Victron IP65 SmartShunt Tail Current Settings

[Tardis]

Greeting from New Zealand…

I have read many posts online regarding tail current settings with Victron SmartShunts and Victron SmartSolar MPPT Charges.
My setup is as follows… 1 x SmartSolar MPPT 100/30 controller, 1 x IP65 SmartShunt 500A/50mV, 1 x Smart Battery Sense, 2 x Century 120AH Batteries AGM Deep Cycle wired in parallel , 2 x 145w BCT145M-12 Solar Panels wired in series.
I seem to have all the recommended settings in both the SmartSolar controller and SmartShunt however I’m unable to calculate the correct tail current value. This is where I would appreciate some kind assistance from the members please. Attached are screen shots and battery information. Please advise if further information is required to determine the tail current. Many thanks Dave.

 

[Rocketman]

A bit ago you were talking about synchronize. One thing I did on my MotorHome Victron Smartshunt is I set the charge efficienty factor to 98% instead of the 99% that is usual recommended for lithium batteries.

What that setting does is on a 100ah battery - you use 20amps - so your SOC says 80%, then you recharge 15 amps- it only counts 15amps times 98% = 14.7 amps as going back into the battery ( some is lost due to heat, etc.)

The reason I did that was so the Soc% was dropping faster than the real value was in my battery.

What happens in my system, my shunt loses about 1% per day that it is not synced. So after a week of not getting enough solar if it then gets enough it will jump from like 93% to 100%.

If I am in an area with enough solar, then my system sync’s every day to 100% - no problems.

I like it setup like that - the worse case is I think the battery is much more empty than it really is so I start the generator. That way I don’t have surprise low voltage alarms.

Good Luck

 

[mikefitz]

With lead acid AGM, tail current may vary depending on manufacturer and battery age. I use a value of 1 amp per 100 Ah of battery capacity. With 240 Ah of battery that's 2.4 amps or 1%.
Tail current charge termination set in a charger may be confused by current used by loads.
Charger absorbtion at 6 hours seems over long, suggest 3 hours.
When the current Into your battery pack has fallen below 2.4 amps at absorbtion voltage, 14.7, ( or has stabilised at a low value with aged batteries) it can be considered the batteries are at full charge. You can use this fact to fine tune charger and shunt settings.

Smart shunt settings may need adjustment when experience in use is gained.

Battery capacity: will decrease with age and use and may not even reach specification.
Charge efficiency: 95% may be too high, again this will vary depending of depth of discharge and battery age.
Time to go: may be useful to increase the time, say 8 minutes
Charged voltage: where charging is via solar set to 0.2 or 0.1volts below absorbtion voltage,

Mike

 

[Tardis]

With lead acid AGM, tail current may vary depending on manufacturer and battery age. I use a value of 1 amp per 100 Ah of battery capacity. With 240 Ah of battery that's 2.4 amps or 1%.
Tail current charge termination set in a charger may be confused by current used by loads.
Charger absorbtion at 6 hours seems over long, suggest 3 hours.
When the current Into your battery pack has fallen below 2.4 amps at absorbtion voltage, 14.7, ( or has stabilised at a low value with aged batteries) it can be considered the batteries are at full charge. You can use this fact to fine tune charger and shunt settings.

Smart shunt settings may need adjustment when experience in use is gained.

Battery capacity: will decrease with age and use and may not even reach specification.
Charge efficiency: 95% may be too high, again this will vary depending of depth of discharge and battery age.
Time to go: may be useful to increase the time, say 8 minutes
Charged voltage: where charging is via solar set to 0.2 or 0.1volts below absorbtion voltage,

Mike

Hi Mike
Thank you I have changed the MPPT Charger settings as you suggested and also changed the Shunt settings and set to 93% and time to go.
Ill let you know how it goes and again your help is very much appreciated
Dave

 

[Tardis]

A bit ago you were talking about synchronize. One thing I did on my MotorHome Victron Smartshunt is I set the charge efficienty factor to 98% instead of the 99% that is usual recommended for lithium batteries.

What that setting does is on a 100ah battery - you use 20amps - so your SOC says 80%, then you recharge 15 amps- it only counts 15amps times 98% = 14.7 amps as going back into the battery ( some is lost due to heat, etc.)

The reason I did that was so the Soc% was dropping faster than the real value was in my battery.

What happens in my system, my shunt loses about 1% per day that it is not synced. So after a week of not getting enough solar if it then gets enough it will jump from like 93% to 100%.

If I am in an area with enough solar, then my system sync’s every day to 100% - no problems.

I like it setup like that - the worse case is I think the battery is much more empty than it really is so I start the generator. That way I don’t have surprise low voltage alarms.

Good Luck

Hi Rocketman,
Many thanks for your reply and I have adjusted some of those settings so we will see how it goes excellent advise
cheers Dave