27 replies to this topic

[buckland]

As part of the LiFePo4 battery install in the Eagle I thought it would be good to have a monitor (though not a Trimetric) to see what is happening in realtime. The new set up will have 2 solar panels (160 W on the roof and a Flex portable 100 W ). The roof panel is wired to the battery box as is the portable via a exterior wall plug. These will pigtailed to the Victron MPPT 100 / 20 Controller which has bluetooth (to iPhone).

I built the Rando Lithium battery to replace the two AGM batteries. There is a Blue Seas battery separator.

 

I would like to wire the shunt in the battery box and then replace my old voltmeter monitor with the new battery monitor which is in the cabinet front with the other FWC gauges.

 

My question is:

Is the shunt installed in the positive and negative lines coming out of the Victron Controller LOAD ? And then continuing on to the Camper DC fuse box? Or is it in-between the battery and the Controller? 

Attached Files

•  IMG_7989.jpg   77.53K   101 downloads
•  IMG_7990.jpg   77.84K   104 downloads

Edited by buckland, 21 May 2019 - 07:30 PM.

[rando]

The shunt should be installed on the negative line to the battery, close to the battery.   However, if you are using the load terminals on the Victron Solar controller, you will already get the current information through the Victron App and the MPPT display (if you have it) so the a current meter won't give you ay extra information.

[buckland]

Thanks... the saved me extra work. So the app display will have the load usage when installed. That’s nice.
I guess I gotta start removing the AGM batteries and get at the install of the new battery.

[ntsqd]

Seems like adding the shunt should make the amperage readings more precise?

[Vic Harder]

i would add the shunt. load connection only shows amps out. victron would have no way of telling SOC without it

[rando]

I this just a current meter, or an actual current counting state of charge monitor?

 

If it is an actual integrating state of charge monitor it could be useful, although I am not convinced the cheap-o ones aren't more confusing than beneficial as they don't re-sync them selves and thus the integrated errors can be terrible after some time and give you completely false numbers. 

 

If it is just a current meter, the Victron has you covered.

[buckland]

I guess if I have them I might as well use them. I do intend to use the load terminals on the Victron.  I am still unclear (gee how unusual!) as to wiring the shunt. As Rando says real close to battery (8" cable should do) Negative post.... then, not sure if the shunt load connection is is in the line to the Victron load ?

 

For those interested (on a basic level of grogging this stuff).... Here is the unit I bought from a suggestion on WTW as well as a poor video of use.

 

This is the spec sheet:

https://leeselectron...duct/15967.html

 

Edited by buckland, 24 May 2019 - 04:52 PM.

[roverjohn]

I'm with Rando on this one and see no point in adding that shunt for any number of reasons.

 

I do have a question though. Why do you think having instant access to info on your phone will make any difference at all? BT has minimal range so can't you just look at the controller if you need that info? You're adding a parasitic drain where one is not needed.

 

BTW: I don't think your controllers MPPT function will have any way to know that two dissimilar panels are wired together so you may not get optimal MPPT functionality.

[buckland]

Well... the Victron MPPT 100 20 does not have  a screen or monitor, nothing to look at. The iPhone app is the monitor.  

Blue tooth power usage is next to zero in power consumption. 

The extra portable panel is only used when the camper is in the shade. More amps is better than no amps. 

What are some of the, any number of reasons, for not having a shunt?

 

Attached find the company's hook up instructions for different set ups.

I am assuming the battery set up would be the one to choose?

Attached Files

•  713WcgbUDpL._SL1500_.jpg 1,500×1,001 pixels.pdf   161.98K   33 downloads

Edited by buckland, 24 May 2019 - 05:51 PM.

[roverjohn]

I guess I misread Rando's post about the displayed info. Still if you are going to use an app why not use the Victron app or purchase whatever display they sell if there is one? Or just skip both. The best way to see SOC is to measure battery voltage at no load and you don't need an app or a display to check it. Just a good voltmeter.  It's a very easy thing to do. Also, there really is no need to keep in constant contact with that sort of info. You either have enough juice to last the night or you don't. So maybe look at SOC once when the sun goes down and plan accordingly or just waste less or produce more. Your panels will make a finite amount of power ea day. Why use any of it to create data that really isn't that useful when you think about it?

I'm the sort that spends most of time with my phone off when I'm outdoors. I also switch off things that are not serving a useful purpose at that moment. Even the green led on my USB charging station bugged me enough that the whole thing is switched off when I'm not charging something.

I still haven't heard why this is some sort of critical info that anyone needs to monitor regularly. 

Also, BT power consumption may be close to zero however it's not zero and when the data might be useful is when you have the least available power to spare.

 

I like things simple and Rando's suggestion to skip the shunt is simpler so I +1ed it.