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Batrium Voltage settings clarification
#1
Hi All,

I'm a bit confused with Batrium settings and would appreciate a help from more experienced DIY builders.
My powerwall is 14s120p (using old 18650's from laptop batteries) the capacity is about 300Ah.
I also have Victron Inverter/Charger 3000VA/48V, and grid tie SMA 2.5kW solar inverter (with 3.0kWp array).

I've just installed Batrium BMS (WatchMon4+Expansion with 14 Longmons) and connect it to Victron (with CANbus), and I'm trying to set it up. I've read hundreds of pages about Batrium and Victron and still haven't got all the answers I was looking for.

I want to run my powerwall between 56.7V (4.05V/cell) and 46.2V (3.3V/cell).
My inverter/charger setting are:
Charging Absorption 56.75V (4.054V)
Charging Float 56.7V (4.05V)
Discharge cut-off 46.2V (3.3V)

And now is the part that I'm not clear on - Batrium settings.
Question1: where my target voltages should be set? In Hardware-CellMon? Or in Control Logic?
I set the voltages like bellow:


Question2: I presume that Control Logic - Critical is a place to set my critical cells condition that hopefully will never happen. That is the settings that will stop inverter/charger and protect cells from over/under voltage. Am I correct?
My settings are:


Question3: If my target voltages are in Hardware-CellMon, should I set the same voltages in Control Logic-Charging/Discharging
See screenshots bellow




Am I correct with my thinking? is this settings correct? What would you change? Please bear in mind that I want to keep 4.05V max and 3.3V min per cell.
Any sugestions will be appreciated.
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#2
I've been running WM4 + Expansion for 2 yrs now and I know what you mean...  not everything is immediately clear...  and there are deeper experts than I, but here's what I do.  

>Question1: where my target voltages should be set? In Hardware-CellMon? Or in Control Logic?
I think of the Hardware -> CellMon settings as being focused on 'bypass'  (balancing).   The Bypass Volt and Bypass Extra Mode (dropdown) are clearly the settings that cause balance to initiate.      

The Low Cell, Nom, Hi Cell - I set to be reasonable but are not as extreme as the Critical page.   I use Nom = 3.7 for Lithium ion.     Here's my CellMon page right now - bypass is higher than max charge voltage so balance remains OFF (I don't balance very often as I don't need to).



>Question2: I presume that Control Logic - Critical is a place to set my critical cells condition that hopefully will never happen. 
Yes - one of the main purposes of this is to cause the shunt-trip to break the battery connection so the battery no longer charges/discharges...  and won't continue to be too hi or too low or too hot etc.    You'll see that my voltages are a bit 'wider' than the CellMon page - but that's OK as far as I understand.   3.0v low and 4.2v hi are truely what I want before the shunt-trip kicks in.   
- I don't worry about ambient temperature as the ambient under the house is 55F to 75F thru the year - no risk at all of it going to extremes - and the Lo/Hi Cell Celsius should detect something extreme such as fire. 
- The Lo/Hi Cell Celsius is on the longmons...  but they don't touch the batteries and the bypass max temp is not likely to cause this to go to 55C.   So I expect this would only go off in a fire or some event like that, so I have it enabled for critical. 
- The Lo/Hi Shunt and Max Current are all set to conservative daily operating specs but less that max design specs.   For example, the battery/wiring is built to deliver 500a but the shunt-trip is 400a max and if I get above 250a (setting) then I'm operating outside what I 'expect' and I should review things - so 250a is safest trip point at this time but I could go up to just below 400a at some point in the future. 
 


>Question3: If my target voltages are in Hardware-CellMon, should I set the same voltages in Control Logic-Charging/Discharging
I think the idea here is not that it's 'critical fault' but rather more of a control scenario to control when charging/discharging happens.   

In my case - I use Midnite Classic controllers - and they are responsible for charge and discharge,  inverter on/off - e.g. I don't use Batrium for this.  

I'm guessing these settings would apply to some equipment that can use them to control charge/discharge.



>Please bear in mind that I want to keep 4.05V max and 3.3V min per cell.
When you say "I want to keep..." - its a question what you mean.  If you mean....
* Charging - my charge controller is responsible for this - so my Batrium settings are set to stay out of the way (e.g. a little higher than the charge controller but less that Lithium ion max).
* Discharge - Again my charge controller controls the Inverter - e.g. turns the inverter on/off based on voltage.   So again my Batrium settings are set to stay out o of the way.
* Shunt-trip (Emergency shut-off) - Batrium does this for me, so these settings on the Critical page are important
* Bypass - Batrium does this for me, but I control this manually by lowering them into charge controller range when I want to activate balancing - so the CellMon page is used for this.

All great questions and I'm sure you'll get more on this!!   I'm interested myself on what people share as I only use a portion of Batrium Smile
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