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scraggs avatar image
scraggs asked

IPzS battery monitoring

Hi
So I now have everything up and running except for one more building (the main one) to connect to my off grid setup.
But I am not sure I have everything set up right on the battery monitoring.
I have a 930ah (C5 rating) IPzS 48v battery setup,
Victron multiplus 2 48/8000/110 inverter
fronius AC 8.2-1 inverter on AC1 out
Smartshunt 500
Cerbo GX

Yesterday it went to absorption at 99%, but this morning it went in to bulk charge at 96%, is this to be expected or too early, it went to absorption again at 99% today
Just wondering if maybe I have something setup wrong in VRM settings
I have Multi set with battery monitor on, 85% when bulk finished, battery capacity 1140ah (C10 rating) and charge efficiency 0.80% and the same in the shunt, if I set the battery monitor in VRM to either the shunt or the Multi the result is pretty much the same.
Using the flooded tubular plate curve.
It does appear that there is a lot more amps going in compared to going out.
Any advice greatly appreciated here.

MultiPlus Quattro Inverter Chargerbattery charging
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1 Answer
JohnC avatar image
JohnC answered ·

Hi @Scraggs

Firstly, in the Multi, disable it's battery monitor. It's not a patch on the SmartShunt and you don't want to see it, nor have it inadvertently pop up somewhere. Yup, really!

In the Smartshunt, use the C20 battery capacity, and 80% Charge Efficiency there will be way too low, try 90-95% for starters. Can you post a screensnip of the shunt settings?

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scraggs avatar image scraggs commented ·

Thank you @JohnC for the reply
Sorry just realised I put OPzS when they are in fact IPzS
I must be having a bad day as the 1140ah is the C20 rating not the C10 as I had put.
So sorry for the mistakes :(
Should I still try those changes ?
Thread title now changed.

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JohnC avatar image JohnC ♦ scraggs commented ·
The batt type doesn't really matter. You just need to get the shunt set up correctly. Understanding what all the settings do is the key, so perhaps download a copy of the manual from the Victron website and keep it very handy. We can help, but the finer tuning will still be up to you..


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scraggs avatar image scraggs JohnC ♦ commented ·

Hi
Screenshot attached.
I did use the manual to set it up the first time, but it wasn't very accurate, I'll have another go and have a play about, I was wondering if it could be due to it not having a huge amount of draw from the battery yet and it being a fairly large battery.
Screenshot (35).png

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screenshot-35.png (166.1 KiB)
JohnC avatar image JohnC ♦ scraggs commented ·
@Scraggs Ta for the snip. Random comments..

The Charged Voltage, Tail Current, and Charged Detection Time are used together to determine when the batts are fully charged, then will reset the shunt to 100% (if it happens to show below that). The CV must be below any likely temp-compensated Abs or Float values (depending on which charge state you decide to sync at). Your 5% of 1140 (1114?) suggests you're happy to call the batts 100% charged when still able to accept up to 57 Amps in Abs state. I wouldn't think this a practical option, but up to you..

For the Peukert, the 1.25 default is quite high. Grab Victron's Peukert Calculator from the website and run through it the C20 and C50/C100 values for your batts. Then enter the result.

The 95% CEF is likely optimistic, and will bring the reported SOC of the batts back to 100% before they are really there. This can vary depending on how deeply you discharge, like topping off the last 5% on a daily basis is inefficient. You can adjust this as you go along.



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scraggs avatar image scraggs JohnC ♦ commented ·
@JohnC

Many thanks for your help on this.
I have altered a few things and will see how it now goes.
Thanks

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