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Basic design
#1
Hello again,

I'm still in the process of testing 18650's, so I am just trying to think ahead. Not posting my build thread till I'm closer to building the whole project, not just battery packs.

Here is a basic diagram of what I am thinking.

 

Inverter/charger: I am leaning toward a LV5048, maybe eventually 2 of them.

Solar: I am seeing a lot of good deals with used solar panels and might give it a shot when ready. Each LV5048 can do I think 8k watts from pv, will be much lower at first. Depending on which panels I go with, it should be in a 3p configuration. Somewhere in the 100v range, 250-350w per panel. What would be the maximum distance the panels can be from my batteries? I know it depends on the size wire I choose, but 8 gauge is about the biggest solar panel wire I can fine. The spot that gets the most sun is about 150 feet away. Not sure if that is too far or not.

Battery: 14s116p at first and will build parallel packs the same size the more battery packs I get built. I should have enough batteries for 3 x 14s116p. The reason it's 116p and not 120p, because I am leaving 4 spots open in the holders to bump up a low pack. I can just slide in a battery or 2 to bring that pack up as needed.

BMS: Batrium of course.


I'm probably still 6 months or more away before I start building the system (and the design will probably change 1000 times before then).

How about some thoughts/improvement/complaints about where my brain is taking me on this project.

Thanks in advance as always,

Zerb
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#2
(07-16-2020, 01:51 AM)zerberfert Wrote: Each LV5048 can do I think 8k watts from pv

Not sure about this model, but in many cases you can attach more than 8kW of panels, and the inverter will software limit itself to 8kW.  Makes sense, since PV panels rarely output 100% power anyway.  Attaching more panels ensures that full power is available more often.  I think the industry term is "oversizing" a PV system


(07-16-2020, 01:51 AM)zerberfert Wrote: maximum distance the panels can be from my batteries? I know it depends on the size wire I choose, but 8 gauge is about the biggest solar panel wire I can fine.

There is no distance limit with PV cables, but the longer the cable, the higher the voltage/energy losses will be.  It's up to you to decide what losses are acceptable... 5%... 10%... 20%...
You can easily calculate how much %loss you can expect on sites like this:
https://www.calculator.net/voltage-drop-calculator.html

Ways to reduce losses are:
* Use thicker cables
* Use higher voltage ( => lower amps => lower loss ) PV panels
* Use multiple cables in parallel (a little frowned upon, possibly illegal in some areas, and requires some safety considerations)
Modular PowerShelf using 3D printed packs.  60kWh and growing.
https://secondlifestorage.com/showthread.php?tid=6458
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