BZ 250W/25A Solar MPPT Charge Controller

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Comments

  • momofgcm
    momofgcm Solar Expert Posts: 35
    Re: BZ 250W/25A Solar MPPT Charge Controller

    I was wanting to boost my V into the controller when conditions made the V from the panels less than the battery charging V. I was thinking if my panel V to the controller was less than 14V I would want to boost it to the charging voltage and at least get some harvest out of the panels rather than losing the energy.

    If the panel are in series they can have a Voc of 88V or 44V if put in series then parallel. Would the higher the voltage I put at the input of my controller give me the best resolution for staying within the buck of the controller? I want to be on the buck side of the controller as much as possible right?

    In Guinea there are a lot of clouds and heat. I wanted to maximize what I could get out of the panels since I'm sure I won't be getting optimal output very often! The insolation value is only 3.5-4. This particular installation has no grid and no generator backup.

    How do you determine if it's cost effective to add a boost section to the controller?

    Kim
  • System2
    System2 Posts: 6,290 admin
    Re: BZ 250W/25A Solar MPPT Charge Controller

    Hey guys,
    I'm new to the forum and solar setup and found this thread googleing the BZ MPPT250. Well I got one 3 days ago, installed it and it's giving me incorrect battery reading which are .3 volts higher than the reading from my old charge controller, volt meter, and xantrex 600SW digital display.

    Reading this thread made me realize that this controller...simply put... sux!
    However, I just need something cheap to charge two 6v golf cart batteries connected to two 45w set of harbor freight panels.

    I plan on getting better panels that will be hooked up to a GTI.

    Let me know what you guys think.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: BZ 250W/25A Solar MPPT Charge Controller

    Just get an inexpensive 10 amp rated PWM charge controller for now. It will work good enough for you to experiment and see how things work... Typically, if you keep your batteries watered and don't let them get too discharged, will last you 3-5 years.

    Get a Hydrometer and, I would suggest, a cheap DC Current Clamp meter for measuring current. It is a lot simpler and safer to use than a DMM and setting it to Current mode.

    If you want to see the details of building out a small, but higher quality system, here are a couple of good threads to read:

    Emergency Power (beginning to end about designing and building a small solar off-grid system)
    nice thread with video from Kevin in Calgary Canada that shows designing and installing solar PV in a small RV trailer.

    And, this thread is just a whole bunch of information and links about solar and conservation:

    Working Thread for Solar Beginner Post/FAQ

    I am not quite sure I understand your question/direction. Generally, a Grid Tied system (GTI--interface) comes in two flavors. One is pure Solar Panel to GT inverter. Cheap, reliable, makes good sense if allowed by your utility and they support 1 year net metering (or other favorable billing plans).

    There are also Hybrid Inverters. The setup is Solar panel to charge controller to battery bank to Hybrid inverter that is cable of both off-grid and grid tied operation.

    Neither system can really start small and be grown into...

    Grid Tie can be done with a single large GT inverter connected to a solar array. Or done on a per panel basis with "micro GT inverters" (one panel, one inverter)... However, you are supposed to get building permits and utility approval--So growing a micro inverter system panel by panel is difficult to do legally and cost effectively.

    And growing systems over time run into issues of solar panels that go out of production after a year or three (replaced by bigger/better/cheaper panels) and hardware that is obsolete in 5-10 years.

    Whatever you do--make your plans on paper first before you go out and purchase new hardware. Much cheaper and you should end up with more knowledge and a better system.

    Also--if you have not done it yet--Look into extreme conservation first before you "go solar"... It is almost always cheaper to conserve a kWH than to generate a kWH.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Gulch
    Gulch Registered Users Posts: 13 ✭✭
    Re: BZ 250W/25A Solar MPPT Charge Controller

    Dredging up this old thread... Must have lucked out when I bought one in about 2009, to replace one of the Wellsee (non) MPPT controllers that lasted only a couple of weeks. I have it hooked up to a Kyocera 205 watt (26.6Vmax) panel keeping a motorhome battery bank charged, and it has worked flawlessly for years, and I was looking for another one to rig up another similar system. But since no one else has had any luck with them, I guess I'll spend the extra $ to get a Morningstar or something even better.