Victron monitor defaults and programming

[GeorgeRad]

So 36amps would be divided by the time since last full discharge ie, battery was full from whatever source until it was recharged by the first source ie; 36 amps from 10pm to 7am would be 36amps ÷ 9 hours = 4amps per hour average?

I used an example of fever at 310 degree to indicate importance of using correct units. It makes big difference if it is 310 K or C or F. Same in physics amps or hours.

36 Ah / 9 h = 4 A, not 4amps per hour which is meaningless.

 

[themexicandoctor]

Not amps. Ah is amp hour or ampere hour.

This I understand, amp hours, not amps.

If anyone who owns & understands these systems as many of you do & are in Los Angeles, I will gladly pay you $100 Cash for 90 minutes of instruction because its not my area of expertise & I believed that I had bought the best possible equipment & yet I appear confused.

I was sitting Fat, Dumb & Happy until the last couple of weeks.

My Fridge arrives next week & I believed that I had enough solar hardware up on the roof & the daily driving (sometimes an hour or more, sometimes not), that the new DC Fridge would not tax my system but merely exercise it.

ANY TAKERS? NOTE; THAT I THINK & LEARN IN PICTURES SINCE MY COMA.

I am not joking, understanding many complex concepts like this has been very difficult & so while I do what I think is adequate research, I then pay Professionals to do all the installation after conferring with them that my choices are on point.

 

[booster]

It makes it clear the default setting is 0200 ah.

I also reset the Auxiliary Input to the original TEMP versus the other options of Start or Mid Point.

Then the writing in the very next sentence is;

The BMV is now ready for use.

I rarely synchronize the unit, I was of the belief that if the batteries reached full capacity for a certain amount of time that the meter synchronizes itself.

You have just plainly stated the exact reason that I started this thread on the Victron defaults and settings.


My point was, and still is, that while the monitor itself appears to be a good quality unit, the instructions have been "simplified" so much, and defaults made to conservatively, that there is nearly no chance that the monitor will work well for many/most people. The whole goal is to help those that have the Victrons get a better understanding of how they are supposed to work and help get the settings to the point that they work well for the system they are installed on. IMO, almost no one would be able to accurately setup the Victron from their instructions unless they were already knowledgeable about how to set up a monitor.


Sharing the experience from existing Victron users and others with different monitors is a good way for all to learn more about their, and other, systems and how to make them work better.


Re the synchronization, with the numbers that you have gotten and posted.


Yes the monitor should synchronize once it sees full batteries (per the programmed specs) for a period of time, and it is probable that your system is synchronizing that way. The following is what I think may be happening for you to show such a low amp hour use and a very low battery voltage for you size battery bank. The voltage, and thus state of charge should be much higher. This is what it appear you have.



* You have the default settings of 13.2 volts and 4% of amp hour capacity set for the thresholds for indicating a full battery (defaults). 200 amp hour battery capacity which is correct, I think. This will cause a very early full battery indication and synchronization.



* You mention the low battery threshold being 12.2 volts, but the minimum voltage hit is shown at nearly down to 11.9 volts. Edit, I just noticed the generator starting thread and checked and that seems to apply here, so later numbers are getting changed to use the12.2v instead of 11.9v as the 11.9v was during generator starting.



* If we choose the 12.2 volts, that is about 50% state of charge for rested batteries per the Lifeline chart.


* 34 amp hours of use used 50% of your capacity, so you had 68 amp hours of real capacity. 68 amp hours from 200 amp hours of battery is pretty low. You would have used 34 amp hours and had 34 amp hours left.


* If the monitor synchronized early because of the settings and used the 200 amp hour full capacity it would tell you that you had about 83% of capacity left, or 156 amp hours after 34 amp hours were used . But you started at 68 amp hours so would only have 34 amp hours left and the monitor would still tell you that you were at 83% full and 156 ah left. You would keep using them until they were near dead because you thought there was a lot of energy left in the batteries.



This would indicate either totally worn out batteries or a severe undercharging situation, I think, and may have been at least partially caused by the monitor resetting early on less than full charges, making you think you had more battery capacity left than you did and running them to near dead on every cycle, slowly walking the battery capacity down to where you are now. Just a guess, but can't think of any other way you could get those readings. The batteries are behaving as if they only have 68 amp hours of capacity in the numbers shown run.


edited to use 12.2v instead of the 11.9v because the 11.9v was during a generator start.

 

[themexicandoctor]

I appreciate your input Booster.

Like I mentioned in another post, if someone gave you the space shuttle you would take it apart so you could restore it for peak performance.

Going to read this slowly before I answer.

 

[booster]

I appreciate your input Booster.

Like I mentioned in another post, if someone gave you the space shuttle you would take it apart so you could restore it for peak performance.

Going to read this slowly before I answer.

Executive (or may Dr.) summary: Your 200 amp hours of batteries are performing like 68 amp hour batteries. Probably because the Victron settings are causing it to synchronize way early. The Victron still thinks you have 200 amp hours to use and tells you that wrong amount. Thinking you have a lot more energy than you do, you run the batteries way too low, possibly damaging them. Repeatedly......

 

[themexicandoctor]

Executive (or may Dr.) summary: Your 200 amp hours of batteries are performing like 68 amp hour batteries. Probably because the Victron settings are causing it to synchronize way early. The Victron still thinks you have 200 amp hours to use and tells you that wrong amount. Thinking you have a lot more energy than you do, you run the batteries way too low, possibly damaging them. Repeatedly......

Somewhere, I think there is an error.

I cannot determine how, where or what of the 50% figure either. I do not have my battery monitor set up to warn me at 50 SOC but to have it warn me when the batteries get to 12.2 volts (although I do understand that 12.2 is 50% of an agm 100ah battery)

I do understand 50% of a 200Ah battery bank is approximately 100ah (usable amp hours), I am getting confused as to where the 50% & 36 amps came together.

I don't even know where the 50% amount came from.

Maybe it was my presentation of the what I saw.

I do know 36ah is 36% of 100ah & there should be a residual 64% or 64ah left before it reaches 50% of total ah but 100% of usable ah ie; the battery bank is 200ah (2x Lifeline AGM Group 27 100ah batteries) but at 50% of 200ah, they are 100% extinguished.

The 36ah was the deepest discharge for quite a while.

Are you saying I should have my amp hour capacity on the BMV712 set to 100ah to accurately tell the system what is 100% of usable capacity?

I am going to include a couple of photographs, the first one is of the BMV712 which shows my House Batteries 30 minutes ago after just solar all day & 6 minutes of driving just now, to me the batteries look really healthy at 12.89.

 

[themexicandoctor]

The second photo is what you saw before highlighting the deepest overnight discharge of 36h in weeks.

If you notice the low starter battery voltage, its because I left my radio on all day & had to get the battery jumped just now & drove it for 5 minutes.

 

[themexicandoctor]

The next 2 photos are of the the MTTP Reading at the same time as the BMV712.

And today's solar history which to me looks really good.

Some bulk, lots of float unless it is going into float too early but remember, I don't have the fridge installed yet.

 

[themexicandoctor]

In the breakdown of time in each category today* it was;

Bulk 6 hours 29 minutes or 47%

Absorption 2 hours or 15%

Float 5 hours 12 minutes or 38%

*did have a light load on the inverter for 90 minutes today.

It was very sunny.

 

[themexicandoctor]

I did notice I had my charge efficiency factor set to only 95% & yesterday it was only 90%.

I just changed it via the Bluetooth to 100%.

 

[themexicandoctor]

Does this help.

This morning when I rest the BMV712 I noticed that I had the LOW SOC Alarm disabled.

But I did have the Low Voltage Alarm set to 12.2.

Now when it gets low say 12.4 or 12.3 & I turn on the Generator could have stimulated the Low Voltage Alarms because of the transient load of the house batteries stsrting the Generator.

When I look at those historic BMV712 figures but for the aberrations of the 11.91 (due to generator start up) or the 5 low voltage alarms, I think my batteries look in good condition.

 

[themexicandoctor]

FYI;

From my friend at Lifeline.

I don't know if all LIFELINE owners are aware of this but the setting Absorption on a Magnum Charger should be 14.4 (not 14.3 like Magnum wants).

Float should be 13.4 (not 13.3).

And Equalisation should be 4 hours at 15.5.

I only mention this because in researching what everyone has written here in an attempt to understand I see the Absorption at 14.3 & Float at 13.3.

 

[booster]

FYI;

From my friend at Lifeline.

I don't know if all LIFELINE owners are aware of this but the setting Absorption on a Magnum Charger should be 14.4 (not 14.3 like Magnum wants).

Float should be 13.4 (not 13.3).

And Equalisation should be 4 hours at 15.5.

I only mention this because in researching what everyone has written here in an attempt to understand I see the Absorption at 14.3 & Float at 13.3.

Here is a quote from the Lifeline Technical Service manual

In the second stage, the voltage is held constant at the same pre-set limit until the charging current tapers to a very low value, at which point the battery is fully charged. The second stage is often called the Absorption charging stage. A voltage setting of 14.3 volts ± 0.1 volts (7.15 ± 0.05 volt for a 6-volt battery) should be used when the battery temperature is 77°F (25°C). The battery is considered to be fully charged when the current drops below 0.5% of the battery’s rated capacity (0.5A for a 100Ah battery). The absorption stage will typically last 2 – 4 hours before the current reaches this level.In the third stage, the charging voltage is reduced to a lower value that minimizes the amount of overcharge, while maintaining the battery at 100% state of charge. This third stage is often called the Float charging stage. A float voltage of 13.3 ± 0.1 volts (6.65 ± 0.05 volts for a 6-volt battery) should be used when the battery temperature is 77°F (25°C). The charging voltages at other temperatures can be determined from the following table:

That said, I have communicated with the Lifeline techs several times on a lot of different issues and questions that have come up, and they feel that the charge and float voltage settings are really kind of a "best fit" type of thing and somewhat dependent on other variables.



Things like repeated deep discharges and only overnight charging might indicate using a slightly higher absorption voltage like 14.6v and 13.5v float. Shallow discharges less often and longtime float, going down to 14.1v and 13.1v could be appropriate to reduce gassing.


A couple of tenths of charging voltage is probably a minor issue compared to chronic over or under charging, which is very common is RVs.

 

[markopolo-ClassB]

This info is encouraging:



It looks as though the batteries are possibly/likely getting back to full or near full daily. You'd need to know the tail amps / current in to know for sure.

 

[booster]

This info is encouraging:

View attachment 9511

It looks as though the batteries are possibly/likely getting back to full or near full daily. You'd need to know the tail amps / current in to know for sure.

Those do look a whole lot better, but as stated without the tail amps we don't know for certain. It would also be interesting to know what the load was at the minimum voltage, as that is what messed us up on other voltages.


The 700 watt hours is about 50 ah at the 14.4 volts and with charge efficiency maybe net 47 amp hours available. This is about 20% of battery capacity, but during the day a lot of it will go to run things most likely, so maybe half to the batteries? Also throw in driving charging and even harder to know.


But the 12.2-12.4v would indicate the charge is bouncing around somewhere somewhere in the 50-70% range on the low end so not as bad as the earlier thoughts. How far beyond the current tapering area around the 80% SOC it is going to depend on how soon during the day it gets there. In good sun, our solar will often have enough time to get to sun if we are down only 30 amp hours or so, and we start out in the tapering area of charging but our bank is big enough to take all the solar anyway.


It would be interesting to see what the charge control on the solar is to see if it is timed or algorithm, which is more likely I think. How long the solar stays in absorption is going to be the critical part of getting full. If it goes to float early, about all it will be doing is running the van for a lot of the day.


The max solar output is about 11 amps at 14.4v, so it wouldn't take much lowering of the output during the day to make the monitor show full batteries with 4% amp setting (8amps), and that would be assuming no van power use reducing the amps to the battery even more.


I wonder if the Victron can give a history for the battery charging amps over time. That would have to come from the monitor as the solar is not tied to the shunt unless you have the whole Victron control system, I think. Knowing the tail amps is, as always, the big deal.


This system is probably cycling in the 50-85% SOC range like most we see and hear about. Rarely completely full, but enough power to run everything, including a compressor frig with 200 amp hours of battery.

 

[booster]

I looked at the Victron information for the 100/30 controller and found some information to look at in the manual. It does not appear to connect to a monitor or shunt for control, but no wiring diagram in the manual which is odd.

Looks like you can set tail current, but it would be internal to the solar so be affected by loads in the van like similar shore chargers are. Getting to below 2 amps and with some load from the van, it would likely never get to float from tail current and would only float at the end of the algorithm absorption timer.


The absorption timer, if it starts at 12.2v or above is only 1/3 of two hours (40 minutes), so there is really very low chance it will get very far into the tapering area of the charge, so not likely to go much above 85-90%. Add to that the timer is going to start at sunrise on a discharge battery and you won't get much good solar output at all by the time the absorption ends. It does say some of this is settable, so this system may have been changed.

 

[themexicandoctor]

Thank you Gentlemen,

I just posted 5 new photos in this thread;

https://www.classbforum.com/forums/...ron-bmv712-and-a-victron-mttp-unit-10771.html

Maybe in those you will be able to get more info.

The last few posts you sent Booster might as well as have been in Swahili - way beyond my present knowledge today.

Here is some more photos of my MTTP & BMV712 Settings next

 

[themexicandoctor]

The first is of the MTTP Settings

The second & third is two views, upper & lower of the Presets.

PS. I have my Magnum set at 20amps Shore Power but the Victron MTTP at 30amps (its a 30/100).

Is there anything in my Settings that is incorrect?

 

[themexicandoctor]

I do see my Tail Current is set for 2.0amps.

Then below that where it says Battery Monitor I see the ominous figures of charge efficiency at 11%, discharge floor at 11% & state of charge when bulk finished at 11%.

Are these numbers important?

 

[@Michael]

The absorption timer, if it starts at 12.2v or above is only 1/3 of two hours (40 minutes), so there is really very low chance it will get very far into the tapering area of the charge, so not likely to go much above 85-90%. Add to that the timer is going to start at sunrise on a discharge battery and you won't get much good solar output at all by the time the absorption ends. It does say some of this is settable, so this system may have been changed.

Absorption timer starts after bulk charge to absorption transition<?>. If so, staring in the morning it'll bulk charge untill it hits the absorption threshold, then start the absorption timer.