MPPT charge controller recommendation

Billyindex
Billyindex Registered Users Posts: 13 ✭
in Solar Beginners Corner #1
Hello I have an existing system in my RV with a BZ charge controller and I think it finally quit. I have read nothing but negative reviews about the BZ so I need a recommendation to replace it.

My system
2 Suntech STP180S-24Ab-1 in parallel for 360w 48v
BZ MPPT500
2 6v golf cart batteries in series for 12v (no room or i would have 2 more)
1000 w sine wave inverter

This system met my needs with no issues to speak of except i think the controller is bad.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: MPPT charge controller recommendation

    Welcome to the forum.

    Looking at your system specs I'd say it's all good except the controller. Really 360 Watts of panel ought to manage 20 to 23 Amps @ 12 Volts, which is just right for 220 Amp hours of 12 Volt battery.

    The bad news is that the best charge controller for this system is currently unavailable: the Rogue 3024. This means the "next step up" is the 45 Amp Morningstar TriStar MPPT @ $400 http://www.solar-electric.com/motr45ampmps.html

    Supposedly MidNite Solar will be introducing a 30 Amp MPPT controller next year, and possibly the updated version of the Rogue will be available as well. How long can you wait?
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #3
    Re: MPPT charge controller recommendation

    I can't speak to the Rogue, never had one, but I've been using Morningstar MPPT controller for a few years now, as has my cousin, and can only sing their praises.
    If there's a chance you'll be expanding your system, you might consider the Morningstar TS-MPPT-60 instead of the 45. Just something to think about. The two controllers are identical other than the max power they can handle. And of course the price will be a bit different.
    Good luck with whatever you decide.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #4
    Re: MPPT charge controller recommendation

    I'm surprised your BZ quit. it may have been, in fact, the only one that ever worked!

    The Rogue is wmvery good controller.

    Tony
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #5
    Re: MPPT charge controller recommendation

    I cant wait at all so it looks like the Morningstar 45 is probably the best option. I don't mind spending the $400 if it is a good quality product.
    The BZ only lasted 3 years but I am kind of assuming the controller is what is bad. My knowledge of electricity is very limited. I do know the volt meter was showing 12v at the battery during full sun which would normally read about 14v. If I disconnect the battery from the controller the leads coming from the controller to battery would read 15v.
    The system fully hooked up would read battery amps 3.7, battery volts 12v and pv amps 1.6.
    I guess I assume the controller is bad because every review says it is a turd.
    By the way the batteries are 1 year old and very well maintained.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: MPPT charge controller recommendation

    One thing you might try is to bypass the controller completely. Don't worry about the Voltage difference. The panels should pass their full current (around 5 Amps each if in parallel - yours seem to be in series) to the batteries and bring them up quickly. Watch the Voltage rise on the batteries and don't leave it hooked up this way for too long or the batteries will heat up as the panels try to push the Voltage well past 15.
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #7
    Re: MPPT charge controller recommendation

    I'm going to send it back to them so they can put it in the hall of fame as the longest lasting specimen. lol
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #8
    Re: MPPT charge controller recommendation
    Cariboocoot wrote: »
    One thing you might try is to bypass the controller completely. Don't worry about the Voltage difference. The panels should pass their full current (around 5 Amps each if in parallel - yours seem to be in series) to the batteries and bring them up quickly. Watch the Voltage rise on the batteries and don't leave it hooked up this way for too long or the batteries will heat up as the panels try to push the Voltage well past 15.

    Agree, you should try ASAP to get some charge in those, up to now "well maintained batteries". Otherwise, left not fully charged for more than a very few days, their life will be shortened, perhaps even drastically, depending on their state of charge.
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  • Volvo Farmer
    Volvo Farmer Solar Expert Posts: 209 ✭✭✭✭✭
    #9
    Re: MPPT charge controller recommendation
    Billyindex wrote: »
    I'm going to send it back to them so they can put it in the hall of fame as the longest lasting specimen. lol

    Nonono. You have to pay to send it back to them, even if it's under warranty. Mine failed in the warranty period, they refused to pick up the return shipping, so I replaced it with a Xantrex C35. Smash it to bits and post a video on Youtube. Anything you can do to to inform the public about the quality of these products makes the world a better place. :D
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #10
    Re: MPPT charge controller recommendation

    After doing some research it looks like the Rogue is exactly what I need. Any news or rumors in the industry when they might be available? The Morningstar TS45 is fine but another $100+ for a display and the extra space needed is not good for my application.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #11
    Re: MPPT charge controller recommendation

    Last I heard (on the forum here) a few months ago was end of December for availability... Try contacting Marc at Rogue directly--He has even posted here some and seems to be quite open about discussing his product.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #12
    Re: MPPT charge controller recommendation

    Thanks for all the info. I will check the status of the Rogue.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #13
    Re: MPPT charge controller recommendation
    Billyindex wrote: »
    Thanks for all the info. I will check the status of the Rogue.
    Please be sure to let the rest of us know what you hear:-) --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #14
    Re: MPPT charge controller recommendation

    The reply from Rogue was around March for the new model.
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #15
    Re: MPPT charge controller recommendation

    I ended up bringing my RV home from storage so I can work on the solar. I tested the panel amps and it was 2.4 on a cold 50 deg So Cal day. is that normal? Cariboocoot suggested it should be about 5amps. Then here comes the the bad part. I may have had the multimeter set wrong and when I touched panel + and - while the system was operating there was a spark and now I read zero amps. I will be searching the site for some troubleshooting instructions.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #16
    Re: MPPT charge controller recommendation

    You may have blown the fuse in your meter (or in the solar power system) if the meter was set to Amps and you went across a voltage source.

    Amp scales on DMMs can be a bit "dangerous" if you are not careful.

    Another reason I suggest using a DC Current Clamp meter for measuring current... You do not have to disconnect any wiring and no touching of bare metal parts (this Sears unit is an AC/DC current clamp DMM type meter).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #17
    Re: MPPT charge controller recommendation

    That sounds like you blew your meter. Very important to have it set right before feeding current through. This is why the clamp-on meters are safer, albeit more expensive.

    Your panel current will not vary much due to temperature, but it will vary due to insolation; if the panel isn't "square on" to bright sunlight you won't see full current (which is what matters with PV). A difference in angle from ideal will change the current quite a bit.

    Fix the meter (some have an internal fuse on input) and try again. :D
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #18
    Re: MPPT charge controller recommendation

    Thanks guys. That's good news. I thought I may have destroyed my panels.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #19
    Re: MPPT charge controller recommendation

    The panels themselves, will not be damaged by a short circuit...

    Hooking them up backwards directly to a battery bank--That is a different answer. :cry:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #20
    Re: MPPT charge controller recommendation

    The PV modules have to be able to pass the series fuse rating current. A battery probably isn't good though but the series fuse ~~should~~ blow at least.

    Happy new year !

    boB
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #21
    Re: MPPT charge controller recommendation

    Got my new AC/DC ammeter today...thanks for the tip BB. The panels are showing 2.7-2.9a before the cc. Is that within range? Another weird thing is the cc seems to be working somewhat now. It is charging and the battery is up to a float it just seems like a weak charge.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #22
    Re: MPPT charge controller recommendation

    Regarding the DC current clamp meter--Make sure you understand how the ZERO button works. DC current sensors drift over time (just a minute or so)--So accurate readings require rezeroing (remove the clamp, push the zero button at least twice, until you see "ZERO" on the LCD. then reconnect to the wire you want to measure current in) is important (this meter is very confusing how the zero button works. basically, it takes whatever is on the display and loads that to a memory on the transition from "blank" to "ZERO" reading on the LCD... You will see the 0 amp current slow drift over time.

    I would suggest playing with your car's electrical system to see how the meter works (head lights on/off, motor off/running, etc.). Note there is a +/- sign on the display--the meter in DC current mode can tell you which direction the current is flowing (battery being charged or discharged, for example).

    OK, it looks like your panels are rated:
    STC Power Rating 180W
    PTC Power Rating 160.5W 1
    STC Power per unit of area 13.1W/ft2 (140.6W/m2)
    Peak Efficiency 14.06%
    Power Tolerances -3%/+3%
    Number of Cells 72
    Nominal Voltage 24V
    Imp 5.05A
    Vmp 35.6V
    Isc 5.4A
    Voc 44.4V

    More or less if Icurrent is around 80% of Imp or higher (near noon, good sun, within 10 degrees of pointing at sun), and they are "loaded" by something (i.e., you will read zero amps if the charge controller has stopped charging the batteries, and you will see less than Imax if the batteries are mostly charged)--Then the panels are usually good.

    If the current in your two identical strings are near equal--the panels are probably OK.

    If you see less than 50% of rated Imp in good weather conditions (and properly loaded), you probably have a problem.

    Varray is a bit more dicey... If you have a PWM meter, the Vpanel will be near Vbatt-charging. If you have a good quality MPPT controller (and the battery bank is significantly discharged), you should see Vmp-array.

    If the bank is full, or you have a questionable charge controller, you may see Varray somewhere between Vbatt and Voc (voltage open circuit).

    If your system is working well--get a meter and do some measurements under different conditions--and write them down. That way, if something goes wrong later--you have some "good readings" (and working knowledge) to compare against. Note that with charge controllers, there is "history" involved (a battery bank may be at 13.6 volts and lots of charging current--Bulk--vs the batteries are full and near zero current--float--Or even 13.6 volt and lots of current--Float with lots of DC loads.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #23
    Re: MPPT charge controller recommendation

    Thanks for all the info. Yes the first thing i noticed is you have to zero that meter every time. I have never used or even heard of a clamp meter until now so i think its a pretty cool tool...like magic.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #24
    Re: MPPT charge controller recommendation

    They are--I have worked on electrical stuff and even as an electrical/systems design engineer--But have always been "too cheap" and not willing to pay hundreds of dollars for a current clamp meter over the last 40 years--Just got my Sears DC current clamp unit a bit more than a year ago--Finally hit my price point. :p

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #25
    Re: MPPT charge controller recommendation
    BB. wrote: »
    Regarding the DC current clamp meter--Make sure you understand how the ZERO button works. DC current sensors drift over time (just a minute or so)--. You will see the 0 amp current slow drift over time.

    -Bill
    I've found the drift often seems to be related to slight changes in magnetic fields near the meter. Even changing the meters position, reference the earth's magnetic field can move mine. But then, it is designed to read very weak magnetic fields to measure small currents.
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #26
    Re: MPPT charge controller recommendation

    does this sound about right?
    2.5a into the make believe MPPT BZ cc. Panels are clean but nowhere near 10 degrees direct to sun and batt bank is under load.
    14a from cc to batt bank

    if this BZ is working half decent I'm gonna hold off until the new Rouge is available since the Rogue is exactly what I need.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #27
    Re: MPPT charge controller recommendation

    How is the array configured (series/parallel?).

    And if the sun is not square to the panels, you can estimate by using the "Cosine" ... I.e., a panel 45 degrees to sun Cos(45)=0.71 derating (estimate, there are other issues too).

    If you are getting less than 50% of what you would expect from the panels (battery discharged or load on bank to use extra power) from the solar array--Then something may not be working correctly. The battery charge controller could be limiting current to battery bank if it thinks the batteries are near full charged/floating.

    Also, really need to now the Volts/Amps from the array, and the volts/amps going to battery bank at the same time.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #28
    Re: MPPT charge controller recommendation

    The array is in series.
    2.1 - 2.9a and fluctuating rapidly
    55 - 70v and fluctuating rapidly

    The battery bank
    11 - 15a and fluctuating rapidly
    12.1v may be reading state of charge?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #29
    Re: MPPT charge controller recommendation

    Sounds like the MPPT charge controller is not really operating in a "stable" way... However, the MPPT function appears to be working (you are getting 11-15 amps into the battery bank.

    At this point, your optimal choices are to
    • Try wiring the solar panels in parallel to the BZ controller (my not like the "high array voltage")
    • Get a MorningStar TS 45 Amp MPPT charge controller for ~$400+meter option+shipping+etc.)
    • Get a Midnite (or similar) full sized MPPT charge controller for $500-$610+
    • Wait for the new Rogue MPPT charge controller (don't know specs yet) in ~March
    • Wire panels in parallel and direct to battery bank or use a PWM controller to battery bank

    A 12 volt battery bank with 15 amps charging current and 12.1 volts is well discharged (probably at 50% point).

    A "good" MPPT controller in "good" conditions should be outputting:
    • 360 watt array * 0.77 panel+controller derating * 1/12.1 volts = 23.1 amps

    Again--Average maximum peak in good conditions near noon with correctly oriented solar panel.

    You are doing about 1/2 that--Just about the point where I would say something is "definitely" wrong (as opposed to clean array, repoint at noon sun, check wiring, etc.).

    -Bill

    PS: The changing V-array voltage is probably a sign that the array voltage is too high (rewire in parallel and see what happens), or the BZ is having "issues".
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Billyindex
    Billyindex Registered Users Posts: 13 ✭
    #30
    Re: MPPT charge controller recommendation

    Well I'm going to send the BZ back for warranty and hope for the best until the Rogue is available.
    I can't thank everyone here enough for the quick response and knowledge sharing.
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  • mahendra
    mahendra Solar Expert Posts: 188 ✭✭✭
    #31
    Re: MPPT charge controller recommendation

    You might as well wait on the rogue or get a morning star or wait for the new midnite solar 30amp mppt controller they claim it should be out by the first quarter of this year.from what i hAVE RESEARCHE BZ ARE JUNK.
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