I've been using our Nissan Leaf as a home backup-power solution for awhile now. Got that huge battery sitting around, why not use it ? Per this thread (to which I contributed heavily) ... https://mynissanleaf.com/threads/us...out-my-leaf-to-home.13097/page-11#post-568213
The Leaf's DC->DC converter (from the ~400v traction battery to the 12v one) can't handle much more than 100 amps of 12vdc power, so I used a 1000 watt 12vdc->120vac inverter. (There's not enough juice there to be able to handle any of the 240vac loads, and inverters with 240vac output are $1000+ anyhow - except maybe some very questionable-looking exceptions).
But I do expect to be able to handle the fridge, the internet modem and router, and a smattering of lights (mostly LEDs of course) and some outlets for the TV and such. But there's only one problem: Sometimes the inverter shuts off from overload, and the fridge is the culprit (turned off everything else); it's not the compressor startup surge, so it must be the auto-defrost. I can't figure out how to temporarily disable the auto-defrost.
So more 120vac power would solve this problem (and maybe another problem, see below).
I note you can get a LOT of storage for your dollar from old EV batteries, such as: https://www.greentecauto.com/hybrid...issan-leaf-nmo-7-6v-64ah-500wh-battery-module . We're talking well under $100 per kilowatt-hour. They'll sell you a packaged 48v unit (2+ kwh) with BMS for $500 or so. Seems appealing. Couple that with a bigger inverter (few thousand watts) and the fridge is no problem. Maybe I could even use a step-up transformer to power the only 240vac load I really miss, which is the submersible well pump. (Next time it fails, I'll replace with a soft-start unit, which should help a lot, but absent a lightning strike, that day is probably far off).
A couple kilowatt-hours should handle most outages, but I can always top it off with a charger powered by the current Lead setup (yeah, I know, high-voltage DC -> 12vdc - >120vac -> 48+vdc -> 120vac is not exactly efficient, but I can't think of a better way, unless there's a charger that incorporates a DC->DC converter so it can charge a 48v battery from the Leaf's 12v).
So I'm curious of folks' thoughts.
One thing concerns me though, and that is the fire hazard. I think lithium-iron-phosphate batteries are relatively safe, but that ain't batteries from an old Leaf. So how much should I worry about having a bunch of these in my basement or mechanical room ? How to mitigate ? Put 'em outside somehow, but obviously the cable to the inverter needs to be heavy, although that situation is a lot easier if the system operates at 48vdc.
The Leaf's DC->DC converter (from the ~400v traction battery to the 12v one) can't handle much more than 100 amps of 12vdc power, so I used a 1000 watt 12vdc->120vac inverter. (There's not enough juice there to be able to handle any of the 240vac loads, and inverters with 240vac output are $1000+ anyhow - except maybe some very questionable-looking exceptions).
But I do expect to be able to handle the fridge, the internet modem and router, and a smattering of lights (mostly LEDs of course) and some outlets for the TV and such. But there's only one problem: Sometimes the inverter shuts off from overload, and the fridge is the culprit (turned off everything else); it's not the compressor startup surge, so it must be the auto-defrost. I can't figure out how to temporarily disable the auto-defrost.
So more 120vac power would solve this problem (and maybe another problem, see below).
I note you can get a LOT of storage for your dollar from old EV batteries, such as: https://www.greentecauto.com/hybrid...issan-leaf-nmo-7-6v-64ah-500wh-battery-module . We're talking well under $100 per kilowatt-hour. They'll sell you a packaged 48v unit (2+ kwh) with BMS for $500 or so. Seems appealing. Couple that with a bigger inverter (few thousand watts) and the fridge is no problem. Maybe I could even use a step-up transformer to power the only 240vac load I really miss, which is the submersible well pump. (Next time it fails, I'll replace with a soft-start unit, which should help a lot, but absent a lightning strike, that day is probably far off).
A couple kilowatt-hours should handle most outages, but I can always top it off with a charger powered by the current Lead setup (yeah, I know, high-voltage DC -> 12vdc - >120vac -> 48+vdc -> 120vac is not exactly efficient, but I can't think of a better way, unless there's a charger that incorporates a DC->DC converter so it can charge a 48v battery from the Leaf's 12v).
So I'm curious of folks' thoughts.
One thing concerns me though, and that is the fire hazard. I think lithium-iron-phosphate batteries are relatively safe, but that ain't batteries from an old Leaf. So how much should I worry about having a bunch of these in my basement or mechanical room ? How to mitigate ? Put 'em outside somehow, but obviously the cable to the inverter needs to be heavy, although that situation is a lot easier if the system operates at 48vdc.
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