Forum Discussion

BFL13's avatar
BFL13
Explorer II
Aug 10, 2014

Saved by Trimetric and Solar Monitor Comparison

Been some threads about whether you really need two monitors if you have solar as long as you have a Trimetric (or that "other one" :) )

As we know, the solar monitor shows all the amps the controller is out-putting (is that a word?) while the Trimetric only shows the amps going into the battery. If the solar monitor shows more amps than the Trimetric does, then that means the solar is running a load plus charging the battery.

So I noticed the solar monitor (on the Eco-Worthy itself, not a remote) showed 4.58 ish amps while inside the trailer the Trimetric was acting weird, showing 2.0/1.8 flashing back and forth. So I thought I had a mystery load of about 2.5a.

Pulled all 12v fuses one at a time, no joy. Turned off solar and Tri now showed 0.3a steady. Aha, that is normal with the fridge burner not on. So it must be something to do with the solar itself, but what?

Much poking around and trying this and that then noticed some green corrosion goop on the battery pos post the solar was onto along with a bunch of other terminals (breaking Mex's Law that you should only have one thing connected to any battery post, using a buss if you need more connections)

Cleaned that all up and Shazam! No mystery load at all, it was just the solar wasn't all getting through to the battery.

I never would have noticed that until the green goop had become so huge even I could see it right away, if I had not the two monitors, since the solar monitor was showing the actual output ok. In this case it was the Trimetric that had the funny number.

Now I am wondering if my complaints about the MPPT solar not delivering as many amps as I am entitled to, might be due to that, and not to the heat lately as I had thought. We will see about that
next chance I get to see full output from the solar. (too late today)

Not saying everyone should rush out and get more monitors (they cost money), but am saying there are advantages to having more than one.
  • walkeraw's avatar
    walkeraw
    Explorer
    Aug 13, 2014
    crcr wrote:
    Can anyone post a link or links to a buss that are suited for said solar application, are of good quality, and good price? I would want the terminals of the buss to be large enough to handle HD lugs for 4 ga wire.

    Thanks!


    Cheap/reliable..less than $10 total...available at any big box store...electrical "old work plastic electrical box" (i.e. Carlon, pvc single) and an electrical "load center ground bar kit" (i.e. Square D, lengths/# of terminals vary) that will fit inside box. I use two of these setups for buss boxes (postive/negative). Easily handles 4gauge (battery cable from Wallyworld). Works great on my solar setup.
  • mena661's avatar
    mena661
    Explorer
    Aug 12, 2014
    crcr wrote:
    Can anyone post a link or links to a buss that are suited for said solar application, are of good quality, and good price? I would want the terminals of the buss to be large enough to handle HD lugs for 4 ga wire.

    Thanks!
    AM Solar has one that mounts to the fridge vent. I don't remember what wire size it takes though.

    EDIT: Correction, their Roof C-Box accepts up to the #2 wire. The fridge vent one only goes up to #6.

    http://www.amsolar.com/home/amr/page_72/roof_c-box.html
  • BFL13's avatar
    BFL13
    Explorer II
    Aug 11, 2014
    Harvey51 wrote:
    Cleaned that all up and Shazam! No mystery load at all, it was just the solar wasn't all getting through to the battery.

    Curious. I wonder where the current went after it got through the solar shunt?


    No idea but the Trimetric reading was wonky due to the pos wire from it having poor contact. At least fixing that contact had everything working properly again, that's all I know. Without the Tri, but just seeing all the solar amps on that monitor, I would have ASSumed the batteries were getting those amps. Maybe they were and the Tri wasn't showing them all, no idea.
  • crcr's avatar
    crcr
    Explorer
    Aug 11, 2014
    Can anyone post a link or links to a buss that are suited for said solar application, are of good quality, and good price? I would want the terminals of the buss to be large enough to handle HD lugs for 4 ga wire.

    Thanks!
  • Almot's avatar
    Almot
    Explorer III
    Aug 11, 2014
    BFL13 wrote:

    ... if you only had one monitor it should be the Tri and it is the solar monitor that is of limited use.

    Same old again...

    1) Yes.
    2) Not really.

    In more details:

    If you have right size of solar, so that it brings batts to Float every day or most of the days, a solar monitor will tell you this, and this is all you need to know. Trimetric would be of limited use then. Other than the described above investigative analysis of improperly done wiring :)...

    If you can't charge your batts fully with solar, or don't need to, then you do need a Trimetric, and then solar monitor would be of limited use.
  • Almot's avatar
    Almot
    Explorer III
    Aug 11, 2014
    Harvey51 wrote:
    Cleaned that all up and Shazam! No mystery load at all, it was just the solar wasn't all getting through to the battery.

    Curious. I wonder where the current went after it got through the solar shunt?

    Where did the rabbit go after disappearing in the hole? Who can tell? To the left, to the right, or escaped to the outside through another hole. Controller current could've gone to loads, or was lost on heating the poor contact. In this mess, nobody can tell. Even BFL can't tell for sure whether his controller cable was still in contact with the trailer system cable, while losing the contact with battery.

    Btw, it's not healthy keeping controller connected to PV while not connected properly to the battery.
  • Almot's avatar
    Almot
    Explorer III
    Aug 11, 2014
    BFL, if you have only done it the right way from the beginning, the way that Mex suggested - with controller to Pos bus in a dry and clean location inside the trailer, with a Pos cable of trailer system to the same bus, so that a Pos cable from Pos bus would be the ONLY cable to the battery, with a proper lug on it - you wouldn't have made this discovery and we wouldn't have enjoyed this amusing read ;)

    Not only because with only one lug on battery terminal there would've been less chances of corrosion, but also because a poor contact on that only cable would've been immediately noted in your loads behavior.

    Getting an AGM would've also helped to prevent the corrosion. Not that I suggest getting an AGM when you can do without them.
  • Harvey51's avatar
    Harvey51
    Explorer
    Aug 11, 2014
    Cleaned that all up and Shazam! No mystery load at all, it was just the solar wasn't all getting through to the battery.

    Curious. I wonder where the current went after it got through the solar shunt?
  • BFL13's avatar
    BFL13
    Explorer II
    Aug 10, 2014
    pigman1 wrote:
    Good information. I've been debating if we should be using a Trimetric or not. We have four 140w panels and a Morningstar Tristar MPPT controller. The Morningstar remote panel gives us a lot of info, but I don't know what else I could use. Besides current in/current out, what other info does the Trimetric give you that the solar charger does not? Sort of hate to spend that much for just a fancy ammeter.


    The Trimetric gives you the total of what crosses its shunt in and out of the battery bank in amps and AH. It also is a voltmeter. You can use it to get an idea of how far down the batteries are and how things are going on a recharge. This covers everything happening in the rig that is on battery. The solar monitor only gives you what the solar is doing.

    The solar shunt is placed upstream of the Trimetric shunt so the Trimetric includes the solar. However the Trimetric only shows battery, so when the batteries are near full and there is extra solar, all you see on the Tri is the part of the solar amps that are charging the battery while the total solar amps that might be running other rig loads shows on the solar monitor.

    Actually if you only had one monitor it should be the Tri and it is the solar monitor that is of limited use.
    ---------

    BTW, fixing the solar connection as mentioned earlier did not change the output showing so the Heat vs MPPT situation previously reported stands.
  • pigman1's avatar
    pigman1
    Explorer
    Aug 10, 2014
    Good information. I've been debating if we should be using a Trimetric or not. We have four 140w panels and a Morningstar Tristar MPPT controller. The Morningstar remote panel gives us a lot of info, but I don't know what else I could use. Besides current in/current out, what other info does the Trimetric give you that the solar charger does not? Sort of hate to spend that much for just a fancy ammeter.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,203 PostsLatest Activity: Feb 21, 2025