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

Posted: Mon Jul 01, 2019 4:55 pm
by RustyShackleford
LeftieBiker wrote:You can limit the current flowing from the Leaf with a 15 amp DC circuit breaker. That protects the charging system. You should be able to charge the marine battery directly from the Leaf's battery, as that is how virtually all of the improvised Leaf Power systems work.
Do you have a pointer to details of such a system, that can handle big surges like a well pump ?

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

Posted: Mon Jul 01, 2019 5:16 pm
by GerryAZ
Here are my suggestions (assuming you have a suitable inverter which has 12-volt input and is capable of running the well pump): Use fuses or 2-pole circuit breaker rated about 50 amperes connected to positive and negative battery terminals of the LEAF and something like No. 8 AWG wire to connect that overcurrent protection to the large battery and inverter. A few feet of No. 8 wire will offer enough resistance to help limit current flow toward the large battery and connecting directly to the positive and negative terminals of the Leaf battery will cause the DC-DC converter to charge at about 14 volts instead of the normal float level of about 13 volts. Use suitable overcurrent protection (fuses or breaker to connect inverter for 120-volt lighting/receptacle power to the Leaf battery (or connect to large battery by well pump if that is more convenient). Keep Leaf in Ready mode while using power.

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

Posted: Mon Jul 01, 2019 6:10 pm
by LeftieBiker
RustyShackleford wrote:
LeftieBiker wrote:You can limit the current flowing from the Leaf with a 15 amp DC circuit breaker. That protects the charging system. You should be able to charge the marine battery directly from the Leaf's battery, as that is how virtually all of the improvised Leaf Power systems work.
Do you have a pointer to details of such a system, that can handle big surges like a well pump ?
I'll find a topic.

viewtopic.php?f=37&t=9578&start=30

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

Posted: Mon Jul 01, 2019 6:26 pm
by RustyShackleford
Thanks, that'll keep me off the streets for awhile :-)

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

Posted: Mon Jul 01, 2019 9:12 pm
by RustyShackleford
GerryAZ wrote:Here are my suggestions (assuming you have a suitable inverter which has 12-volt input and is capable of running the well pump)
The Spartan inverter/charger I linked above might do (with the charger turned off). It actually has an automatic transfer switch, so it could be used to connect the essential-loads subpanel, and literally the only other thing needed would be the big battery to handle surge.

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

Posted: Mon Jul 01, 2019 9:26 pm
by GerryAZ
RustyShackleford wrote:
GerryAZ wrote:Here are my suggestions (assuming you have a suitable inverter which has 12-volt input and is capable of running the well pump)
The Spartan inverter/charger I linked above might do (with the charger turned off). It actually has an automatic transfer switch, so it could be used to connect the essential-loads subpanel, and literally the only other thing needed would be the big battery to handle surge.
I just looked at the 4 kW split phase, sine wave inverter/charger with transfer switch. It looks ideal for your needs. I will bookmark that site for future reference.

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

Posted: Mon Jul 01, 2019 9:52 pm
by LeftieBiker
That does look like a good inverter/charger. I use a similar but smaller setup to keep our sump pump running in power outages. I find that the ones I use (not the same brand) tend to short their battery chargers out after a couple of years, maybe from dust in the cellar. I'm currently running one with charging turned off, and a Battery Tender Jr on the marine battery I use. I know that AGM batteries are better, but we get about 5 years from the marine batteries and an AGM would also be getting old at that point.

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

Posted: Mon Jul 01, 2019 9:57 pm
by RustyShackleford
GerryAZ wrote:I just looked at the 4 kW split phase, sine wave inverter/charger with transfer switch. It looks ideal for your needs. I will bookmark that site for future reference.
I was thinking of this one: https://invertersrus.com/product/sp-ic3312/ just 3300 watts and under a $grand. Seems like you'd have to disable the charger (switch setting) though, or it'd be fighting with the DC-to-DC on the Leaf. And it can also handle disconnecting the essential-load subpanel from the main panel, automatically.

But I'm not crazy about your idea (if I understand correctly) of just using wire to limit the current from the Leaf's 12v system to the external battery.

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

Posted: Mon Jul 01, 2019 10:00 pm
by LeftieBiker
I was thinking of this one: https://invertersrus.com/product/sp-ic3312/ just 3300 watts and under a $grand.
That was the one I meant. 9kw surge, too.

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

Posted: Mon Jul 01, 2019 10:17 pm
by RustyShackleford
LeftieBiker wrote:
I was thinking of this one: https://invertersrus.com/product/sp-ic3312/ just 3300 watts and under a $grand.
That was the one I meant. 9kw surge, too.
Didn't see the 9kw surge, yep, that'll probably handle the well pump and fridge compressor coming on at the same instant.

I think this issue of maybe the inverter can suck too much power out of the Leaf and possibly damage the DC-to-DC, needs more thought. Yeah, a certain resistance of wire can guarantee the current is limited; seems like there might be a better way though. My original idea of not connecting the surge battery to the Leaf at all, and rather connecting the AC-input of the big inverter to the Leaf via a small inverter, would more or less guarantee the current limitation. But then it requires a separate transfer switch on the essential subpanel. Seems awkward as hell.