aerowhatt

 

[vh2q]

Well we are going to find out what this big battery/little battery setup can do. I may put a second lead acid battery in parallel with the car's 12v battery to provide for some surge demand but in the final analysis the average draw has to be under 80A at 12V otherwise the dc to dc transformer won't be able to keep up.

At some point I will install a solar array (when the size shrinks to the size of a double door). But you can't charge the car direct from the solar array, at least I don't think so. You need a humungous battery bank (at least 16 batteries) to store all that power before dumping it into the vehicle. And if you have that battery bank you don't need the car battery for power backup.

The inverter low voltage threshold/alarm is around 10V if memory serves. I think it's programmable as well.

 

[pbui19]

Well we are going to find out what this big battery/little battery setup can do. I may put a second lead acid battery in parallel with the car's 12v battery to provide for some surge demand but in the final analysis the average draw has to be under 80A at 12V otherwise the dc to dc transformer won't be able to keep up.

At some point I will install a solar array (when the size shrinks to the size of a double door). But you can't charge the car direct from the solar array, at least I don't think so. You need a humungous battery bank (at least 16 batteries) to store all that power before dumping it into the vehicle. And if you have that battery bank you don't need the car battery for power backup.

The inverter low voltage threshold/alarm is around 10V if memory serves. I think it's programmable as well.

hi vh2q - any update ? did it work out with big/little battery in parallel ? winter is approaching and we've already a few power outages.
Thanks

 

[bradleydavidgood777]

(2012) Mitsubishi Motors introducing MiEV Power BOX 1500 Watt Power Feeder for its EVs
http://www.greencarcongress.com/2012/03/mits-20120309.html

Lots of news in 2012 about this thing. $1800.

 

[vh2q]

I have it all rigged up and tested (with lights only ... and for some reason they come on and off, something to do with a load sensing feature on the inverter and the fact that most of our lights are LED) .. I have not tested it under load and have not really had a reason to. My one concern is the water pressure pump is 3/4HP and I think that's too much on startup for the dc to dc and lead acid battery in the car to handle. The inverter is quite robust, from memory 3kw surge 9kw