Magnum Energy Battery Monitor issue

[jrobe]

I don’t seem to get consistent and expected readings with my Magnum Energy Battery Monitor system for the State of Charge (SOC). I use it to monitor by AGM battery bank with my Sprinter second alternator. Has anyone else had similiar issues.

For example, I will be at 100% SOC at home after a full charge. I can then be out camping and run the batteries down to 70%. I then may drive for 8 hours expecting to be fully charged again but the reading may actually be down to 60%. I can then just wait for 6-8 hours and see a reading of 80% or often 99% by the next morning with absolutely no further driving or charging. The problem seems to a significant delay of many hours in correctly reading a higher reading after I charge with my alternator. I had assumed the SOC would be close to a real time reading. Thanks for any ideas.

[booster]

Originally Posted by jrobe

I don’t seem to get consistent and expected readings with my Magnum Energy Battery Monitor system for the State of Charge (SOC). I use it to monitor by AGM battery bank with my Sprinter second alternator. Has anyone else had similiar issues.

For example, I will be at 100% SOC at home after a full charge. I can then be out camping and run the batteries down to 70%. I then may drive for 8 hours expecting to be fully charged again but the reading may actually be down to 60%. I can then just wait for 6-8 hours and see a reading of 80% or often 99% by the next morning with absolutely no further driving or charging. The problem seems to a significant delay of many hours in correctly reading a higher reading after I charge with my alternator. I had assumed the SOC would be close to a real time reading. Thanks for any ideas.

It would be good if we knew the inverter/charger model and size, monitor model, BMK if used, and temp comp if used. Plus any settings you know of in the monitor settings area.


It should not be working the way you describe, as all power in and out of the battery should be instantaneous and updated in real time by the monitor. It certainly appears that there may be something going on with the second alternator, which on a Sprinter is likely a standalone with a Balmar regulator on it. If there is an issue with either the alternator or Balmar, it could be using power rather than generating power while driving, for instance.


There are a lot of Magnum, Nations, Balmar, combinations out there, and we also have one (but with an Amplepower regulator) and they don't usually have what you are seeing and work well. Hopefully, we can get yours doing the same.

[jrobe]

Our Sportsmobile has a Magnum Energy MS2000 inverter with a Nations alternator but no Balmar regulator. For some reason, Sportsmobile only uses a Balmar regulator with their lithium batteries (I suppose for a more complex charging profile). I balked at not having the regulator a little but figured they have been building vans for many years and knew what they were doing.

My alternator seems to charge my batteries fine but the monitor just seems to be delayed in showing this on the SOC meter. My battery voltage can be 12.7-12.8 volts when the SOC says 60% and also when it says 99% several hours later. I will call Magnum Energy on Monday and see what they think. Thanks.

[booster]

Originally Posted by jrobe

Our Sportsmobile has a Magnum Energy MS2000 inverter with a Nations alternator but no Balmar regulator. For some reason, Sportsmobile only uses a Balmar regulator with their lithium batteries (I suppose for a more complex charging profile). I balked at not having the regulator a little but figured they have been building vans for many years and knew what they were doing.

My alternator seems to charge my batteries fine but the monitor just seems to be delayed in showing this on the SOC meter. My battery voltage can be 12.7-12.8 volts when the SOC says 60% and also when it says 99% several hours later. I will call Magnum Energy on Monday and see what they think. Thanks.

That is very interesting. Do you have the ARC-50 remote with the BMK and shunt kit? If the used a Nations alternator without the Balmar, it would have to have an internal regulator in it. The ones they use (we had one on a Nations) tend to be pretty high voltage in general, but that wouldn't cause your issues, I think.


What would, perhaps cause the funky readings you are getting would be when you are looking at the SOC % on the monitor. When the battery gets to a full 100% charge based on the parameters set in the monitor (which would be very interesting to see to confirm they will work correctly) it will reset the SOC to 100% so it is ready for the next discharge cycle. The SOC will be very accurate on that discharge cycle as long as the right battery capacity is set in the monitor, and it should be very stable as long as there are no inputs from charge sources like solar or engine charging. As soon as you start to recharge, you are in a mode that has an extra variable in it, and that is charge efficiency, which is basically how much of the charging ah you put in actually make it into the battery. Charge efficiency varies depending on how far you are discharged, how fast you are charging, and other things so hard to allow for extremely accurately. You can put in to the settings a best guess or let the Magnum average what the charge efficiency has been over past cycles and use that (it calculates the charge efficiency off of the full charge parameters being met and ah in vs ah out of the last cycle). Neither way is exact so your SOC on recharge may be high or low compared to actual. Once the battery gets to full again on the recharge cycle based on the monitor settings, it resets to an accurate 100% to be ready for the next cycle.


Where the inaccuracies can come in are when the charging does not get the batteries to totally full and trigger the reset to 100%. Multiple cycles up and down without getting that calibration will make the SOC get further and further off of actual because of charge efficiency error. This is why it is important to have the correct full battery specs in the monitor, so you always get the reset calibration at the right time and place.


We have an MS2000 in our van with ARC-50 and BMK, and with the proper settings in place in the monitor it charges and keeps track of SOC very well, especially on discharge where it counts most, but we always see a bit of a jump between the reset calibration and what it was just before the calibration because of charge efficiency differences in every charge cycle.


Your settings will be very similar to ours except for likely adjustments for battery bank size as ours is 440ah, but easy to do.

[GeorgeRa]

I have Magnum MMS 1000, ME-MRC50 and ME-BMK, 230 Ah AGM, 300W PV, alternator connected via ME-SBC and never had problems described by OP.

[booster]

Originally Posted by GeorgeRa

I have Magnum MMS 1000, ME-MRC50 and ME-BMK, 230 Ah AGM, 300W PV, alternator connected via ME-SBC and never had problems described by OP.

I have a couple of questions about how your system works, as I may be misinterpreting how you use it.



According to the very confusing Magnum charger/remote compatibility charts an MMS series MRC-50 has level 3 features.


It appears that you would not be able to set the charging to do the float transition based on BMK amps. I couldn't tell on any of the manuals for those models if you would be able to set the the amps in the BMK section to generate the trigger needed to do the calibration reset at full battery needed to keep the SOC and ah in and out correct. It would appear to possible, but not stated in the literature, that the reset happens at the transition to float, which is charger controlled by time only at level 3.



Would you be able to let us know what you have available for the charging and monitoring settings and how it determines the batteries are full at calibration reset?


With our ARC-50 and MS2000 we get level 4 settings so everything is based on the BMK amps seen by the charger. I just set the amps for transition to float and the charging uses that to go to float and the BMK appears to use it to trigger the auto calibration of SOC and ah in/out.

[GeorgeRa]

Originally Posted by booster

I have a couple of questions about how your system works, as I may be misinterpreting how you use it.
According to the very confusing Magnum charger/remote compatibility charts an MMS series MRC-50 has level 3 features.
It appears that you would not be able to set the charging to do the float transition based on BMK amps. I couldn't tell on any of the manuals for those models if you would be able to set the the amps in the BMK section to generate the trigger needed to do the calibration reset at full battery needed to keep the SOC and ah in and out correct. It would appear to possible, but not stated in the literature, that the reset happens at the transition to float, which is charger controlled by time only at level 3.
Would you be able to let us know what you have available for the charging and monitoring settings and how it determines the batteries are full at calibration reset?
With our ARC-50 and MS2000 we get level 4 settings so everything is based on the BMK amps seen by the charger. I just set the amps for transition to float and the charging uses that to go to float and the BMK appears to use it to trigger the auto calibration of SOC and ah in/out.

I never dived deep into custom settings staying with defaults. Indeed, absorb to float stage trigger is time based, not current. I set battery type, voltages, and capacity and go. Charging efficiency is set to default Auto.

I never felt that I needed to use custom set-up, SOC is very consistent in similar charging conditions day by day.

I did have a problem a few years back with a code displayed (don’t remember the number). With Magnum service folk’s assistance, I was able to bring the system back to life. It was inconclusive what was the problem, could be overheating. It works flawlessly since. I hope I answered your questions, if not I can dig more but I am far away.

[booster]

Originally Posted by GeorgeRa

I never dived deep into custom settings staying with defaults. Indeed, absorb to float stage trigger is time based, not current. I set battery type, voltages, and capacity and go. Charging efficiency is set to default Auto.

I never felt that I needed to use custom set-up, SOC is very consistent in similar charging conditions day by day.

I did have a problem a few years back with a code displayed (don’t remember the number). With Magnum service folk’s assistance, I was able to bring the system back to life. It was inconclusive what was the problem, could be overheating. It works flawlessly since. I hope I answered your questions, if not I can dig more but I am far away.

The settings would all be interesting, but sometime if you could get us just one piece of data for a couple of different charge cycles, we should be able to learn a lot.


Since you are timer based, I would assume that you will know pretty closely when the charging is going to switch from absorption to float. If you could watch the monitor at that time, looking at the BMK amps you should be able to see what the amps to the batteries is at the transition to float. This will indicate very plainly how full the batteries are getting during charging and would be very interesting and useful.

[GeorgeRa]

Originally Posted by booster

The settings would all be interesting, but sometime if you could get us just one piece of data for a couple of different charge cycles, we should be able to learn a lot.


Since you are timer based, I would assume that you will know pretty closely when the charging is going to switch from absorption to float. If you could watch the monitor at that time, looking at the BMK amps you should be able to see what the amps to the batteries is at the transition to float. This will indicate very plainly how full the batteries are getting during charging and would be very interesting and useful.

I will do that during our next camping trip, November or December this year.

[booster]

Originally Posted by GeorgeRa

I will do that during our next camping trip, November or December this year.

Sounds good to me, thanks George.