Ordering a BMV 702, installation and first impressions...

WilliamA

I suppose it's time to order a battery monitor. I have not had issues with my mostly stock 12V setup and have no desire to put in solar, but my current monitor is pretty basic and doesn't give me much feedback on consumption without getting out my multimeter and probes. I'd like to be able to monitor running amperage and that's the one thing I can't currently do.

I'm looking at the 712 but don't have any need for Bluetooth so has anyone had experience with one of the other monitors from BMV? Perhaps the 702?

Any thoughts would be appreciated

WilliamA

Sharon_is_SAM

@WilliamA, we had the BMV 700 installed with the optional dongle. I think the only thing that the 702 offers is another port to monitor a starter battery. The only weak point that we have discovered is a tiny fuse on the display feed line that collected some water around the cable casing. Other than that, it has worked seamlessly. I know you are not interested in Bluetooth monitoring, but it has been slow to connect at times.

WilliamA

Sharon,
Good to know. I'm about to order the 702 black but have been trying to parse out the differences between the 700,702 and 712. I don't need multiple battery capability nor bluetooth, but don't really care if it has those features so long as I don't need to muck about with some insipid app to use the monitor. I have read that setup is much more seamless with the app but I won't install more junk on my phone unless that is a requirement to use the thing. I assume that the monitor also monitors it's own power consumption and, lastly, does the screen go off automatically when idle. If so, is that idle time progammable?
WilliamA

WilliamA

Ordered the BMV702 Black.....boom....done....boom.
I will post an install when I get it

WilliamA

CampHub

Your going to really like the quality and precision of this unit.

Sharon_is_SAM

@WilliamA The feed line allows the display to remain active, but it has a very, minimal draw. Our TaB is in storage, so I can’t check if it lights up and fades. I can’t recall.

Duce95

Looks neat. I love gadgets. Can’t wait to see how and where you mount it. Looking forward to your write up.

WilliamA

Got it hooked up.

More to come...

WilliamA

TomD

I love gadgets too. Especially ones that tell me the status of stuff.!

WilliamA

Huzzah....

BMV 702 and Lisa Stanfield....

Take the win....

WilliamA

WilliamA

My old First Sergeant would look at this and say:

"What we got hea' be's jus a rat Ness. Clean that up!"

"I'm on it top. I'm on it"

WilliamA

WilliamA

It's time to work out the details of the whole affair. First? An explanation of what I feel is the most important reason to get a high-precision battery monitor. As I noted in my diesel heater thread, I have (had) 3 different Powerwerx voltage gauges for different things. 2 of them were standard voltmeters and 1 had an amperage shunt built in. I was getting 3 different voltage readings on them, so I determined to work out what that was about. I decided to be a bit scientific about which was lying so, using my high precision multimeter as a tester, I checked the voltage of each device at that device using my multimeter. Turns out, none of the 3 matched my multimeter readings at the device. All were off by more than .2 volts, 2 were low and 1 high. That combination gave a maximum voltage difference of .5 volts from low to high. I went through my trailer and cleaned up all of the screw-on connections, then tested again with the same results. Okay. My $20 dollar gauges were crap. That's not a thing in a hot rod, but for monitoring my trailer battery, a half a volt is a big deal. I pulled 2 of them, leaving the one with the amp shunt in line. The reason for that is because the amperage shunt for that gauge is wired through the ground on my diesel heater and I like to know when the diesel heater glow plug is on, pulling 8 amps. I may get rid of that one at some point but for now, it'll stay put.
Working through the differences of the Victron BMV series.
There's the 700, 702 and 712. I spent a lot of time working out the differences between the 3 models. The 712 has built in bluetooth. The 700 and 702 don't, but a dongle is available for them to add that feature. The 712 and 702 have a user-friendly relay wired in but the 700 does not. That's potentially a handy option for reasons I'll get into later, but for now, my 702 relay isn't connected to anything. The 702 relay is only N.O. (normally open) while the 712 has both N.O. and N.C. (normally closed) options. As I said, I'll get to that in a bit.
I ultimately chose the 702 black. I have ordered the bluetooth dongle and will install that when it comes in. Why not just get the 712 with built-in bluetooth? Range. The dongle has a 1.5 meter cable so if I so desire I can mount the dongle where it will have more range. That's the main reason. Depending upon where the 712 is mounted, the bluetooth range might be crap, so I wanted more options. The 702 and 712 come standard with dual inputs for voltage monitoring and I wanted that as well, so that pretty much crossed the 700 off the list for me.
I often leave my trailer plugged into my tow vehicle when doing overnights and I wanted to be able to monitor tow vehicle voltage separately. I hooked the auxiliary battery monitor probe up to the "main" socket of my smart battery isolator so that even if it disconnects the 2 batteries, so long as the tow vehicle is connected I can monitor tow vehicle battery voltage. I tested that yesterday and it's working well.
I installed the shunt inside my group 31 battery box with my group 27 battery. There's room (barely!) For both, but I need to unbolt the shunt and pull it out to connect/disconnect wires to the shunt. That's fine. I don't anticipate having to connect anything else to it.
I ran the R12 wire from the shunt under the trailer and zip tied it to the propane hose that goes from front to rear. I ran it up into the trailer using the same propane line hole, coming out into the cavity behind the radio. I snaked the end through the hole in the firewall (sic) where all of the radio wiring comes through and hooked it up to the monitor in the dash. While it was a lot of putzing, none of it was particularly difficult. Just time consuming.
I moved all of my ground wires to the load side of the shunt and made a short harness from the main side of the shunt to the battery using 2 short sections of 10 gauge wire and ring connectors. That'll be good for 40 amps. I'll pick up a short ground cable if I ever get to go to the store again.
I turned on the battery switch, set my battery amperage on the bmv702 to my battery's 90 amp rating and spent a bit of time scrolling through the various inputs and outputs. One of the first things I did was test and compare the 702 voltage reading to my multimeter. They agree. That pleases me.
I plugged the trailer into house power and let it come up to a full charge and as the literature says, the bmv reset to 100%. Now to get used to it.
Initial impressions are that it is working as advertised. I like being able to test current in real time for various systems and that's a plus. I DON'T like the tiny screen, which for me is difficult to read.
So far, so good...
WilliamA

CampHub

William, good to hear you have it installed and it is working as advertised. You will be happy with the Bluetooth interface. It is easier to read.

CampHub

I should have also mentioned you can update your device through the app!

lipcio

Can display be turned off completely?

CampHub

@lipcio No. It draws so little I don't worry about it.

lipcio

I was more concerned about backlight illumination at night if it's mounted inside.

WilliamA

Illumination goes off within a few seconds (under a minute). Poke any key to turn illumination back on WITHOUT scrolling the menu! That's a nice, well designed feature that I like.
WilliamA