Wellsee MPPT

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  • GulchGulch Registered Users Posts: 13 ✭✭
    Re: Wellsee MPPT

    Thanks for the further input...

    Which brings up a couple more questions.

    Say I trash the Wellsee....

    I have a spare Sunforce (they may be junk too, for all I know) 30 amp controller... The specs on it say 25Vmax input... these panels seem to occasionally hit 27 V under load a few times a day, usually only for a few moments at a time... and this during winter... I wonder if that would fry the controller?

    The other option is to swipe back the Xantrex C35 that I have charging one bank of 225AH of batteries on my current main system... I have a C60 feeding another bank of 450AH.... Occasionally the way I have the main system configured, I'll get 70 Amps out of the array... Usually for only a few minutes at a time.

    One thing I don't quite understand about the controllers: Is the amperage rating on a Xantrex C60 CC only for output, or is it for input also? Will the occasional 70 A surge fry it, or not?

    And in the same vein: I wouldn't mind (much) spending the money to buy a 'real' MPPT charger for the little RV system, but I can't find a moderately priced one that will handle 425 or so watts on 25V+ input and 12V output... I COULD cut down to one panel, and use the Morningstar 15A MPPT controller, but that would be borderline for running my furnace blower on a couple of consecutive cold and cloudy days.
  • BB.BB. Super Moderators, Administrators Posts: 29,724 admin
    Re: Wellsee MPPT
    Gulch wrote: »
    I have a spare Sunforce (they may be junk too, for all I know) 30 amp controller... The specs on it say 25Vmax input... these panels seem to occasionally hit 27 V under load a few times a day, usually only for a few moments at a time... and this during winter... I wonder if that would fry the controller?
    The dimensions on modern electronics and transistors are extremely small... When you exceed the voltage input of the design, you are probably causing 1,000's of volts or more per inch of electric field (because the dimensions are so small) on those small features. When you over volt the design, you stress and can punch through the insulating materials on the die.

    You may pop it now, or you may weaken it for days/weeks/years down the road--It is very hard to tell what caused a failure without decapping the part.

    So--I would not recommend exceeding input voltage ranges ever for reliability. Add inductive kickback from wiring--and it is very easy to exceed design voltage limits if you exceed the controller spec.
    One thing I don't quite understand about the controllers: Is the amperage rating on a Xantrex C60 CC only for output, or is it for input also? Will the occasional 70 A surge fry it, or not?
    According to one Cx0 spec, they say: "85 amps intermittently-electronically protected"

    So, it looks like you are probably OK (not a great idea, but within capabilities).

    For a PWM controller--basically Current In equals Current Out (on/off switch--nothing more fancy that that).

    Remember that heating is based on I^2*R so:
    • (70a/60a)^2 = 1.36
    So, you have 36% more heating with only 1.17x more current. That is why running more current seems to overheat electrical devices more than one would expect (squaring current worth of power/heating effects).
    And in the same vein: I wouldn't mind (much) spending the money to buy a 'real' MPPT charger for the little RV system, but I can't find a moderately priced one that will handle 425 or so watts on 25V+ input and 12V output... I COULD cut down to one panel, and use the Morningstar 15A MPPT controller, but that would be borderline for running my furnace blower on a couple of consecutive cold and cloudy days.
    About the best bang for the buck MPPT 30 amps 12/24 volt unit is the Rogue MPPT at this point.

    It will handle your 24 volt array--and MPPT controllers because they are power converters can limit their output to rated current--regardless of how much solar array they have connected to their PV intput.

    For a 12 volt battery bank, about the maximum "optimum" size of solar array for a 30 amp controller would be:
    • 30 amps * 14.5 volts * 1/0.77 system derating = ~565 watts
    That will, on perfect days, push the controller to near 100% output capacity for a little bit--but most of the time, the controller will be operating under its 30 amp maximum current limit...

    You can put more solar array out there--but then the controller will hit current limit more often and "waste" the extra solar power that may be available...

    Note: Numbers are approximate... 540 bad vs 580 good--Not really--close enough (within 20%) is good for horseshoes, hand grenades, and solar PV systems.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • GulchGulch Registered Users Posts: 13 ✭✭
    Re: Wellsee MPPT

    Yes, Thanks..

    The specs on that Rogue look just about right for what I have in mind. While the price seems reasonable, it is still about 20% higher than I would pay without flinching.

    (Sorry all, for having drug this thread so far off the original topic)
  • BB.BB. Super Moderators, Administrators Posts: 29,724 admin
    Re: Wellsee MPPT

    Gulch,

    I can move your posts to its own thread if you want to continue the discussion along your needs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • GulchGulch Registered Users Posts: 13 ✭✭
    Re: Wellsee MPPT
    I can move your posts to its own thread if you want to continue the discussion along your needs.

    Up to you... All my current (no pun intended) questions are answered, and other novices who may be considering the Wellsee charge controllers would probably benefit from the discussion. Either way, Thanks much.
  • System2System2 Posts: 6,290 admin
    Re: Wellsee MPPT

    I'm glad I found this thread. I bought a InstaPark Mppt-30. I opened it up and discovered it's just a rebadged Wellsee mppt-30. I was disappointed to see how little there was inside and wondered if it was really an mppt charge controller. I noticed the little black box and wonder what that was.

    Here's a picture of my main board.

    i'm returning this and getting a morning star ss-mppt-15l. Twice the price with half the current capacity, but it works.

    Gary
  • mike95490mike95490 Solar Expert Posts: 8,470 ✭✭✭✭✭
    Re: Wellsee MPPT

    is there another board with a computer chip on it ?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • penjosephpenjoseph Registered Users Posts: 12
    Re: Wellsee MPPT

    The quality of Wellsee Solar Charge controllers is highly questionable.

    In our apartment we have three solar installations.

    Each setup consists of
    24x 90w panels. 4 each are connected in series. There are 6 sets of 4 paralleled. Maximum read open voltage is 78v. Maximum current while charging is 9 amps when checked with a clamp meter. Battery bank is of 48v DC. 24x 2V 500Ah are connected in series. A 3 KVA 48V DC bus inverter is connected to the batteries directly.

    The existing Solar Charge Controller 48V 40A could build the battery bank voltage upto 52v only. Hence we could use the street lights only for 2 1/2 hours in a day.

    Came know of Wellsee through the net and ordered 1no of 48v 30A Wellsee MPPT Solar Charge Controller. Though its cheaply made, it is charging battery to 54.8v. We have extended backup for the street lights to 4 1/2 hours.

    Ordered 2 more of the 48v30A MPPT Wellsee Solar Charge Controller. Surprisingly these didn't have the 'WELLSEE' mark on the cover though dimensionally it looks the same.

    While connecting the Wellsee Solar Charge controllers we were careful not to reverse the polarity of panels or batteries. The polarity & voltage was checked with multimeter prior to the connection. While fitting, the batteries were connected first (as in the manual) & then the panels. While removing the panels were disconnected first & then the batteries.

    These 2 worked only for a day & then stopped charging the batteries. When I opened the units to my horror I found out that the MOSFETs are blown inside the controller. However the 1st one is working fine.

    Contacted Wellsee and I am yet get a response from their engineer.

    Joseph Eapen
  • BB.BB. Super Moderators, Administrators Posts: 29,724 admin
    Re: Wellsee MPPT

    Penjoseph,

    Sorry to hear about the problems... Are you trying to setup street lamps in remote locations?

    What are you using for batteries and lamps?

    Also, are you doing anything to protect the batteries from over discharge during bad weather (monsoon season)?

    To build a bullet proof remote/unattended solar power system that will last (and not destroy the batteries) seems to be a difficult and expensive job... Unless you choose something like NiCad batteries with matched sets, or diodes or similar to prevent them from reverse polarity charging. And NiCads are "bad words" in the world of Cadmium/heavy metal pollution.

    Seems like somebody could take a small micro controller and setup the hardware/firmware to help reduce production costs while protecting the battery bank.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • penjosephpenjoseph Registered Users Posts: 12
    Re: Wellsee MPPT

    The picture below is our setup. Batteries are distilled water type 24x 2v 500Ah. Solar panels are 90w 4 in series, 24 in total (6 sets of 4 in parallel). We use a 3KVA 230VAC / 48VDC Inverter

    Attachment not found.

    Attachment not found.

    We use the inverter to power 230V 1500W of street lamps 2-3 hours in the night. The inverter itself has a output cut-off to prevent deep discharge of batteries. It shuts down if the battery voltage drops below 44v.

    Joseph Eapen
  • penjosephpenjoseph Registered Users Posts: 12
    Re: Wellsee MPPT

    Attachment not found.

    Analysis of failed 48v30A Wellsee MPPT Solar Charge Controller -

    Failed parts marked:
    RED - Mosfet Bank has burned out & failed.
    GREEN - Regulator Capacitor has become so hot that the plastic label cover fell off.
    BLUE - Switching Load Relay has melted. I am wondering how this has happened because we do not use this option. The 230VAC 48VDC bus Lighting inverter is directly connected to the batteries.

    The front panel control circuit is fine & LEDs are stilll working

    Update : As on 21/1/12 the BLUE marked is an inductor coil & not a relay

    Joseph Eapen
  • BB.BB. Super Moderators, Administrators Posts: 29,724 admin
    Re: Wellsee MPPT

    Depending on loads and temperatures, deep cycling to ~44 volts is a pretty healthy discharge. Normally, we recommend that people try to keep the minimum voltage to around 46 volts minimum.

    So, these are 500 AH @ 48 volt batteries (single series string)?
    • 1,500 watt of lights * 1/48 volts * 3 hours * 1/0.85 efficient inverter = 110 AH per night
    • 110AH per night / 500 AH capacity = 0.22 = 22% discharge
    That sounds about right for amount of discharge per night...
    • 90 watt per panel * 24 panels * 0.77 panel+charger deratings * 1/58 volts charging = 28.7 Amps average charging current
    Assuming ~5 hours of sun per day:
    • 90 watts * 24 panels * 0.52 system derating * 5 hours of sun * 1/58 volts = ~97 AH per day
    The numbers sound OK... Assuming you use the lights less if the batteries are not fully charged / during poor weather.

    If you could ever justify it... A Battery Monitor would be interesting to have on the system (current shunt, measure Amps*Hour during charging and discharging).

    Have you actually verified the Wellsee model you are using is actually a MPPT charge controller? The few we have seen here are not. They are just simple PWM charge controllers (no large inductors for energy storage as typically seen in switching power supplies).

    Assuming the panels have Vmp in the range of 17.5 volts each--A PWM controller would be OK for your application (at least not much different than using a MPPT controller with only four "12 volt" panels in series.

    A good MPPT charge Controller, you could put 5 (or possibly 6) panels in series. This would reduce the current (and losses) a bit between the array and the controller/battery bank. It would also allow you to charge/equalize your batteries better in hot weather (which I assume you have a lot of). Solar panel Vmp falls with higher temperatures and that could also limit your maximum charging voltage some too (hitting Vmp-array-hot and Vbatt-charging/equalizing).

    -Bill

    PS: I see you posted a picture... Yes, that is not a MPPT type charge controller--Just a PWM unit (in my humble opinion--I am not an expert).
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • penjosephpenjoseph Registered Users Posts: 12
    Re: Wellsee MPPT

    I educated myself on MPPT Charge controllers. Yes Bill, as you said it is not a genuine MPPT. It is a PWM type (Wellsee mentions it as both PWM with MPPT -hybrid!) with a small air core & an inductor transformer to buck \ boost.

    Thank you for the math. Is a learning experience.
  • GulchGulch Registered Users Posts: 13 ✭✭
    Re: Wellsee MPPT

    I had completely forgotten about this thread until today when I got the email from the new contributions..

    Here is my update: My Wellsee kept the batteries properly charged for about two months, then it quit working : It just passed through whatever the panels were putting out, Fortunately I had a separate voltmeter where I saw it several times a day, and caught it when it had the 12V batteries up to about 16.5V.

    Fortunately the batteries forgave that abuse after I added some water to replace what had boiled off, and are still in good service.

    I opened up the controller and couldn't see anything that obviously fried. I didn't have time to mess with it further, so ordered a relatively inexpensive, but 'real' MPPT from somewhere else.
  • telljftelljf Registered Users Posts: 20 ✭✭
    Re: Wellsee MPPT

    I have very good reason to believe that Wellsee is indeed MPPT. I have used it for the last 8 months. You need to have meters connected to the input and output of the controller to see the effect. Also the battery needs to be in low charge state to see the difference. If you have a doc wattson kind of meter that registers the peak current, connected at the output of the controller, it will show that it will regularly break the sum of open circuit peak current limit of the panels.
  • penjosephpenjoseph Registered Users Posts: 12
    Re: Wellsee MPPT

    I had the units inspected with an Electronics Engineer who designs inverter & charger circuit boards.

    BLUE marked is an inductor coil & not a relay. This coils adds to the MPPT function of the controller. Wellsee lists this controller as PWM with MPPT function.

    However the circuit tracks are poorly made (thin) for a 30A controller.

    I contacted Wellsee for a replacement main board. They said it will be the cost of a new 48v 30A controller ! or else I'll have to repair the components failed from the local electronics market since they have not blanked out the chip nos.

    Suprisingly the first one I ordered is working fine still. Anyway its no Wellsee for me & I have raised a Credit Card dispute.
  • boBboB Solar Expert Posts: 966 ✭✭✭✭
    Re: Wellsee MPPT
    telljf wrote: »
    it will show that it will regularly break the sum of open circuit peak current limit of the panels.

    Hi telljf, What is "Open circuit peak current" ??

    When you talked about using meters on the input and output, were you looking at the voltage input and voltage output and noticing that the input voltage was higher than the output (battery) voltage ?? An MPPT or a PWM charger would both do this if the PWM was in the Absorb, Float or EQ stage (voltage regulation).

    boB
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Wellsee MPPT

    good catch boB as there is not such thing as current flow in an open circuit.
  • telljftelljf Registered Users Posts: 20 ✭✭
    Re: Wellsee MPPT

    By open circuit current, it is the maximum current Isc specified on the back of the panel. Now the current from the charge controller recorded by Docwattson, Ap cannot be expected to be above the sum of Isc of the panels connected in parallel if it didn't have MPPT function. I just mean to say that I receive more current than what the panels can produce.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Wellsee MPPT

    isc is short circuit current
  • bmetbmet Solar Expert Posts: 630 ✭✭
    Re: Wellsee MPPT

    While this has nothing to do with the topic, I saw a different product under the name of Wellesse, and wondered if they were from the same company
  • BB.BB. Super Moderators, Administrators Posts: 29,724 admin
    Re: Wellsee MPPT

    Appears to be an unrelated brand/vitamin company.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • penjosephpenjoseph Registered Users Posts: 12
    Re: Wellsee MPPT

    An update - the 3rd WELLSEE controller blew last month ! - Shucks ! too bad I can't get a refund on this one

    I had a discussion with the Electronics Engineer. He said there is no charge current control/regulation for these type of controllers. If you deep drain your batteries - ( ours is 500 Ah), the next day the load will be maximum on the controller & unless a constant current control is applied the driver MOSFETS will blow due to overload.

    I am in the process of designing with the Electronics Engineer a new 48v 25A Charge Controller with proper MPPT buck-only design. It will have a inductor transformer to reduce excess voltage & increase the current. It will be constant output voltage (<=56.4v) & current(<=25A) design limiting the input current. Maximum input voltage will be 150v.

    Its feature will be such that even if the input current is increased by addition of solar panels in parallel (not voltage) or output current requirement is increased by adding battery banks in parallel, it will not blow the controller.

    Future plan is a add a separate voltage Boost circuit which will 'switch on' below solar panel voltage of 30v. It will boost the voltage to 54v with a current limit of 5A. This circuit will useful for maintaining float voltage during fading sun - rains or sunset.

    Hope what I said made sense. If the forum permits discussing own Electronic designs, I will post the follow-up in a separate thread
  • BB.BB. Super Moderators, Administrators Posts: 29,724 admin
    Re: Wellsee MPPT

    Sure--You are more than welcome to start a thread about your design.

    Good Luck. You will learn a lot and hopefully have a nice controller in the end.

    Are you planning on running a micro-controller to do some sort of MPPT function?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • penjosephpenjoseph Registered Users Posts: 12
    Re: Wellsee MPPT

    Yes it will be programmed micro-controller based with a buck transformer for MPPT.

    The charging threshold voltage would be adjustable with a preset. This feature is for if found batteries are heating up or if the distilled water consumption is high (in case of flooded cell), it can be reduced.

    We are prototyping as to whether the driver stage should be MOSFETs or IGBTs. IGBTs handle more voltage & current, require higher frequency but are less efficient than MOSFETs. IGBT circuitry can be made more compact for the current rating.
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