Multi input charge controller

BeauvilMDBeauvilMD Registered Users Posts: 3
Hi all
I m working on a project currently but I have one question.
Can t I find a charge controller that can hold different input ( Solar, car alternator and utilities) but not simultanoussly.
It's a battery power pack for rural and recreation uses and I need that people can charge in any of this type of source, from a solar panel, from the cigarettes light of their car or with a 12 utility volts charger. Any advice please?



  • BB.BB. Super Moderators, Administrators Posts: 32,639 admin
    edited September 2016 #2
    The problem is that you have widely varying input power sources... Some like solar panels can be turned on and off without damage. Others, like directly connecting a car alternator, will be damaged (or cause damage) if you use a "series controller" (like a solar charge controller) and just turn their output on/off.

    And AC to DC power sources can have wildly differing output voltage/current/designs/requirements.

    Can you tell us a bit more about what you are trying to do? The loads you want to drive (i.e., large or small power requirements), cost vs weight (use large heavy lead acid batteries or light weight/expensive LiFePO4 type), etc. We have had quite a few questions from people that want to run CPAP machines or other medical devices.

    In general, the loads are very important--Because conservation of energy usage is almost always a better investment than using less efficient loads and designing a large off grid power system.

    Will all of the power sources be brought with you and/or consistent interface (i.e., using a 10 amp 12 VDC lighter plug on car with the car running or stopped)?

    How big/what voltage/what type of battery bank? How large of solar array (and voltage/panels you want to use)?

    Just a ton of questions.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BeauvilMDBeauvilMD Registered Users Posts: 3
    Thank you very much for your feedback, let me try to answer some of your questions.
    A small diagram is enclosed to give you a better idea.
    First it will be a mobile system, with a 120 volts AC/ 12 volts DC charger, a 200 w/12 volts solar panel, and socket cable to hook up to the the truck lighter.

    A universal DC-DC Charger controller to protect my battery. This is my request.

    The  bank will be one battery 100 AH or two parralel batteries 50 AH optional. The inverter is 400 watts/12 Volts Pure Sine wave. For this system I m looking for DC/DC Charger controller that can hold even solar, truck and other 12 DC volts that's going to recharge the battery.

    I don't want to use a selector for this three type of input charging source.

     I m not sure if I m so clear, but for other questions please feel free to let me know, and sorry for my old fashion english.

    Marckenson Beauvil
  • BB.BB. Super Moderators, Administrators Posts: 32,639 admin
    If you plan on weekend use--Then you can get away with 5 amp (5%) rate of charge. However, if this is a daily use system, then I would suggest ~10 amp (10%) rate of charge.

    If you have a 10 amp simple AC battery charger and 200 Watts of Vmp~18 volts at 11 amps total--Then you could use a simple PWM solar charge controller (DC from utility charger, or DC from solar panels) to regulate the average charging current to the AGM battery.

    The truck lighter charging is a question... Typically, a 12 volt automotive type alternator charges around 13.8 to 14.2 volts. AGM batteries should not see more than 14.4 volts (typical) maximum charging voltage.

    If the truck/car is not running, then you have ~12.0 to 13.0 volts (12.7 nominal) voltage and this will not recharge your battery bank.

    For charging when the engine is not running, you would need a "boost" type battery charger to raise the votlage from 12.x volts to 14.x volts charge the AGM battery. Or, you can look for a buck/boost charger so that it can take any "reasonable" charging voltage from your vehicle to recharge the AGM battery (you could also probably move the AC to DC power source to this buck/boost charger).

    Anyway, you have very different types of charging sources with a wide range of voltage/current profiles. It is difficult to give a generic answer--Each charging source needs to be defined and designed to meet those requirements.

    Unless you want to make an electrics DIY project out of this--I would suggest that you may end up with 2-3 separate chargers connected to your one battery bank. It will be less complicated.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BeauvilMDBeauvilMD Registered Users Posts: 3
    Thank you very much bill, very useful your comments I will figure out what is feasable from your advices in my case and I ll keep you on tract.

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