Using the Leaf for power in a Blackout: MY "Leaf to Home"

[RustyShackleford]

But getting back to the Leaf, I use a xantrex sw2000 connected to the Leaf that in turn feeds a iota dls 54-13, 13 amp 48 volt battery charger. It draws about 800w from the Leaf and supplies a bit more than the house uses to keep the main 48v bank full.

So your battery bank is 4 series-connected lead-acid or AGM car batteries ? SW2000 is connected to AC input of Iota charger, DC output of Iota is connected to battery bank, which is also connected to big split-phase inverter ?

So Iota is guaranteed not to try to pull too much juice from the SW2000 (which in turn might try to pull too much juice from the Leaf), even if the demand on the battery bank is very high ?

Why do you have a 120v->240vac step-up transformer if you have a split-phase inverter ?

[BrockWI]

So your battery bank is 4 series-connected lead-acid or AGM car batteries ? SW2000 is connected to AC input of Iota charger, DC output of Iota is connected to battery bank, which is also connected to big split-phase inverter ?

Our banks is actually eight 6 volt (400 ah) lead acid batteries wired all in series to get the 48 volts the inverter wants to see.

So Iota is guaranteed not to try to pull too much juice from the SW2000 (which in turn might try to pull too much juice from the Leaf), even if the demand on the battery bank is very high ?

Exactly, the smaller inverter on the Leaf will just pull a steady 800w and dump that amount in to the big bank, if the house is using 500 watts the extra goes in to the batteries and if the house is pulling 1000 watts it uses the 800 (750) watts from the leaf then pulls some from the lead acid battery bank to make up the change. And the surge loads for motor starting or anything else doesn't affect the Leaf in any way.

Why do you have a 120v->240vac step-up transformer if you have a split-phase inverter ?

In this system I don't since we upgraded our main inverter. In our last home I had two 2400 watt inverters but was only 4800 watts at 120 volts so all my critical loads needed to be 120 vac, that was when I had the transformer in place in front of the well pump.

[RustyShackleford]

So Iota is guaranteed not to try to pull too much juice from the SW2000 (which in turn might try to pull too much juice from the Leaf), even if the demand on the battery bank is very high ?

Exactly, the smaller inverter on the Leaf will just pull a steady 800w and dump that amount in to the big bank, if the house is using 500 watts the extra goes in to the batteries and if the house is pulling 1000 watts it uses the 800 (750) watts from the leaf then pulls some from the lead acid battery bank to make up the change. And the surge loads for motor starting or anything else doesn't affect the Leaf in any way.

I'm still worried about Leaf damage. If the house is pulling more than the 800 watts, how do you know the extra comes from the battery bank ? Why doesn't the Iota try to pull the add'l wattage from the 800watt inverter which in turn tries to pull more DC amperage from the Leaf (possibly damaging its DC-to-DC converter) ?

I guess if you can count on the 800watt inverter to not try to deliver more than 800 watts, regardless of the load put on it ...

[BrockWI]

The Iota can only pull 800 watts no matter what. That is the limiting part of this. I have run a 3000 watt inverter with over 2000w load on it connected to the Leaf. It will drain the 12v battery but the Leaf itself has a limiting conversion from the highvoltage to the 12 volt system, I believe it is 1500 watts or about 130 amps at 15 volts. So pulling anything more than what the inverter can supply comes from the Leaf's 12v battery.

[LeftieBiker]

The Iota can only pull 800 watts no matter what. That is the limiting part of this. I have run a 3000 watt inverter with over 2000w load on it connected to the Leaf. It will drain the 12v battery but the Leaf itself has a limiting conversion from the highvoltage to the 12 volt system, I believe it is 1500 watts or about 130 amps at 15 volts. So pulling anything more than what the inverter can supply comes from the Leaf's 12v battery.

I'm pretty sure from what I've read that the limit is about 1800 watts. I was going to use a 1500 watt 12 volt breaker to avoid getting that high.

[RustyShackleford]

Phil (@Ingineer) proved long time back that "The Leaf's DC-DC converter can supply up to about 1.7kW or 135a", which is enough current to easily power this configuration ...

I'm wondering about one thing. Why would Nissan have put such a beefy (presumably quite a bit more expensive) DC-to-DC converter in the car ? Great for us doing these kinds of shenanigans to get backup power. But it seems like the car only needs enough 12vdc juice to run the lights and accessories and such, and to keep the 12v battery charged. And 100+ amps seems like WAY overkill for that.

[LeftieBiker]

The system has to be able to handle all the seat heaters, plus the steering wheel heater, the blower on high, the wipers on high, the headlights on with the flashers on, all while providing enough current to also charge and warm the 12 volt battery in subzero weather. Plus a 10A accessory in the 12 volt power port.

[GetOffYourGas]

Makes you wonder how long before all of those high-power accessories are converted from 12V to 400V. It seems like it would be far more efficient to simply run them off the traction battery directly.

[RustyShackleford]

Makes you wonder how long before all of those high-power accessories are converted from 12V to 400V. It seems like it would be far more efficient to simply run them off the traction battery directly.

I think safety concerns would preclude this. Most of the things LeftieBiker listed would have some potential to expose people to the 400vdc. Right now it's pretty tightly contained down in the engine compartment.

[GetOffYourGas]

Valid point.

12V as a standard is really just used in an EV since it is well established. While there may be another voltage level with a better balance of safety and efficiency (e.g. 48V), it will likely never happen. Just as I am still typing this comment on a QWERTY keyboard, 12V is probably here to stay.