Old Magnum MS2812 and new Lithiums

[Kevin D Pem]

I see a possibility for a feed back loop at the transfer switch, the AC side to the DC side. Some inverters have an issue with such a feedback while others don't.

BUT!

At this time it's a trouble shooting effort. If you want to shield the inverter,then use the ground lug on the inverter. Grounding is an art that sometimes even professionals in lightning protection get wrong. I am of the school that believes in letting it float!

As for RF issues a good ground plain is paramount, so using the AC grounding system is important.

I try to listen well, but sometimes I get it wrong! This is a trailer right?

So the ground to frame is for the trailer brakes. A dedicated battery is in order. However we should be talking two independent systems. I would keep that in mind, when disconnecting the grounding cable.

As far as where to disconnect the cable? That will depend on if this corrects the issue.

Battery chemistry is irrelivent!

 

[nsr1357]

Good mornng,
As usual with learned people, sometimes their answers can beg even more questions.
I know this is a public place and I am always very glad to contribute to such a
"body politic", if you will, but at the same time, and especially as I ask many questions that some may not want to wade through, I fear filling the place with things that others may not have the time or desire to entertain.
I completely understand that this is not a professional consultation, but I think I could save you a lot if time, if somehow you might permit a few short minutes on the phone.
Is such a thing acceptable? (I am happy to take all the time needed, for the sake of public consumption, to ultimately post any detail involved so that all may learn).
If not, as your post did beg questions, and because of the complex nature of what I am doing here with two unrelated systems (except for chassis grounding on opposite ends of the trailer) and I am well aware of such as "feedback loops", AND DUE TO MY OWN INABILITY TO DO TOO MUCH RIGHT NOW WITHOUT NEEDING TO SIT TO BREATHE, before I start disconnectng things, I hope to have just a bit more of your thinking (since I agree from my own knowledge, that "grounding" is an "art", many professionals DO get it wrong, and it is fascinating but potentially pesky matter that needs planning and execution to avoid making things worse)....but I am excited by the prospect after almost two years of this issue, to finally get to the kind of arcane and "hidden" area, that might reveal a fix (and not make things worse with anything else I am doing) as well as satisfy my own technical curiosity about it all
you obviously know what you are doing in this area (I know one when i see one, so to say, from my years in radio) and you are the only person I have had "access" to, that I think has gotten to a potential fix which I have suspected, myself.
Would you permit a call from me on a one time basis?
if not, no offense taken, of course, and I will post all my follow-up questions, such as :
1. are you talking about the ground wire in the picture I sent and which I attach to this post again?
2. since I do have a variety of concerns before I start disconnecting things, and insofar as I have two good multimeters with clamp measurement capabilities, and I would prefer to use that rather than disconnect (for my physical reasons if nothing else), if you confirm that this is the wire you refer to (I have looked in the 2812 manual too, and have also read that the ground wire for it should have been one size below the largest wire connected to it...which means that this wire should have been 3/0 and it looks smaller to me than that...perhaps this is <also> part of the problem?)
3. if then, this IS the cable, what load on this wire do you want me to measure when disconnecting trailer mains and seeing the inverter and transfer mechanism invoke themselves?
4. yes, this is a trailer...fifth wheel......made by New Horizons, fyi and fwiw, in case this helps.
5. my new "separate system, is indeed, in the rear of the trailer (including, inside, all batteries and victron equipment in that instance) and with a chassis ground connection waiting for me via a busbar, in the rear of the trailer down on the floor (at this point, NOTHING is connected to that busbar, but what will be connected are various equipment pieces of this new system, including, for example, the midnite controller box that THIS second system is using for the additional solar panels (LG 375 watts each).
So, Kevin, would, then, please, a quick call be allowed?
My continued expressions of gratitude are heartfelt to you and all. Thank you!

 

[Kobie]

Hi,
I know this is coming a long time after your note, but I hope you can still see this and are still here.
I have had the oddest thing and extensive testing with input from battleborn, magnum, a genuine rv expert electrical troubleshooter and a ton of headscratching from all......and that is, that with a bank of four battleborn 12v 100aH batteries, all four known to be good individually (we substituted four others, also known to be good and problem is the same, so we know it is not the batteries), and while the batteries register as having a full charge (all settings are absolutely correct in the magnum...I know you have heard this before, but this is the cse)......as soon as the charge is full and the batteries go to rest from a resting voltage of 13.6, the batteries as a bank, drop down to 13.2 in a matter of 10-20 minutes (longer in daytime with solar panels but still "precipitous") and then upon an inverter load, with just a fridge and some 12 volt lights, kind of thing, it is only a matter of another 20 minutes or so before the batteries threaten to go below 13 volts (even at 13.2, the specs show that this is only about a 30% charge but one way or the other, this happens 100% of the time.
there are no other known loads...no ACs runnng...yes, the frdge is a full size but even there, we have replaced it for unconnected reasons and the problem still exists, so it is not that.
we have also tried TWO separate 2812s....both working and tested and STILL no change in the problem.
we can find no ground issues, have triple checked all wiring, have a victron small shunt spliced in so we can also see the voltate on our phone and both the magnum readout inside and the phone show, within a tenth of a volt or so, EXACTLY THE SAME ISSUES.
needless to say we are at wits end.
given your electrician status and that you are an RVer as well, can you opine on this mess? (the panels are connected to a midnite solar controller....all is well, there, too......but even with the batteries showing a full charge and turning the entire solar array off, the precipitous drop is there every time.
tonight, from storm condiitions, the shore power went off and sure enough, from a full charge to 12.9 volts was greased lightning.
can you help?
tnx in advance to you and all and I apologize for th e length of this post but there is a lot going on as you can see.

NSR1357, have you replaced your remote from the current to the ME-RC controller above in the Video. We just replaced our AGM batteries to lithium as well -- 4 batteries just like you. We also added a victron battery monitor and the old controller settings for AGM did not work. We had to put the new controller, to charge lithium batteries, in and do a custom setting to get our Magnum 2812 to charge the batteries to full capacity. Batteries and charging all seem to work well now. Only issue we have now is randomly our steps will roll in when the door is closed and when that happens our awnings don't power in or open. Still trouble shooting that one.

 

[nsr1357]

thank you for your note. good thought, but "yes", I actually tried a new remote, but as well, my older one had firmware sufficiently updated to be capable of these "drop-in" batteries. i also have a victron shunt pliced in in the right place, but it mirrors the problem that i can already see in the magnum controller.
this has been so problematic that I wish it were something so easy, but from Kevin, here, I have gotten a great lead which I will be following up in the coming days, and, as well, with some remote help from someone from the factory that originally made this RV, we are going to go into inverter mode, and test the current on every breaker behind the panels to see what, if anything, might be unnaturally drawing a lot of current (such as, for two examples, breaking system or tank heaters...neither of which appears to be the case, but because they are two examples, i mention them here.
I had another weird artifact as well as the ones I mention...a trimetric voltage reading device (a good piece of equipment) , which is basically just a resistor with a readout, started flashing and so did 12 volt lights until I figured out why...disconnected the trimetric device (maybe it is coincidentally bad or maybe part of whatever weirdness is going on) and *that* problem went away immediately.
my point? these batteries have sophisticated electronics of their own, then you have whatever inverter/charger is involved, then you have the basic wiring that came with the trailer, such as the grounds to chassis (grounds are known to be pesky and involve "art"....just look up, for example, what happens to lightning when it hits the ground and what you need to do to try to protect yourself and how crazy THAT can be).......and especially as trailers are their own ecosystems, I am not surprised that some wretched people, such as I (and you) have less than a simple "drop-in" experience.
anyway, i pontificate a lot for someone who does not know what he/she is doing , but there it is.
i wish you the same "best" I wish for myself.

 

[nsr1357]

sorry..."braking" systems