Shunt is reporting 100% but still only 13.47v. The controller is jumping between Absorption and Bulk so I assume there's still a bit to go.
What does the Power 120watts mean?
Victron Solar Mppt 100/30 - Detail monitoring
- Thread starter acenip
- Start date
What does the Power 120watts mean?
Power 120watts: The voltage reported from the battery is 13.47v and you have a current flowing of 8.94amps - This will produce 13.47volts X 8.94amps = 120.42Watts. A watt is a measure of power or how much work it can do. Volts and amps on their own don't tell you much, but Watts do so a 1000w Kettle, could be 230v drawing 4.3amps, or 12v drawing 83amps, both will boil the water at the same speed.......
Has the battery got up to 14.2v yet? Might be worth turning any loads off to keep the charge high as possible....
The shunt is obviously out of sync with the battery, but to get it back in line the voltage/tail current etc must get up to the values in your shunts settings when it will reset.
You can also reset it manually, but the only time you can accurately know what the correct SOC is, is when it is full (and cell balancing is complete).
Lithiums are difficult to estimate, because the voltage will not change much as they charge - then when they are nearly there the voltage will rise very quickly (few mins) to 14.2.
Not sure why the solar charger is dropping in and out of absorption though, but at 13.47v it is close, so hopefuly the voltage will jump soon.....
PS. might help it along a bit if you put the shunts tail current up to 2%ish - but the battery must get up to 14.2 as well.
Has the battery got up to 14.2v yet? Might be worth turning any loads off to keep the charge high as possible....
The shunt is obviously out of sync with the battery, but to get it back in line the voltage/tail current etc must get up to the values in your shunts settings when it will reset.
You can also reset it manually, but the only time you can accurately know what the correct SOC is, is when it is full (and cell balancing is complete).
Lithiums are difficult to estimate, because the voltage will not change much as they charge - then when they are nearly there the voltage will rise very quickly (few mins) to 14.2.
Not sure why the solar charger is dropping in and out of absorption though, but at 13.47v it is close, so hopefuly the voltage will jump soon.....
PS. might help it along a bit if you put the shunts tail current up to 2%ish - but the battery must get up to 14.2 as well.
Last edited:
Finally some really bright sunshine so hopefully I'm coming to the end of thie journey setting up my solar/lithium.
From what I see this morning on both apps charging seems to have stopped as I've reached full capacity.
From what I remember I now need to manually reset my shunt to have it recalibrate the battery. Is this correct?
From what I see this morning on both apps charging seems to have stopped as I've reached full capacity.
From what I remember I now need to manually reset my shunt to have it recalibrate the battery. Is this correct?
Yes its doing what it should!
Given the solar is still in the absorption phase I would let it finish or at least give it an hour or so for cell balance, but the shunt has already reset to 100%, so you should be fine to leave it now.
The shunt doesn't reset the battery as such, it simply measures and displays the net result of incoming and outgoing currents (charging and loads), and for simplicity it nets those off against the battery capacity you enter in the battery settings screen.
A shunt is very good when the battery is in use and cycling regularly, but a small error can build when currents are very small, and or very large. Its difficult to get these errors dialled out completely using the various settings, and over time the error will compound unless the battery gets full (as it now has) and resets back to 100%
Given the solar is still in the absorption phase I would let it finish or at least give it an hour or so for cell balance, but the shunt has already reset to 100%, so you should be fine to leave it now.
The shunt doesn't reset the battery as such, it simply measures and displays the net result of incoming and outgoing currents (charging and loads), and for simplicity it nets those off against the battery capacity you enter in the battery settings screen.
A shunt is very good when the battery is in use and cycling regularly, but a small error can build when currents are very small, and or very large. Its difficult to get these errors dialled out completely using the various settings, and over time the error will compound unless the battery gets full (as it now has) and resets back to 100%
Great news, thanks to everyone who contributed. 
Subscribers do not see these advertisements
I know it's a bit of thread hijack, but I wanted to say that I got the 4 way connector that OldAgeTravellers suggested along with the cables, bought a usb to usb-C cable to connect it to my Pi running Venus OS and it's all working perfectly.
I can now monitor my MPPT controller and Shunt from anywhere in the world. I've also got two spare slots for any future Victron additions.
Lots of other features in there I've yet to discover but I found that there's a geofence option that sets an alarm off if your van is no longer where it should be!
I can now monitor my MPPT controller and Shunt from anywhere in the world. I've also got two spare slots for any future Victron additions.
Lots of other features in there I've yet to discover but I found that there's a geofence option that sets an alarm off if your van is no longer where it should be!
Fill your boots, I got all the help I needed from this chat regarding setting up my solar.
On the victron btob display is the input voltage the starter battery voltage
Yes it is.
This I mean. I have all victron stuff. Solar charger, btob, smart shunt
Subscribers do not see these advertisements
Cheers for that. When I set up my smart shunt, I had a cable that I was going to connect from the starter battery to the auxiliary input but I knackered up the input connection in the smart Shun trying to use a screwdriver for some reason, so I was never able to connect this cable to the smart Shun.
Yes, as I confirmed, however it won't be accounting for any voltage drop between the battery and the B2B, make sure all your connections are sound.
My smart shunt doesn’t always sync to 100% even if I’ve connected my mains charger and the mains charger is reading “storage “.
I have agm batteries
I have agm batteries
When the mains charger drops to storage voltage you may notice the shunt registering a small discharge the shunt counts amps in and out so this may drop the SOC to 99% or even a little lower, it should return to 100% if you go for a drive or have a sunny enough day for the solar to top it up. One thing to note if you have the mains charger connected to the network with solar and shunt, the mains charger will take preference and may shut down the solar, the solar controller will display storage mode but you will see it is not inputting any current into the battery.
Thanks for the info.
Is it quite common for smart shunts to occasionally need to manually reset the soc to 100% for AGM batteries.
As I have 600w of solar and a btob my batteries rarely go below 85%.
Is it quite common for smart shunts to occasionally need to manually reset the soc to 100% for AGM batteries.
As I have 600w of solar and a btob my batteries rarely go below 85%.
Subscribers do not see these advertisements
I've never had agm leisure batteries but it may take a little tweaking to get the shunt tuned in, especially over time the battery capacity will slowly reduce so the SOC may be incorrect, you may need to reduce the battery capacity in settings. Look at trends in the shunt when off hookup and see what your voltage drops too at night when there is no solar input and use that as a guide to your actual SOC.
Thanks again.
I don’t really use my mains charger much when I’m away, even on hook up.
it’s mostly used in winter when the vans sat on my drive and the batteries very slowly get drained.
The btob settings where a bit tricky to set up due to the euro6 engine, the input lockout voltage and the shutdown settings I mean, but I think that’s for another thread one day.
I don’t really use my mains charger much when I’m away, even on hook up.
it’s mostly used in winter when the vans sat on my drive and the batteries very slowly get drained.
The btob settings where a bit tricky to set up due to the euro6 engine, the input lockout voltage and the shutdown settings I mean, but I think that’s for another thread one day.
Join us or log in to post a reply.
To join in you must be a member of MotorhomeFun
Join MotorhomeFun
Join us, it quick and easy!
Log in
Already a member? Log in here.