cheap Mppt any good ?

[fafrd]

The microinverter is plugged into a smart plug on a power strip which is the output from the LF inverter. LF inverters can run in both directions. The microinverter syncs to the LF ac and generates power. If the battery is 28V then Home Assistant turns the smart plug off so the microinverter shuts down.

Nice - so Home Assistant is the master controller to prevent the AC-coupled system from getting into difficulty once the battery gets fully charged (and can no longer allow the battery charger to work as a dump load).

The black/red extension lead comes from the microinverter. White plug is power strip and the orange lead runs to my laundry. Orange/black extension lead runs to the garage fridge.

 

[pollenface]

its never colder than plus 10 Celsius here and I am aware of the maximum voltage problem.
160 Volt input is good for 3 panels 72 cells in series, and nearly 60A should be produced by 4 Strings.
So theoretically ina a 3s4p configuratiion that would be >50 Amp >100V over 5000Watt, to good to be true!

I use 2x 72cell panels in series with a 100v controller and never see more than 90v around 2°c ... it doesn't really get any colder where i live.

 

[12VoltInstalls]

LF inverters

If you were north america I’d be interested in knowing what LF inverter that was but it’s irrelevant as I am USA. Sounds like a decent low-tech approach.

as they were cheap

I noticed your unit’s labels stating “max PV voltage 150V” and was curious about that.

The powrMR manual states 190V maximum.
Although I’m not overly impressed with the powrMR units for a couple reasons I am pleased with what they do for the $$ they cost. I’d like not to kill them and have to buy again.
I have six REC 72 315W panels, 45.8VOC. I want to finish my original intentions and run two 3S arrays into two of the PowrMR 60’s. My concern is the 160.51V potential at -40* as “some reviewers” say they will burn down over 40A output and I’m hoping for someone who has driven them to confirm that indeed 160V at label nominal 945W will be acceptable usage. (no need to discuss ’wasted’ wattage- my panels are vertically mounted to avoid snow accumulation so I have preconfigured watt reductions and the ‘overpaneling’ is part of my strategy. Whatever unharvested watts I will have are known and expected)

The MPPSolar 1012LV-MK has a max PV voltage of 145V otherwise I would utilize it for its 1000W PV input for one of the strings. 2S is ~90V and my one way run is around 75’ and I don’t want the voltage loss of 2S versus 3S even though it’s reasonably small.

Another option is a 200V 50A Epever I have but I have another 2500W above the 2500W I want to fully enable now.

Thoughts?

 

[sun walker]

I you need a replacement board or don't mind a naked circuit see

60A MPPT Solar Charge Controller Circuit Board with Fan and Backlight LCD 12V 24V 36V 48V Solar Regulator Module ​

US$75.68​

banggood.com/60A-MPPT-Solar-Charge-Controller-Circuit-Board-with-Fan-and-Backlight-LCD-12V-24V-36V-48V-Solar-Regulator-Module​

No idea if they are good value.
Sorry about all the bold, can't seem to unbold copied text.

 

[BuffaloTrace]

I would try it out, with the caveat that you may lose one of those inexpensive SCC.
May be going way out on a limb here, but that being said, perhaps a cheap solution would be a little patience and a lot of testing involved using a temperature sensor relay. You could test exhaust Temps or case temperatures on existing units that work well in a standard or lower voc setup, and than set a 12v relay to switch off PV input when temp goes over your pre determined threshold to at least save the SCC. More testing can be done to perhaps enhance this or bump the temperature up.
Perhaps it's a lot of work, but than one could cheaply find out a perhaps higher limit for these without destroying it instantly....

 

[12VoltInstalls]

US$75.68

When that’s basically the price of the whole cheap unit… why?!

would try it out, with the caveat that you may lose one of those inexpensive SCC

that is the possibility for sure.

If you read the backstory here and other places you might be aware I bought these to ‘fight back’ due to my dissatisfaction with the voltage spike / cutout ‘bug’ that Epever has made me chase my tail with.
I like- love- the epever price point for the effectiveness and apparent durability of the Epever units but when the ‘bug’ shows up it either has to go overnight or if you are present (and notice it) you have to unpower it and reboot to get more than dribbling watts out of them. They’ll work fine for month or a week or six weeks but then you come home to mostly discharged batteries one day and be in a pickle (I’m fully offgrid).

The solution imho was to either buy MPPSolar SCC’s (similar money and appear to do fine) or Victron (higher priced a lot), or try a cheap unit that most people say good things about. I decided to ‘play’ with cheap units.

The 1012LV-MK takes up to 1000W of solar up to a max volts of 145VDC and just works well (can contribute 80A of solar charging, too). I do not use its inverter- there for backup. Running a 2000W QZRELB pure sine
At ~$650 for the MK model of the 1012LV I don’t want to buy another just for the SCC duties. Plus the 145V ceiling is an issue for three ~46VOC series panels.

At this juncture I ‘think’ I’m going to run my “morning panels” through a powrMR (600W panels ESE-facing), and two strings of three 315W/~46VOC in series (S facing, 9am to 4pm best coverage) with one on an Epever 50A, the other on a powrMR); and find a place for SW-facing 400W to send at the 1012LV. That will be a net potential of ~3kW of panels with all day coverage- in winter. In summer (spring/fall) I’ll be WAY overpanelled for my household needs but the current ~1650W during these Dark Months has too many 500Wh days to make sense not overpaneling. (while it varies some I’m about ~1600Wh/day consumption for practical planning purposes and terms.)

The question is: has anybody fed the old-style powrMR 60A with ~950W and/or ~160V low-temp corrected VOC?

 

[Ellcon123]

I think you should be careful of max ratings on these. I don't have the powMR but my 60A units have 1200W of 2p3s panels on each. Generally operate with 71V on the panels and max 40A output for 24V batteries. Heat is an issue. I have added fans and plenty of clearance but the fans will still run constantly. I suspect at max amps the SCC's would throttle back or turn off from over temp.

On the voltage, the components are barely rated for the max input. Won't take much of a spike for them to release the smoke. On the conversion side your power will take a big hit at high voltage. The simple buck converters in these like to operate at 1.5 to 2 times voltage. I'm at about 2.5 times and seeing 80% efficiency. Your a 12V system(?) so with 160V you're over 10 times differential.

I don't see your cold weather but don't underestimate how well panels can perform in the cold. Peak power is often equal to or better than summer but you just don't have the sunlight hours. If you are maxing ratings there's a good chance these can be exceeded in winter.

Your experience is likely to be different but maxing or over panelling on these cheap units is probably going to fail at some point.

 

[ericfx1984]

n't see your cold weather but don't underestimate how well panels can perform in the cold. Peak power is often equal to or better than summer but you just don't have the sunlight hours. If you are maxing ratings there's a good chance these can be exceeded in winter.

Your experience is likely to be different but maxing or over panelling on these cheap units is probably going to fail at some point.

I had a pair of panels, 300x2. They would peak out just over 750w from time to time in the winter

 

[Kiwi2000]

As I have been upgrading my SCCs from Epevers to Victron SCCs, I came to realise that the drive for more efficient PV panels is pretty small gains compared to the big gains of more efficient SCCs. They can make a big difference in PV array performance.

 

[Ellcon123]

As I have been upgrading my SCCs from Epevers to Victron SCCs, I came to realise that the drive for more efficient PV panels is pretty small gains compared to the big gains of more efficient SCCs. They can make a big difference in PV array performance.

Everything is a trade off but relative. Really old panels are maybe 15% and mine are 20%. New panels are 22% or better so that's absolute efficiency gains of 10 to 30%.

I estimate my SCC at 80% and maybe one day I will replace and possibly see 95%. After that though it's quickly diminishing returns.

 

[sun walker]

As I have been upgrading my SCCs from Epevers to Victron SCCs, I came to realise that the drive for more efficient PV panels is pretty small gains compared to the big gains of more efficient SCCs. They can make a big difference in PV array performance.

But if your paneling your home, you probably have heaps of space (different case for a yacht etc), I don't really see the gains in grabbing a few % in gains from an expensive mppt, when for the same extra cash you can add several more door size panels.

 

[12VoltInstalls]

should be careful of max ratings on these

Not pushing back on your statement, just wanting a broadening of knowledge:
The manual states “190V max PV”

The 161.x Volts is panel specs (135VOC at 77*F) factored for my lowest temperature of -40* which seems ‘safe’ - so at that for worst case I’ll be <85% of label (we had one night of -46*F in 1993, and last winter -39*F but typically -25 to -28*F is lowest. We had -20*F for a week ~2003ish).
So do you think I’m nuts or just mentioning that I’m “too close for comfort” with your sensibilities?
Takeaway: at $85 for these SCC’s if one smokes but doesn’t cause a fire I’m ok with one dying- I have backups.
And if one smokes I may not want to run them anymore anyways. I have a 200V max 50A Epever for primary SCC, and the powrMR will be the second string, and the 1012LV-MK will take 500W, so the setup is redundant as well. Longterm if the 50A 200V Epever doesn’t exhibit the ‘high voltage cutout bug’ with the lithium batteries I’ll probably add a second. Will’s vids and various comments on the forum indicate Epever handles overpaneling fine.

don't have the powMR but my 60A units have 1200W of 2p3s panels on each

I don’t recall if you previously posted what brand SCC? Of course:

24V batteries. Heat is an issue. I have added fans and plenty of clearance but the fans will still run constantly

24V can deal with 1200W input.
I’m 12V lithium so ~13.4V at 60A is ~800W; so my 3S is “945” watts- or 15% overpaneled.

On the voltage, the components are barely rated for the max input. Won't take much of a spike for them to release the smoke. On the conversion side your power will take a big hit at high voltage

2S for me would be ~90VOC and the higher 135 voltage desire is due to ~75 feet one way of run, plus the many cloudy days this time of year where these 315W 2S panels (~92VOC) can often be only ~200Wh/day or less. With other panels, pushing the VOC up gave me as much as two more hours of ‘some’ charge than they did at lower VOC during our months of cloudy days.

If what I’m doing is unsafe (fire hazard) then I’ll rethink it. If it’s just risk of smoking off a $89 SCC- though undesirable- I’ll accept that.

buck converters in these like to operate at 1.5 to 2 times voltage. I'm at about 2.5 times and seeing 80% efficiency. You’re a 12V system(?) so with 160V you're over 10 times differential

Manual states 20-80V “input specification” for 12V systems which I believe is the efficient operating range. Whatever is ‘lost’ is lost as heat, and the highest voltage concern occurs when I am needing heat…
Unless someone provides data of these burning down houses I’m ok carrying on with my experiment.

Peak power is often equal to or better than summer but you just don't have the sunlight hours

Yes. This is my fourth offgrid winter, third full timing it. I’ve seen 600W of 3S2P put out 46A into my lead acid batteries. (Lithium now)
The overpanelled goal is to get >500Wh/day, hoping (aiming?) for 1kWh/day with our cloudy days. My ~2days of storage can be “stretched” to many days with ‘some’ usable input cuz LiFePo won’t die if they do not get fully charged every day.

I’m just trying to know what I don’t know.

don't really see the gains in grabbing a few % in gains from an expensive mppt, when for the same extra cash you can add several more door size panels.

There’s truth to that. But also “it depends” in my mind. If a cheapo mppt is safe to not be likely to cause a fire, more panels, sure. It’s inexpensive- agreed. I like having multiple SCC inputs; multiple ‘good’ SCC expenses can add up, so can panels but not as quickly versus SCC’s for wattage. I’ll accept some sacrifice of SCC ‘efficiency’ if the cost is reasonably less than buying Victron or something top shelf.

 

[Kiwi2000]

But if your paneling your home, you probably have heaps of space (different case for a yacht etc), I don't really see the gains in grabbing a few % in gains from an expensive mppt, when for the same extra cash you can add several more door size panels.

Unfortunately I haven't got lots of large roof space area that gets good sun free from shadows from neighbours' trees and fixtures on my house.

On one of my systems I only have 2.8kW of PV feeding a 25kWh lithium battery bank. That's almost a 1:10 ratio of PV to battery storage. I simply cannot afford to have significant periods of the day where my Epevers can't be bothered and go into their slumber mode.

 

[12VoltInstalls]

FWIW I tried to claim my “asurian” protection I purchased when I ordered from Amazon and it was denied.
They gave instructions on getting a contact link on Amazon website, but that link was 404.
Called Amazon and killed a couple hours getting disconnected three (four?) times. Gave up and emailed powMR but ~5? days and nothing but a confirmation it was received.
Asurian website today told me to call. I did. They are refunding $89.99 to an amazone giftcard.

Going to test a new-in-box epever 5420AN I have once I find my old iphone to use the Bluetooth dongle with (it does not work with current/later iOS) so I can program it.

Summary: one powMR mppt60 works fine, the other “hunts” and is net 20% of output in good sun that the other unit puts out. Poor sun it won’t do anything but hunt, no effective charging.
Swapped one for one with three arrays and proved one is defective somehow. It never worked right from day one but now that it’s winter it became obvious that it’s junk.

Unclear atm if I will buy again.
Also unclear if the 5420 Epever will exhibit the ‘cutout bug’ but a recent post on this forum indicated a firmware update cures this. Time will tell?

While it is true I depend on this stuff for a fully off grid situation- and as irritated as I was trying to get support- this whole thing of experimenting around and trying lower-shelf stuff is fun for me. It’s a hobby-level pursuit, yes, but I also depend on my experiments to keep the fridge, lights, furnace, and coffeemaker running LOL

I am convinced I cannot rely on these powMR units at this point.

edit: fwiw the ‘good’ unit is performing identically for output as the SCC in the MPPSolar 1012LV-MK. The best the other unit ever did was 1/2, usually 20-25%

 

[Kiwi2000]

While it is true I depend on this stuff for a fully off grid situation- and as irritated as I was trying to get support- this whole thing of experimenting around and trying lower-shelf stuff is fun for me. It’s a hobby-level pursuit, yes, but I also depend on my experiments to keep the fridge, lights, furnace, and coffeemaker running LOL

That's why with hindsight I would advise anybody starting out to go straight to Victron gear. Most people will probably end up there anyhow so don't waste your time and money buying inferior products.

 

[12VoltInstalls]

That's why with hindsight I would advise anybody starting out to go straight to Victron gear. Most people will probably end up there anyhow so don't waste your time and money buying inferior products

Well Epever works very well aside from the high-volt “cutout bug” that leaves you at 10% of production until you reset it or sun goes down. Though it was posted here or on another thread they have apparently addressed that issue with a firmware update.
Nothing wrong with Victron or the other higher-end proprietarily integrated manufacturers. While I haven’t looked recently the three-times-the-cost versus Epever for a non-centralized, non-AIO-centric offgrid system is a bit of a point for pause for many including myself. I’m my situation, I like having redundancy in case of failure (even though Victron is highly dependable).
Having four separate charge controllers means if one should fail I still have most of my production available. And other than that one powMR 60 nothing has failed- which I sorta can still say since the ‘bad’ one was bad out of the box.

These powMR are cheap which makes them attractive. Sorta confused as to how one could work fine and the other have issues tracking mppt / loading the panels as one could typically be safe in assuming that is a software issue. But why would they need to do different programming for identical units?! So something’s wrong with the components, assembly, or board if it’s not the software.

If there were one thing that I really like about the powMR-60A over Epever is the fact that it has a load/temp controlled fan.