Question about charging my battery bank using a second source

ghostofthenorth
ghostofthenorth Registered Users Posts: 13 ✭✭
Hi very helpful community.  I've been reading on here for a couple of years, and just built my first system.  Its working well so far, but I have a question about a backup charging source for my system.

I have installed 4 x 230W photowatt panels in 2 x 2 parallel-series connection to a Midnite Classic 150 CC, charging a 24V bank of 4 x CR430 batteries.  My inverter is an ST-1000-124.

I followed as many recommendations as I could and so far everything is working very well.  The setup is working in ~central (actual central, not what people call central) Ontario, Canada in an off-grid application.  So far we typically take the batteries to ~95% charge after each night of use.  I might have over spec'd the batteries a bit, though I want them to be able to handle low peak sun hour times of the year, such as Moose season and winter.  

My question is the following:  There are times that we will run a generator (for water pump and water heater), and I want to make use of the extra power to charge the batteries.  Do I need to do anything to the CC when using the battery charger (powered by genset)?  Does the Midnite Classic need to know in some way that the battery charger is charging?  

I've tried searching the site for this, but haven't found anything specific to this question other than a very general "it should be ok".  I'm curious for my specific CC (which so far I LOVE, thank you NAWS users) if there is any setting I should/need to set when using the external charger.

Thanks greatly in advance!!!!
GhostOfTheNorth

Comments

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited August 2018 #2
    No need to do anything special, just parallel the charging sources, the battery voltage will regulate both just use a quality charger particularly if using AGM, cheaper automotive ones can over voltage the bank if left unattended. It's also better to use one that can supply enough current to use the available energy, but not over tax the generator..

    An example of the kind of charger which is well suited for such an application, there are other amperage version.
    https://www.solar-electric.com/iota-engineering-dls-27-40.html
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    You may already be aware, but I'll throw one potential issue out there anyway.

    Depending on charging voltages and whether you have a whiz-bang jr, the generator could end up supplying most of the charging current, and make the controller go prematurely into float. Using a WBjr to measure actual current to the bank (vs Classic output) avoids this. Setting the Classic to not use end-amps while generator charging would also avoid the issue.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    You can probably find a cheap used 24v floor scrubbing machine charger and that should get you started.
    You won't be able to use the inverter when it's equalizing.
    I have one I bought from the scrap yard I was planning to use when I build a 24v system. Only makes 7 amps.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • ghostofthenorth
    ghostofthenorth Registered Users Posts: 13 ✭✭
    Thanks for the quick feedback guys!  I do have a Whizbang Jr in the set-up, monitoring the amps out of the batteries.

    Glad I don't have to do anything too special, sounds like its a simple add.

    Thanks Again!!