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01-10-2025, 10:27 AM
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#1
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4 Rivet Member 
2019 22' Sport
Sharon
, Massachusetts
Join Date: Apr 2019
Posts: 292
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Need Help Understanding BMV-712
I recently installed a BMV-712. My system now includes an IP43 12/50(1+1), an Orion XS, and a SmartSolar MPPT75/15 along with two Lifeline AGMs and a single factory solar panel.
My question is why does the BMV show the batteries at 65% charge when the battery voltage (with only parasitic loads) is at 12.05 volts. I thought 50% was around 12.2 volts for a lead acid battery.
Also, while towing, will the batteries be charged by both the Orion XS (DC-DC charger) and the solar? Everything is in the same VE network.
Thanks in advance, Mark
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01-10-2025, 09:27 PM
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#2
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Rivet Master 
1988 32' Excella
Robbinsville
, New Jersey
Join Date: May 2012
Posts: 3,645
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Are your batteries 100 amp hour each?
If they are only 80 AH each your BMV-712 is configured wrong.
How old are your batteries?
If your batteries are a few years old they may have lost some capacity. Also AGMs have less capacity in cold temps. What temp are the batteries at?
The batteries also need to be fully charged to sync at 100% charge(which can take more then 24 hours charging on shore power) before you can get an accurate reading..
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01-11-2025, 09:03 AM
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#3
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4 Rivet Member 
2019 22' Sport
Sharon
, Massachusetts
Join Date: Apr 2019
Posts: 292
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Wondering about Configuration
Quote:
Originally Posted by Wazbro
Are your batteries 100 amp hour each?
If they are only 80 AH each your BMV-712 is configured wrong.
How old are your batteries?
If your batteries are a few years old they may have lost some capacity. Also AGMs have less capacity in cold temps. What temp are the batteries at?
The batteries also need to be fully charged to sync at 100% charge(which can take more then 24 hours charging on shore power) before you can get an accurate reading..
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I was wondering about the configuration, but I think it's correct. Maybe sync? I did not do a manual sync; I just let it figure it out automatically. Photo of config is attached. Sorry, I should have included this with my original post.
I have two 80 Ah batteries, so I have capacity at 160Ah. Charged voltage is set to 13.2V. Battery temps are 20-30F and they're 5 years old.
Thanks, Mark
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01-11-2025, 12:25 PM
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#4
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Rivet Master 

2023 25' Globetrotter
2021 16' Bambi
Forest Lake
, Minnesota
Join Date: Mar 2021
Posts: 1,893
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And as you know you're all set up for lithium batteries which have gotten pretty cheap and there's a number of good options that fit the battery box up to 300Ah.
With our Victron shunt I gave up on the automatic reset settings. I found it will reset after an "event" which might not be valid unless you fuss with the settings and get them just right. I turn this option off and do a manual reset occasionally after being plugged in for an extended time. I have never tested the stated capacity of our 400Ah of batteries to see if they really hold 400Ah, but we have never played it that close to where we are less than 20% or so of assumed capacity.
With the XS and solar, yes they both should be charging. I have a similar setup and with the VE.Smart Networking turned on they play together (make sure it's turned on at each device).
__________________
2023 Globetrotter 25FBT "Curly"
2017 Audi Q7 3.0T
WBCCI 6343
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01-11-2025, 04:27 PM
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#5
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4 Rivet Member 
2019 22' Sport
Sharon
, Massachusetts
Join Date: Apr 2019
Posts: 292
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Quote:
Originally Posted by JeffKim
And as you know you're all set up for lithium batteries which have gotten pretty cheap and there's a number of good options that fit the battery box up to 300Ah.
With our Victron shunt I gave up on the automatic reset settings. I found it will reset after an "event" which might not be valid unless you fuss with the settings and get them just right. I turn this option off and do a manual reset occasionally after being plugged in for an extended time. I have never tested the stated capacity of our 400Ah of batteries to see if they really hold 400Ah, but we have never played it that close to where we are less than 20% or so of assumed capacity.
With the XS and solar, yes they both should be charging. I have a similar setup and with the VE.Smart Networking turned on they play together (make sure it's turned on at each device).
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Yes, I have two LiTime 100Ah batteries ready to get installed; that's why I installed all the new Victron devices. I wanted to make sure the Victron items were installed correctly, and I understood the various configurations, prior to installing the batteries.
When you say, "I gave up on the automatic reset settings", I assume you are referring to the synchronization. After reading your post, I did a manual synchronization, so I'll test the 50% SOC reading in several days when I have time to keep an eye on things.
Regarding the VE Smart Networking, yes, I have all devices set up and the system shows they're all online. Thanks for letting me know they do in fact work together.
Thanks again, Mark
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01-11-2025, 05:39 PM
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#6
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Rivet Master 
1988 32' Excella
Robbinsville
, New Jersey
Join Date: May 2012
Posts: 3,645
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That seems strange, your first picture shows 81.8 Ah consumed and 65% charge. That would be close to 50% of 160 Ah.
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01-11-2025, 06:34 PM
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#7
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Rivet Master 

2015 Interstate Grand Tour
Salem
, New Hampshire
Join Date: Jun 2022
Posts: 1,115
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Quote:
Originally Posted by MSL
I was wondering about the configuration, but I think it's correct. Maybe sync? I did not do a manual sync; I just let it figure it out automatically.
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Below is a very good detailed post on setting up the BMV 712 that was posted the other day on another forum. The poster is a darn Victron guru and I always seem to learn something from his posts. This is good information for everyone as there are always questions on Victron shunts.
https://diysolarforum.com/threads/vi...-others.97606/
__________________
"If you can't send money, send tobacco."
-George Washington
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01-11-2025, 07:58 PM
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#8
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4 Rivet Member 
2019 22' Sport
Sharon
, Massachusetts
Join Date: Apr 2019
Posts: 292
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Quote:
Originally Posted by Wazbro
That seems strange, your first picture shows 81.8 Ah consumed and 65% charge. That would be close to 50% of 160 Ah.
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Yes, that's why I created the original post; it didn't make sense to me.
Mark
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01-11-2025, 10:45 PM
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#9
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Site Team

1994 25' Excella
Waukesha
, Wisconsin
Join Date: Sep 2020
Posts: 6,365
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In order for the BMS to be accurate ALL the negative cables must route through the shunt. If you have anything routing to the battery bank's negative connection which bypasses the shunt you will get inaccurate and confusing readings.
Are you sure that all your negative cables are routed through the shunt?
__________________
Richard
11018
1994 Excella 25 'Gertie' Follow the build on Gertie!
1999 Suburban LS 2500 w/7.4L V8 'Bert'
1974 GMC 4108a - Custom Coach Land Cruiser 'The Bus' (Sold)
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01-12-2025, 09:47 AM
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#10
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4 Rivet Member 
2019 22' Sport
Sharon
, Massachusetts
Join Date: Apr 2019
Posts: 292
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Quote:
Originally Posted by richard5933
In order for the BMS to be accurate ALL the negative cables must route through the shunt. If you have anything routing to the battery bank's negative connection which bypasses the shunt you will get inaccurate and confusing readings.
Are you sure that all your negative cables are routed through the shunt?
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Yes, all loads go to the correct side of the shunt; only shunt connected to negative side of battery. Mark
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01-12-2025, 09:49 AM
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#11
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4 Rivet Member 
2019 22' Sport
Sharon
, Massachusetts
Join Date: Apr 2019
Posts: 292
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Quote:
Originally Posted by StogieMan
Below is a very good detailed post on setting up the BMV 712 that was posted the other day on another forum. The poster is a darn Victron guru and I always seem to learn something from his posts. This is good information for everyone as there are always questions on Victron shunts.
https://diysolarforum.com/threads/vi...-others.97606/
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Thanks. This is very informative, but I think I have everything configured correctly. I read thru the post, will do so again (and save it on my laptop).
Mark
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01-13-2025, 11:50 AM
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#12
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Rivet Master 

2023 25' Globetrotter
2021 16' Bambi
Forest Lake
, Minnesota
Join Date: Mar 2021
Posts: 1,893
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Quote:
Originally Posted by MSL
Yes, I have two LiTime 100Ah batteries ready to get installed; that's why I installed all the new Victron devices. I wanted to make sure the Victron items were installed correctly, and I understood the various configurations, prior to installing the batteries.
When you say, "I gave up on the automatic reset settings", I assume you are referring to the synchronization. After reading your post, I did a manual synchronization, so I'll test the 50% SOC reading in several days when I have time to keep an eye on things.
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Sounds good! I think it might be simpler having the lithiums, the charging profile is simpler and don't have to worry about discharge temperature, etc.
Yes, the synchronization is what I meant. It would explain why you were seeing higher charge percentage if it reset at some point automatically. I might still dink around with the settings and make it automatic, but after getting burned before, I trust the manual reset more. If it resyncs automatically and it's wrong then I'm out of luck until we get to a place I can plug in and charge them up fully so I know they're at 100%.
__________________
2023 Globetrotter 25FBT "Curly"
2017 Audi Q7 3.0T
WBCCI 6343
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01-15-2025, 10:34 AM
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#13
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4 Rivet Member 
2019 22' Sport
Sharon
, Massachusetts
Join Date: Apr 2019
Posts: 292
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Quote:
Originally Posted by JeffKim
Sounds good! I think it might be simpler having the lithiums, the charging profile is simpler and don't have to worry about discharge temperature, etc.
Yes, the synchronization is what I meant. It would explain why you were seeing higher charge percentage if it reset at some point automatically. I might still dink around with the settings and make it automatic, but after getting burned before, I trust the manual reset more. If it resyncs automatically and it's wrong then I'm out of luck until we get to a place I can plug in and charge them up fully so I know they're at 100%.
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Thanks again, Jeff. I'm glad I went with Victron for all this stuff, but there definitely is a learning curve.
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