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48v off grid battery back-up system help

Islandwes

New Member
Joined
Nov 29, 2022
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Hello to all who can give us any advice.

We are installing a new 48v Offgrid system on our property.

Our system equipment:
- Solark15kw inverter
- 2 - eg4-lifepower4 battery racks
- 33 535watt panels

I curious as to what additional equipment(disconnects, etc..) we should have in place with our system.

Also, is there anything I need to know when I link two of these battery racks together? Any advice on wiring them up would be amazing.

My father an I have had a simple 48v Outback offgrid system for over 20 years and we decided it’s time to upgrade to new and better equipment with the hybrid solark inverter.

Our first time using one of these inverters so we want to make sure we do things right.

We are no professionals we just have experience running our own system.

Any tips and advice that you think can help us, we’d really appreciate it!
 
Ok, I'll start... be ready!
Proper sized wire between each item (this will a fun topic) perhaps lighting protection for a ground mount PV system (another fun one) combiner boxes for the multiple panels when connecting strings and parallels. And, a big one... when connecting 12 lifpo4 batteries (6 and 6) perhaps midpoint busbars. You should connect these with equal length cabling with proper interrupters, such as T class fuses or large 600amp breakers. This will be the ONLY safty issue I will be a part of, because that much DC power is actually dangerous!!! No kidding, I'm not the safty police and I'm not concerned if you see a spark somewhere, those are each person's decisions to make.
 
It would be helpful to know:
Typical loads you will be powering, both max instantaneous and daily, if they vary summer and winter, then give some idea of this.
a bit of a hint as to what part of the globe you may be positioned upon.. not too specific just an idea of winter/summer solar potential kind of info
your title says "off grid back up" implies you have other forms of energy available perhaps a genset?
a 17kW PV array is very large, with five hours of good solar you could recharge from zero 17 100Ah 48v LiFePO4 rack batteries, it would be interesting to know why so many PV for this sized storage, perhaps cloudy days are rare, and using the power during the daylight hours (AC loads?) are the prime power use. but we don't know enough yet.
As far as cables and fuses, breakers:
Fuses and breakers are to protect wires,
wires are sized by max current, voltage length & temperatures.
knowing max loads on an inverter we can make suggestions on wire gauge, and that leads to selection of suitable fuses/breakers. long DC wires push up wire sizes rapidly, so keeping batteries close to inverters helps avoid this.
you should let us know how those PV panels are wired, #S-#P and an idea of how far from the PV array(s) to the battery banks and inverters.
What country will inform us as to what codes you should be following. Edit.
 
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