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Outback charge controller not using all of the arrays volts
#71
(06-07-2020, 02:02 PM)Doin it Wrote: I realize that with only a 10v higher array than the 24v battery isn’t giving enough volts to supply enough amps so arrays volts have to be higher.. so this is why there’s more losses with a 24v battery than a 60v battery, because with a 24v battery the array voltage has to be higher to supply more amps and controller has to make more amps, therefor have to have an array much higher than the optimal mppt voltage for the battery so more amps can be created = more losses..

Again pure nonsense. The MPPT system that runs on 24V is just as efficient as a 48V. Amps stay the same. The controller is just limited by amps. This is just basic electrical energy concepts that you fail to understand here.
#72
(06-07-2020, 03:16 PM)not2bme Wrote:
(06-07-2020, 02:02 PM)Doin it Wrote: I realize that with only a 10v higher array than the 24v battery isn’t giving enough volts to supply enough amps so arrays volts have to be higher.. so this is why there’s more losses with a 24v battery than a 60v battery, because with a 24v battery the array voltage has to be higher to supply more amps and controller has to make more amps, therefor have to have an array much higher than the optimal mppt voltage for the battery so more amps can be created = more losses..

Again pure nonsense. The MPPT system that runs on 24V is just as efficient as a 48V. Amps stay the same. The controller is just limited by amps. This is just basic electrical energy concepts that you fail to understand here.

Yes it’s just as efficient but that depends on how many voltage over battery voltage your array is. Like using a 120v array for a 24v battery is less efficient than using a 70v array for a 24v battery. Due to everything I said in the last post... I controller cannot be expected to be as efficient (as a 70v array) when having to take a 120v array All the way down to a 24v battery.... or I’m completely lost and I need to give up...
#73
doint THERE IS NO SUCH THING AS A 150V OPTIMAL! Please stop that now. You have just found that out your self and its not such a thing!!


The best setup totally depends on the charger. Have you read the specifications of your charger? You are aware that they do define best Vmp area where the device is the most efficient? If thats at 90V or 140V totally depends on the controller..

For instance my large controller have both 650VDC and 800VDC input.. Its taken to around 450VDC and then down to 48VDC... If your nonsence would be true imagine how non efficient that would be!....

Once again STOP guessing. Read the specifications of your charge controller.
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#74
Ofcourse higher volt charge controllers have different internal parts-max voltages that make them efficient using the higher voltages u describe,,, What I’m saying about the 150v controller wouldn’t apply to higher voltage controllers... every controller has optimal voltages the the controller should see from the array and optimal mppt voltages for the battery.
For the150v controller charging a 60v battery, the array should be 30% higher than battery voltage optimally for best efficiency-production of the array, anything above or below that 30% will have more losses due to it not being optimal. for my battery that’s an array Vmp of 90v max which is still over the 30% higher than battery voltage, 30% would be 80v.. so with the array being 90v and battery being 60v it equals 150v... I can’t change that...i have read the specifications of my controller and other 150v controllers and everything I see leads me to think the same.. I agree tho it’s time to stop this.. so no response will come from me. Again apologies for ruffling feathers..
#75
No and NO. You can not draw such a conclusion based on your setup.

Have YOU looked at the specification for that charger? Or any other?
Obviously not. Your charge controller clearly states at what voltage it is the most efficient... If you look at others there are no such thing as battery + vmp should equal 150 just because its an 150V charge controller.


Sorry m8. Im not even going to bother any more with ya. You dont read what we write and go on with something that isnt rellevant.
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
#76
To be clear, an MPPTs difference in efficiency in these situations:
a) 24V batteries, 120V Vmp from panels
b) 48V batteries, 80V Vmp from panels
c) 65V batteries, 80 or 120 or 140V Vmp from panels
will be only a few % points different, eg within ~2% of 98%.

In all cases the POWER out of the MPPT will be approx 0.97 x POWER in.

POWER in is Panel Volts x Panels Amps at NOCT
POWER out is Battery Volts x Battery Amps
That's all the math you need & the only way it works.
Running off solar, DIY & electronics fan :-)
#77

These graphs shows more efficiency losses the further the input array voltage gets from the battery voltage. This is why only a voltage high enough to charge your battery should optimally be used for best efficiency.. the optimal voltage for the array to mppt at for a 60v battery is 80v (shown in a previous pic) which is 30% higher than the battery voltage (% of voltage over battery recommended for array Vmp in the manual) .
To assure mppt of 80v is achieved and to assure max power point can be achieved I’d add 10v to that 80v array making the Vmp of the array 90v, anything over this is causing unnecessary efficiency losses displayed in the graph. So for the highest battery voltage (60v) the 150v controller can charge,, 90vmp plus 60v battery= 150v..
for battery voltages lower than 60v it is definitely worse-unnecessary and inefficient to use a combined battery + Vmp over 150v since 150v combined is the max (as I explained above) combined voltage that should (for best efficiency- the least powerlost from array) be used for the higher 60v battery.. there’s no guessing or wrong math or non sense.. arrays should almost always be kept as close to the optimal mppt (for your battery) as possible for the least amount of losses from your array.. Just a 3.5% loss from having the arrays volts higher than is needed, on a small array the size of mine (3660w) = roughly 150w
#78
The 150v Number is nonsense. Thats the max input voltage on solar Side and not a combined max for efficienct.
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
#79
Two numbers only. Vbattery & Varray.
No adding of the two!
REALLY. NO. ADDING. OF. THOSE. TWO!!!!

Efficiency:
Those graphs seem to be out of date, manual is here:
http://www.outbackpower.com/downloads/do...manual.pdf
See page 104.
 

OK take what you posted, the 48V battery system gets best efficiency with 20V higher Varray at (hard to read but lets say) 68V
Compare & adjust for your 65V battery, with Varray at 85V, your predicted efficiency looks like approx 97.5% 
 

Let's extrapolate the page 104 graph to your NOCT operating point of 2700W for the Vbatt = 24V & Varray = 34V (+10V on Vbatt) 

You get approx 96% efficient. So lets say in your system the FM60 should be running at least 96% efficient or so.

Hmmm, let look at the FM60 screen shot you posted on page 1 of this thread: 
 
What do we see?  
Varray = 86.1, Iarray= 30A, so power in = 2,583W same as screen
Vbatt = 65.3, Ibattery = 38.6A, so power out = 2,520W
2,520/2,580 = 97.56% efficient  so you're getting better efficiency. 
and that efficiency loss at 2580W is just 60W according the FM60's screen.

Exactly the sort of numbers we've been telling you right in-line with numbers I just calc'd for you.
OffGridInTheCity and daromer like this post
Running off solar, DIY & electronics fan :-)
#80
The pic of my controller was at 10:00am, not peak operating time.. I get closer to 3000w.

I did at the first post think more of my losses were coming from the issue I’ve described. From red showing me what my panels should produce (1000w) less than 3660, I’ve realized that not as much of my losses were coming from the issue I described. (I’ve said that already) but I still get roughly 350w more production than 2680w sustained that red has described.
I cannot change the fact that the controllers are most efficient-less losses using certain array voltages . I also can’t change that the controllers are most efficient- less losses at certain amount over battery voltage, this is shown in all the graphs.. for my battery size the most efficient array voltage is a voltage that is closest to the most efficient mpp voltage,, that happens to be a 90v array for the 60v battery,, and those 2 numbers added together =150v..... I can’t change that to make anyone happy, that’s just the way it is.. an array over 90v is less efficient- more losses because the controller has to bring a higher voltage down to the same battery voltage.. the graphs show the controller becomes less efficient the higher the incoming array voltage is.. so if a 24v battery user is using a 120v array instead of a 40v array then they would have more losses because their array is to far from battery voltage... this is all I’m describing... so in an effort to get the most out of a solar setup when designing it, it is best to keep that combined voltage for a 60v battery at roughly 150v..for a 48v battery that combined number is roughly 126v,, 48v battery + 78v array= 126v.. If some of u want to keep recommending that it’s no different- same efficiency to have a combined voltage over 150v then go ahead but I have to respectfully disagree.. just because the controller can handle up to a 150v array doesn’t mean it should be done that way.. as a matter of fact the max array voltage for the controller should be avoided for best efficiency-less losses and instead the roughly 150v combined should be followed for best efficiency-less losses.. I really would like to be able to find where I read the outback tech saying the same things I describe


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