Victron 712 Battery Monitor install question

[Want a B]

2009 Born Free, Built for Two.
Victron Battery Monitor system BMV-712
Parallax 7300 series power supply

Where can I mount the shunt?

I've got limited space on the slide out batteries tray. Current cables that exit the floor are sealed tight and I really don't want to run the risk of drilling another hole. Even if I did the Battery tray slide out is tight for space, really no place to install the shunt (picture #1).

How about intercepting the Negative at the Parallax power supply (picture #2)!!!!! Then I can mount the Victron shunt above and to the right of the Parallax (picture #3).

I'm smiling until I trace the Negative from the Parallax back towards the batteries and find a negative bus bar (picture #4).

For the Victron to monitor ALL usage, as designed, it would need to be installed between the negative buss bar and the batteries. The only way I can do that is to remove the driver's side bed to gain access. This would make for a nice install IF I don't unintentionally destroy the bed when I try to remove it.

The 12 VDC power for the shunt I'd take from a circuit on the Parallax.

Any thoughts, suggestions or guidance anyone could give would be appreciated.

[Winston]

We'd place the shunt just about where you picture it, possibly to to left immediately proximate to the negative terminal. Due to clearance, you may have to place the shunt 'laying down'. Of course you will have to run the RJ cable out of the battery compartment so you'll need at least one hole for that. Incidentally, it appears there are two wires connected to your negative terminal - - both will have to be removed and attached to the shunt with only the shunt, itself, connected to the negative battery terminal.

[avanti]

It is easy to make a custom bus bar out of a flattened piece of copper tubing. Here's what I did:
user114_pic1719_1425170264.jpg

user114_pic1721_1425170922.jpg

user114_pic1724_1425171032.jpg

In your case, perhaps you could make a more complex shape that rotates that large shunt such that it lies parallel to the top of the battery?

[Want a B]

Winston. Thank you noticing the two ground cables. Since they both needed to be attached to the shunt, that leaves me no option but to mount the shunt with the batteries.

Avanti. Great idea on how to make a copper buss bar. Did you use "K" copper? 1/2" or 3/4" diameter?

[avanti]

Originally Posted by Want a B

Avanti. Great idea on how to make a copper buss bar. Did you use "K" copper?

Don't remember.

1/2" or 3/4" diameter?

3/4"

[GallenH]

Originally Posted by Want a B

Winston. Thank you noticing the two ground cables. Since they both needed to be attached to the shunt, that leaves me no option but to mount the shunt with the batteries.

I'd say that has to do with the amount of room that you have. My situation was different: I was adding both a battery disconnect switch and a victron to my system. I connected the wires that were originally connected to the battery [-] (I think I had 3) to a Blue Sea bus bar with a cable that went to a different location where the switch I added was mounted. That cable was first connected to the shunt and then went to the switch and then from the switch back to the battery negative.

neg cables--->bus bar--->shunt---->switch---->battery negative.

I realize that yours is probably different. But your only option isn't to mount the shunt directly on the battery. Avanti's solution is, however, very neat if you have the room.

[tgregg]

Originally Posted by Want a B

Winston. Thank you noticing the two ground cables. Since they both needed to be attached to the shunt, that leaves me no option but to mount the shunt with the batteries.

The picture is a little dark, but it appears that one of those ground cables is the cable connecting the 2 batteries together. If that's the case, it would remain connected directly to the battery and only the other one would need to be attached to the shunt.

[Want a B]

Project is working!

I removed the clamps holding the fresh water tank floor drain in place. Then I could gently pull the drain up and out of the floor. This allowed enough space to thread the Victron cable down the hole. Picture #1. I still need to caulk it.

Picture #2. The Display is mounted beside the convection/microwave. But it didn't read any usage!?!?!? So I moved the second battery negative cable as tgregg suggested. Now the Victron reads the ampage, voltage and etc. Picture #3.

Following Avanti instructions I made a copper buss bar out of 3/4" ridged copper pipe. Couldn't round the corners like Avanti's because I don't have the means to do so. I did file off the sharp edges before mounting. There was a 3/4" piece of wood acting as a spacer on the right side of the batteries. I move the spacer to the left side of the batteries which gave me just enough room for the shunt.

I still need to caulk and tie wrap the cable in place. Minor compared too getting the cable from the microwave cabinet, up and over in the roller cover to the opposite side of the coach.

Thank you all for your comments, advise and comments.


P.S. Don't know why the Forum software rotated Pictures 2 and 3????

[GallenH]

Nice job! Congrats.

[Want a B]

The old "Battery management" with LEDs; charging, good, fair and weak.

And the new! Now I know long my batteries will last at the current usage and what the usage (watts) is!

[booster]

What settings did you make in the Victron 712? I just looked at the manual for it to see what it had for options, and was surprised that they said the defaults were good for most setups, and to just set the amp hours of the battery bank.


Further into the manual, they showed the defaults and setting ranges, and IMO they are certainly not suited to most, or even many, applications.


In particular, the parameters that determine a "full" battery while charging are at less the 4%C (4 amps per 100ah of battery) at over 13.2 volts.



Typical wet cells would be something like 1-3% at 14.4-14.7 volts per the manufacturers specs for full.


Typical AGM batteries would .5-1% at 14.4-14.6 volts.


That is quite a difference and would almost certainly leave the batteries less that at rated capacity, I think. Maybe in the range of 5% less than full, maybe a bit more or less. The small lack of capacity is probably less of an issue right away, but over time, the battery will keep walking down in capacity because of it, if done regularly.


In defense of Victron, they may feel they have no choice but set the meter there, as there are very few chargers that can actually get to the battery manufacturer's specs without either over or under changing, and if the meter never says full, it will never "synchronize" or calibrate like it should to prevent accuracy loss over time.


I think I should be able to test how much below full the Victron specs would leave our AGM batteries, as our charger runs off a shunt and monitor. I will just change the parameters to stop charging at 4% and 13.2v, and then change the settings to .5% and 14.3v, which are our normal settings for our Lifeline AGMs, and run another cycle. The amp hour counter will show me how much more charge they took to get to the lower amps and higher voltage specs.

[Want a B]

On boot up the only required information was the CCA. All the other options I left at defaults until I learn how or if I should make changes..

[booster]

Originally Posted by Want a B

On boot up the only required information was the CCA. All the other options I left at defaults until I learn how or if I should make changes..

Did they really ask for CCA, cold cranking amps? The manual says you would set the 20hr amp hour capacity rating, which is what I have always seen in all monitors.

[Want a B]

Originally Posted by booster

Did they really ask for CCA, cold cranking amps? The manual says you would set the 20hr amp hour capacity rating, which is what I have always seen in all monitors.

You are correct. 20 hr amp hour capacity. I used the CCA rating from the battery labels until I could reserach my batteries.

[engnrsrule]

I put the shunt in the compartment of my sprinter that contained the charger, inverter and DC distribution relays. I wanted it protected from the weather, which it would not be in the battery box. This required running a new 2awg cable from the battery to the shunt and from the shunt to ground.

[Sehc]

Rod Collins has a good explanation of programming the Victron.

https://marinehowto.com/programming-a-battery-monitor/

[booster]

Originally Posted by Sehc

Rod Collins has a good explanation of programming the Victron.

https://marinehowto.com/programming-a-battery-monitor/

We have discussed the Collins columns several times here on the forum. The threads contain some interesting observations and some agree and some don't.


My opinion on it is that he misses the some of the premise of how an monitor and batteries work in an RV, and from that draws conclusions that I don't think reflect what the monitor is capable, or not capable, of.


Personally, I would not use the settings that he recommends for some of the reasons discussed in the other threads.



Accurate charging and monitoring go hand in hand, so how the monitor is setup is very system dependent, often with various compromises needing to be made.


I am currently running the test I mentioned earlier to determine the actual usefulness and accuracy of the Victron recommended default (good for most users) settings. Hopefully, it will be done by tonight as it does take quite a bit of time to do.

[booster]

Just finished by test of the Victron settings on our AGM system.



Results in this discussion:


https://www.classbforum.com/forums/f...ing-10753.html