Mixed panel wattage/voltage dileamour!

BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
I've just been asked to "tune" the following system. I'm not sure if it should even be working:

2 Kyocera 240W, Vpmax 29.8V, Ipmax 8.06A, Voc 36.9V
4 bp solar 170W, Vpmax 35.4V, Imp 4.8A, Voc 44.2V
2 astropower AP 120, Vpmax 16.9V, Imp 7.1A, Voc 21V ( in series)
2 other what look like older 65W panels in series

All then hooked up in parallel to an OB flex 60 to an OB 3524 and two strings of lifeline AGM L 16

The CC, inverter and battery install looks good, but the mis match of panels concerns me - especially one of the 65W(?) panel cells look brown (burned?)

Before I go further into this, I'd appreciate your thoughts....
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Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Run away.

    There's no way that can work properly as-is. The Vmp's of the panels are all over the place and the only way to correct that is with separate controllers for each panel set.
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!
    Run away.

    There's no way that can work properly as-is. The Vmp's of the panels are all over the place and the only way to correct that is with separate controllers for each panel set.

    Then why is it working and floating the batteries? If I was to suggest separate controllers, how could I verify the cost of that plus new wiring etc. AND whic set would go to the OB60 as it would be the master that will hook to the Mate for AGS.

    Can't run away, kinda sorta committed......
  • BB.BB. Super Moderators, Administrators Posts: 31,765 admin
    Re: Mixed panel wattage/voltage dileamour!

    Looking at the numbers for a 24 volt battery bank:

    2 Kyocera 240W, Vpmax 29.8V, Ipmax 8.06A, Voc 36.9V (will charge a discharge battery somewhat)
    4 bp solar 170W, Vpmax 35.4V, Imp 4.8A, Voc 44.2V (probably doing most of the work)
    2 astropower AP 120, Vpmax 16.9V, Imp 7.1A, Voc 21V ( in series) (probably working most of the time fairly well)
    2 other what look like older 65W panels in series (browned spots on my panel, make sure surface of glass is clean, they were at 1/2 current or less, replaced)

    I could sort of see the system working... The 65 watt panels, probably junk.

    The 2 kyocera panels could be moved to their own MPPT controller and connected in series... Would be perfect fit for the 24 volt battery bank.

    If cost is an issue, move the Outback 60 to the Kyocera, and take the 4x BP and 2x Astropower panels and connect them in parallel/series parallel through a PWM controller.

    With two MPPT controllers, and if they need more panels, you can compare the new panels against the Vmp-array for the other two controllers and see if you can get more matching panels (the Astropower could still be used through a PWM controller).

    What is the Battery Bank AH rating and configuration (any issues there)?.

    Any obvious signs of too much power usage (do they know how much power they use), not enough panels/battery bank?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Hi Bill,

    Thanx, at least I know I'm not crazy to take this on now!
    Two banks of Lifeline 400AH batteries in 24V banks.

    So a Xantrex C40 for example would work for the PWM? Or another Flexmax60 tied into the network.

    Can the two different controllers have close enough charge settings so as not to make one string of panels work harder than the other?
    Also, I presume use the existing #6 for the PWM and run #8 for the Kyoceras?
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Sorry, forgot to answer the power usage:
    There's a 1HP water pump with plenty of pressure tanks which only appears to cycle half a dozen or sometimes a day. A small aquarium pump 24/7, nomTV usage just occaisional DVD's but a laptop, iPad and wifi antenna all day and apparently sometimes left on at night. Otherwise, doesn't appear to be excessive usage.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!
    BajaSun wrote: »
    Then why is it working and floating the batteries? If I was to suggest separate controllers, how could I verify the cost of that plus new wiring etc. AND whic set would go to the OB60 as it would be the master that will hook to the Mate for AGS.

    Can't run away, kinda sorta committed......

    If it's "working" why are you trying to "fix" it?
    Being able to achieve the "right" Voltages is not the same as charging the batteries properly. You can in fact have the right Voltage settings without the right current and/or Absorb time, go to "Float", and the batteries will sulphate faster than they should effectively reducing the actual capacity. This can go on for years before it suddenly shows up with the lights going out at 8:00 PM and the batteries only half as old as they should be.

    The four BP Solars at 35.4 Vmp will work through a PWM controller no problem, as that is the "right" Voltage for a 24 Volt system.

    The two Kyoceras at 29.8 Vmp are too low to directly charge a 24 Volt system; they should be in series on an MPPT controller to optimize them.

    The two Astroenergys in series at 33.8 Vmp are too low to directly charge a 24 Volt system. They will contribute to Bulk when system Voltage is low, but lack the Voltage necessary to bring the batteries up through Absorb (normally around 28.8; the typical system losses will easily use up the Voltage difference).

    The 65 Watt panels are probably useless.

    480 Watts from the Kyoceras, 680 from the BP's, 240 from the Astroenergys.
    I don't know the capacity of your batteries (L16 is a case size, not a capacity) but best-case scenario the panels (1400 Watts) could support about 450 Amp hours @ 24 Volts. L16 size batteries tend to be 300 Amp hours plus, so two strings would be probably over 600 Amp hours. That's <7.5% peak rate if you had everything optimized (charge controllers).
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Thanx cariboocoot,,

    Looks like a 30A fuse/panel breaker for each string would suffice then? Guess he could use the 65's to trickle charge his boat and generator batteries then.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!
    BajaSun wrote: »
    Thanx cariboocoot,,

    Looks like a 30A fuse/panel breaker for each string would suffice then? Guess he could use the 65's to trickle charge his boat and generator batteries then.

    Which strings?

    The BP's "as is" through a PWM are <5 Amps each, so a 10 Amp fuse per would be fine. The Astroenergy panels could be included as a string here too; add a bit during Bulk.

    The two Kyoceras in series on the MPPT don't need fusing.

    The water pump is probably the heaviest load. With the right size pressure tank(s) that could be limited to daytime/charged battery use only. The other loads seem pretty light but run longer so may add up to a surprising amount of Watt hours. My satellite Internet connection uses as much in a day as the refrigerator; lower Watts, but longer running time.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    lifeline has 6v and 2v l16s. the 2v is 1200ah and the 6v is 400ah. we don't know what exactly you have going where to know the capacity of the bank. if 2 banks of 4 in series you probably have 800ah of capacity and what your current mish mash of pvs will yield is most likely insufficient for the batteries. i would suggest settling on one pv type and buy many more of them to be placed on an mppt controller like the classic or fm80. i suggest this high because you may need to go to a 10% charge rate in the near future, but i wouldn't go less than about 7% or 8% right now as after efficiencies are realized you could be closer to the 5% minimum charge rate we often recommend to any battery bank. now you could use 2 of the 60 cell pv makes if you handle them into a separate mppt cc for each make. the astropower is fine for 2 in series into a pwm controller for 24v. i also agree to get rid of the 2 smaller 65 watters unless they prove to be working and have similar voltage specs as the astropower unless they are thin films and then i recommend taking them out of the picture for your system.

    remember when adding pvs together that for putting in series that the current should be similar and when paralleling them the voltages should be similar. the farther out the worse it is for losses and functionality. i like to recommend within 5% and bb often recommends 10%, but you can see a vmp of 35.4v is almost 16% higher than 29.8v and should not be placed together and the 29.8v is far too low to bring a proper charge to a 24v battery bank meaning 2 of these in series would be needed to make it work through an mppt cc.

    bottom line here is to make each pv make into a separate system with their own ccs going into a common battery bank or elect to go with 1 pv make and get rid of the others. in both cases i recommend more pv to be bought.

    hope i didn't confuse you as much as your system is.
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Thanx everyone,

    No/yes confusing! It actually, i think, depends upon how the questions/data are posted by the "solar beginners corner"! Obviously we need to be much clearer and precise, or more likely read the rules and regs. better!

    From these posts, I glean that the majority of the panels - bp's, astropowers and maybe even the 'unknown' 65's can be put into a "melting pot" ( for lack of better description) and run through a PWM (non-descriminating) charge controller, ie a Xantrex C40 (as that is available onsite) as "one string, fused through a 30A existing fuse" in their existing bp's in parallel, astropowers in series, unknown in series - all in parallel configuration.
    The Kyoceras wire in series to the existing OB flexmax60.

    As for monitoring, the PWM sits there and does its thing, chugging away, adding to bulk etc and when the system floats, adds its two or more cents... While the OB flexmax 60, becomes the 'brains' of the deal, with the serious monitoring and has the capability of starting the generator if needed....

    Does that sound about right?

    If so, waddayatink - a workable system??

    BTW 6V lifelines.....800AH battery bank.

    Thanx,
    Mike
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Yes, that's about right.

    Niel's suggestion of moving towards all one panel is a good idea. Especially supplanting the old ones with more KD240's.

    That 800 Amp hour battery bank is going to hunger for charging even so. At best you'll be around the 5% minimum for peak charge current. The maximum current from panels on a PWM controller, btw, is only the panels' Imps added together.
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    However, when you are in a place where thins are not too accessible, you have to work with what yer got! Baja is becoming more accessible but we are still 1000 miles away from a good hardware store....probably should mention that in the threads too...?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Location is definitely important to solar installs. Mainly due to the effect local conditions have on production (hot panels = lower Voltage). Obviously it does have bearing on what is available, or readily available. Some people are willing to haul things from far away, others need the assurance of replacement from nearby sources.

    Initially at least we can only give "generalized" answers. But as more details emerge answers can be revised and refined. :D
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Yup, gotcha there.
    Have I supplied enough info. to help figure this out? We have to stick together down here as we are so far away from "civilization" and there are too many "experts" down here who can help everybody out, yaya. So, not having easy access to any panel, battery etc we might desire, we have to sometimes improvise, or at least adjust if possible.
    So, next question: If, after these modifications, the battery bank still is hungry and there is the possibility of wiring in a generator to the AGS function on the OB 60 string, taking into account the other panels on the PWM comtroller,....what would be the recommended runtime and when...morning? We're talking an 11KW generator.

    Thanx again everybody from a newby, rapidly becoming an oldie!!!
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Well an 11 kW generator will feel no pain charging an 800 Amp hour 24 Volt battery bank. Or even a 48 Volt one. You could do it on a lot less, but it's what you've got right?

    AGS systems invariably operate from Voltage levels, which is not the best indicator of SOC especially on an active system. So some trial and error will be needed so that you can get it to start before the batteries get too low and stop before you're wasting too much fuel running a gen to provide some small amount of charging. We have this same problem with small generators; I shut down my 2kW inverter-gen when the current drops to 5 AAC.

    My personal preference for low Voltage shut down and/or generator start is the system nominal, i.e. 24 on a 24 Volt system. This means that if the system does shut down when the batteries "rebound" to their resting Voltage it will be above 50% SOC. You would want it to stop when the Bulk charging is done or part way into Absorb perhaps.

    Not all generators are compatible with AGS, or not all with the same type of AGS (some are "2 wire" some are "3 wire"). Basic: you have to be able to make contact to engage the ignition (or allow fuel flow on diesels) and then send a signal to activate the starter for a time, removing it when the gen starts (plus things like "retry after" and such). Can be quite complex. You may have to have a stand-alone AGS rather than use the FM60.

    What are you using for an inverter? What have you got for a battery charger? This info will be important too.
  • BB.BB. Super Moderators, Administrators Posts: 31,765 admin
    Re: Mixed panel wattage/voltage dileamour!

    800 AH at 24 volts plus a 11 kW genset... Hmmm.

    Assuming worst case loses and power factor... And 25% rate of charge, the minimum genset would be:
    • 800 AH * 29 volts charging * 1/0.80 charger eff * 1/0.67 PF * 0.25 rate of charge = 10,800 VA...

    Well color me surprised, if you use a "typical" AC battery charger (non-pf corrected, not terribly efficient):
    • 800 AH * 0.25 rate of charge = 200 amps @ 24 volt battery charger

    You could justify the 11 kW genset to really pump in a bunch of current into an 800 AH battery bank (at least to ~80-90% SOC--let the solar finish up).

    If you could get down towards 1/2 that or a bit less--The system, on average, may be a bit more fuel efficient.

    The "minimum nominal" charger I would look with an efficient/PF corrected battery charger would be:
    • 800 AH * 29 volts charging * 1/0.90 charger eff * 1/0.95 PF * 0.10 rate of charge = 2,713 VA maximum draw
    • 800 AH * 0.10 Rate of Charge = 80 amp @ 24 volt battery charger

    It might save a whole bunch of fuel costs... Especially if the you get the 80 amp class charger and run it on an 11 kW genest (probably around 1-2 gallons of fuel per hour; vs ~2 hours per gallon for the smaller genset--Of course, setting up autostart on a smaller genset is not always easy/possible).

    There has been a lot of generator discussions lately--But this recommendation sounds like a sweet generator:
    ChrisOlson wrote: »
    Bill, the new Honda EM-series deluxe generators now have an electronically controlled iGX engine. It has computerized ignition and the engine's ECU is directly above the carb where it also controls throttle and choke. The key switch completes two different circuits in the "ON" position - one for the ignition module and the other for the engine ECU.

    As far as wiring it up, the Trace GSM has two relays. The Run relay Common and NO terminals are used to turn on 12V power from the genset battery to the ignition, and I also had to install an additional relay on the genset that uses that 12V signal to enable the ECU. The third wire is the crank signal.

    It was very easy to wire up. Not quite as simple as our old EcoGen with the two-wire start. But frankly the Honda is twice the generator the Generac ever thought of being. That little EM4000SX with the iAVR system where it maintains voltage and freq at 25% overload for 10 seconds easily rivals the EcoGen's surge power for starting air compressor, well pump, etc..
    --
    Chris

    I have been looking for a full autostart "small" genset--And this sounds like the smallest one I have seen discussed so far.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    This is one of the reasons I was called in to this situation as in the past I have dealt with AGM situations involving larger Kohler generators.
    This system has an 11KW Powermate genset (inherited) twin cylinder Honda. Kinda sweet genset as it has a "GenControl" switch conversion to a two wire start system, compatible with the AGS of an OB 60. All that's left is to convert it to propane which negates the choke start requirement of this Honda.
    See - I got myself into a very interesting project?!
    So, now everybody has helped me figure the weird panel situation, I can concentrate on the AGS part - which now might not be as nec. as first thought?!
    However, I'm not too good on running the equations concerning charging requirements.
    The generator came with the system but was never wired up. It does work and will be a huge benefit once converted to propane.
    Even with the input on the panel situation, I'm not sure what presence is needed, if at all, by this generator?
    Yes, it's overkill, but it's here and ready to use....
    Inverter/charger is an OB FX 3524

    Getting a headache now.....
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Good ol' OB FX3524! :D
    I hope there's a MATE with it, or else you've got another problem.

    This can be programmed to start the gen too. Basically it will fire up the gen whenever the Voltage of the batteries goes below the set point.
    But there are exceptions! You can program both mandatory run times (generator exercise times) and mandatory no-run times (quiet times). This can make sure the gen does run some, and make sure it doesn't start in the middle of the night when you're trying to sleep.

    Yes the Outback stuff can do all sorts of interesting things. The fact that the programming manual looks like half of the encyclopaedia Britannica is a small price to pay! :p

    So down the aspirin and get ready for Adventures In Outback Programming. :D
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    OK,
    Great news.
    Now the hard stuff.
    Considering what needs to be done with the panels, ie Kyoceras thru the OB60 and all the others thru a PWM (likely C40) , FX 3524 WITH mate, a humongous 11KW AGS compatible generator and an 800AH, 24V battery bank, 5 hrs a day @ Lat. 22?
    Generator run time per day, or not?

    Believe me...in some of the conversations I have had with OB, aspirin don't cut it - that's why I here with the experts!!!

    Love this forum - thanx everybody.....
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Whether or not the generator will need to run is going to depend on how much the batteries are drawn down by the loads. If the panels can keep ahead of usage, the generator stays off. If it does need to run, how long will depend on how deeply discharged the batteries are and how much you need to charge them before you can trust the solar to handle the rest.

    Ideally the generator does not run unless you have bad weather, need power for heavy loads, or stay up too late watching TV. :D
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Okeydokey,

    Sorry, one other thing. Now that I have to separate the panels to different controllers, can I use the negative #6 cable as a common to both controllers and only run a new #8 for the positive for the Kyoceras, in other words jump the negative from the Flexmax 60 to the C40? Then, obviously run new battery charge cables from the C40. Also if the charge in cables enter at one end ofe each battery string, make sure the charge in from the C40 is at the other end? Does that make sense, not sure how else to explain it?

    Thanx again
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Negatives will be common electrically, and ordinarily are pass-through on controllers.
    The issue is one of current sharing. Current flowing through two wires from two arrays' positives then through one wire to the negatives means the negative wire has to be able to handle the combined current of both arrays.

    So let's say 6 AWG can handle 50 Amps and 8 AWG can handle 40 Amps (this varies according to the actual application). As long as the combined current on the 8 AWG does not exceed 50 Amps the 6 AWG won't be overloaded. But that's 25 Amps each on the 8 AWG, which can handle 15 more. The fuse rating on each positive wire needs to be for the single negative so that it can not be overloaded.

    Usually current won't be an issue on wires this size connecting an array. Instead Voltage drop will. The V-drop will have to be calculated separately for the 6 and the 8. Most calculators assume the same size wire coming as going, so this will be a bit problematic.

    Example:
    24 Volts, 10 Amps for 50 feet (one-way) 'round trip' on 8 AWG: 2.69% V-drop. Half way is like cutting the wire length down: 1.35% (0.323 Volts)
    24 Volts, 20 Amps for 50 feet (one-way) 'round trip' on 6 AWG: 3.39% V-drop. Half way is like cutting the wire length down: 1.69% (0.406 Volts)

    So for one of the circuits with the shared return line the V-drop is 0.323 + 0.406 = 0.729 Volts, or 3.03%.

    Confused yet? :p
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    No not confused, all makes sense. I'm thinking there has to be a way to protect the #6 from over current, maybe a diode? Then the respective #8's can be fused according to their actual load expectations?
    I'm not disputing at all, just trying to keep as much original equipment as possible.
    However it appears that there is a need for a second fuse, we're only talking 20' cable per run - its the question of another conduit for separate wiring or squeeze one #8 in with the three #6 in the existing 1 1/4" conduit!
    Almost ready to get at it!
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!
    BajaSun wrote: »
    ... - its the question of another conduit for separate wiring or squeeze one #8 in with the three #6 in the existing 1 1/4" conduit!
    Almost ready to get at it!

    It is a good idea, although not as important as with AC, to keep the + and - wires from the same circuit together. It will reduce the stray magnetic field and electrical noise radiation caused by the pulsed current input and output of a CC or GTI.
    SMA SB 3000, old BP panels.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!
    BajaSun wrote: »
    No not confused, all makes sense. I'm thinking there has to be a way to protect the #6 from over current, maybe a diode? Then the respective #8's can be fused according to their actual load expectations?
    I'm not disputing at all, just trying to keep as much original equipment as possible.
    However it appears that there is a need for a second fuse, we're only talking 20' cable per run - its the question of another conduit for separate wiring or squeeze one #8 in with the three #6 in the existing 1 1/4" conduit!
    Almost ready to get at it!

    Diodes do not protect against over-current. If the two #8 wires are fused according to the max the #6 can take this is how you protect the "half-combined" circuits. If that fuse is too low for either/both #8 lines then you are trying to feed too much current through the #6. In essence the #6 is acting like two wires in one. If you are expecting full current on both #8 wires then the #6 should be #4 so that it can handle the combined current.

    Squeezing too many wires into a conduit lowers the Ampacity of all of them due to restricting heat dissipation.

    Sometimes it's best to just bite the bullet and re-wire. Or in this case simply split off one array section and install new wires for that. You'd get best results by doing this for the array with the highest current, leaving the existing wiring for the lower current and knowing the new wire is right to handle what it has to.
  • PhotowhitPhotowhit Solar Expert Posts: 5,588 ✭✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    I have no idea of the local economy there, but where I am (Missouri) used 12v nominal panels can still sell for close to $1 a watt, so the Astropower and the odd 65 watt panels may help purchasing a couple more of the Kyoceras...
    ...just a thought...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    the generator and charger will lend itself well with the solar if you use the genny for bulk charging and the solar can do the finishing absorb charge and possibly a small load too if it doesn't detract from the power needed in the absorb charge. that means the genny being run early before the solar fully kicks in. this could be the night before too, but any loads during the night will force the need for some time on bulk again before the absorb takes place. how you arrange the times will be up to you and you have to manage the charge to the batteries being sure to get them to full charge as often as is possible. a battery monitor may help for a rough idea of where you stand and can help you with getting the times arranged, but don't take a battery monitor too literally as small errors can add up over time.

    i'm also not too sure you want to automate a genny turn on as i think it best to not be, but your choice.
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Hi everyone.
    I just finished installing a Xantrex C40 on the BP, astropower panel string and it was charging nicely, albeit slow. I adjusted the potentiometers to 1.3V bulk and 0.8V float to match the lifeline specs and what was on the flexmax 60. I then wired the two kyoceras in series and sent that down to the Flexmax60 which checked it out and registered 66V, immediately read 'absorbing' and showed no current??? C40 is still flashing away.
    Am I missing something? Why no current on the flexmax 60?
    Thanx
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Mixed panel wattage/voltage dileamour!
    BajaSun wrote: »
    Hi everyone.
    I just finished installing a Xantrex C40 on the BP, astropower panel string and it was charging nicely, albeit slow. I adjusted the potentiometers to 1.3V bulk and 0.8V float to match the lifeline specs and what was on the flexmax 60. I then wired the two kyoceras in series and sent that down to the Flexmax60 which checked it out and registered 66V, immediately read 'absorbing' and showed no current??? C40 is still flashing away.
    Am I missing something? Why no current on the flexmax 60?
    Thanx

    You're not missing anything. The FM60 will show "Absorbing" if the Voltage level is right and it's done Bulk. Bulk can be 1 minute for all it cares, and if the batteries are receiving charge from another source this will shorten the Bulk time on the FM60. The only thing the FM60 knows is the Voltage; it doesn't care where it's coming from.

    BTW, there could also be a Voltage discrepancy between the two controllers; when the batteries show Float (no loads) check the V at the batteries with a Voltmeter and on the FM60's meter and compare those readings to the setting on the C40. Never mind if they are off during Bulk or Absorb; the three can only possibly agree when current in is at a minimum.
  • BajaSunBajaSun Solar Expert Posts: 72 ✭✭✭✭
    Re: Mixed panel wattage/voltage dileamour!

    Thanx, got it! The FM60 must have been hooked up as the system was absorbing. Threw me for a loop! The water pump kicked in and put the FM60 back to bulk showing current etc and quickly went back to absorb, etc. Phew!
    So, float, turn off inverter, check voltage on batteries, FM60 and C40? If different adjust C40 to battery level (if correct) and keep adjusting all three until the same?
    Thanx
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