Upgrading present system....

Jim45DJim45D Solar Expert Posts: 102 ✭✭
Hello guys, I'm on the eve of expanding my present system. Presently I have [email protected] Kyocera 80 Watters, and a new addition, it is a 85 Watter, (TS Kyocera.) NAWS didn't have them, or they would have got the business. (Not yet connected) I want to order the remaining necessary's from NAWS; that being a Morningside (PMW) 45 amp. charge controller/with remote meter. Why? I've used the Blue Sky 2000 CC, and the 2000E meters, and I get no satisification, whatsoever. Occasionally I have seen a 3 to 5 % increase in amperage...but very seldom it happens. Thus, I have decided to go PWM. Mabey the location has something to contribute. I don't know, nor do I care. Granted I'm well below 600 watts, and it probably should be more. Desert area of Arizona.

With the present setup (In a RV) and a lot of real estate above deck. I want to install a additional 85 watter (Kyocera, nothing but) to satisfy 300 amp. hrs. of AGM Concordes. However, with past experience....I want to diligently monitor all. Therefore, I'm looking at 4x4.73 amps + 5.02+5.02 amps of solar production=29 amps. (rounded up). I also incorporate a Heart Interface (2kw) inverter....big mistake! The learning curve is a B.....! Don't need it!

Question is; do I need a extra shunt for the Bogart Meter? the Tri-Metric, ( as a 300 watt Morningside inverter will follow) Reason.....I already have a 500 shunt for the Heart Interface inverter installed.

My proposed order this week is as such.......MS 45 amp.( PWM) CC,......Remote meter for the Morningside,...... Bogart Tri-Metric 2025 Meter. Morningside RM, as I plan to install a MS 300 watt inverter in the near future....like next month, please advise....Need help.

Comments

  • bmetbmet Solar Expert Posts: 630 ✭✭
    Re: Upgrading present system....

    Welcome to the forum. Usually the best place to start, is to estimate your required loads, then once you can get a real-world number, the members here are happy to help with the 'math' for a smart upgrade. For the purpose of establishing a baseline, I am going to use a series connection of your panels, and adding your new 5th panel to your existing 4 to get a starting place, 405W of 'nameplate' watts. And since your panels are all 12 volt, I am going to use typical charging voltage of 14.4V, for deep-cycle AGMs. Recommended charging rates vary from 5% - 13%, so we will include both numbers for comparison.

    Now, a couple of the math variables I am going to borrow, are from 'typical' values assigned for different aspects of a system. For example, solar panels are rated in a controlled lighting environment, so their real world output may only be 80% of 'nameplate'. Another example, solar charge controllers require some power to run themselves, so their efficiency can differ depending on their 'type', and the amount of energy they manage.

    When you throw these variables into a math equation, a generic 'typical' efficiency can be used to get a quick look at what your 405W is going to produce.

    So here goes:

    405W of Panels x 0.77 Efficiency x 1/14.4V charging x 1/0.05 rate of charge = 433.125AH @ 12V battery bank (Max)
    405W of Panels x 0.77 Efficiency x 1/14.4V charging x 1/0.10 rate of charge = 216.562AH @ 12V battery bank (Nominal)
    405W of Panels x 0.77 Efficiency x 1/14.4V charging x 1/0.13 rate of charge = 166.586AH @ 12V battery bank (Small)

    So it appears as tho your '405 Watts' would be charging your 300AH battery bank at about 7% rate, which would be fine unless
    Concord AGM's have a specific recommendation (Trojan often requires a 10% rate on their deep cycle batts). Double check your documentation to know what they need.

    As far as your dissatisfaction with your present charge controller, you've got to have some idea of the energy you're producing in order to compare specs with your needs. Here's another math equation, as a place to start, of your power produced through your inverter.

    300AH x 12V x 0.85 inverter efficiency x 1/8 rate of discharge = 382.5 Watts of power available though an AC inverter. If you are running a 2KW inverter, then I think you're drawing your bank down past the maximum recommended 50% state of charge, possibly to an early failure.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Upgrading present system....

    i don't understand why you would want a pwm controller if you see a gain in your power. even if the blue sky isn't up to snuff (out of adjust) it would do at least as well as the pwm would. maybe a better mppt if anything would be in order if you intend to spend more for another cc.

    you could probably use that shunt for the tri-metric if it is wired in properly.
  • Jim45DJim45D Solar Expert Posts: 102 ✭✭
    Re: Upgrading present system....

    Thank you BMET & Niel for your input, and math. I have seriously considered installing one more 85 watt Kyocera, to make it a even 6 panels=28.96 amps. I have considered a 24 volt battery configuration, but my battery compartment space is limited to 3 batts, of the 12 volt version & physical size restrictions. However, I could proably extend into one of the lower compartments. It would require a lot of cutting out end panels of the compartment, and a reconfiguration. As stated earlier, I do have the room for a couple more panels, mabey three, and earlier I considered a Kyocera 135 or 140 watt panel. Then they (physical size) would fall into the shading catagory. So that was out. So far there's not a flicker of shade on any of the panels. It's a situation of darned if you do, and double darned if you don't.

    The reason that I decided to go with a PWM, instead of the MPPT; is as follows. First I have noticed a increase in current during the month of Dec. and early Jan. After that nothing. The second reason is that I started with the SB2000. It was sent in to, at the time RV Power Products two different times. Why? Both times it would show the proper current when immediately connected...then go nuts, showing anywhere from +95 amps to -2.5, as fast as it could move the digits. The voltage reading always seemed to be correct. At first I deemed it was static electricity from me, so I started using the eraser end of a pencil....same results while moving the switch through all three settings of array current, output charge current, and voltage readings. The only thing that ever held proper was the voltage reading. Then I went with the 2000E, it performed properly, however it revealed the same senario in mid Dec to early Jan. with somewhere in the neighborhood of 5 to 7% diff. This happened three or four times, and never again.

    Then I decided to go with a larger array. Well, as someone stated on this forum that the 2000E was not a true 25 amp controller as advertised, (I believe it was Crewzer) and that it was actually a 20 amp controller. I made a decision based on that, and decided to go with the MS 45 amp PWM controller, simply based on the gains, not much, that I had experienced just in Dec., and Jan. However, by then I was exceeding the capacity of the controller, and not getting the advertised buck's worth. Neither in amps or performance.

    The inverter; yes that was a mistake by going too big. Live and learn I guess, and the learning curve hasn't been cheap. The inverter hasn't been used more that three times, and probably never will be again. I use the charger at times when it's overcast, or in the winter when it's cooler here, but it'll never get the chance to invert again. I will go with the 300 watt MS, probably two, as soon as I get caught up on the required meters and other related componets. Question is; would it be wise to install a separate shunt for each meter, or use just one shunt? The MPPT controller.....I don't think in my situation of panel array, and extreme heat for 6 to 7 months of the year in my location warrants the extra expense for two or three days of additional current during a given year. At least that's all I've seen from the last two MPPT's.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Upgrading present system....

    i would not give up on mppt even if you opt for a pwm cc now. to be honest the sb2000 didn't impress me and i do own an sb50, but i threw the thing out of whack on its adjustment.:cry: there are some good mppt controllers around now and more to come. the blue sky stuff is old technology.
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Upgrading present system....

    Yes, that was a discussion between Crewzer and myself on my SB2000e CC that you reference. Still have it and like it hooked up to my NiCds, interestingly it has a setting for them and is doing a good job with them, in a small bank setup...

    Something is bugging me about your comment that you had 2 CCs that BOTH performed erratically ... very strange ??? wiring or ??

    With the various panels I would look at an MPPT again, say Rogue? and a small inverter as you state.

    HTH
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • SolaRevolutionSolaRevolution Solar Expert Posts: 407 ✭✭✭✭✭✭
    Re: Upgrading present system....

    You can connect more than one meter to a single shunt. Run seperate sense and fused battery + wires for each meter and make sure your wires are properly connected to the "kelven" connections (small screws on the sides of the shunt). Use good crimp-on fork or ring terminals with some antioxident wire connection compound to insure low resistance connections.

    If you are in a hot desert environment and running PWM with all of your panels in parallel the heat can easily decrease your panel's Vmp from 17.4 to <15.4 and leave little voltage "headroom" to overcome wiring losses which are increased by high temps and many parallel connections. On the other hand, warm batteries do not require as high charging voltage as cooler batteries do.

    The Blus Sky MPPT CC and any PWM CC does not allow you to configure your PV array for a higher nominal voltage than the battery bank so you do not gain the benefits of fewer strings at higher voltage/lower amperage. A CC like the Tristar MPPT45 or an Outback FM will allow you to configure all 6 of your (nominal 12 v) panels into a single string and have 1/36th of the wiring loss in your PV output circuit, save money and installation hassel on combiner equipment and wiring, and prevent any losses you may have when your modules are forced to operate below their maximum power point.

    Alex
  • Jim45DJim45D Solar Expert Posts: 102 ✭✭
    Re: Upgrading present system....
    niel wrote: »
    i would not give up on mppt even if you opt for a pwm cc now. to be honest the sb2000 didn't impress me and i do own an sb50, but i threw the thing out of whack on its adjustment.:cry: there are some good mppt controllers around now and more to come. the blue sky stuff is old technology.

    Thanks Niel, and all the other guys for their input. I haven't given up on the MPPT.....yet! I already have one in storage, and another coming up soon, that being the Blue Sky 2000e.

    Westbranch: "Something is bugging me about your comment that you had 2 CCs that BOTH performed erratically ... very strange ??? wiring or ??
    With the various panels I would look at an MPPT again, say Rogue? and a small inverter as you state."


    What happened is the first controller, a RV Products SB2000....the name was changed to Blue Sky a few years ago....was that I had sent it to them for repair, (under warranty) twice, had all wiring checked on my end, but once reinstalled it still gave nutty readings on the PV current in, and output charge current, sometimes it read +95 amps, and other times it read -2.5, 3.5, and more....whatever it felt like at the given time. The second controller was a Blue Sky 2000e. However, I feared of blowing the controller due to the fact that the charger amperage was advertised as a 25 amper meter, but was rated much lower, as I discovered later. With that in mind....trust only goes so far!! Yes, I did consider the Rogue. As a matter of fact it was the number one on the thinking list until I discovered that I was pushing the limit on the Isc side. Mark explains it very well in the manual. As it stands presently...I have [email protected] Kyocrera 80 watters, [email protected] Kyocera 85 watter,(they say 87) but that remains to be seen, and another 85 watter of the same on the way. Making a total of 6 panels. The ratings as follow are Isc ratings. The 4 Kyocera's are rated at 4.97 Isc each=19.88 Isc. The the 85 watter is rated at 5.34 Isc. Those alone are 25.22 Isc....it has already exceeded the NEC, and Mark's recommendations. The one on the way will definiately break the bank at 30.56 Isc. This forum and the intellict of various members brought that to light.....otherwise I wouldn't have given Isc a first thought, not to mention the NEC.
  • Jim45DJim45D Solar Expert Posts: 102 ✭✭
    Re: Upgrading present system....

    Thanks Alex for your reply concerning meter to shunt connections. Yes, I'm in a desert environment, and it get's hot, extremely hot here. I will soon install a temperature remote meter to the underside of a panel rack, in the shade, and report the temps on the roof. The temp here this past Aug., and Sept. twice exceeded 118° F. in the shade. Usually it remains arounf the vicinity of 106 to 110° starting in late June until the latter part of Sept. This last season was unusually hot thru the middle of Oct. I have considered the PWM in relation to the panel temperatures, but I've only seen a slight increase in mid Dec., and sometimes Jan. where I did get an increase using MPPT. That only happened two or three times. I don't think anything CC, or otherwise would give me a considerable gain in this location, other than mabey a snowstorm....that isn't likely.

    All of the afore mentioned senarios have led me to the PWM route. I don't have the panel array to justify it, the heat is against me, and it don't get cold enough to warrant any tracking of any great degree.; With the intensity of the sun in the past, prior to 11am., I'm charged. I just don't know to what, as the MPPT previously used goes into absorb mode by 9:30 am. There, the MPPT sits until the next morning. What I've seen in the past 7 years doesn't justify the cost. Sure, I can see a voltage reading of 13.8 at float, but is it correct? I don't know. That's the reason I questioned wiring in various meters. The Blue Sky I simply couldn't trust any longer.

    Voltage drop? Not unless there's a drop when using less than 12' of #6 throught the panel connections, siliconed greased, soldered fork connectors into junction boxes, and a #8 going to the charge controller, and from the controller to battery, still #8. There is # 6 going (4" long splices) from the present fused shunt to the battery's. The wiring was not skimped upon. UNless there is a definiate need to change wiring size, then I opt to leave it as is. Yes, it did cost a small fortune, but so did the 80 watters. We just wanted a one time installation .......period! It appears it didn't work out the way we had hoped and paid for.

    Anyway, as I see it, and have....a PWM is all I need for a 33' RV. I have some real estate on the roof to install more panels, not many. However, I have a unique method of installing the panels to avoid shadows. It's a catch 22 situation; when I park, it must be in the sun, facing south. The hassle commences when it's time to go elsewhere, if the distance requires lowering of the panels, and locking them down for a trip. I will post photos as soon as I make the final installation. Hopefully, the ultimate install.
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Upgrading present system....

    Jim,I think you are at the juncture that most of us here come to at least once, and the only solution at the time is to "bite the bullet'...

    We want our system to do something that is achievable but a bit 'quirky' for the average equipment available... Like 'all I want is a bit more power to/out of my batteries'... that is how we end up with 'spares', at least I did..

    My gut is telling me that a Classic or like sized Cc is probably your best long term solution, a bit of over the top but wont be too small if you add that next panel(s)
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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