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Nissan Leaf charging 7s powerwall - ideas
#1
Question 
So my powerwall is basically finished(mostly), its a 7s120p with about 4kWh, with this setup
powerwall -> 200A China BMS -> PIP Solar 3024 -> 1,2KW Solar(with extreme high shading atm)
Its completely offgrid, with a small generator as "last resort" backup, which I normally dont use

As I got a Nissan Leaf(2018) with 40kWh battery now I'm thinking of using it to recharge the powerwall in times of high powerusage(LANparty sometimes, etc ;-).

Because of the warranty I dont really want to tinker with the 400VDC system auf the actual battery but instead use the 12V Lead acid(yes, really) car battery, which is recharged(when car is ON) by the big battery. The DCDC converter auf the car can supply up to 1500W, but I'm planning to use no more than around 800W max, just to keep things safe.

My first impulse was to install an inverter in the car, so I can use it for camping stuff too, and because an outlet in a car is just really cool :-)
I ordered a Victron phoenix 800 which would be a really nice fit for my needs, but this thing is just too big for a permanent install without sacrificing too much space in the car, or modding it a LOT.
Also the PIP is not the hybrid version, so if I supply AC I have to supply about 600 - 1200W for computers PLUS use the "rest" for charging the wall.

So now my idea is to hook up an XT connector or similar(100A max) to the 12V battery and charge the powerwall in addition to whatever the PIP is supplying.
Also I should see a bit less conversion losses...
before: 400VDC -> 12VDC -> 220VAC ->24VDC
after: 400VDC -> 12VDC -> 24VDC
cable length(car to wall) is about 8 - 10m
What i need is a charger that can charge with about 500 - 800W max., with adjustable voltage and amperage
I got an old 3024 LSB PWM 30A solar charger from my lead acid "era", but as far as I understand PWM needs higher voltage on the input(solar) side.
Looking around the web for alternatives(needs to be cheap as its not used very often), for example a lab power supply(which I guess would be perfect) is too expensive.
Did i miss something or do you have any ideas which circuits I should look for?
CC CV step up? but do the change from CC to CV when end of charge is reached like the small 18650 chargers? I would hook it before the BMS to prevent any type of overcharge situation anyway...

thanks for reading this!
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#2
As far as using the lead-acid to power an inverter.    800w / 12v = 67amp draw.   That's pretty hefty sustained drain on the 12v lead acid battery - you probably want to make sure the car keeps it charged in 'real time' - e.g. I'm thinking that you don't want the 12v battery to discharge to any degree as this will wear it out quickly.

If you find trouble, perhaps a 12v LifePo4 replacement (they make these for cars) would do better with sustained draws.

Just thinking out load Smile
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#3
(09-08-2020, 11:57 AM)Korishan Wrote: gazoobajp: please don't make your font so small. This is a tactic spammers do to sneak in links, which you have a link as well. This raised a quick red flag on your post. I have fixed your font size back to normal size.

If it smells like spammer and looks like spammer, it's most likely a spammer. His post has no relevance to the original post.

The link is nothing but a link to an auction site.


But I would still rethink using a Leaf to power a house. If it's used for emergencies, then yes, otherwise no. The reason is that by using the Leaf as a power source it would just degrade the battery. That means less mileage and that's what's important in a car. It's like having a phone you always have to charge all the time, quite annoying!
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