Battery Monitor Kit

[K Pearce]

Looking for help from electrical experts in this group;

We have a 2015 Roadtrek CS and feel that, after investing in four new 220 AH AGM batteries, a battery monitor is critical to measuring the health of our electrical system (the Roadtrek monitor just doesn't cut it). Over the next few days I will tackle the installation of a multi-function battery monitor with a 300-amp shunt. I realize that, to make it work properly, I must establish a common ground point for the shunt. I have purchased 25 feet of 1/0 cable in order to consolidate grounding of the two front GC2s with the rear GC2s and the inverter converter. And I plan to run a ground line from the solar controller to the shunt as well.

I have a couple of electrical questions--the answers to these would help me a lot.

1 Any ideas on where the ground line from the MPPT solar controller is fixed? Both the red and black cables disappear into the wall in the cabinet where it is mounted. Does the black (negative) wire end up at a battery set or is it fixed to the chassis somewhere along its route?

2 The existing Roadtrek monitor panel (battery level, LP level, black, grey and fresh water level, battery and pump switch etc.) in the CS is on the passenger side above the sliding door. I would like to mount my new monitor on that panel and take advantage of existing battery monitor wires that I hope are accessible (looks like some other redundant wires there that may be helpful). The cluster of wires leading from the panel seem to feed into the ceiling over the bathroom and beyond. Do all these wires loop around and work their way to the fuse panel above the driver? Is the "beyond" the centre ceiling panel and do I remove that to access this "wiring harness"?

Any assistance would be greatly appreciated.

[themexicandoctor]

Good questions from a non-expert.

[themexicandoctor]

Originally Posted by themexicandoctor

Good questions from a non-expert.

What I meant to say is "I, am the Non Expert. But I know a good question when I see it ..."

I am surprised nobody has co e forward to answer these.

As to Battery Monitors I use a Victron BMV712 (I believe Victron is far & away the best technology), but Rowiebowie mentioned that he uses a Renogy Monitor that gives him instant access to more data, at a single glance.

But since I don't understand half of what you are talking about I am sure you already jave the Battery Monitor of your choice already.

[themexicandoctor]

The above is a snap shot of my Electrical Box & the Shunt - please give me a moment to determine where my Victron MTTP Controller ground line is.

I just bought all my batteries from where they sat on the outside of the Rig (2005 Roadtrek OEM Battery behind the rear tire & optional Add On Battery used to sit in a outside cubby in front of the rear tire).

They are all now under the bed.

[themexicandoctor]

I have one of your answers which is a Giant Step for Makind as I am the last person here to answer electrical questions but my phone isn't uploading any photos where I am.

[themexicandoctor]

If you look at the first photo you will see where my Solar Cables enter the back corner of my Roadtrek Upper Cabinet.

Second photo you will see my Electrical Box contents.

Third photo you will see the flashlight beam of those same two cables which as you see in the second photo, attach to the two lower posts of my MTTP.

[themexicandoctor]

In the next three photos you will see photo #1 you will see in the upper left corner a black cable (negative), that comes off the MTTP unit and attaches to a post below the unit, I am assuming that is the ground.

Photo #2 you will see a continuation of another black cable coming off the ground post & attaching to another post on the wheel well.

Photo #3 you will see where that same black cable terminates at the left side of the shunt.

I am not technically savvy when it comes to electrical wiring, i leave it to the professionals so there is a possibility that my wiring has been done incorrectly but this time, I doubt it.

As it is, I was under the belief that I only had one negative ground post - perhaps you can seemore as I seem to have described to to you already.

As to upper wiring & the relic monitor, I would leave it where it is at as for me even though I have Bluetooth, the most convenient location is at the rear lounge just above the box as pictured.

[themexicandoctor]

I kept my Original Monitor Idiot Lights intact.

As you can see my Battery Monitor, the Temperature Sensor, etc & the Magnum sensor connect right there at the shunt which from talking to Booster is the only place your Battery Monitor should connect for accuracy.

The bright lights are great for celebrating Xmas & they remind me of my naivete around Battery Dynamics the first 4 years of blissful ignorance as an Owner.

The only one that is remotely accurate is the Propane.

And I guess the top Green Light on the Battery Monitor which tells me the unit is charging despite my Bluetooth, etc.

[K Pearce]

Thank you themexicandoctor. I installed my new monitor last week and all went well. A lot more work than I anticipated though it ended up being a fun project. Thanks for your pics and words of encouragement. It really helped.

[themexicandoctor]

Originally Posted by K Pearce

Thank you themexicandoctor. I installed my new monitor last week and all went well. A lot more work than I anticipated though it ended up being a fun project. Thanks for your pics and words of encouragement. It really helped.

Are you serious?

My pleasure.

I hope the photos were not too cryptic - I am very new to this.

[Sehc]

There is a new type of battery monitor. It is self learning. Here is Rod Collin's review. https://marinehowto.com/balmar-sg200...ttery-monitor/

[booster]

Originally Posted by Sehc

There is a new type of battery monitor. It is self learning. Here is Rod Collin's review. https://marinehowto.com/balmar-sg200...ttery-monitor/

Manual for the monitor here:


https://www.balmar.net/wp-content/up.../PDS-SG200.pdf


I really don't see anything very revolutionary in it based on the manual (which goes into little detail to how it works), as it appears to be probably a normal battery monitor that is shunt based and has automatic charge efficiency in real time. Magnum also has the autoset for charge efficiency as toggle on and off. I found it to be pretty accurate if you have uniform discharge depths, but not nearly as accurate if your discharges vary be a bunch. This is only a guess of what it is doing, though. It uses Peukert, which IMO is not very applicable to most RV applications because the load varies too much from tiny to very large for many of us. Peukert is based on load to determine capacity, and from what I have tested only the load on the system when it hits 10.5v (dead) matters. The total energy in the battery doesn't change or get wasted. We don't use a Peukert in our monitors and Trimetric doesn't even have it in them for these reasons.


I think the "smartest" thing they have done, again based on the manual, is how they wrote the instructions on how to program the very normal monitor settings needed, the float transition amps (their fully charged amp setting) and the voltage minimum threshold at that point in time. It auto sets an amp and voltage based on battery type only, but they don't tell you what those settings are. Then you use your charger to "fully charge" the battery to the point the charger goes to float. At that point you are instructed to change the amps and volts you saw at that transition to float by changing the settings in the monitor so it will show 100% full at that point. Chargers are famous for not getting batteries charged to full, and mostly they undercharge, so all you are doing it telling the monitor to say the battery is full, based on what the charger did, which could be grossly in error, and if it is a timer or algorithm model it will also be highly variable in most cases. It has nothing to do with if the batteries are really full or not, I would guess.


All monitors have the same kind of issues as above, and Victron has even gone to very conservative settings as defaults so it shows batteries full when they could be very less than that, because customers complain they never show full. We often suggest that if people aren't going to upgrade their chargers to get to totally full charges, they should do the same type of fudge, but understand that they are not really getting full batteries at 100% but it is needed to use that point as a recalibration point to preserve accuracy.


If this is truly what the SG200 is doing, it really isn't telling you the whole story, I think.


Bottom line is that I think the SG200 would only give an accurate reading of a full battery if you used the recommended calibration procedure using a charger that did float transition based on the correct amps for the given batteries or if you set the amps in the SG200 to the battery manufacturers recommendation for amps when 100% full. Of course, if you set the amps to recommended by the battery maker, it is highly likely you will not get full 100% resets and accuracy will suffer, just like with all other monitors would.




Rod Collins has pushed revolutionary monitors in the past, like the shuntless Smartgauge which may still be available, and they are often tied into Compass Marine which he appears to be affiliated with. He has also claimed that shunt based monitors are grossly inaccurate, but with the settings he used, they would be because, IMO, they were not good ones to use.

[themexicandoctor]

Rod Collins has pushed revolutionary monitors in the past, like the shuntless Smartgauge which may still be available, and they are often tied into Compass Marine which he appears to be affiliated with. He has also claimed that shunt based monitors are grossly inaccurate, but with the settings he used, they would be because, IMO, they were not good ones to use.

As always, Thank You Booster

[witzgall]

Hi,

Chris from Balmar here. I found this thread and joined the Forum!!!

I am hoping to clarify some things. The SG200 does things a bit differently than a traditional Shunt-based product. We have adapted battery health technology originally developed for the cell phone and device industry, where knowing the actual capacity of the battery is crucial to the user experience.

Firstly, it was battery chemistry specific profiles. These profiles were built from data in our labs while charging and discharging of the batteries. The data includes voltage, current and (this is the big difference) Impedance when at points of rest. When a battery is put into service and cycled, this information is augmented with actual information from the actual batteries. The impedance information is used to both calculate the State of health, and also to correct for measurement errors that plague all shunt based monitors.

When discharging, it does simply count coulombs flowing out. At rest, it compares the impedance calculation with the table information, and corrects for any errors from synchronization drift. If you are charging your batteries fully every day, this is not a big issue. However, if you bookdock, and don't charge fully, each day that passes a traditional shunt-based system will drift out of accuracy, with 10-20% after week possible. The SG200 is designed to fix that problem.

It does not calculate any Charge Efficiency factor, or use it in any way. It does not use Peukert other than in the time remaining calculations.

I am not an engineer, but I would be happy to answer any questions I can.

Chris