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Surviver76's avatar
Surviver76
Explorer
Apr 04, 2018

96 Lance 3000: Systems Monitor - Battery Monitor Questions?

Hi Guys, I have what seems an odd occurrence I need guidance on soon.
A short or some sort of failure is interrupting the charge signal to my AGM 115ah battery so it gets less & less which I know is damaging to the battery. First, I am in Yuma so getting lots of sun on my solar. So far I have no battery monitor and realize my shortcomings for this lack.
Here is a brief description of my current system. 3 Siemens 50W panels on the roof, ASC Charge Controller, 600W Inverter & FullRiver 12V 115ah AGM Battery. I purchased this battery last week believing my old one was failing and it seems that the old batt may have been ok and my system was where the failure was occurring.

I think the problem may be in the cheesy Lance issue "Systems Monitor" on the wall of the TC. A few weeks ago we had a hot spell and my systems mon showed batt all the way up to the green. Then, with the same basic weather pattern, it went down to one red light at the bottom and the pump was laboring, battery very low. I then thought the problem was the batt. After installing a new batt the same thing is happening and pretty sure I didn't need that new battery after all.
My question is if I install a good Trimetric Batt Mon, how do I deal with the Systems Monitor on the wall? Can I just disconnect it?
If so, how would I do that and I'm thinking the Trimetric could tap into the wiring near my existing charge controller. Also what size shunt should I install and does that go out in the battery bay?
Any help appreciated...

  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Apr 04, 2018
    Surviver76 wrote:

    A short or some sort of failure is interrupting the charge signal to my AGM 115ah battery so it gets less & less which I know is damaging to the battery.

    I purchased this battery last week believing my old one was failing and it seems that the old batt may have been ok and my system was where the failure was occurring.



    Some critical details are missing.

    How old was the "old" bettery ?

    Did you manually charge the new one before installing (or immediately after) ?

    How exactly are you determining that things are not working right ? Battery "monitor" panels are often not reliable and sometimes downright confusing.

    If you don't already have a multi-meter, you NEED to get one.
  • BFL13's avatar
    BFL13
    Explorer II
    Apr 04, 2018
    You don't really need a Trimetric, but it would be a "nice to have" for sure. Read the installation instructions for the Trimetric on line (Bogart) which will answer some of your questions.

    Do check those panels if they are 33 cell or 36 cell. Makes a difference in what your solar can do. ( In 1996, Siemens made both size panels)

    You might have a failure in the ASC. You can check for that in its manual, which is also on line (Specialty concepts) They have an excellent manual.

    The sudden drop in battery voltage might be from a load you didn't know was on, such as leaving the inverter on running something? Or if whole house, the converter left on with the inverter--draining the battery?

    You mostly need a digital multimeter to cross-check what the systems monitor is saying, and for many other RV related measurements.
  • Surviver76's avatar
    Surviver76
    Explorer
    Apr 04, 2018
    BFL13, Thanks for your response. I have a meter and have been monitoring the wattage coming down from the panels. Yesterday afternoon I read 13.8 so charging does appear quite good overall.

    For sure the inverter has never been left on. The key so far seems to be that Systems Monitor on the wall. It comes and goes. I know my tank cycles very well and seldom use the idiot lights on systems mon for tanks but regarding battery health, sometimes it shows what would appear a normal reading for batt and then suddenly it shows just one red light at the bottom. I hit it several more times and it returns to normal again. What I am wondering is this. When it has a failure and shows no or low signal, is that actually affecting the charging system or is it merely a charge "viewing" problem?
  • BFL13's avatar
    BFL13
    Explorer II
    Apr 04, 2018
    When the monitor shows that red light for battery voltage (all it is, is a coarse voltmeter--each colour is for a band of voltages between 12.7 for Full on down) then check the battery voltage at the battery with your meter.

    What is the "high set point" voltage in that ASC? 13.8 is low voltage for an afternoon reading on a sunny day--should be 14.x. --unless voltage was still climbing through 13.8.

    Some ASCs have a screw in the back for adjusting the set voltage. If that is an ASC from the 1990s, you could do a useful upgrade to a better controller for under $75.

    It is not the wattage of the panels that counts for how many cells it has. There can be 50w 33s and 50w 36s. To get proper charging voltages in the high 14s, it is better to have 36s.

    EDIT-Missed the bit about the pump labouring when the monitor showed red for low battery. Also confused about the "charging light" which is the one in the ASC??? Not the monitor's light???

    Anyway, check the actual battery voltage at the battery compared with the monitor's light. You could even have a good battery voltage at the battery, but low voltage inside the rig--use your meter a the Dc fuse panel where battery wires come in and elsewhere such as inverter input, a DC lamp, etc. Might be a loose connection somewhere, or water in the porch light, all sorts of possibles.
  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Apr 04, 2018
    Surviver76 wrote:
    Yesterday afternoon I read 13.8 so charging does appear quite good overall.


    Depending on the exact situation, 13.8 really does not qualify as "quite good"; more like barely adequate I would say. And in some situations, not even adequate.

    But I say once again, putting too much stock in the battery monitor panel might be a mistake.

    It is starting to sound like you might have a loose connection, causing the monitor to fluctuate AND preventing the batteries from getting a good charge.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Apr 04, 2018
    I rate manufacturer instrumentation right up there with the "FREE TOY INSIDE" boxes of breakfast cereal. A snabble of plastic worth a fraction of a penny.

    They are inaccurate
    They are unreliable
    Battery manufacturers love them if the battery warranty period has expired.

    I played around with a new FOX OEM meter. After swapping out resistors and other components, I got voltage fairly accurate. A month or so later, the accuracy went all to hell. The cereal box toy went into the dumpster.
  • westend's avatar
    westend
    Explorer
    Apr 04, 2018
    I'd suggest to use an after-market monitor with a measurement readout. The idiot light system is just that. I have a Victron and believe it's a good, reliable monitor. The Bogart Trimetric is well regarded, too. If you do go this route, you would probably disconnect any OEM shunt and replace it with the new shunt. It is installed between the (-) phase battery terminal and frame ground.

    There are also voltage/amp meters that are less in cost than the Victron/Trimetric but the cost should be considered amortized over the longevity of the battery.
  • Surviver76's avatar
    Surviver76
    Explorer
    Apr 05, 2018
    OK, thanks to all for the great responses. Since my last post, I have been monitoring both the reading on the ASC for voltage coming down from the panels and outside at the battery bay for actual batt reading.
    The current Yuma weather is somewhat cloudy so not a perfect day for taking solar readings I would think however I did read 12.8 again from the panels. I took several readings on the battery. Early yesterday it read 11.4 and I know that's low and by the afternoon it was up to 11.8 so at least I know it is heading in the correct direction. UP!

    As for how to proceed, wondering about those little Chinese power meters on eBay or just anything for now to keep tabs on the battery condition.
    The other question I still have is regarding the cheese wiZ monitor and whether there is a short in the wall wiring there? The fact that it often registers different for each button press?
  • BFL13's avatar
    BFL13
    Explorer II
    Apr 05, 2018
    Mystery is why you are getting 12.8 at the ASC and 11.x at the battery itself. Is there another battery source? Truck battery via 6-pin?

    Yes the intermittent monitor reading could be from a fault in it. EG, on my range hood monitor that came with the 1991 MH, the rocker switch that operates the various indicator lights was broken. You can buy those rocker switches.

    That battery sitting at 11.x is getting ruined. It needs a full recharge ASAP plus an "overcharge" to clear up the sulphation now forming. Without shore power to run a charger I don't know a good way to do that with no solar. Your solar is not reaching that battery, although it might be reaching the truck battery somehow--I can't tell what is going on there from here.

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