Battery power with generator charging

volunteervolunteer Registered Users Posts: 1
Hello, I am a volunteer for a non profit org. Doing great work in Tanzania,Africa. There is no power grid. They have a guest residence 8 rooms and a kitchen. There is a 21 kV diesel generator (230v 50 hz) that is the only source of power. My thoughts are to add a battery bank to provide CONSTANT power, needed for water filtration and refrigerated medical supplies. What is the best approach to get this resolved in Tanzania? The plan is to expand and add a medical clinic. They are on a limited budget and are resisting solar panels because of cost. Can we start with a smaller battery bank and add on as needed? Do you know of any contacts in Dar es Salaam?


  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    The first step should be to identify the critical loads that are to be powered by battery in terms of daily consumption, and surge currents for pump motors etc. Using battery power to replace all loads currently powered by the 21kw generator may not be practical, but running a subset of them may be.
    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
  • BB.BB. Super Moderators, Administrators Posts: 33,082 admin
    "Hybrid" generator systems were/are being used in Africa.

    Basically, during the day and night (when loads are light), run from a battery bank + ac inverter.

    During the evening (and possibly morning) run the genset to power heavy loads and recharge the battery bank. You can add solar now or later as finances allow (save some fuel charging battery bank).

    Ideally, you need to locate and cost either locally available good and/out of country suppliers.

    Basically as Estragon says. Identify your smaller loads that run during the day & late at night, and size the battery bank (2 days storage and 50% maximum discharge for longer battery life... basically battery bank 4x daily loads) and ac inverter fit your peak power needs and surge loads (like starting a well pump).

    As you know, of grid power is expensive (cost of installation, cost of fuel, and cost of repairs+batteries as the wear out, etc.).

    More or less, in the USA, off grid power costs something like $1-$2 per kwh... Around 5-10x the cost of utility power. Plus you are responsible to keep it running.

    Conservation on your side can save you a bunch of money (smaller of grid system, smaller battery bank, less fuel, etc.).

    If this is a "village system", sometimes you run into the " tragedy of the commons" situation. A few people use all the power...

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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