Battery Monitor Victron BMV-712 Installed

BrianZ

After reviewing other installations of this battery monitor, I wanted to share my method, which adds at least one new option.  


First, here's an overview of the wiring.  Included with the BMV-712, but not shown, is a small wall-mounted display & control unit that connects to the coil of data cable, which BTW is an RJ12 cable with 3 twisted wire pairs (not RJ45 as some have said) that uses a standard telephone type RJ-12 connector jack. RJ-45 cables, such as Ethernet cables & connectors use 4 pairs of wires with 8 contacts on the connector.
The negative battery cable is not included,
(https://www.amazon.com/dp/B06XR7XYLP) and the temp sensor includes a second power wire & may not be included unless listed by the seller.  Also purchased separately was the junction box for mounting the shunt.
(https://www.amazon.com/dp/B07G8S9ZCB)
I later temporarily removed & replaced the shunt, so I could coat any soldered connections on the shunt's circuit board with a waterproofing "conformal silicone" coating to help prevent corrosion from any condensation.
(https://www.amazon.com/dp/B008O9YIV6)
I avoided coating any electrical contacts, such as inside the RJ-12 socket or positive battery power & temperature sensor lead sockets.  I also added some dielectric grease in the holes at the ends of the fuse holder on the shunt's positive battery lead & to its screw threads, then wrapped those ends in electrical tape to help prevent corrosion around the fuse contacts.


Here you can see where I mounted the box vertically on the tub wall, with the cables hanging out from the bottom end and connecting to the battery, except for the data cable which runs inside to the wall-mounted display.


Closer view of the junction box with shunt.  I wanted to avoid drilling holes, if possible, but needed to get the data cable from this box to inside the T@b.  I had read of three ideas (using a vacant Alde vent hole, the frig vent hole, and the same wiring hole for wire bundle from distribution box).  


Here is the location of the hole for wires from the distribution panel box shown.  I had read it was a tight fit, but had not read of anyone actually doing this, but thought it was the ideal location.  Some have drilled new holes in this area.


After several tries, I was able to pass this thin folded wire into the space behind the toilet, then attach the data cable to the end.  I had to cut the RJ-12 telephone connector off the end (actually cut the cable about in half, since it doesn't take anywhere close to the long amount they provide).  Even then it was a tight fit, but I managed to pull it down through the plastic conduit, then into the tub for wiring it into the junction box. 


After enclosing the data cable (arrow) in split loom conduit, wrapping with tape, and sealing the mouth of the conduit going through the floor of the T@B with "Liquid Tape".
(https://www.amazon.com/dp/B000FPAN2K)


Here is the cut end of the data cable after crimping on a new 6-pin connector for plugging into the shunt socket.  Note the order of the wires, which is the same on both ends when held side-by-side.  Solid colors are on the right in the order shown & striped colors on left in the reverse order.


This is the crimping tool I used.  From Lowes I think, but have had it for years since wiring the house with ethernet cables for home network.


I used a 2-inch hole saw/drill to install the monitor into a 2" hole above the SeeLevel, whose readout appears to compare well enough.  The mount was slightly too big for the hole, but fortunately I had a masonry version of a 2" hole saw that was slightly wider and had a coarse sandpaper-like edge instead of teeth, which was perfect for grinding out the hole to enlarge it. 
To fish the cable from the space behind the toilet, I first removed the SeeLevel display panel without disconnecting anything, and passed the stiff wire in the same direction as the Seelevel wires towards the front of the trailer & into the space behind the toilet.  After pulling the cable through, I then passed it up into the new mounting hole.
There was not enough depth in the wall space to use the threaded plastic nut on the back to hold the new display panel in place & leave it with just the round bezel.  Instead, they provide an optional square bezel with screws plus snap-on cover plate to secure it from the front.


Finally, after making all the connections, I could see via the phone app the exact state of charge, history of consumed Amp-Hours, and that pleasing "infinite" estimate of battery time remaining when the current is positive instead of negative due to connected solar panel generating more power than is being used.  I was also happy to realize, as indicated by the network symbol to the upper right of the circular SOC indicator, that by assigning both this monitor & the Solar Charge Controller to the same Victron local bluetooth network in their respective app settings, the monitor will share battery temperature & voltage with the charge controller for optimizing solar energy transfer to the battery.


Here is a screenshot of the SCC status from the same time.  It was late in the day & shady, so not many watts, but more than enough to keep up with background power consumption by T@B electronics (those so-called "phantoms" & "parasites").

Unfortunately, the next day while tidying up the cables with some split loom conduit & electrical tape, I managed to pull apart one of the crimped cable connections in the positive battery cable from the SCC where I had installed an inline fuse.  Really need to get a ratcheting crimper instead of the el cheapo one I've been using.  The multimeter was handy for tracking down why my SCC app was suddenly unable to connect.

The only thing left is some actual field testing of the whole system, hopefully soon.

All images are 600x800 or less. 

tybladesmith

@BrianZ Great writeup! I will use your junction box and conformal coating ideas to waterproof the shunt. It doesn't like moisture. I also used the same route for the comm cable. It was a challenge but doable. So far I have been using a Renogy 100W folding portable PV less controller, but may mount it to the back rack less LoadWarrior basket between two bike fork mount trays.

What clear box did you use for the charge controller? Are there any issues with box volume and air circulation or overheating of the heat sink?

Again, excellent documentation! Thank you.
Tom

Michigan_Mike

Brian, thanks for taking the time to share your project work and for the excellent write up!  This is great information and goes a long way in helping out others who have thought about and contemplated installing these monitors.  I love the Victron in my 400 and also have one installed in a travel trailer parked out in Arizona.  The real time data is very useful and these units also provide history and usage patterns as well.  It’s also nice to be able to blue tooth in to the trailer while it’s parked and check things in real time.  Thanks again!  

Jilong

@Michigan_Mike What gauge wire did you use to wire the shunt to the negative terminal of your battery on the 400?

jkjenn

Good write-up, Brian. I had attempted the same pass-through, as you, but did not have the correct crimping tool and if I recall, correctly, they are not cheap.

Did you use and cable glands in your junction box?

Michigan_Mike

Jilong said:

@Michigan_Mike What gauge wire did you use to wire the shunt to the negative terminal of your battery on the 400?

I believe the wire size we used was #2 copper.  

BrianZ

Thanks, @tybladesmith, the waterproof coating was @dhauf's idea in this discussion..
http://tabforum.nucamprv.com/#/discussion/7779/no-12v/p2
There is a closer photo of my junction box there, but before it was completely finished (no battery cable & some conduit yet)..

And the SCC box was @elbereth's idea in the link "perfect watertight box" he gives here near top of the page..
http://tabforum.nucamprv.com/#/discussion/7432/our-portable-solar-suitcase-setup/p1
My solar setup is near the bottom of that page & more about my rooftop & ground mountings on next page.

Thanks, @Michigan_Mike, yes, I can hardly wait to try it out.  Gotta love that bluetooth realtime monitoring.  When testing in our driveway, I could even see the battery monitor popping up a message showing "sending information" (batter voltage & temp), while the SCC was showing "receiving".  I used a #6 gauge cable to the negative battery post, so I hope that's sufficient.

Thanks, @jkjenn, yes, I saw your write up too & how you wanted to use the same route, but of course there's no way one of those modular telephone plugs would fit.  Don't know what the crimped tool costs now, but gotta be more than whatever I paid some years ago. I did order some of those cable glands and another box that I could have drilled holes in for a somewhat more waterproof connection, but the box was a bit on the small side & the fittings wouldn't have given a totally waterproof connection for all the different sized cables.  The black box I used was thicker & more durable, and I figured if I hung it with all the wires going out the bottom & holes blocked by rubber grommets clamped around the conduit & waterproofing on the electronics that would give me the best possible protection.  I guess time will tell.

Michigan_Mike

Here is a crimping tool from Amazon.

PENSON CAYQK007010 Hydraulic Wire Battery Cable Lug Terminal Crimper Crimping Tool, ... https://www.amazon.com/dp/B0114QC3OY/ref=cm_sw_r_sms_c_api_-9KXBbW024519

BrianZ

Thanks, @Michigan_Mike!

TerryV6

Reading about your install method...  6 months later....

As always, I love your very complete instructions for installing or modding something.  Very impressive...

On a scale of 1-10, how would you rate the difficulty level for this?

BrianZ

Thanks, @TerryV6.
That's hard to say, because it would depend on various things, like how "handy" or DIY-oriented one is and what tools one might have available, or even physical challenges like laying on the ground on your back under the trailer while trying to shove a wire through a tight space and the strength to pull another wire through a tight space, etc.  My way is also not the only way, as others have chosen to drill a new hole in the floor either near front or back to run the cable through a larger hole without having to clip off the connector & install a new one.  So that can save needing a special crimping tool & parts.  You still need a hole saw & drill to mount the display into a wall board & a fish tape for routing wires through walls.  Wires at the battery need to be rerouted to the shunt, and if there are more than a couple then another question arises whether you may need to also install a bus bar to avoid the clutter of wires at the shunt and/or battery.
I might give it a 7 maybe?  (Give or take, depending on your comfort level, with wiring,  experience, tools, time, etc). Maybe others could give their estimate.

TerryV6

Looking at your battery and propane, its a wonder you can get at them...  Putting my new battery in was a challenge to be sure...  As the bruises and cuts on my hands can attest...

BrianZ

Well, getting the lid of my battery box on & off is kind of like one of those wooden puzzle boxes.  I have to move it in a sequence of proper directions & with the tub lid positioned just right.

morey000

I just installed my "solar system".  100W RichSolar flex panel, into a Renogy Renovo controller.  The controller has a bluetooth port... so I bought the $30 bluetooth transmitter which sends all the info to my phone app.  panel voltage, current, power.  Battery voltage, current, temp, % capacity, Load voltage, current, power- and all kinds of history metrics, charging and discharging Ahrs, power consumption, generating capacity, etc etc.  

i.e. stupid question:  What do these $200 things do?  that I'm not already getting?  

JEB

morey000 said:

I just installed my "solar system".  100W RichSolar flex panel, into a Renogy Renovo controller.  The controller has a bluetooth port... so I bought the $30 bluetooth transmitter which sends all the info to my phone app.  panel voltage, current, power.  Battery voltage, current, temp, % capacity, Load voltage, current, power- and all kinds of history metrics, charging and discharging Ahrs, power consumption, generating capacity, etc etc.  

i.e. stupid question:  What do these $200 things do?  that I'm not already getting?  

A solar charge controller is not capable of measuring the battery's "true" state of charge when the battery is either being charged or drained.  A load on the battery artificially reduces the state of charge; a charge on the battery artificially inflates it.  A battery monitor compensates for these charging/depletion sources and thus is much more accurate.

BrianZ

@morey000, I could not find anything called "Renogy Renovo" to read how it works.

If your controller is only monitoring its own connection to the battery terminals and not the other loads connected to the battery terminals, then how could it know how many Amp-Hours have actually been consumed by those loads and thus know the battery's true state of charge? 

The Victron battery monitor uses what is called a "shunt" to connect itself between the negative battery terminal and all loads using the battery, so it can actually measure all battery current being consumed by those loads, instead of just reading the battery's voltage to try to inaccurately estimate what its charge condition might be.

Sharon_is_SAM

@morey000, you must mean the Renogy Rover MPPT controller.  As Jeb and Brian mentioned, your battery info is indirect and not as accurate as a shunted battery monitor.

morey000

Ahh- got it.  thx.  Makes sense.    and yes, the Renogy Rover.   Guess I'll learn how good it is over time and if I feel the need for something more accurate.  Right now- the battery voltage  and % full seems to vary considerably from moment to moment and cloud to cloud, so not hot on its accuracy so far.  

JEB

morey000 said:

Ahh- got it.  thx.  Makes sense.    and yes, the Renogy Rover.   Guess I'll learn how good it is over time and if I feel the need for something more accurate.  Right now- the battery voltage  and % full seems to vary considerably from moment to moment and cloud to cloud, so not hot on its accuracy so far.  

If you want to get more accurate readings on the batteries' state of charge, but don't want to commit the time and money to a hardwired battery monitor, you can spend about $10 and get an Innova voltmeter that plugs into a standard auto 12V DC socket.  It won't be as accurate as the Victron and will only give you a voltage reading, but if you use it correctly, you can get better readings than the Victron solar controller will give you.  Take readings at night, when the panels are inactive and the charge controller is deenergized, and try to turn off as many loads as you can, like the fan, refrigerator etc. while taking your readings.  From this voltage measurement, you can consult a standard voltage chart to estimate the percent charge remaining on your batteries.  Again, not as accurate as the Victron, but it's pretty good and will provide you advance warning about when you need to start looking for an external charging source if your solar panels aren't keeping up with your usage.

morey000

JEB said:

If you want to get more accurate readings on the batteries' state of charge, but don't want to commit the time and money to a hardwired battery monitor, you can spend about $10 and get an Innova voltmeter that plugs into a standard auto 12V DC socket.  It won't be as accurate as the Victron and will only give you a voltage reading, but if you use it correctly, you can get better readings than the Victron solar controller will give you.  Take readings at night, when the panels are inactive and the charge controller is deenergized, and try to turn off as many loads as you can, like the fan, refrigerator etc. while taking your readings.  From this voltage measurement, you can consult a standard voltage chart to estimate the percent charge remaining on your batteries.  Again, not as accurate as the Victron, but it's pretty good and will provide you advance warning about when you need to start looking for an external charging source if your solar panels aren't keeping up with your usage.

OK- good info.  so- what does the $200 Victron do that's useful, that one of these for $16 doesn't do?  https://www.amazon.com/MICTUNING-6-5-100V-Digital-Voltmeter-Multimeter/dp/B01JOUZELG

JEB

BMV-712 is more predictive/forward-looking.  You can program into the Victron battery-specific data, such as amp-hours and battery type, and the Victron will convert this battery-specific data to display state of charge in percentage terms, total amp-hours consumed, time to discharge at current usage, etc.  In other words, it can extrapolate into the future and provide an estimate as to when your batteries will die.  Plus, the Victron retains this calculated data over time so you can chart usage.  And it's Bluetooth, so your not tied to a specific monitor location. What you have here is just a monitor that provides a snapshot of your battery's condition at a specific moment in time--it displays a few more data points than the Innova, but it's the same idea.  It is not predictive.  

jkjenn

JEB said:

BMV-712 is more predictive/forward-looking.  You can program into the Victron battery-specific data, such as amp-hours and battery type, and the Victron will convert this battery-specific data to display state of charge in percentage terms, total amp-hours consumed, time to discharge at current usage, etc.  In other words, it can extrapolate into the future and provide an estimate as to when your batteries will die.  Plus, the Victron retains this calculated data over time so you can chart usage.  And it's Bluetooth, so your not tied to a specific monitor location. What you have here is just a monitor that provides a snapshot of your battery's condition at a specific moment in time--it displays a few more data points than the Innova, but it's the same idea.  It is not predictive.  

Plus, it can "talk" to your Victron solar controller to invoke additional smart charging features and prioritize battery life.

Cbusguy

@morey000 Here is a reasonable equivalent to the victron without the bluetooth or fancy app.    I have been running this on my garage solar system for 4 months so far works great

Link

jkjenn

Cbusguy said:

@morey000 Here is a reasonable equivalent to the victron without the bluetooth or fancy app.    I have been running this on my garage solar system for 4 months so far works great

Link

It is not in the same league, at all, with the Victron. It is limited to 100 ah and many of us use 150-225ah.

In addition t ou @JEB 's comments, the Victron also provides:
- Communication with the solar co nrolle for smart charging to extend battery life,
- The ability to set low and high voltage alarms to alert you of problems in your system
- The ability to add and control relays based on state of charge.
- Mobile phone and PC apps for easy monitoring.

It is a budget alternative for those who who use the basic battery provided by the dealer, but not really an equivalent.

Cbusguy

@jkjenn there are two different devices on that page you simply pick the size you want.   there is one that you saw for 100 AH and another that goes to 999 AH,   and it cost $38.50 currently.   

 but other that the fancy packaging, branding and slick bluetooth interface it is functionally the same.   It tells you whether you are charging or discharging your battery,  how much the current is and how many amp hours you have remaining in your battery.

jkjenn

Cbusguy said:

@jkjenn there are two different devices on that page you simply pick the size you want.   there is one that you saw for 100 AH and another that goes to 999 AH,   and it cost $38.50 currently.   

 but other that the fancy packaging, branding and slick bluetooth interface it is functionally the same.   It tells you whether you are charging or discharging your battery,  how much the current is and how many amp hours you have remaining in your battery.

The reviews indictate that it even though it says it goes to 999ah you are still limited. Like anything, buyer beware.

Cbusguy

It is a very viable alternative for those who are more financially conservative.

And it works very well,   I put about 3kw through the one on my garage every day.   which from 300-480AH a day.

elbereth

Thanks, @BrianZ for the details!  If helpful to anyone else, I found another slightly different path for running the Cat5 cable on my 2018 CS-S that was easier than I thought and did not involve drilling any holes.  Looking under the T@B, I unscrewed one screw holding up the Coroplast near the grey water pipe:



I snuck my phone in there to look around and saw this:



I believe the yellow/white wire in the foreground is the tank sensor lead coming from either the grey or freshwater tank to the SeeLevel.  Pulling down on the coroplast a bit more, I found it entered through a hole drilled in the floor, and was sealed with just a little silicone caulk that was easily pulled off, revealing a hole I could run the Cat5 wire through next to the other wire without having to enlarge the hole (this is a picture after the cable was run in)



Inside the T@b, I opened the bottom cabinet on the left, unscrewed the tiny access panel to the space next to the bathroom, and voila!  There was the wire.  (Again, mine is the 2018 CS-C with cabinets and drawers up front - this would be the same cabinet that used to be under the bench on older CS-S models, and the same space as under the sink on a regular 320).  This pic is after running the cable up.




I cut a 2 1/8” hole with a hole drill attachment above the SeeLevel and pushed a wire fish down the wall between the bathroom and cabinets until I could catch the Cat5 cable.  This was tricky, there was a screw toward the front of the floor that the fish tape kept catching on but eventually it worked.  Easy enough to use the faceplate attachment to mount the BMV-712.



Shunt was installed in another $5 Menards waterproof container with holes drilled in the bottom to let the cables run out.  The container then was attached to the vertical metal inside the tub with 3M permanent velcro.



All told it took me a few hours, most of it with fiddling trying to find the places to run the wire.  Hope this saves folks time.

Sharon_is_SAM

@elbereth, the factory installed our shunt in the same area that you ran your monitor cable through.  Instead of having your shunt in the tub, you can locate your shunt inside that access panel.  Our monitor is on the same wall as yours.

BrianZ

Nice solution, @elbereth!  Your route is more direct to get the cable right between the two walls where it needs to be.  I would bet there was more space in that hole for another wire than the one I used, which was very tight already with many wires.  That space at floor level holds the SeeLevel circuit board I believe.  I wouldn't have thought there would be enough room there for a shunt, but I  guess so.  Always nice to see a new & better way to get the job done.

elbereth

@Sharon_is_SAM, I thought you’d mentioned that in another thread, that’s what gave me hope that I could use that space.  Running a long 0 or 2 gauge negative lead back to the battery as well as the negative to hook up the solar charge controller would definitely require drilling more holes.  If my shunt fails like @jkjenn’s, I’ll do it, but for now will see how we do with the (mostly) watertight box in the tub.

Now has me wondering whether one could repurpose that lower cabinet for an AGM or LiFePO4 battery... Hmmm... always more tweaks to make!

@BrianZ, there’s definitely a circuit board in there though I didn’t completely trace it out.

For folks needing to get through the T@b’s “firewall” for whatever reason, though, this seems a relatively safe and easy place to drill holes if needed, especially with later models having that coroplast on the bottom protecting the whole area from road spray.