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Need a little help with Batrium + Victron Multiplus CAN settings.
#1
Hi all,

I have a pair of Tesla module S packs which are connected in series to produce a ~48v pack.

Would like to double check if i have my head screwed on correctly from someone who has some experience of using Victron gear (Multiplus and Venus GX) with a Batrium Watchmon.

The general specifications from each pack is  
Voltage nominal: 3.8V/Cell, 22.8V/Module
Charge voltage cut-off: 4.2V/Cell, 25.2V/Module
Discharging cut-off: 3.3V/Cell, 19.8/Module


The cellmons (under Hardware) have been set to the following to keep the pack in check.

Lo Cell - 3.30v
Nom Cell - 3.80v
Bypass - 3.98v
Hi Cell - 4.00v

What i'm a little confused about is the control logic. 

Would anyone have some recommendations of the settings that i have configured or have i just been barking up the wrong tree? Smile







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#2
So it looks like you have got a few conflicting settings? Eg:
- discharge cutoff set to 3.43V? In your summary you've got 3.30V?
- cell hi critical you've got 4.0V like the summary value but in charging you've got cell hi cutoff (stop charging) at 4.10V
- bypassing set to 3.98V but charge to 4.10 will make the cell mons bypass all the time.... charge to 4.0 would be fine.

You probably want the critical values different to normal daily operating values or you'll get nuisance alarms all the time.
Eg set critical high to 4.15V if normal charge =4.0V
set critical low to maybe 3.15V if normal low = 3.30V
Running off solar, DIY & electronics fan :-)
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#3
(01-25-2020, 12:39 PM)Redpacket Wrote: So it looks like you have got a few conflicting settings? Eg:
- discharge cutoff set to 3.43V? In your summary you've got 3.30V?
- cell hi critical you've got 4.0V like the summary value but in charging you've got cell hi cutoff (stop charging) at 4.10V
- bypassing set to 3.98V but charge to 4.10 will make the cell mons bypass all the time.... charge to 4.0 would be fine.

You probably want the critical values different to normal daily operating values or you'll get nuisance alarms all the time.
Eg set critical high to 4.15V if normal charge =4.0V
set critical low to maybe 3.15V if normal low = 3.30V

Good eyes!

Yes, looks like i'll need to bump up the discharge cutoff to 3.43 as the Victron has a minimum DC Low Restart of 41.2 (41.2v/12 = 3.43v)


I'm a little confused about the batrium statement about the 'charger tab' , there is reference to setting VEConfigure to 
https://support.batrium.com/article/111-...h-watchmon

"13.2 Charger tab

Absorption voltage
60.75 V
Float voltage
60.00 V

Note: make sure to double check the float voltage after completing Assistants, and if necessary set it back to 60.00 V.
This needs to be adjusted to match the BMS operating targets"


Should this not be set to 48.8v for absorption and 48.7v float ?

There's also reference to 50V for sustain mode... would that not be better set to something like 42.5v ?
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#4
Yeah "absorption" is pretty much irrelevant for Li cells & should not be used, it's a lead acid cell thing.
Absorption can be used with a small difference to help top balance with some "gentle" bypassing
Yes set the charge voltages to suit your 12s pack, ie 49.6 (4.1/cell) with a float just under at maybe 49 (~4.08/cell).
Because you have a 12s system vs the typical 14s, you'll need to run your cells to 49.5 (4.1V/cell) = charge full to get decent pack AHr capacity.
Tune the bypass voltages to match & also use "auto level" above about 80 or 85% SoC.
Yes the set the discharge cutoff to match the Victron's min V cutoff.

I'd ignore sustain mode, but set it mid voltage, eg between 3.43 & 4.1, eg 3.7v/cell = 44.4V for your 12s pack
Running off solar, DIY & electronics fan :-)
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#5
Thank-you for your help and boy has it been an adventure!!!



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