Charge controller ?

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willardj
willardj Registered Users Posts: 15 ✭
in Solar Beginners Corner #1
Hello new here and looking for a charge controller to go with my new DM solar 145w panel I picked up. After checking that panel out I was getting 21v x 7.6a so about 159.6w without a controller. So even at 145w / by 14.4v I should be able to get 10a right? So my ? is. What is a best controller( for the money) to use to get all that voltage and amperage out of it?

Thanks
Jaime
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
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    Re: Charge controller ?

    welcome,
    actually you measured that wrongly as it is not the voc x the isc. these do not occur at the same time and when one of those is high the other one is lower.

    as to which cc to get, that will be up to you and you have small mppt ccs you could get or cheaper pwm style ccs.

    look them over here,
    http://www.solar-electric.com/chco.html
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  • willardj
    willardj Registered Users Posts: 15 ✭
    #3
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    Re: Charge controller ?

    K Thanks. So I need to put a load on it to see what kind of real v/a load I get?
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
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    Re: Charge controller ?

    this isn't such an easy thing to do because you don't know what load would be proper to determine if it's ok and that changes a bit with insolation hitting the pv. it is a semi-good test to be sure a pv is working close to its voc and isc specs though. you don't know at the time if you aimed accurately and if the sun is at the right intensity to know for sure if the 7.6a is low, high, or just right.

    no goldielocks jokes either guys.:p
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  • willardj
    willardj Registered Users Posts: 15 ✭
    #5
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    Re: Charge controller ?

    Yea, when I checked it I just leaned the panel on my truck and it was early in the day as well say 0930 or so.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #6
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    Re: Charge controller ?
    willardj wrote: »
    So even at 145w / by 14.4v I should be able to get 10a right?
    It doesn't work that way. The most current you can ever get is Isc (short circuit current).
    willardj wrote: »
    So my ? is. What is a best controller( for the money) to use to get all that voltage and amperage out of it?

    To get the most you need an MPPT controller. Problem is that an MPPT controller costs much more than a PWM controller. Depending on circumstances it may be more cost effective to buy two panels and a PWM controller than to buy one panel and a MPPT controller.

    You will get better advice here if you explain what you are trying to accomplish with your panel, and provide us with the specs on the panel (Isc, Imp, Voc, Vmp)

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • willardj
    willardj Registered Users Posts: 15 ✭
    #7
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    Re: Charge controller ?

    Sorry here is what I am doing. I have a sailboat and looking at running the lil things I have and maybe put in a small fridge. The panel I have is a 145w- vmp 18v, imp 8.05, isc 8.95, voc. 21.6. My batt bank at this time is 180ah and seems to be enough to run what I have for 2-3 days w/o charging. I have a smart charger, Trimetric 2025 and a Honda 2000i gen that I only run at night for a/c for the wife. I don't have much room on my small boat for multiple panels. I was looking at a 230-245w panels first, but got a super deal on this one less than a $1 a watt including shipping and thought this would be big enough for what I have. So now I am just looking for a good charger to get things going.

    Thanks
    Jaime
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #8
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    Re: Charge controller ?

    The panel you have is barely capable of charging your 180 AH battery. A battery that size would really like to have an 18 amp charge (10% of its AH capacity). Your panel with a PWM controller can, under best circumstances, deliver about 8 amps. With a MPPT controller you might get about 12 amps into the battery.
    look at some of these controllers and their prices: http://www.solar-electric.com/mochco.html

    No way you can run a fridge with that panel. On the other hand, if you are running the generator every day you can place all sorts of loads on that battery. You might consider getting a battery monitor to keep an eye on things. The battery won't last very long if you cycle it too deeply.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • willardj
    willardj Registered Users Posts: 15 ✭
    #9
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    Re: Charge controller ?

    I have a Trimetric 2025 to keep ck on my batts so I don't drain them to much. I don't drain them down to more than 60%.
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  • Jim45D
    Jim45D Solar Expert Posts: 102 ✭✭
    #10
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    Re: Charge controller ?

    Welcome Willard: The Trimetric is a good choice in meters. I have one , just not installed yet. I have seen several in action and it made a believer out of me. There's nothing wrong with the panel you have. It's just not enough, especially on a sailboat. With the constant deck movements, line, sail, and mast shadows....that will kill your production. Two would be better. With that you'd get roughly around 8% charge. That's good, but ify.....looking at the shadow senario thing again. Do you intend to mount the panels off the stern? Does the boat have a roof, bikini, or otherwise? Try not to take those batteries below the 50% state of charge. You'll get a little longer life from them. Should you go with one more panel, take a look at the 20 amp Morningside MPPT from our host. If you decide to stay with the one panel you'll have to go at least a 10 amp charge controller.
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  • willardj
    willardj Registered Users Posts: 15 ✭
    #11
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    Re: Charge controller ?

    I have had mine for a lil bit now and I'm quite happy with it. The good thing is we have switched just about all our light's to LED's so our power drain is not much. Yes, we are looking at mounting it aft over the bimini that way any shading should be at a min.. I guess the Morningstar Sunsaver 15a mppt is about it for small mppt controllers right? Is there any other controller any cheaper that has the same kind of features? We are trying to make this lil boat ready so when we drop anchor for a few days we don't have to hear the gen no more than we have too.. About 5-7 years we will be moving up in boat size where we will be able to have more panels. The next boat I want to put on 2-250w panels with a Tristar 45 mppt. Should work for our needs.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #12
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    Re: Charge controller ?

    Not cheaper, but larger (30 amps)... It does not have as high of Vmax-array as the Morningstar controllers--but a very good 12/24 volt controller in its own right (with logging and on-board LCD display at no extra cost).

    Rogue 12/24 volt 30 Amp MPPT charge controller

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • kayen
    kayen Registered Users Posts: 17 ✭
    #13
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    Re: Charge controller ?

    Why not use a small wind turbine?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #14
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    Re: Charge controller ?

    Kayen,

    I am not a fan of small wind, highly variable and not very predictable--Plus, people usually live where there is not too much wind (I have been in areas that are consistently windy, and it is miserable).

    I would suggest starting with solar, and if there is interest, look at a turbine and tower. Turbines are not too expensive, but the towers tend to be pricey (if are going with a minimum of 60' tower, 30' above local obstructions, 500' away from buildings/trees). And usually require a fair amount of maintenance (and crane truck if don't have other way to access turbine).

    I guess you are somewhere around Saudi Arabia--Are you using small wind? How has it been working for you?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • kayen
    kayen Registered Users Posts: 17 ✭
    #15
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    Re: Charge controller ?

    yes I have a 300w windmill, use it with my LED lights. sorry didn't finish, it is ok, but solar is better. We have average 3-4 wind speed and my wind mill start up speed is 1.8, so i get around 100watts per hour/ wind should hit 10mph to get the full 300w.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #16
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    Re: Charge controller ?

    How has it been working for you? Any information on how much power per day/month you get from it (AH/WH/etc.)?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • kayen
    kayen Registered Users Posts: 17 ✭
    #17
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    Re: Charge controller ?

    yemen like them because they have a higher wind average. They can get the around 250watts per hour, not sure about amp. As for me, we have outside and would have to ask engineer about it. I know that we have an average 3-4 wind speed and get 100watts per hour not the 300, as for amps i'll ask. I'm new to solar; and am trying to educate myself. Want to understand confiqurations and solar drawings. Hope to gain knowledge from this Forum. Many thanks
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