Victron smartshunt lifepo4 settings

[jonasw19]

2x sterling 100ah lifepo4 batteries, 270w solar, lrm1218 controller, votronic 45amp b2bwe
My query is around the smart shunt settings.
This a.m we had 59% battery remaining, quite reasonable as we charged our ebikes and havent moved much, and dull weather.

No surprises, weather perks up, we get a few amps for an hour and the shunt reports 100% soc, with 8 amps charging.
Settings as per screen shot.

Any suggestions?
Jon

 

[Hoovie]

2x sterling 100ah lifepo4 batteries, 270w solar, lrm1218 controller, votronic 45amp b2bwe
My query is around the smart shunt settings.
This a.m we had 59% battery remaining, quite reasonable as we charged our ebikes and havent moved much, and dull weather.

No surprises, weather perks up, we get a few amps for an hour and the shunt reports 100% soc, with 8 amps charging.
Settings as per screen shot.

Any suggestions?
Jon

Two things to do:
1. Watch the Victron Videos on how to configure the SmartShunts and BMVs.
Note: watch the VICTRON ones, and not other ones if you want the best info. This will help you understand why you can get erronous resets to 100% SOC when you have poor solar harvesting.
This is the main one that discuses what the settings mean. There are a couple of other videos also:

2. Turn off the "Battery starts synchronized" setting. This being enabled is the default and it is just plain stupid (IMO). First thing always do on an installation is disable that. If you have that set on and disconnect the +ve, or have an unknown intermittant connection to the shunt from either +ve OR -ve, the monitor resets to 100% and you are none the wiser (and you think you have a fully charged battery when it could be anything but, which can be even worse).

 

[jonasw19]

Thanks for the links, I have looked at them before, and my present settings are my understanding.
However, I dont know what I should set the charged voltage to. My aim is to set the charged voltage to slightly below the theoretical max, to mildly increase longevity.
The discharge floor at 15% has a similar aim.

Any pointers gratefully received.
I have removed the battery starts synch setting
Jon

 

[Hoovie]

Thanks for the links, I have looked at them before, and my present settings are my understanding.
However, I dont know what I should set the charged voltage to. My aim is to set the charged voltage to slightly below the theoretical max, to mildly increase longevity.
The discharge floor at 15% has a similar aim.

Any pointers gratefully received.
I have removed the battery starts synch setting
Jon

Remember the SmartShunt is a monitor only. It does not affect anything to do with how the chargers are working. If you want to change the charging parameters, you do this on the charger/s themselves.

Respectfully, watch the video again, especially from 2:36 and you will see an explanation on what the charged voltage setting should be on "regular" systems and on systems with solar (the setting required is significantly different, and your present setting is wrong)
Make sure you watch past 3:00!

 

[Pausim]

Thanks for the links, I have looked at them before, and my present settings are my understanding.
However, I dont know what I should set the charged voltage to. My aim is to set the charged voltage to slightly below the theoretical max, to mildly increase longevity.
The discharge floor at 15% has a similar aim.

Any pointers gratefully received.
I have removed the battery starts synch setting
Jon

The shunt settings do not control the charging they just tell the shunt how to monitor the battery. Charging depends on the B2B and solar controller settings, which need to be taken into account for the shunt settings so that it knows what is going on.

Your charged voltage setting of 13.2V looks way too low. I am guessing that as soon as your solar finds a bit of sun the controller output voltage shoots up to something above 14V, so the shunt thinks the battery is full because this is well over the 13.2V it is looking for.

I have my shunt set to a charged voltage of 14.6V. Having reached this voltage it then should automatically synchronise when the tail current falls below the set level, in my case 2% of 100Ah i.e 2A. Your 5% of 200Ah is 10A which looks too high.

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[jonasw19]

Thanks both
I have rewatched several times now, and conclude that my charged voltage should be 14.1V.
Referring to the video and the specs copied below

• Max charge V=14.6V, Recommended =14.4V, Float V=13.8V
• Jon

I have also lowered the tail current to 2%

I realise that changing a load of parameters at the same time is not ideal, but I will try these settings
Thanks again to both
Jon

 

[Hoovie]

Thanks both
I have rewatched several times now, and conclude that my charged voltage should be 14.1V.
Referring to the video and the specs copied below

• Max charge V=14.6V, Recommended =14.4V, Float V=13.8V
• Jon

I have also lowered the tail current to 2%

I realise that changing a load of parameters at the same time is not ideal, but I will try these settings
Thanks again to both
Jon

Looks about right.

What you can do to stop any premature resyncs to 100% is to set the charge voltage setting on the SmartShunt ABOVE any of the chargers Absorption Voltage value. This will mean you will never see a full 100% displayed on the monitor and it will max out at 99.9% but that is better than a exaggeration of the state of charge.

 

[Pausim]

Thanks both
I have rewatched several times now, and conclude that my charged voltage should be 14.1V.
Referring to the video and the specs copied below

• Max charge V=14.6V, Recommended =14.4V, Float V=13.8V
• Jon

I have also lowered the tail current to 2%

I realise that changing a load of parameters at the same time is not ideal, but I will try these settings
Thanks again to both
Jon

I would think it might still be a little low at14.1V. I assume your B2B and solar controllers are set to LiFePO4 profiles which on my kit means having only 2 phases, a main one rising to about 14.4V/14.6V and a maintenance one of perhaps 13.6/13.8V, an absorption phase is omitted. I have watched the charging figures for my set up and seen the voltage rise steadily to 14.6V at which point the charge current falls off a cliff and shortly thereafter the charge voltage drops to a maintenance level of 13.8V. If your shunt charged voltage setting is below the actual charged voltage it may still give misleading figures.

 

[jonasw19]

Just got back from plodding round some woods to find my panels are now shaded.
I think I will try my present settings until I move, at which point the b2b will come in and I can review once more.

Jon
Lost in France

 

[Raul]

Hi jonasw19
Try this for LiFePo4, works for me and keeps percentage SOC down to 0.5%; pretty accurate.
Charged voltage 0,2v below absorb( if absorb is at 14,4v -then set shunt at 14,2v charged).
Tail current 0,5%
Peukert 1.03

The rest leave as it is.
The victron recommendations do not work for every one, specially for intermittent solar harvest.

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[jonasw19]

All,
A new fault?
The cab battery no longer seems to charge from solar (Schaudt lrm 1218)
The alternator does charge it.
The b2b works.
Solar works to the extent that 7 to 8 A are being pushed into the shunt. Shunt says 100% but I am unsure as to how discharged the leisurs batteries were. The last discharge recorded was 80 AH, and I have driven plus solar til that now says zero.

For the last 2 hours 16AH solar recorded,
My expectation is that the solar input should be zero, if both hab and cab batteries are full,
Or approx 1 amp to the starter if that is not yet full.
Confused?
Or just a bit thick?

 

[Raul]

The solar will still produce for the loads, but 16ah in two hrs means a solid 8a coming from the solar. The solar charger does not communicate with the shunt, unless both connected to a GX with DVCC active and set.
If that solar 16ah went past the shunt in the battery, despite the shunt saying is full, the battery is not full yet. It means shunt re set prematurely and battery is still charging. It will take few cycles to sort its self out.

 

[Hoovie]

All,
A new fault?
The cab battery no longer seems to charge from solar (Schaudt lrm 1218)
The alternator does charge it.
The b2b works.
Solar works to the extent that 7 to 8 A are being pushed into the shunt. Shunt says 100% but I am unsure as to how discharged the leisurs batteries were. The last discharge recorded was 80 AH, and I have driven plus solar til that now says zero.

For the last 2 hours 16AH solar recorded,
My expectation is that the solar input should be zero, if both hab and cab batteries are full,
Or approx 1 amp to the starter if that is not yet full.
Confused?
Or just a bit thick?

You don't know if the batteries are charged fully though, do you? it doesn't matter what the Smartshunt says if if is not calibrated correctly and you know it reset to 100% prematurely.
when the shunt says 100%, it will show zero AHs even when the batteries are accepting charge as a 100% full battery (as far as the Shunt is concerned - it does not know the reality always) will not take more Ahs. It will however show current flow as that is a different function.

What can be interesting to do to get a better idea is to actually reset the SOC to a lower value - say 50% - so you can see the cumulative Ahs change. And then when the batteries are consistantly taking no more current, THEN reset the SOC to 100% as that is the time the battery is full (assuming the charger is still active, which can be a problem with Solar. plugging into EHU is much more reliable to do a full battery calibration.)

 

[jonasw19]

Ok
Is the b2b current (45A as std) a good indicator, ie when it drops to ?0A that will indicate lifepo4 batteries are charged. I have not seen this recently.
Jon

 

[Hoovie]

pretty well. a LiFePO4 battery will charge at full rate and then when full within a minute or so drop to nothing.

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[jonasw19]

I have reset the soc to 50%
This immediately reset the AH used to 100AH
This implies that the shunt does not count AH honestly, otherwise it would have read AH used as 2.9AH and Soc 50%, reflecting the usage after the panels were out of the sun.

 

[Hoovie]

I have reset the soc to 50%
This immediately reset the AH used to 100AH
This implies that the shunt does not count AH honestly, otherwise it would have read AH used as 2.9AH and Soc 50%, reflecting the usage after the panels were out of the sun.

No, that is not correct.
You have the capacity set at 200Ah. You reset the SOC to 50% and it made the calculation you have used 100Ah i.e. 50% of 200Ah.
I am not sure where you are getting the idea that it should show 2.9Ah and 50% but it won't and shouldn't.

I think you have an idea that the Smarthunt knows about your system? it does not. It reads the current in, it reads the current out. and works out the Ah used over time.

 

[jonasw19]

I did not appreciate the purely arithmetic link between Soc and AH used.
so when I reset the Soc to 50% I expected, wrongly, that it would reflect the previous AH used, and merely change the Soc.
Tomorrow I will try to drive far enough until the current drops to zero.
I think much of the confusion arises because I have been chrging our ebike batteries more than usual and moving less than usual, leading to a gradual divergence from reality, given my previous shunt settings.
Jon

 

[Hoovie]

The Smartshunt is a purely arithmetic device.
Basically the Ah is a calculation based on a combination of the Amps and Peukert value, using the battery capacity as a start point to work out how it affects the SOC.
The Ahs calculated depends of the load level. This means that once the smartshunt is doing its monitoring, 100Ah consumed may well not equal 50% of a 200Ah battery due to battery chemistries. This is part of the design of the Smartshunt (other SoC monitors don't tend to have this level of sophistication).
The Wattage is a multiplication of the Amp and Voltage.

The Cumulative Ahs and Wh are the only thing of note that are retained after a reset and kept in the history, plus an average and last Ah discharge. There are some other Maximum values saved as well

 

[jonasw19]

Drove for 90mins today and got the batteries back to the Soc of 9am today.
However it has also recharged our 2 depleted ebike batterries (~750Wh input) so still hanging on and the van battery seems back to normal.
Hanging in there!
Next time we move may be over to Spain so an opportunity to do a longer drive.

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[jonasw19]

Update
I finally drove until the charge current dropped to approx 1 A.
Reset the Soc to 100%.
The final cumulative error seemed to be about 6%, but it took some time and a lot of help to chase it down.
Thanks to all your help, esp Hoovie who wrote screeds in understandable language.
I have adopted settings from multiple contributors, and will now monitor and adjust as necessary.
Thanks again
Jon

 

[Hoovie]

Good its sorted
You may find you have to do the occasional manual reset (Victron actually say it is around once a month but I don't do that with mine (and I have 3 BMVs in my system!) ) but having a good view of the battery SOC within a couple of percent is generally good enough.