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

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48V will soon be the new standard, as it is used in just about all mild hybrid systems. Not quite enough voltage to be a high level hazard, but enough to propel a car from a stop.
 
Seems there was some noise about this a few years back, changing the standard to either 36V or 48V. Haven't seen anything about it in a while though.
 
Nubo said:
Seems there was some noise about this a few years back, changing the standard to either 36V or 48V. Haven't seen anything about it in a while though.

Mild hybrids with 48 volt systems have been quietly multiplying. Everything from upscale pickup trucks to Mercedes cars are using them.
 
A mild hybrid uses a 48 volt starting motor (often also capable of generating power and acting as the alternator as well) to do two things: instantly restart the engine after it shuts off whenever the vehicle is stopped, and also to add power (especially torque) to the drivetrain when accelerating. The cheapest systems just do auto stop/start, while the more expensive ones add power when driving as well. The full-function systems make the car or truck feel more responsive without the engine having to put out any more power.
 
Trying to duplicate the OP (a little late for Dorian, oh well) ...

He gives pretty detailed info about the parts he uses, but not the 150 amp breaker. Anyone got a good pointer for one of those ? And why not a 125-amp breaker ? That's more than enough juice for the 1000watt inverter he uses, and 150 amps could overload the Leaf's DC-to-DC converter (theoretically the 1000watt inverter couldn't pull that much juice, but if you totally trust your car's welfare to theory, why have a breaker at all ?)
 
OP has the cryptic comment " I could throw in an LED lighting load by tripping the main for the panel, and back feeding one side, and It wouldn't make THAT big a difference. For giggles, I plugged 2 of them into the cord as well."

I get that he made a suicide cord (120vac cable with male plug at both ends) , plugged one end into the inverter, and another into a wall outlet. Thereby connecting the inverter output to the loads on one "side" of his split-phase main load center. I guess you'd figure out which side your fridge is on, and then hope the couple of other low-load circuits that have useful lighting loads and stuff like your modem, are on the same side; maybe switch some loads around to different breakers if need be. But, WHAT does he mean by the "for giggles ..." sentence ?

And yes, this has the critical requirement that you turn off the main breaker, to avoid backfeeding the grid. Also want to make sure you turn off breakers for any big loads on the side of the panel you're backfeeding. Maybe have a checklist, and strict instructions not to even attempt it unless you know what you're doing.
 
RustyShackleford said:
Trying to duplicate the OP (a little late for Dorian, oh well) ...

He gives pretty detailed info about the parts he uses, but not the 150 amp breaker. Anyone got a good pointer for one of those ? And why not a 125-amp breaker ? That's more than enough juice for the 1000watt inverter he uses, and 150 amps could overload the Leaf's DC-to-DC converter (theoretically the 1000watt inverter couldn't pull that much juice, but if you totally trust your car's welfare to theory, why have a breaker at all ?)

Iirc, some inverters can support transient loads above their normal rating. Same with the DC power -- for a transient load above the DC-DC capacity, the 12V battery would take up the slack. The breaker is there to protect the wiring and safeguard against short-circuits. The inverter should also have a low-voltage threshold so too high of a load would cause voltage sag and it would turn off. And also, if the voltage does sag a bit but stays within the inverter's limits, the amperage draw for a given load increases.

Amazon seems to carry a variety of high-amp 12V breakers.
 
Just as an FYI this https://www.amazon.com/12V-24V-Inline-Circuit-Breaker-Protection/dp/B07SH8RHXC/ref=sr_1_1?keywords=Tingtor&qid=1567472100&s=gateway&sr=8-1&th=1 line of "breakers" will trip well below their rated limit. I had a 150 A unit that was tripping under a 75 amp continuous load.

I have given up on "breakers" and gone to inline fuses

https://www.amazon.com/gp/product/B01N2YEVCH/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
 
BrockWI said:
I have given up on "breakers" and gone to inline fuses

https://www.amazon.com/gp/product/B01N2YEVCH/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I saw those kinds of connectors on some of the breakers at Amazon too. Looks like you just stick the end of the wire in and tighten a set screw ? How does it adjust for different size cabling (I'l probably want to use 2awg like the OP) ?
 
They will list the maximum size wire they can clamp down on and mine came with 2 sizes of smaller sleeves that fit in to take smaller wire. You can also get them that have bolt on for lead with eyelets on them.
 
BrockWI said:
They will list the maximum size wire they can clamp down on and mine came with 2 sizes of smaller sleeves that fit in to take smaller wire. You can also get them that have bolt on for lead with eyelets on them.
Yeah this seems better - whether I use the breaker or fuse version - skips a connection step.
 
GetOffYourGas said:
Makes you wonder how long before all of those high-power accessories are converted from 12V to 400V.
Apart from the extreme safety issue, there is the problem of switching off 400 VDC. A cheap rocker switch isn't going to do it; the contacts will arc and the current will keep flowing. DC rated contactors need magnetic blowouts and/or near-vacuum to switch even moderate power levels. Traction batteries will probably drift towards 1000 V for ultra-fast charging, making the safety and switching problems even more extreme.

This is even a problem with 48 VDC, even 24 VDC to an extent, but it's much easier to manage. I suspect that mild hybrid cars will have the blower, headlights and a few other high powered loads on 48 VDC, but the cigarette lighter, interior lights, dash etc may still run off 12 VDC via a DC-DC converter. Anyone know for sure?
 
I suspect that mild hybrid cars will have the blower, headlights and a few other high powered loads on 48 VDC, but the cigarette lighter, interior lights, dash etc may still run off 12 VDC via a DC-DC converter. Anyone know for sure?


Not I, but I agree with your guess. It makes more electrical and financial sense to keep using 12 volt accessories where there is no big advantage to 48 volts, and DC-DC converters are cheap and plentiful. Now they just need to make them more robust and reliable. ;-)
 
I've purchased the Xantrex PROWatt 1000 inverter used by the OP. I've a bit confused about connections, as there is a chassis ground terminal on the inverter, as well as the battery cable connections '+'and '-'. I understand the '+' terminal should be connected to the Leaf battery's '+' terminal (via a fuse or breaker) and that the '-' terminal should be connected to a threaded hole on the car's engine nearby (the DC-to-DC converter ?) and NEVER to the '-' terminal on the Leaf's battery. But what should that chassis ground terminal on the inverter be connected to ? Also to the car ? Need I drive a grounding rod near where I intend to park the car when using it for 120vac backup ?
 
I had a similar issue with the chassis ground with my inverter. In my case I'm going to disconnect it because the inverter is grounded through the house wiring when plugged in, and having two separate grounds was tripping the inverter's GFCI outlet. You, however, need to ground the inverter. You can use a grounding rod, or a ground wire connected to the house ground circuit or to metal plumbing nearby. Don't try to use the Leaf, as it's isolated from ground.
 
LeftieBiker said:
I had a similar issue with the chassis ground with my inverter. In my case I'm going to disconnect it because the inverter is grounded through the house wiring when plugged in, and having two separate grounds was tripping the inverter's GFCI outlet. You, however, need to ground the inverter. You can use a grounding rod, or a ground wire connected to the house ground circuit or to metal plumbing nearby. Don't try to use the Leaf, as it's isolated from ground.
Actually, I'm now thinking I'll try to back-feed some house wiring; if the GCFI outlet's ground is tied to that ground lug next to the battery connections, sounds like I can just leave the latter disconnected.

Plan for back-feeding house is just to plug a double-male cord from the inverter to a single-pole (120vac) house circuit (as I described a few posts back). Obviously need to be careful; I'm imagining a checklist that goes something like this:

1. Switch off the main breakers (in the load center).
2. Switch off all branch-circuit breakers in the load center, except for the critical loads. I guess theoretically the ones on the other "side" could be left on, but why create confusion and risk).
3. Connect a double-male 14awg (or better) cord between the inverter and an unused outlet on one of the critical circuits.
4. Making sure inverter is switched off, plug the inverter 12vdc cord into the wifty rig described in the OP.
5. Put Leaf into "READY" mode.
6. Switch on inverter.

Critical loads could include fridge*, living room lights and ceiling fan, modem, outlets for phone and laptop charger. Oughta last over two days with 40kwh battery. Fridge is pretty modern and I measured 100+ watts running, but difficult to measure compressor startup surge, and I'm not sure how much the un-defeatable auto-defrost uses. Darn range won't let propane flow without electricity; it's got a neutral, so probably has 120vac components and the gas shutoff is probably one of them, so I could leave the double-pole breaker on and hope the energized hot supplies the 120vac components (or switch the hots if it doesn't); sounds good in theory, a bit spooky in practice ...
 
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