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Community and Q&A

Energy Monitor for Tracking Solar Generation and Consumption

maine_tyler | Posted in Mechanicals on

Does anyone have recommendations for an energy monitor to track solar panel generation and consumption.

This is an off-grid cabin with a 24v battery bank (8 6v lead-acid batteries in series/parallel). It’s a DC coupled system with a couple small panels. MPPT controller and a Conext SW 4024 Inverter/charger.

Given the above, I would like it to have the following characteristics:

Log the data and not rely on wi-fi or cell service (both lacking)
Not draw too much power
Not be expensive
Track generation per unit of time
Track consumption per unit of time

The goal is to see how much is being generated vs how much is being used by guests (rental cabins) because the system can’t quite keep up it seems.

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  1. maine_tyler | | #1

    For bonus points, can anyone explain why an 'inverter/charger' was used when the MPPT is what's doing the actual charge management? Is the 'charger' feature of the Conext SW just for AC input charging, like a generator or grid?

    1. charlie_sullivan | | #3

      Yes, its charger feature is for charging batteries from the grid, or a generator. I don't know whether that was chosen simply because of it being a good quality product that was available at a good price, despite that unneeded feature, or whether it was to plan for a possible future generator connection. In some inverters, it's possible to do that with the same hardware as the inverter function, so it doesn't add much cost.

  2. Expert Member
    Akos | | #2

    Schneider's Combox is probably the easiest and should work. I've mostly used this in on-line application but it does log to the the SD card locally. It is not cheap though.

    The charger feature of the inverter is for charging from grid/generator. If you don't have either of those, you don't need to configure it.

  3. GBA Editor
    Martin Holladay | | #4

    In case it isn't clear from the other responses: the MPPT controller optimizes the voltage and current begin delivered to the batteries by the PV array.

    The charger is a feature on some, but not all, inverters. These chargers are used by off-grid homeowners to charge their batteries from a gasoline-powered generator. The charger tapers off the current being delivered to the battery as the batteries get full.

  4. maine_tyler | | #5

    Thank you all.
    After I posted this I did see that Schneider made a Combox, native to the system. But yes pricey indeed.

    Rather than toy with increasing solar capacity I may use that AC charging feature with a generator.
    It would boost system reliability, but I am assuming if I want auto start I need a genny with electric start. Not sure if that exists in my desired price range.

    Any advice on small and affordable generators with auto-start capabilities?

    Given the intermittent use of the system, I think it could be pretty small. Something quiet and ideally less than 800 dollars or so. Propane or gasoline. Does that exist?

    Or I should revisit the solar capacity and just add a couple more 280 watt panels. Probably cheaper by the time I get the entire auto-start generator system up.

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