Magnum Battery Monitor Problem

chopper · March 2014

Hello,

I recently installed a solar system in our RV. It consists of the following equipment:

4- Lifeline 6 volt 300ah wired in series and parallel to 12 volts
1- Magnum 2812 inverter 2800 watt
1- Magnum battery monitor
1- 500 amp shunt
2- 270 watt solar panels wired in parallel
1- Morningstar Solar charger 60 amp MPPT

The question I have: When I am hooked up to shore power and charging battery bank with Magnum inverter/charger, the amp hour meter will count down from negative numbers (amp hours used when running on battery bank) back to zero when bank is 100% charged.

However, when I am charging the bank with solar panels only and have very little draw on the system, the negative numbers on my amp hour meter get more negative than moving toward zero even though the battery bank voltage indicates the bank is being charged. Of course if I cut power to the battery monitor, the amp hour meter reading resets to zero. Isn't it supposed to also reset to zero when the bank achieves 100% charge? Why are my amps coming into the bank from the solar indicate I am using power (negative increasing)rather than making it (moving in positive direction)?

I have the monitor hooked up to the shunt as per instructions and both sources of charge are wired to the load side of the shunt. Do I have to wire the shunt differently to get the solar amps to go in the positive direction, and if so, what will that do to the amps coming in from the magnum charger? What if I have the magnum charger going with the solar panels at the same time? Thank you for any assistance.

BB. · March 2014

Re: Magnum Battery Monitor Problem

Can you post a link to the manual you used and the page number/diagram you used?

In general, you want one side of the shunt too attach to the battery negative common bus. And the other side connect to all of your loads/power sources/etc.

And since this is an RV with (I presume) a metal frame/chassis, the "load side" of the shunt will be grounded to the trailer chassis too.

Anything that has a negative lead attached to the "battery side" of the shunt will "bypass" the shunt and cause it to "miss" any loads/charging current. If you have the solar battery charger attached directly to the battery shunt, you will "not see" any current flow from the solar charger.

Batteries - bus common ==== shunt === loads+charges+RV ground

Nothing else but batteries should be attached to the left side of the shunt.

-Bill

vtmaps · March 2014

Re: Magnum Battery Monitor Problem

chopper wrote: »

I have the monitor hooked up to the shunt as per instructions and both sources of charge are wired to the load side of the shunt. Do I have to wire the shunt differently to get the solar amps to go in the positive direction

Welcome to the forum,

I don't know if you need to wire it differently because I don't know how you have it wired now. I have not heard of a shunt having a "load" side. Is one side of the shunt connected to the Negative side of the battery? Is there anything else connected to the negative side of the battery?

--vtMaps

chopper · March 2014

Re: Magnum Battery Monitor Problem

vtmaps wrote: »

Welcome to the forum,

I don't know if you need to wire it differently because I don't know how you have it wired now. I have not heard of a shunt having a "load" side. Is one side of the shunt connected to the Negative side of the battery? Is there anything else connected to the negative side of the battery?

--vtMaps

Yes, one side of my shunt is connected to the negative battery bank terminal and the other side connected to all sources of charge and the negative side of all loads (vehicle frame). I don't know why my battery monitor keeps a running total of amp hours used and returned by the inverter/charger, but will not track the amp hours and increasing % of SOC returned by the solar panels. Perhaps because the magnum monitor is integrated(plugged into) into the magnum inverter itself it does not see the amps being pumped in by the Morningstar controller. I would think that if everything is moving through the shunt the monitor would see it all. The bank is being charged by the solar controller. The monitor is just not seeing it.

I ran across this at the Trimetric website:

"The connections shown on the diagram for the “wind” and “solar” measurements cause the “AMPS” value on the
meter to read a NEGATIVE value when the sun is shining, or the wind is blowing. This will also cause the “AMP
HOURS FROM FULL” to become MORE NEGATIVE as more energy is accumulated. This is counter intuitive,
and if you wish to have the incoming amps read POSITIVE instead, just reverse the connections between G2 and
Sig to the meter. (But be sure to read note 5 below) The reason for the suggested wiring is that you can then use
two of the meter functions for accumulating the “amp hours” from these sources. One can be used for a short term
measurement (like an hour, day or perhaps a week) whereas the other can accumulate production over months or a
year. If you wire it with the amps (and amp hours) coming in as a positive number, you won’t have available the
longer term measurement."

I don't know if this means I can only get an accurate read in and out with only one charge source hooked up to the meter. I realize I don't have a trimetric battery monitor but magnum might have a similar problem.

My solution right now is to pull the fuse out of line of the battery monitor which resets the amp hour and SOC to zero and 100%. It is not just a meter reset but it actually monitors the system for the resting voltage before it resets the SOC to 100%. That's is how I know the solar controller is in fact charging the battery bank.

KeithWHare · March 2014

Re: Magnum Battery Monitor Problem

The Magnum Battery Monitor is measuring power going through the shunt, so if things are wired correctly, it should not be able to distinguish between power from the charger and power from the charge controller.

Here's a photo of the shunt in a Midnite Solar e-panel with a Magnum MS4024 and the Magnum BMK.

Attachment not found.

The black 4/0 cable on the left side of the shunt is the negative from the battery bank.
The black cable with the white shrink wrap on the right of the shunt is the negative from the inverter.
One of the black wires (#6) connected to the shunt bus bar is the negative from the charge controller (Outback FM60). The other #6 black is from the solar panels.
The orange & blue wires connected to the top of the shunt are the sense wires from the ME-BMK.

Here's a screen shot of the monitoring data for this installation. The Amp Hours In/Out graph is never much above zero, because once the batteries are fully charged, not much power goes through the shunt.

Attachment not found.

From your description of what you are seeing, it sounds like the negative from the PV system is connected to the battery side of the shunt.

Keith

KeithWHare · March 2014

Re: Magnum Battery Monitor Problem

KeithWHare wrote: »

...
From your description of what you are seeing, it sounds like the negative from the PV system is connected to the battery side of the shunt.

Now that I think about it a bit more, another possibility is that you are getting less amperage out of your charge controller than you expect and more load with "very little draw" than you expect.

It is time to bring out the amp clamp and start measuring the current from the charge controller and the current to the inverter.

Keith

vtmaps · March 2014

Re: Magnum Battery Monitor Problem

chopper wrote: »

Yes, one side of my shunt is connected to the negative battery bank terminal and the other side connected to all sources of charge and the negative side of all loads (vehicle frame).

So then you are saying there is NO connection from battery negative to the chassis? (in other words, the chassis is bonded to the battery negative on the other side of the shunt)? I was guessing that might be the problem... for troubleshooting this I like Keith's advice: get yourself a DC current clamp meter.

--vtMaps

chopper · March 2014

Re: Magnum Battery Monitor Problem

vtmaps wrote: »

So then you are saying there is NO connection from battery negative to the chassis? (in other words, the chassis is bonded to the battery negative on the other side of the shunt)? I was guessing that might be the problem... for troubleshooting this I like Keith's advice: get yourself a DC current clamp meter.

--vtMaps

If I bond the negative terminal from the battery bank directly to the frame and not on the load side of the shunt, won't the shunt miss any amps being used by the battery bank? I thought everything coming out of the negative side of the battery bank had to go thru the shunt in order for an accurate count of usage in and out. Am I missing something here?

BB. · March 2014

Re: Magnum Battery Monitor Problem

No--You got it correct. vtMaps is saying that grounding at the battery - common point to the chassis would be a problem.

Get a DC current clamp DMM like this "cheap one" from Sears. And start measuring current flows. It sounds like the solar power system is not generating any charging current (or below the threshold of the Magnum system's ability to monitor).

-Bill

chopper · March 2014

Re: Magnum Battery Monitor Problem

Thanks. I will get a DC amp meter and check the system. I let you know what I find.

chopper · March 2014

Re: Magnum Battery Monitor Problem

Someone left me this post on another forum. Any merit to this idea?

"Not being totally familiar with Magnum's battery monitor, is it possible it is like the Conext (Xantrex) system where it will only work with networked components plugged into the system's hub or network? Our system will not work with "foreign" controllers either. The whole system has to be all Conext/Xantrex components in order for power logging and battery monitoring, etc to work."

BB. · March 2014

Re: Magnum Battery Monitor Problem

A current shunt in the right location and with the correct meter/software should operate just fine as a "standalone" meter. Very simple "system".

If you want to integrate the output into a tablet screen or use the data to turn on/off a genset through another controller, etc... Yep, much more difficult to integrate all of the standalone controllers/communications.

-Bill

Cariboocoot · March 2014

Re: Magnum Battery Monitor Problem

According to the company the Magnum battery monitor will keep track of all current going through the shunt regardless of source just like any other battery monitor. It uses the Magnum inverter as an interface to the meter. Keep in mind Magnum does not make solar charge controllers so the monitor would be quite useless if it couldn't follow the input from one.

The only reason the current from the charge controller would not be monitored would be if there is something wired wrong. Since this is a Morningstar charge controller I'll ask if you have the Voltage sense wires hooked up? Guess what happens if the negative wire for this is on the wrong side of the shunt.

If not, something else is wrong. With the shunt positioned between the battery negative and all other connections it will read all current going through the shunt in either direction. I wonder if it fails to function due to programming or having the inverter in off/standby mode?

chopper · March 2014

Re: Magnum Battery Monitor Problem

That is an interesting question about not working because the inverter is off or standby. If that is indeed the case, then I will rack up some background amps from the inverter running. That's not a bad trade if it is the case. I have also read that many who have had the Magnum battery monitor either wished they had gone with the Trimetric or actually replaced it with one. Perhaps because it was not integrated and a bit more user friendly. I will add your idea to my investigation and report back. Thanks.

pyintheye · March 2015

Cariboocoot wrote: »

Re: Magnum Battery Monitor Problem

According to the company the Magnum battery monitor will keep track of all current going through the shunt regardless of source just like any other battery monitor. It uses the Magnum inverter as an interface to the meter. Keep in mind Magnum does not make solar charge controllers so the monitor would be quite useless if it couldn't follow the input from one.

The only reason the current from the charge controller would not be monitored would be if there is something wired wrong. Since this is a Morningstar charge controller I'll ask if you have the Voltage sense wires hooked up? Guess what happens if the negative wire for this is on the wrong side of the shunt.

If not, something else is wrong. With the shunt positioned between the battery negative and all other connections it will read all current going through the shunt in either direction. I wonder if it fails to function due to programming or having the inverter in off/standby mode?

Hello Coot
How close to Bowron Lake are you?
I just finished the retrofit install as per my signature.(hope I got that right now)

Seems my BMK has issues also. 1- The BMK will not sync to the RC50 voltage (off by .12v) but matches both CC's voltages exactly.
2- The BMK is not seeing all 3 DC Amps Input, and only shows about 20% of what the 2CC's and Hydro combined is producing.
So is anyone else having a similar problem with a FIX? Been through all the testing with a UEI DL49 Digital clamp on meter but will have to get a sunnier day to test the Milliamps in the twisted wire pair.
TT

westbranch · March 2015

Py, FWI 'Coot has been on and off the board sporadically of late, so he may not respond right away...
He lives in 100 Mile

pyintheye · March 2015

Hi Westbranch
Thanks for the heads up. I really enjoy his posts and the info. I see you have a ton of Posts, should a fella be starting a new post every time in order to get user feedback quicker? I ask because I do not see my last post in the " Today's Posts" page.
THX TT

pyintheye · March 2015

Sorry westbranch, please excuse my ignorance as I learn how to navigate this forum properly!

westbranch · March 2015

A new post allows you to refer to your specific problem that may differ from the original question asked. It all depends on you and what you want answered. Lots of threads end up wandering a bit which is not necessarily a problem as they usually come back on track... then when a search is done the searcher can get usable info...
hth

ps a 100W hydro source is not Nano, it is ~ 2400Whr a day... I'm envious!

South Africa · March 2015

Hi,

I have a Victron battery monitor that at one stage gave me ridiculous readings after I made a system change.

After confirming the cables where properly connected on the correct side of the shunt, I charged the batts to 100% SOC, then I resetted all the settings, manually synced it after ensuring zero volts in / out point was set.

Since then it has worked perfectly again.

pyintheye · March 2015

westbranch wrote: »

A new post allows you to refer to your specific problem that may differ from the original question asked. It all depends on you and what you want answered. Lots of threads end up wandering a bit which is not necessarily a problem as they usually come back on track... then when a search is done the searcher can get usable info...
hth

ps a 100W hydro source is not Nano, it is ~ 2400Whr a day... I'm envious!

Hi westbranch
Well a day of pretty good sun and 6hrs of testing has solved my BMK problem.
Seems the Inverter is stealing the PV power before it hits the battery bank and the BMK (DC Amps) only picks up the residual power not used by the loads.
So the best way I found to see if the Remote and the BMK were in sync was to shut down the CC's and put a constant load on the system.
Then I was able to see how both "read only" screens were seeing the volts and amps without bouncing around to much.
The fact that the RC screen and the BMK screen display the decimal point differently(.0 vs.00) is also not very helpful.
Seems strange that Magnum would not have that aspect reading the same way.

To your PS, the hydro is in fact a Nano Hydro 600 from Off- Grid Engineering ( www.off-gridengineering.ca/ ) from Mission BC.
This little "Jewel" will produce power with as little as 3 L/Min flow at my pressure of 69lb PSI (flowing)
Right now the 100W that I get is what a full 1 inch line can flow.
The really neat thing that this unit has that Off Grid built in for me, to maximize power production, was 2 different winding configurations activated by a simple switch for when my variable Spring water flow feeding the turbine falls below 10L/min flow rate.
After many years of searching, this is the lowest flow rate turbine I have been able to find.
Forgot to add this turbine is putting out 48 volts.
TT

brichards · May 2018

I have just wired up my Magnum Battery Monitor and have some strange readings.... I am on a 12 volt system,
My Amps in is showing +349 AMPS.... I have not fully charged my system since installing the meter.

As I am writing this, I turned off my Generator that I was running and and its showing +264 AMPS IN, (85 AMPS difference,) which is correct, my Charger was charging at that rate when I turned it off.

Now there is no current coming in from outside sources and its showing +264 AMPS, I am turning on my Solar Controller now and its showing 22.5 AMPS on the Solar controller going to the batteries and the Battery monitor is showing +286 now (22 difference) which is correct.
264 AMPS from nowhere... the meter is reading.

Wiring the meter up: I did exactly what the instructions said and showing a green light on my front of the meter module.

These things I removed from my negative post of battery and hooked up to my Shunt on the load side.
1)Solar Negative
2)Generator Negative
3) Negative 12v fuse panel to rv
4) Charger/Inverter negative

I moved everything over to the Load side of the shunt, until nothing would come on in the RV.

What would be causing these crazy number on the +AMPS IN in on the meter?

I am good to get 25 - 30 amps IN from my solar on a good day.

Do I have a ground issue you think?

*** After typing the above, I ran a Ground to my Frame from the Load side of Shunt to Frame and Still getting these Crazy Incoming AMPS on the meter.

Any ideas I would appreciate it. Thanks

Current battery bank is approx. 90% after todays solar and a few mins with the Genset this AM.

4- Lifeline 6 volt 300ah wired in series and parallel to 12 volts
1- Magnum 2812 inverter 2800 watt
1- Magnum battery monitor
1- 500 amp shunt
6- 100 watt solar panels wired in parallel / Series
1- Midnight Solar 150 controller

brichards · May 2018

I received this reply this AM from Magnum..

The only thing I can think of that might be causing this would be stray voltage getting to the orange and blue twisted wires. If you have a voltmeter that reads millivolts, could you take a millivolt reading on the orange and blue wire at the BMK module? If you have 22.5 amps then you should be reading 2.25 millivolts if there is truly 264 amps going through the shunt then you should be reading 26.4 millivolts. If the BMK amps reading isn’t matching the millivolt readings at a 10 to 1 ratio then there is an issue inside the BMK and it will need to be replaced.

Thanks,

Darren Massey

Sr. Product Support Technical Specialist

Magnum Energy, a product brand of

Magnum Battery Monitor Problem

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