my "unsolvable problem"

HighTechLab said:

Settings posted @olmz looks fine. I don't think you should change anything from where you started.

I'm not sure there is really an issue. Use a shunt and watch % SOC instead of battery voltages. LiFePO4 voltages are very hard to judge. For example, 12.8v could be 90% or 10% depending on what's going on with the system.

I never look at battery voltages in my RV, I use a Victron Smartshunt and look at the SOC% on that. Best $130 ever spent. My batteries are dead at 0% and stop charging at 100%. This means they are full capacity and life is good.

The nominal voltage of LiFePO4 is 12.8v. If what you were reporting was that they were dropping to 12.2 vs 13.2, I'd raise an eyebrow. At 13.2, your batteries are still pretty much full...is this unsolvable problem actually a real problem?

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thank you. if I may, and respectfully, it seems to be a significant problem to many, including battlenorn when I first approched them about it...they are a good company, btw.

indeed, as you will see from this link, they say that 12.8volts is not even 20% reserve:


so that may be enough to keep the inverter running...andf I am becoming aware that it is correct that this may not always be even a totally exact science...............more complicated, including solar than just get it and hook it up ....................it needs to see 12.x volts, but unless I am missing something significant, it makes a substantial difference.

so while I am not knowledgable enough to be aware of every nuance, this seems to be well beyond "nuance" into "something is not right'.

but I welcome any other comments so please have at it...as i would find it awful if indeed, it turns out that voltage readings even from the charger, mean nothing....in favor of SOC readings on a shunt (I am not doubting you, but I am in a situation where there are very heavy demands on my electrical system..emergency radio equipment, for one example.............. and in the circumstances that I am concerned about with this whole issue, should I find myself with real diminished capacity (not talking about my mental state from all these new things I have to learn ), that would be a very nasty matter...so I am going with all those voltage readings, especially as they come from the maker.

HighTechLab said:

Settings posted @olmz looks fine. I don't think you should change anything from where you started.

I'm not sure there is really an issue. Use a shunt and watch % SOC instead of battery voltages. LiFePO4 voltages are very hard to judge. For example, 12.8v could be 90% or 10% depending on what's going on with the system.

I never look at battery voltages in my RV, I use a Victron Smartshunt and look at the SOC% on that. Best $130 ever spent. My batteries are dead at 0% and stop charging at 100%. This means they are full capacity and life is good.

The nominal voltage of LiFePO4 is 12.8v. If what you were reporting was that they were dropping to 12.2 vs 13.2, I'd raise an eyebrow. At 13.2, your batteries are still pretty much full...is this unsolvable problem actually a real problem?

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You do have a very good point. The only thing that makes me wonder is the OP mentioned that his system has been functioning okay for seven years and now things are different. The other thing that I noticed on my system is that right now I have a smart shunt in my system and the state of charge is about 50% according to Victron's math and my cell voltage is 52.19 volts or 13.05 volts. (12 volt equivalent voltage).

But then again you may be entirely correct.

WindWizard said:

You do have a very good point. The only thing that makes me wonder is the OP mentioned that his system has been functioning okay for seven years and now things are different. The other thing that I noticed on my system is that right now I have a smart shunt in my system and the state of charge is about 50% according to Victron's math and my cell voltage is 52.19 volts or 13.05 volts. (12 volt equivalent voltage).

But then again you may be entirely correct.

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HRTKD said:

The cheapo clamp on meter that I keep in my RV is no longer available, so I can't recommend it. Here is one that came to the top of the list when I searched on Amazon:

https://www.amazon.com/Multimeter-Auto-ranging-Temperature-Capacitance-Plusivo/dp/B08MTY51R4

It doesn't have to be this one. The key is that it MUST be capable of "DC current".

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Hi,

I've been held up with an unscheduled medical issue......just wanted you to know that I have certainly not forgotten the measurements you asked for. also, that device you suggested is supposed to arrive today, as well.
Kindly bear with me...this remains at the top of my list for things I have any choice about....just been waylaid by doctors.
thank you.

SparkyJJO said:

I am going to presume (for the moment) that all the batteries are reaching the same voltage. Measuring one of them (for now) should suffice. What I am aiming to do is to see if the voltage at the inverter matches the voltage at the battery. If not, then there is some connection issue someplace causing voltage drop. If it is the same, then we're likely ok on the connections and need to find why the batteries are appearing to slump so fast.

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Hi,

Just wanted to let you know that I have been held up by unexpected medical needs. This remains at the top of my list and I hope you will kindly stand by for just another day or so...and I will be forwarding the measurments we discussed. thank you so much.

olmz said:

Hi,

Just wanted to let you know that I have been held up by unexpected medical needs. This remains at the top of my list and I hope you will kindly stand by for just another day or so...and I will be forwarding the measurments we discussed. thank you so much.

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SparkyJJO said:

I am going to presume (for the moment) that all the batteries are reaching the same voltage. Measuring one of them (for now) should suffice. What I am aiming to do is to see if the voltage at the inverter matches the voltage at the battery. If not, then there is some connection issue someplace causing voltage drop. If it is the same, then we're likely ok on the connections and need to find why the batteries are appearing to slump so fast.

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Good morning,

Just wanted you to know that I have begun to take the measurements you suggested. the charger/batteries are in the middle of this never ending charge cycle, showing "absorb" on the magnum panel, with voltage at 14.3 volts, "flickering" to 14.4 volts (and at 10 amps at the moment, but this is probably late in the charge cycle and I am just first able to get to this now, after a few less than accomodating days).

i have actually measured at all four batteries, and each is showing 14.4 volts, with two flicking momentarily at 14.5 volts.

I have designated, as you suggested, one battery for this little project, so going forward I will report on just one....but so far all looks to match...meaning the magnum panel readout and the batteries (all are obviously still hooked up).

kindly stand by...as soon as the absorb finishes and we get to "silent", I will go out and measure again.

thank you!

olmz said:

Good morning,

Just wanted you to know that I have begun to take the measurements you suggested. the charger/batteries are in the middle of this never ending charge cycle, showing "absorb" on the magnum panel, with voltage at 14.3 volts, "flickering" to 14.4 volts (and at 10 amps at the moment, but this is probably late in the charge cycle and I am just first able to get to this now, after a few less than accomodating days).

i have actually measured at all four batteries, and each is showing 14.4 volts, with two flicking momentarily at 14.5 volts.

I have designated, as you suggested, one battery for this little project, so going forward I will report on just one....but so far all looks to match...meaning the magnum panel readout and the batteries (all are obviously still hooked up).

kindly stand by...as soon as the absorb finishes and we get to "silent", I will go out and measure again.

thank you!

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the panel voltage has already begun to drop in silent mode.....just a few minutes after going *into* silent mode, and with the magnum panel showing 13.9 volts, two batteries, including the one we are paying close attention to, measured 13.8 volts. here we are now...jut a few minutes later, showing 13.5 volts on the magnum panel and the battery (actually two of them, including our "official" test battery) measure 13.6 volts at terminals.

so provided that we have a consistent tenth of a volt difference between magnum panel and battery(s), unless you think that is significant, they are the same.

thanks again.

Please post up the settings from your magnum remote so we can see the charging settings and inverter settings.

You do not have a magnum BMK shunt kit, correct?

olmz said:

the panel voltage has already begun to drop in silent mode.....just a few minutes after going *into* silent mode, and with the magnum panel showing 13.9 volts, two batteries, including the one we are paying close attention to, measured 14.8 volts. here we are now...jut a few minutes later, showing 13.5 volts on the magnum panel and the battery (actually two of them, including our "official" test battery) measure 13.6 volts at terminals.

so provided that we have a consistent tenth of a volt difference between magnum panel and battery(s), unless you think that is significant, they are the same.

thanks again.

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so one thing. my previous observation of the panel voltage "settling in" at 13.6 was not actually correct....very sorry...it is clear that this time, anyway, and perhaps this has been the case all along, the voltage at silent, has begun, at least some times, higher than 13.6....this is all happening so fast that perhaps the "13.9" volt panel measurement actually started at, say, 14.0 or 14.1......but nevertheless, the precipitous drop starts immediately and is already not far from the 13.2 or 13.1 at which it rests every time (regardless, then, of the starting voltate, so to say).

jberger said:

Please post up the settings from your magnum remote so we can see the charging settings and inverter settings.

You do not have a magnum BMK shunt kit, correct?

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sure. they remain at 14.4 for "absorb", 13.6 for "float" and 13.2 for "REbulk".
at this "custom" setting group, there is no separate setting for "bulk", but BB says that the bulk and absorb settings should be the same at 14.4 (and as high, I think, as 14.6).

at BB's direction, I have, indeed, tried 14.6 volt setting for "absorb", but it made no difference in the matter.

thank you.
PS later today or tomorrow, I am going to try CC/CV settings, the one thing not tried yet with all this back and forth.

olmz said:

sure. they remain at 14.4 for "absorb", 13.6 for "float" and 13.2 for "REbulk".
at this "custom" setting group, there is no separate setting for "bulk", but BB says that the bulk and absorb settings should be the same at 14.4 (and as high, I think, as 14.6).

at BB's direction, I have, indeed, tried 14.6 volt setting for "absorb", but it made no difference in the matter.

thank you.
PS later today or tomorrow, I am going to try CC/CV settings, the one thing not tried yet with all this back and forth.

Click to expand...

PS the problem remains whether I use these custom settings as BB directed, or the magnum preset for Lion batteries

olmz said:

sure. they remain at 14.4 for "absorb", 13.6 for "float" and 13.2 for "REbulk".
at this "custom" setting group, there is no separate setting for "bulk", but BB says that the bulk and absorb settings should be the same at 14.4 (and as high, I think, as 14.6).

at BB's direction, I have, indeed, tried 14.6 volt setting for "absorb", but it made no difference in the matter.

thank you.
PS later today or tomorrow, I am going to try CC/CV settings, the one thing not tried yet with all this back and forth.

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sorry...I do not have a shunt kit. have been using voltages/direction from BB to try to run this down.

I would suggest getting one of these :


I use that clamp meter to know how much is being drawn all the time. With it you will know how much power is actually being drawn from your batteries and you can use it to actually track down what is using the power be it the inverter or another drain from the rv's 12v stuff.

Crowz said:

I would suggest getting one of these :

Uni-T B4Q094 UT210E True RMS AC/DC Current Mini Clamp M W Capacitance Tester: Amazon.com: Industrial & Scientific

Uni-T B4Q094 UT210E True RMS AC/DC Current Mini Clamp M W Capacitance Tester: Amazon.com: Industrial & Scientific

www.amazon.com

I use that clamp meter to know how much is being drawn all the time. With it you will know how much power is actually being drawn from your batteries and you can use it to actually track down what is using the power be it the inverter or another drain from the rv's 12v stuff.

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thank you kindly. a moderator here ("boondocker") who has been so gracious...as have so many....in guiding me, suggested the same thing, gave me a link for one which he felt would work....making sure it measures both AC AND DC voltages.....I ordered and received it....and am now reading instructions on using it.

I have a fluke VOM and believe in them, and thought I needed some expensive piece of equipment to do this, too...but he suggested not, and the piece came in yesterday.

thanks for the suggestion!

fyi and fwiw, this is the one:

Now that you have the clamp meter then put it over your wires and put it on DC amps and show us what you measured and where you measured it and possibly we can figure this thing out.

Just an FYI, I've got (2) MS2812 with LFP batteries.
I often see that the inverter voltage and the BMK voltage are different with the BMK. The BMK is much more accurate to what I actually measure at the batteries themselves.
I have mine set to CC/CV and finish based on end amps. I don't rebulk until the back is around 10-15% charge and I don't float at all.
rebulk in magnum settings is really just restarting the full charge cycle.

I think you have 2 issues you are dealing with here:
I think your wiring is drawing down one battery before the others and that's leading to a lot imbalance on the low end.
I also think your batteries themselves are never getting fully charged, and are themselves imbalanced both internally and compared to the others in the group.

WindWizard said:

Now that you have the clamp meter then put it over your wires and put it on DC amps and show us what you measured and where you measured it and possibly we can figure this thing out.

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i am looking at the documentation now...and within a day or two, expect to take the measurements and report in. many thanks

jberger said:

Just an FYI, I've got (2) MS2812 with LFP batteries.
I often see that the inverter voltage and the BMK voltage are different with the BMK. The BMK is much more accurate to what I actually measure at the batteries themselves.
I have mine set to CC/CV and finish based on end amps. I don't rebulk until the back is around 10-15% charge and I don't float at all.
rebulk in magnum settings is really just restarting the full charge cycle.

I think you have 2 issues you are dealing with here:
I think your wiring is drawing down one battery before the others and that's leading to a lot imbalance on the low end.
I also think your batteries themselves are never getting fully charged, and are themselves imbalanced both internally and compared to the others in the group.

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Now, that is very interesting.

First, I am about to change to CC/CV to see what, if anything that does. I expect to have that done, if not tonight, by tomorrow. I would love for that to be the issue.

as to your comment about "wire", would you be so kind as to say "why" you think this. just about everyone I have heard from ....even at BB.....does not think there is any problem with the wiring.....and perhaps you saw here that I posted a graphic, never mind actual photos of the wiring, that I got from BB and used to wire the batteries.

Indeed, when I can get my tech back here (he is unwell, himself), I am going to have two victron busbars mounted on the side of the compartment and then try the wiring though those, as I have been concerned about one terminal....the positive terminal on the battery in my photo to the right of the compartment as you are facing it through the photo...the one "closest" to the compartment door on the right as you look at the photo.....as even though it is as per the instructions, there is a lot going on on that one terminal and it has made me wonder.

yet, so many have suggested that that is not an issue....so I am not challenging you, but I sure would like to know why you think this, PLEASE...and what you think the alternative should be....and if it is two busbars whether or not you think that solves this.

at the same time *why*, please, do you think that the batteries are not being fully charged? same reason?

many thanks.!

ps what BMK do you use?

PPS because I usually believe in overkill in crucial matters, and insofar as I intend to vastly increase the number of batteries in the near future, I chose wires that are larger than what was needed. "nobody" had any problem with any of that. indeed, the comments were always that there is a problem with "too small" but not "too big". do you agree with this?

again, thanks.

olmz said:

sorry...I do not have a shunt kit. have been using voltages/direction from BB to try to run this down.

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Without a shunt you are chasing your tail with voltage. LiFePo4 need a shunt for coulomb counting for the SOC of the batteries, I find it hard to believe that BB didn't say this but it is mentioned in their battery monitor section but use Victron stuff. Magnum has the ME- BMK. So you are saying that there is no shunt that is communicating/ interacting with the charger/ inverter? I believe this is your problem and not getting the full functionality of the charging/ inverting system.

After charging the lfp batteries they will always drop in voltage to their resting voltage if you have no loads on them but an rv will always have some sort of 12v loads. You have something that is drawing 12v draining the battery even slighly. Co detector, fridge, fans for fridge, maybe landing gear but something is drawing power and that is what needs to be found.

Edit... wiring batteries especially 8 of them, something to read and think about. BB batteries have a lot of small cyclinder cells making up 1 100ah battery now multiple by 8.

http://www.smartgauge.co.uk/batt_con.html

Sojourner1 said:

Without a shunt you are chasing your tail with voltage. LiFePo4 need a shunt for coulomb counting for the SOC of the batteries, I find it hard to believe that BB didn't say this but it is mentioned in their battery monitor section but use Victron stuff. Magnum has the ME- BMK. So you are saying that there is no shunt that is communicating/ interacting with the charger/ inverter? I believe this is your problem and not getting the full functionality of the charging/ inverting system.

After charging the lfp batteries they will always drop in voltage to their resting voltage if you have no loads on them but an rv will always have some sort of 12v loads. You have something that is drawing 12v draining the battery even slighly. Co detector, fridge, fans for fridge, maybe landing gear but something is drawing power and that is what needs to be found.

Edit... wiring batteries especially 8 of them, something to read and think about. BB batteries have a lot of small cyclinder cells making up 1 100ah battery now multiple by 8.

http://www.smartgauge.co.uk/batt_con.html

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ok.....let me try to ask this in a way that I can be sure I get it all.

first, are you saying that without a shunt, the batteries are not even charging properly or that I am simply being deprived of a better way to measure capacity?

next, i certainly do have a few things drawing on the electrical system, albeit these days, while always hooked up to shore power. are you saying that such as, say, a large residential fridge (or an airxcel AC...that the fridge being the only things drawing any appreciable power under most circumstances), even with shore power, is drawing enough power to make an immediate difference such that they will lower a fully charged battery bank within 20 minutes to a voltage level which BB's own charts show to be a heavily depleted battery?

I do have big foot struts, so to say, but once down they are off.........and other than small LCD tvs and lights, I have no clue what else would be drawing enough power, especially on shore power, that I would lose...at least based on voltages which BB says represent a huge drop in capacity...........such large amounts every single time...with the system automatically going back into another charge cycle each time. do you have any thoughts about that?

also, just to be sure, as you mentione 8 batteries. I HAVE 8 batteries, but it is only material in terms of having tried two separate groups of 4 while I sort this out. are you saying what you are, thinking I have all 8 hooked up at one time?

I have previously had, as mentioned, 2 sets of batteries....both AGMs.....one a no name Chinese set of 4 (6 volts wired serially) and the second set, Lifelines...great batteries but for a variety of reasons, I decided to move to BBs..........neither set of AGMs produced this "oddity" with voltate dropping precipitiously. why would that happen "now"....all my equipment is the same.....same fridge, same ACs and so on......and not for 7 years prior? this literally happened the minute I "dropped" these in.

I am getting a lot of input from a lot of people and I am grateful for it, but my head is spinning from some of it and I need to be better understand all this. if you would be so kind as to answer the above in as granular a fashion as you can, I would much appreciate it.

many thanks1

I'm guessing and correct if wrong you do not have bluetooth on the BB batteries to see their individual voltages? Whether you have 4 or 8 batteries hooked up they need to be balanced and wired evenly for this to happen. Read that link that I posted.

If you had a shunt you would be able to see what you dc draw live time on the batteries.

olmz said:

first, are you saying that without a shunt, the batteries are not even charging properly or that I am simply being deprived of a better way to measure capacity?

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The shunt would tell you if current is going in or out and how much. In your case, the shunt would not limit how much the batteries get charged.

Until you hook up your clamp meter over the wire from your red positive battery cable and let us know how many amps you are using out of your battery, then it is only speculation whether you have bad batteries or a large current draw.

Have you determined that none of the batteries BMS are tripping or tripped and you are not running on less than four batteries? With four hooked up in parallel you will see proper voltage even if only one battery is operational.

If you have a clamp on amp probe run the system and get it to finish charging where it has the voltage drop and check each individual battery for amp draw, if you had three of your batteries BMS tripped and were running on one I would bet when finished charging the load would pull the surface charge off rapidly causing the voltage to drop and the charging to start again depending on you settings.

I might be totally off base here but it is simple to rule it out.

olmz said:

neither set of AGMs produced this "oddity" with voltate dropping precipitiously. why would that happen "now"....all my equipment is the same.....same fridge, same ACs and so on......and not for 7 years prior? this literally happened the minute I "dropped" these in.

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This implies that there is something wrong with the BB's

WindWizard said:

This implies that there is something wrong with the BB's

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Or how they are being charged.

I'd try running with 2 BBs and then with the other 2.