Victron BMV-702 battery capacity question

I have 8 x 12V, 260Ah batteries. 2 banks of each 4 batteries.
So each bank has 4 batteries in series.
And the 2 banks are connected in parallel.

This delivers 48V.

Its connected to a Growatt SPF5000ES and a Victron BMV 702 Battery monitor (with 3 Victron battery balancers)

To setup the BMV-7802, I must enter the battery capacity. I don't know what to enter. I contacted Victron and they replied that I need to enter 520Ah. Is that correct?

Any ideas what to enter in the BMV-702 as battery capacity with this battery setup?

520Ah is correct.
Connecting 4 batteries in series will yield 48V at 260Ah. (Voltages add but Ah stays the same)
Then, connecting the 2 banks in parallel will yield 48V at 520Ah. (Voltage stays the same, Ah adds)

wholybee said:

520Ah is correct.
Connecting 4 batteries in series will yield 48V at 260Ah. (Voltages add but Ah stays the same)
Then, connecting the 2 banks in parallel will yield 48V at 520Ah. (Voltage stays the same, Ah adds)

Click to expand...

Ah, that makes sense. Then I will set 520Ah as battery capacity in the BMV. Thanks!

When you use this battery monitor, if you are noticing the state of charge not what it should be, you can adjust:

-Puekert Exponent for lead acid
-Tail Current
-Charge Efficiency Factor

What got me was the tail current on the base settings was too high. I was getting to an SOC of 86% and the SOC jumped to 100%. Tail Current rests the SOC to 100% when the current drops to a certain percentage of what you enter in the battery capacity. I knew it wasn;t at 100% SOC because the batteries were still taking in current. I lowered the tail current to 2% and that problem went away.

If you want a deep dive into setting all the options on the BMV, read this. Warning, it might hurt your brain.

You can actually enter any number you like. If you want to physiologically hold a readout display reserve like 10% or 20% you can set the number lower than actual battery capacity.

The number you enter is used for its calculation for 100% full capacity and the tally of discharge and charge amp-time is banked against that full number.

The monitor is set to 100% full when you reach its set charge voltage level. This is typically set just a little below your charge absorb level setting on the charger. When you continue to hold absorb voltage the display will still remain at 100% full.

It is important to allow the monitor to reset to full state of charge periodically (month or two) with a full absorb charge level to clear accumulated errors in the cumulative tally bucket. For LFP cells the absorb charging time is also necessary periodically to maintain good cell balancing.