Settings for Victron 500a smart shunt

[Willbiker]

Hi all

I added a Victron smart shunt to my solar setup and it works great (except for the terrible Bluetooth range). The only issue I have with it is the state of charge read out. After a full night of discharge, the shunt will read 66% but will then show 100% again after just a couple of hours of morning sun. This isn't possible.

I have set my battery capacity (390ah at C20) and have synchronised to 100%, the rest of the settings are the default settings. I have 3 of these batteries https://www.batterymegastore.co.uk/product/hankook-xl31-leisure-battery/

Ive got 2 questions:

1) when is the right time to synchronise to 100%. Is it when my solar charge controller is on float charge mode, or should I disconnect the charger and let the voltage settle overnight before syncronising?

2) Do I need to change any other settings?

Thanks

 

[Rocketman]

You need the charged voltage to be just below your absorbing voltage (like .1v below). This is causing the early resets.

What the current settings are saying is anytime the voltage is above 0.0 v and you are charging less than 4% of 390a = 15.6a reset to 100%.

I never do manual resets.

 

[newbostonconst]

Is your battery lead acid? if it is lithium the Peukert value is set wrong....I think it is supposed to be 1.05 for lithium.

Charged value is at zero and needs to be just before where you want your charging voltage to end. Or as stated above.

 

[Willbiker]

You need the charged voltage to be just below your absorbing voltage (like .1v below). This is causing the early resets.

What the current settings are saying is anytime the voltage is above 0.0 v and you are charging less than 4% of 390a = 15.6a reset to 100%.

I never do manual resets.

I see! Thanks for the info.

When you say absorption, I assume you mean the stage of charge after bulk ? Do I simply wait until my solar charger enters this mode and then make note of the voltage? Or will it be in my battery spec data sheet ?

 

[Willbiker]

Is your battery lead acid? if it is lithium the Peukert value is set wrong....I think it is supposed to be 1.05 for lithium.

Charged value is at zero and needs to be just before where you want your charging voltage to end. Or as stated above.

Yep lead acid

 

[Rocketman]

It will be in the solar charge controller settings.

Do you have a Victron mppt solar charge controller? Just post its settings page - like you did for the Smartshunt.

 

[jasonhc73]

I installed my smart shunt last October '21.

2.1 Mega Watt hours out of my battery and 7 cycles.

So if I am getting 1 cycle a month, and the cells have a 6000 cycle warranty (using 100% discharge) that means these should last me 500 years. ?

 

[Willbiker]

It will be in the solar charge controller settings.

Do you have a Victron mppt solar charge controller? Just post its settings page - like you did for the Smartshunt.

I have an epever tracer. Here are my settings...would it be equalise chsrge voltage?

 

[mikefitz]

For the Smart Shunt set these values for your lead acid batteries sealed calcium dual purpose;
Charges voltage 14.30 volts
Tail current 2%
Charge efficiency factor 90%

The others are OK.

The unit will self sync to 100% when,
The charge voltage is greater than 14.3 volts and the charge current is less than 2%(7.8 amps) and both these conditions have existed for 3 minutes.

With your Tracer charger the every day charging voltage is Boost voltage, Equalise voltage is set higher and is applied every 28 days to Equalise open cell lead acid batteries. Your batteries are sealed, so set this voltage the same as boost voltage.
Boost voltage duration is not indicated but should be a minimum of 2 hours, set to higher if possible.

Your XL 31 batteries are modest leisure batteries and will give resionable service if the regular discharge is kept above 50% SOC, just over 12.0 volts for a rested battery.
Recommended maximum charged current typically is less than 10 to 15% of capacity, say 40 amps.

Mike

 

[Willbiker]

Thank you very much Mike! Much appreciated

For the Smart Shunt set these values for your lead acid batteries sealed calcium dual purpose;
Charges voltage 14.30 volts
Tail current 2%
Charge efficiency factor 90%

The others are OK.

The unit will self sync to 100% when,
The charge voltage is greater than 14.3 volts and the charge current is less than 2%(7.8 amps) and both these conditions have existed for 3 minutes.

With your Tracer charger the every day charging voltage is Boost voltage, Equalise voltage is set higher and is applied every 28 days to Equalise open cell lead acid batteries. Your batteries are sealed, so set this voltage the same as boost voltage.
Boost voltage duration is not indicated but should be a minimum of 2 hours, set to higher if possible.

Your XL 31 batteries are modest leisure batteries and will give resionable service if the regular discharge is kept above 50% SOC, just over 12.0 volts for a rested battery.
Recommended maximum charged current typically is less than 10 to 15% of capacity, say 40 amps.

Mike

 

[Willbiker]

Thank you very much Mike! Much appreciated

Hi again. Thanks for the previous help, the shunt now seems to behave as expected however when my batteries dropped to 12.16v (rested), the shunt says 65% charge. This cant be correct surely? I thought 12.1v represented 50% charged for lead acid?

 

[newbostonconst]

Hi again. Thanks for the previous help, the shunt now seems to behave as expected however when my batteries dropped to 12.16v (rested), the shunt says 65% charge. This cant be correct surely? I thought 12.1v represented 50% charged for lead acid

Have you ever charged the battery all the way up and then discharged it to get the true capacity? Maybe your battery isn't at like new state.

 

[mikefitz]

The charts showing SCC and voltage are approximate. Your batteries are general purpose leisure batteries, calcium sealed batteries. These tend to have higher voltages than flooded lead acid.
Provided your shunt is connected correctly so all current passes via this to the battery bank negative it will read correctly.

Mike

 

[Rocketman]

Your shunt says it has used 165Ah of power - you stated your batteries were 390Ah at C20 - so did you drain your batteries in a 20 hour rate or was it faster?

With lead based batteries if you drain faster than a C20 rate the voltage will drop faster than it “should”. If you let it rest the voltage will slowly climb back to mostly where you would expect it to be - that is part of the puekert effect.

One other item - you may want to reduce the capacity in the shunt app a bit every year because your battery has aged and will not longer hold the full original capacity.

 

[mikefitz]

Your batteries are budget leisure batteries sold in the UK. They are general purpose starter batteries that can be used in leisure vehicles with modest loads and infrequent cyclic operation. In practice the load cycles could be well below 100 before significant capacity reduction occurs. The XL 31 is intended for ocasional leisure use not daily cyclic application.
C20 stated capacity is 130 Ah, thus pack capacity 390 in theory. Unless they are new the actual capacity will be lower.
If they have seen some using a figure of 350 Ah may be more suitable.
Don't worry unduly about SOC and battery lifetime, enjoy using your system and save up for a lithium replacement.

Mike