Question about a Solar Charge Control Panel

Discussion in 'Off Grid Living' started by Falcon15, Jul 8, 2014.

  1. Falcon15

    Falcon15 Falco Peregrinus

    The family and I are full time living in our RV. It has a small solar system, about 180 watts (2 panels), and a small bank of 8 batteries (the bank can hold upwards of 12 as designed).

    My problem is my charge control panel. Currently installed is a Solar Commander III. It has analog gauges, showing battery levels and solar panel output. I would like to upgrade this panel, as I am not certain how good it is or if it is really even worth keeping. It is mounted in a bulkhead, and the panel itself has all connections in the rear. It measures 5x7" approx and I would like any recommendations for replacements.

    Thanks in advance.
  2. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    The very best Charge Controllers are the Outback Power Systems MX Series.... they come in 60 Amp and 80 Amp versions, and will take up to 150VDC InPuts, and can charge any Battery Bank Buss Voltage, between 12Vdc and 48Vdc. They are an MPPT Type. (MPPT = Maximum Power Point Tracking) this means that then are 95% Efficient in converting the DC Input Voltage, to whatever your Battery Bank Buss Voltage is, and they have Three Stage Battery charging Built-In. They are Fairy expensive, but will be the last Charge Controller you will ever have to buy. .....
    Tevin likes this.
  3. Tevin

    Tevin Monkey+++

    As stated, the Outback controllers are highly rated. I use a Morningstar (also well respected) TriStar 45 amp MPPT controller. Like the Outback, it will work with almost any voltage.

    For my smaller system I have a Blue Sky SB2000E 25 amp MPPT with a digital volt and current meter. It will not display other data such as kilowatt-hours and charging stage. It cost about $250 without extra goodies. It was originally designed for RVs and later adapted for other solar applications.

    The Morningstar will run you about $400-$425. The digital meter is an extra $100 (in unit)-$120 (remote) and it will tell you more than you really want to know about your system. For you I suggest the remote meter because it allows you to mount the controller anywhere you want and still have easy control. The remote meter fits in a standard 4x4 electrical box. My controller is in a closet and the meter is flush-mounted in the wall near my thermostat. It looks and works great. You get 100 feet of cable with the remote kit.

    All these controllers are probably more than you need/want for a small RV system, but they have tons or room for expansion and will give you the instrumentation you're looking for. Your local RV dealer may have some options too.

    I buy all my solar stuff here: Solar Electric Power Systems For On & Off Grid they are great people and will not jerk you around.
    Last edited: Jul 9, 2014
    kellory and BTPost like this.
  4. Airtime

    Airtime Monkey+++

    I did a fair amount of digging into the various solar charging and inverter systems a year and a half ago. Outback seem to be the best as BT noted. There are several second tier systems including Xantrex. If you didn't pick up from the previous posts, MPPT charge controllers were being recommended. In addition to being efficient, they can boost the voltage output and still charge batteries when the sun is low or cloudy. This can result in as much as an additional 30% of charging compared to more simple charge controllers. Well worth it.

    Yard Dart likes this.
  5. Falcon15

    Falcon15 Falco Peregrinus

    Simply put guys, my contract job is done. I am back to zero income and was looking for a relatively inexpensive replacement for a very basic panel. I have the Solar Commander III as seen in this photo:
    The bottom meter on my Solar Commander does not register any activity from the panels, but my batteries stay charged, so I assume charge is going through.

    I appreciate all of the feedback.
  6. kg4jxt

    kg4jxt Monkey

    MPPT controllers give you about 30% boost in efficiency for a few hundred dollars or more (depending on capacity). For a small system, say less than 1000W, the cost of more panels has recently become less than the cost of the MPPT controller. Of course, you might be limited by the amount of area you have available for panels. If you have 8 batteries, then you might have around 800 amp-hours of capacity in the bank (at 12V), and 1000W of panels with NO controller could put out perhaps 50 or 60 amps at the most - it depends on the panel design and a lot of newer panels are designed for grid-tie so they have relatively high maximum voltage. You could always buy panels while you have space, and later if you need more capacity, THEN buy the MPPT controller. A solar panel is somewhat a constant-current device - that is, if it is rated for 120W, and has a maximum voltage of 24V, then it can make 5 amps. If you connect it to 12V, it will still make 5 amps (and produce only 60W). That is why MPPT controllers are so popular. They let the panels operate at their maximum power point. But the panels will still work at lower voltages.

    Of course, if your panels regularly manage to fully recharge the battery bank, then they can merrily dissociate water when they get to about 14.3V and "boil" the batteries dry. You have to pay attention to peak voltage daily if you decide to go without regulation - and keep the water level up if you regularly go over 14V.
    Tevin and BTPost like this.
  7. MarcelWisd

    MarcelWisd Monkey

    Hello friend I think you have got nice effective solar system..I do need one such system so can you help me out?
  8. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    Ask your questions, here, and the Monkey Folks will give you good answers...
  9. kg4jxt

    kg4jxt Monkey

    Solartech 85 Watt Multicrystalline Solar Module - 1 to 100 Watt Solar Electric Panels - Buy Solar Electric Panels - Solar Panels, Mounts, Kits & Accessories is a good 85W panel. Three of these in parallel would give you 250W peak, so probably around 200W with sub-optimal mounting. You could run a group of four 6-volt golf cart batteries with these and use a 1000W or smaller inverter. You could use about 1kWh of power from such a system on a daily basis. That would run a small, efficient refrigerator and some LED lighting. You could also charge a smartphone. You can find a better price, no doubt - but the website has a lot of good information about sizing equipment and will give you a fair idea of prices. I bought my first equipment from them in the late 90's but have not had a chance to do business with them since - but they were really top-notch folks back when.
  10. AronBribiesca

    AronBribiesca Monkey

    Hello friend have you replaced the charge control panel? Well I do want to make similar changes so please help me out..
  11. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    The issue here, is, and was, if you can afford to spend, the money for a Good MPPT Charge Controller. At the time @Falc0n15 wrote the original Post, he was not in a position to do that, so that limited his options. A Good MPPT Charge Controller runs about $500+US, and that is a "Chunk of Change". If one does go that way, it will provide MORE Energy to the Battery Bank, provide Three State Charging, that will extend the life of the Batteries, and take care of ANY mismatch in Input Voltage (12-120VDC)/Battery Bank Voltage, (12/24/36/48VDC) that may be in the System Design. It also allows for System Design changes, as the System grows, as your Loads, and Source, may grow, or change.
  12. Falcon15

    Falcon15 Falco Peregrinus

    Not yet. I am still making choices.
  13. Cruisin Sloth

    Cruisin Sloth Special & Slow

    Look at this link HARD !! I have a few of these & now trying to do beta testing on the Brat .
    The "KID" charge controller
    The "Brat" Charge Controller
    MidNite Solar The Kid MPPT Solar Charge Controller

    Made in USA just east of me of the USA House. Arlington WA

    MidNite Solar Inc. Renewable Energy System Electrical Components and E-Panels

    Free courses on whats it's all about ! : MidNite Solar's Video Library

    Now we need to know the real spec's on the panels , but Im sure if your Growing 30 amp KID is better than a Brat that is less amps . Having 8 batterys in series/ parallel is not the best to make 12 volts for charging . Better to go 8 in series to do 48 volt to a 48 volt inverter & add panels to get them to charge your 110 ah 48 v .
    Lots of reading I posted , but we normally go from loads / power used to building a sustaining system !!

    just came off the roof from securing another panel on my install . Storm on the wet coast & Im soaked

    Last edited: Oct 21, 2014
survivalmonkey SSL seal warrant canary