Anyone with smallish battery? Like 1kwh or similar?

[greymda]

Looking for some advice as i am pretty new to all this but really want to build something by myself.
So, if you are using a smallish battery please chime in as i have some questions.

For example- i get that i need a fuse between Victron MPPT and the battery.
I plan to use 6mm wires - is this okay?
If yes, do i need a 20A fuse, or 25, or 30?

Apologies if this sounds silly, but bear with me please.

Edit: forgot to add, all connected to a Hoymiles HM-800.

[spcqike]

Fuse size does not depend on battery capacity. It depends on battery discharge current and wire diameter.

For 6mm^2 you could use any of these fuses. But only if your battery can safely handle that much discharge current.

[greymda]

it’s 16 of these guys in series https://www.evlithium.com/hot-lithium-battery/40135-20ah-cylindrical-lifepo4-cell.html

Standard Charging Current 10000mA
Standard Discharge Current 10000mA
Max Continuous Discharge Current 60000mA

[spcqike]

High rate discharge: Capable of maximum 50A

so it has different ratings given in the same site.

As it’s a 20Ah cell, I wouldn’t go much above 20A. So I would probably look for a fuse between 20-30A. Which gives you something between 1-1.5kW of discharge power.

Edit:
What BMS are you using? The BMS could limit your max current, too.

[greymda]

@spcqike my total capacity is at around 1kWh.
the BMS is JK-BD4A20S4P https://www.jkbms.com/product/jk-bd4a20s4p/

[greymda]

forgot to add, all connected to a Hoymiles HM-800.

[DonJohnLong]

How much solar imput do you have? These 20A cell's seem a little bit small to me.

[DonJohnLong]

6mm2 cables should be plenty, a fuse between the victron and your busbars is not necessary in my opinion (will not trip anyway), however you should have a breaker for your solar input and for your battery output.

Something like this:
https://a.aliexpress.com/_Eu9RZ51

[greymda]

@DonJohnLong oh, that’s interesting. so skip
the fuse and put 2 breakers? what amperage?

I have a Victron 150/35.

By the way, the idea behind mu setup
as i am newbie i just wanted to “recreate”
the Zendure AB1000 setup.

[greymda]

@spcqike here’s the official datasheet https://www.evebatteryusa.com/_files/ugd/b4afc3_5f83846234374b7fa995bb3a913d3447.pdf

[spcqike]

As it says on page 9: 0.5C standard charge and discharge current. So 10A. However you can charge with 1C up to 80% SoC and you can discharge up to 3C but only for 30s pulse.

So I would stay within 10A I guess. Max 20A.

[greymda]

@spcqike another stupid question: where inset this limit? in the victron mppt, or in opendtu-onbattery?