Old Magnum MS2812 and new Lithiums

[Kevin D Pem]

What you want! (In above Pic)
The picture isn't clear that is what you have!

You showed the ground lug, but explain your reasoning for it!

My preference!(in above Pic)

The cable size is not going to be the problem under low load! So for trouble shooting don't change that. If you want to upgrade later that's fine

On the first diagram, I can't tell if your power is being drawn from (cables from one battery)one battery,or each end of the bank!

Because that issue is significant clarify that for me!

 

[nsr1357]

Please complete these connections

View attachment 25273

 

[nsr1357]

View attachment 25279

What you want! (In above Pic)
The picture isn't clear that is what you have!

You showed the ground lug, but explain your reasoning for it!

View attachment 25280

My preference!(in above Pic)

The cable size is not going to be the problem under low load! So for trouble shooting don't change that. If you want to upgrade later that's fine

On the first diagram, I can't tell if your power is being drawn from (cables from one battery)one battery,or each end of the bank!

Because that issue is significant clarify that for me!

got it all. the ground was there when the factory first produced this trailer, which included 3 asto panels, a midnite solar controller and the ground wire you saw. when we changed to what we understood to be a "drop in" replacement, we simply left it there, used it again the way it had been previously,..but changed all the battery to battery wires and those off of the array, as well.
as to the cable sizes, i am glad to say I am learning fast and actually guessed you would say what you did...and for now, the loads when shore power goes off, are, indeed, small. HOWEVER, one wonders if 1/0 rather than 4/0 might be affecting the charge currents coming in, although even there, my guess is likely not....i note that when in bulk and absorb charging, even when amperage is three figures for a while, it does not approach the max handling of the 1/0 cable that is on there..so I am going to change it but as you suggest, will leave it all alone for now.
meantime, I received today, appropos this thread, the following chart from my cable supplier and put this link here to try to give a little back to all of you here. hopefully folks here will find it useful (I note the specs on 1/0 vs. 4/0...also, fwiw, I always order UL multi-rated cable):

https://www.batterycablesusa.com/assets/images/battery_cable_compare.pdf

 

[Kevin D Pem]

OK I found what I wanted in the pictures.

Now on to my second thought.

The only difference is the batteries right?

 

[Kevin D Pem]

Or is the inverter different?

 

[nsr1357]

glad to hear that!

there is no difference. the batteries are the same ones that are in the pictures....in trying to isolate the problems, I tried a different set of four batteries of the same exact model, albeit a couple of years newer, and that did not change the issues I described here. ....................so I took out those newer batteries (which are now in another installation that is completely unconnected to the one you are helping me with...and which is not part of the trailer's ecosystem......IOW, for these purposes, it does not electrically exist)...................and put back in the older ones...which you see in the pictures.

in the process of all this swapping, all eight individual batteries (two banks of four) were independently charged without issue, by a standalone victron charger and all were normal.

the original inverter was eight years old, and I replaced with a newer one...same model.....to see if IT would make a difference and it did not. I then had the older one also tested by an authorized magnum distributor, and they pronounced it completely healthy, but I left the newer one in, and have kept the older one for emergency backup, since it is still working perfectly. IOW, both magnum 2812s performed the exact same way.

I also tested two separate magnum panels...the original one which came with the trailer, and a new one which I obtained for this purpose (to try to eliminate all electronic equpiment as a source of the issues) both panels performed exactly the same way and had no effect on the problems...but I left the newer one in, although you are not seeing that in any picture.

thank you, kindly, still!

 

[Kevin D Pem]

I pulled up the 2812 manual.

I will not explain my logic, but I would try disconnecting the system ground to frame.

If I had a clamp meter I would test for a loss on that cable, but testing by disconnecting will suffice.

Don't worry though I will tell you My thoughts If it takes care of the issue.

 

[nsr1357]

first, thank you.

I am not sure I am surprised, and I am impressed by your suggestion...have genuinely felt since day one here that you had your arms around this.

I hope, however, you will still permit me to ask the following (my perspective includes that I am a longtime amateur radio opererator who is going to use some of this solar power to run what is called "emcom", an acronym for "emergency communications", which I am interested in to help people in emergencises, such as hurricanes).......and I have for many years, always understood the need...in many areas, never mind that I am no expert in this area as you obviously are............... for grounds for performance, and/or safety). That said, then, and if I may:

1. where would you make the disconnection? right at the frame, itself?

2. would you have made this same suggestion if these were not lithiums but rather the original AGMs?

3. do you think the ground was a bad idea to begin with (I am wondering why the factory put it there in the first place)

4. am I the first case where you concluded that the ground was a possible or actual issue (due to the above, I am well aware that, generally speaking, grounds can also be sources of trouble as well as wellsprings of performance and safety, so I am not suggesting you have not discovered fire on this one)

5. is the suggestion related only to magnum or do you see issues with other equipment performing the same function, such as midnite or victron, just to name a few (to wit, I am about to finish creating that seond unconnected system I mentioned, and there are plenty of places to ground equipment with instructions to do so..such as with midnite's combiner box, through which on this SECOND system i keep mentioning I am, indeed, using their combiner box which will also go to chassis ground, albeit in the trailer rear, where I had a ground busbar type strip put into the trailer at the time it was made, albeit for radio purposes (without proper grounding of various kinds of equipment, one of the issues can definitely be heavy radio frequency interference with receivers and transmitters.

6. because "grounds" in so many areas, can be related to safety or performance or both, even as you are reluctant to discuss your logic, would you consider giving me at least a most basic, general idea as to why you have come to this conclusion?

you asked me about this ground previously, so it does not surprise me that you find that an area of interest.

and again, thank you so very much!

 

[nsr1357]

first, thank you.

I am not sure I am surprised, and I am impressed by your suggestion...have genuinely felt since day one here that you had your arms around this.

I hope, however, you will still permit me to ask the following (my perspective includes that I am a longtime amateur radio opererator who is going to use some of this solar power to run what is called "emcom", an acronym for "emergency communications", which I am interested in to help people in emergencises, such as hurricanes).......and I have for many years, always understood the need...in many areas, never mind that I am no expert in this area as you obviously are............... for grounds for performance, and/or safety). That said, then, and if I may:

1. where would you make the disconnection? right at the frame, itself?

2. would you have made this same suggestion if these were not lithiums but rather the original AGMs?

3. do you think the ground was a bad idea to begin with (I am wondering why the factory put it there in the first place)

4. am I the first case where you concluded that the ground was a possible or actual issue (due to the above, I am well aware that, generally speaking, grounds can also be sources of trouble as well as wellsprings of performance and safety, so I am not suggesting you have not discovered fire on this one)

5. is the suggestion related only to magnum or do you see issues with other equipment performing the same function, such as midnite or victron, just to name a few (to wit, I am about to finish creating that seond unconnected system I mentioned, and there are plenty of places to ground equipment with instructions to do so..such as with midnite's combiner box, through which on this SECOND system i keep mentioning I am, indeed, using their combiner box which will also go to chassis ground, albeit in the trailer rear, where I had a ground busbar type strip put into the trailer at the time it was made, albeit for radio purposes (without proper grounding of various kinds of equipment, one of the issues can definitely be heavy radio frequency interference with receivers and transmitters.

6. because "grounds" in so many areas, can be related to safety or performance or both, even as you are reluctant to discuss your logic, would you consider giving me at least a most basic, general idea as to why you have come to this conclusion?

you asked me about this ground previously, so it does not surprise me that you find that an area of interest.

and again, thank you so very much!

ps that ground was, indeed there from day one, in a system which used a magnum 2812, and the non lithium batteries always performed flawlessly, with none of these issues, so I am trying to simply understand, without asking you to make comments you are not comforable making at this point, what it is about this present problem that makes the ground suspect now but never before...and I trust/hope you will forgive me for belaboring this a bit?

 

[nsr1357]

ps that ground was, indeed there from day one, in a system which used a magnum 2812, and the non lithium batteries always performed flawlessly, with none of these issues, so I am trying to simply understand, without asking you to make comments you are not comforable making at this point, what it is about this present problem that makes the ground suspect now but never before...and I trust/hope you will forgive me for belaboring this a bit?

pps..sorry for stutter stepping, but I do have a clamp meter, just fyi......a kleintool and a fluke, both..although I am not unwilling to disconnect to see, either.