Charge settings - Victron Multiplus + REC ABMS

[GnrlPatton]

I have a question about charge rates and what I should be expecting to see out of my system. My installation includes:

Victron Multiplus Compact 12|2000|80
REC Active BMS
Victron CerboGX
Victron Lynx 1000
Victron 500A Smart Shunt
Victron MPPT Solar Controller 100|30 + 2x 105W solar panels
304 aH prismatic cells in a 3p4s configuration (912aH @12v house bank on my boat)
Westerbeke 7.6BTD diesel generator

Everything is installed and working correctly, I am just questioning what I should expect to see when I am charging. Currently when I have the shore or generator providing power, I'm getting between 50 and 60 amps charging input to the batteries. I have DVCC enabled, and the Max Charge Current is set to 80A (have also tried higher - up to 100A). Is 50-60A as much as I can expect, or are there other settings I can look at to extract the most out of my system when charging? I depleted my house bank over the past few days to around 45% (per the BMS SOC), and I ran the generator for a little over 3 hours today and it got back to 70%, a 25% increase. I would love to be able to run it for shorter time and get more out of it if possible. I've read others saying they are pulling in over 100A during charging, I don't get that even when on shore power - it's always around the 50-60A level. Am I being unreasonable in that?

Here are some relevant settings:

REC ABMS
Balance END V: 3.55
Balance START V: 3.5
END of charging: 3.5
Max allowed cell V: 3.55
Min allowed cell V: 2.95
Max charging current per inverter device: 100A
Max Discharge per device: 250A
Charging Coefficient: .8C
Discharge Coefficient: 1.5C

Victron (Firmware v3.30 w/ GUIMods):
DVCC: On
Limit Charge Current: On
Maximum Charge Current: 80A
Limit managed battery charge voltage: Off
SVS - Shared Voltage Sense: On
STS - Shared temperature Sense: On
Controlling BMS: REC-BMS Battery

Thanks much!
Kevin

 

[sunshine_eggo]

The inverter/charger is limited to 80A charging. It will also limit itself if its internal temperature increases.

What's your AC input current limit?

 

[BillCaswell]

Balance END V: 3.55
Balance START V: 3.5
END of charging: 3.5
Max allowed cell V: 3.55

why is your "END of charging: 3.5" less than your "Balance END V: 3.55"

 

[GnrlPatton]

The inverter/charger is limited to 80A charging. It will also limit itself if its internal temperature increases.

What's your AC input current limit?

I've tried everything from 60A to 100A, but it's always a max of between 50 and 60, even when the temp is around 60F.

 

[GnrlPatton]

why is your "END of charging: 3.5" less than your "Balance END V: 3.55"

I had originally set them to be the same of 3.55 based on an email reply I got from Time at Rec. I probably was trying to change a few things to see if it made any difference and left it like that, I'll put it back to both of 3.55. The cells are staying balanced nicely, so I'm appreciative of that at least. I'm just trying to figure out how to get more charging amps to reduce my generator run time when I'm on the hook.

 

[svsagres]

I think it has to do with the Weak AC option on the MultiPlus. I have the same thing on mine, but have left it more or less as is. The idea is to reduce the amount of ripple the multiplus is injecting back into long/weak power connections and/or do nasty things to the windings on smaller generators.

You can tweak the option with VE.Configure and see if it makes a difference.

 

[BillCaswell]

@GnrlPatton - how is your system working now?

Also, does your logs on the REC-BMS should a time/date stamp? I have two REC-BMS systems on my boat. One has the correct time and the other only shows the sample number. I have not found where to set or get the time-stamp for the REC logging.