Looking For A Non ON/OFF Solar Controller?

Maine SailMaine Sail Registered Users Posts: 11
Hi All,

I am wondering if anyone can recommend a good solar controller that does not shut on & off when the batteries are getting close to full and the voltage comes up to absorption level. The literature from the manufacturers is unclear sometimes to see precisely how they operate. Some even go so far as to suggest "smart charging", which usually in the marine world means, bulk, absorption and float stages yet many of these controllers don't actually do a true reduced voltage float.

I do installs in the marine environment where boats are left on moorings with no loads on the batteries. The wasted time between the OFF voltage and ON voltage kills charging times in the limited sun times in the NE.

Was watching a boat yesterday with a Blue Sky, I think it was a 2000, and the time between on & off was considerably longer than the ON time at 93% bank state of charge. This is completely wasted time that could be better spent charging if the unit had a float mode that was constant voltage applied and the batteries were allowed to determine the acceptance rate.

I am sitting in front of another controller right now, not one I installed, that goes on at 13.6V and off at 14.4V. Right now the on time is about 13-15 seconds and off time waiting for the bank to fall back to 13.6 is over 60 seconds. At this rate it can take days to get the bank back to full no matter how big the panel is.. Unlike an off grid application boats often sit with no loads and the surface charge on the plates remains high so the controllers spend more time OFF than ON..:grr

I am sure there is a controller that does what I need I just have not found it yet?

Comments

  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?

    Any Mppt controller fits what your looking for
  • PhotowhitPhotowhit Solar Expert Posts: 4,994 ✭✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?

    I don't think any PWM does this, and I don't think my Rouge MPPT does this. Perhaps this is just w/Blue Sky?

    If the boat is sitting idle, they likely don't need much in the way of charging?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • BB.BB. Super Moderators, Administrators Posts: 29,497 admin
    Re: Looking For A Non ON/OFF Solar Controller?

    Efficiency wise, turning on and off is how these controllers work--they do not usually do voltage regulation directly (inefficient and/or more expensive to make the charge controller).

    However, it this case, it sounds like the charge controller is more in the "float" mode than the charge mode.

    If the controller is working correctly--What is the wire gauge and length (and the charging current) for the controller to battery bank connection. Too high of voltage drop can confuse a charge controller and cause it to back off the average charging current too soon.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Looking For A Non ON/OFF Solar Controller?

    Look here: http://www.solar-electric.com/chco.html

    The two main types of charge controller used for solar are Pulse Width Modulation (PWM) and Maximum Power Point Tracking.

    Technically the PWM does turn on and off; but very rapidly as needed according to set charge Voltage points and stages. In other words it applies full available current during Bulk until the Absorb Voltage set point is reached. It will then turn on/off as needed to maintain that Voltage point against the current draw. Once Absorb is completed it will drop back to Float Voltage level and function the same until there is insufficient sunlight available to maintain that level.

    The MPPT type operates on a more complex level. It too will supply all the current it can muster from the panels during Bulk, but it has the added advantage of being able to down convert higher array Voltage and turn it into additional charge current. This gives it an advantage over the PWM type, with somewhat greater efficiency. During Absorb it will maintain a steady-state Voltage at the set-point, and likewise with the Float stage.

    The el cheapo "shunt" type controllers that simple regulate to a fixed Voltage are not suitable for solar except in the very smallest applications.
  • Maine SailMaine Sail Registered Users Posts: 11
    Re: Looking For A Non ON/OFF Solar Controller?
    Photowhit wrote: »
    I don't think any PWM does this, and I don't think my Rouge MPPT does this. Perhaps this is just w/Blue Sky?

    If the boat is sitting idle, they likely don't need much in the way of charging?

    It actually does. The alternator can bring this bank back to about 80-83% state of charge, unless you run the motor for looong periods of time, as the bank starts reducing what it accepts the more full it gets so running a 150A alternator on a 75 hp $12,000.00 diesel engine producing 12A of current is simply wasteful and making little sense.

    This is a sail boat so running the engine for 10+ hours to get back to full simply is not an option. The solar panels are here to bring the bank from 80-85% back to 100% but when the batts begin to get into the 90% range with no loads on, except for a couple of mA to power the Link Pro battery monitor, the voltage is coming up to 14.4v very quickly, like a few seconds then the controller goes off and it takes over a minute for the voltage to fall and the controller to come back on. AGM's hold a surface charge very well. At this rate it takes days to get those last few Ah's back into the bank. This boat is using AGM's which really require topping up as often as possible to get the longest life and this controller is killing the charge times for the last 10% of Ah's...

    The Blue Sky MPPT I was working on yesterday seemed to be doing the same type of behavior. Perhaps though it was a Blue Sky PWM controller and not MPPT? The owner did not have the manual and I did not install that one.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?

    What do you have for solar panels, what do you have for batteries, and is this a 12 volt system?
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?

    if i read what you are saying properly i don't believe the blue sky is operating properly as it should not shut off when going into absorb and float. the only time i ever heard the relays kicking was when it first kicked on in the morning and when it was kicking off at night (or the result of really bad weather fooling it to be sunset) and it would kick on/off several times before settling in.
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?
    Maine Sail wrote: »
    The Blue Sky MPPT I was working on yesterday seemed to be doing the same type of behavior. Perhaps though it was a Blue Sky PWM controller and not MPPT? The owner did not have the manual and I did not install that one.

    BlueSky is junk ... and thats giving junk a bad name. Any quaility Mppt controller will function as you desire. MorningStar has 15/45/60 units Xantrex a 60 amp, Outback 60 or 80 amp this are the main UL listed units to check out
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?

    I'm also inclined to think your particular controller is bad / junk. I have two Morningstar SunKeeper PWM controllers - pretty simple, not particularly "high end" - and they have never acted as you describe. In fact, the only controller I ever had that did was the lousy thing that came with my Harbor Freight solar panels - it literally just switched on and off at fixed wide-spaced voltage points exactly as you describe. I very quickly got rid of it and went with the Morningstars.

    When I have watched voltage on my systems, the PWM controllers only allow the voltage to vary by a couple tenths between switching on/off - if that. They cycle very rapidly to do that too, several times per second, even while floating. Mine are used on AGM batteries, and have no problem getting them fully charged, dropping to float by midday easily if I've not been using the battery overnight.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?
    BlueSky is junk ... and thats giving junk a bad name. Any quaility Mppt controller will function as you desire. MorningStar has 15/45/60 units Xantrex a 60 amp, Outback 60 or 80 amp this are the main UL listed units to check out

    Maine Sail, you want your problem solved? Then listen to Solar Guppy, he knows what he's talking about. And no, I'm not joking!
  • VicVic Solar Expert Posts: 2,970 ✭✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?

    And, missing from SG's list are the MidNite MPPT controllers, altho, SG may have never worked for MN.

    Believe that the MN CCs are ETL listed, which has the same status as UL (IMHO).
    Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,662 ✭✭✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?
    Maine Sail wrote: »
    Hi All,

    I am wondering if anyone can recommend a good solar controller that does not shut on & off when the batteries are getting close to full and the voltage comes up to absorption level. The literature from the manufacturers is unclear sometimes to see precisely how they operate. Some even go so far as to suggest "smart charging", which usually in the marine world means, bulk, absorption and float stages yet many of these controllers don't actually do a true reduced voltage float.

    I do installs in the marine environment where boats are left on moorings with no loads on the batteries. The wasted time between the OFF voltage and ON voltage kills charging times in the limited sun times in the NE.

    Was watching a boat yesterday with a Blue Sky, I think it was a 2000, and the time between on & off was considerably longer than the ON time at 93% bank state of charge. This is completely wasted time that could be better spent charging if the unit had a float mode that was constant voltage applied and the batteries were allowed to determine the acceptance rate.

    I am sitting in front of another controller right now, not one I installed, that goes on at 13.6V and off at 14.4V. Right now the on time is about 13-15 seconds and off time waiting for the bank to fall back to 13.6 is over 60 seconds. At this rate it can take days to get the bank back to full no matter how big the panel is.. Unlike an off grid application boats often sit with no loads and the surface charge on the plates remains high so the controllers spend more time OFF than ON..:grr

    I am sure there is a controller that does what I need I just have not found it yet?

    I would not use a controller with a fan unless I knew it was designed for circulating humid salt laden air. Many PC boards are conformal coated to help with this but moving parts in this environment are just another nail in the coffin in my opinion. Many do not realize that a boat on a mooring unattended is a situation where reliable power is almost as critical as manned space electronics. Do it right!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?
    I would not use a controller with a fan unless I knew it was designed for circulating humid salt laden air. Many PC boards are conformal coated to help with this but moving parts in this environment are just another nail in the coffin in my opinion. Many do not realize that a boat on a mooring unattended is a situation where reliable power is almost as critical as manned space electronics. Do it right!

    Agree. And the Morningstar units, both controllers and inverters, are designed without the need, or use of fans. Very, very reliable.
  • VicVic Solar Expert Posts: 2,970 ✭✭✭✭
    Re: Looking For A Non ON/OFF Solar Controller?

    The new-ish MidNite Classic line of MPPT CCs have fans, but allow the option of running "sealed", or "vented" IIRC. This allows circulating internal air vs circulating outside ambient air. This seal is not perfect, but allows some reduction in circulation of whatever crap is in the outside air.

    AND, the MN Classic allows moving the included operator interface/dispaly panel to a more convenient location for human control, while having the CC hardware close to the battery bank. On a boat, this might be a plus. This four-line LCD display is very comprehensive vs the two line one on the X SCC. Recall that EVERY extra function on the MS CCs are optional at extra cost. If memory serves, even the BTS is an extra $30 US or so ... this might have changed.

    Am not a shill for MN, but the Classic is a very nice box IMHO. Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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