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Deye 8KW Inverter efficiency

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Hbbyd

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Hello guys, I have bought a Deye 8KW hybrid Inverter(). It is stated in the spec sheet that the mppt efficiency is 99.9%. But it is not mentioned at which conditions or voltage. In my case the panels I bought have a Voc of 258v and a Vmpp of 212v (string of 6 660w Trina panels in series). Will this voltage cause a substantial decrease in the efficiency of the mppt? As the manual specifies a Vmpp of 370v. I will attach the inverter specifications.
Thanks in advance for the help!
D5C60910-8631-428D-A8AA-E235A2AAB892.jpeg
 
I would bump up the voltage to be more in the 370V isc range. It’ll work as you have it, but it won’t be ideal.
Anything over 150 would work.
 
I know that it will work. I just want to know the approximate efficiency. I wish they would make an input voltage vs. efficiency graph for each mppt.
 
In the specification you are asking about, mppt efficiency, is how close the unit tracks to the actual vmp value of the solar array connected. It is not losses in the mppt charger hardware.

Being one whom has designed these things, I can also say, there is no mppt algorithm that can dynamically track to that level of precision or even a test setup that could verify it, so this manufacture has it in the spec sheet for eye candy ...
 
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Yes, could be the case. To measure these type of efficiencies, I would suggest a setup to try and measure it. They could connect the inverters to Variable High Power DC sources and vary the voltage while measuring input and output power and thus come out with a graph I was referring to.
 
Power supply's do not have the VI curve of solar panels, nor do they emulate multi hump that shading creates on multi-panel strings of solar or temperature or irradiance variations
 
All in One inverter has many ways to 'game' the power conversion efficiency numbers.

Deye and SolArk have a boost converter from PV input to an intermediate 500 vdc SCC output. When PV input voltage is close to the intermediate 500vdc level the actual MPPT SCC is doing little voltage conversion, so its efficiency is close to 100%. When the PV input voltages is lower DC voltage, and the boost converter has to do more voltage conversion from a lower input PV voltage to intermediate 500vdc so its efficiency drops.
"MPPT efficiency of 99%" is meaningless as it must go through several more power conversions before it can be used to provide AC output or battery charging. Each of these additional power conversions have their own efficiency that degrade the overall efficiency to output something useful.

In order to electrically isolate and feed the two independent 120vac HF inverters for split phase 120/240vac, the PV MPPT SCC 500vdc outputs are fed into a 500vdc to 250vdc forward converter. This second stage 500vdc to 250vdc converter has about 92% to 97% conversion efficiency.

All this gets the PV power delivered to the two independent 250vdc internal high voltage DC supplies that run the two 120vac sinewave PWM bridge inverters that are connected in series for 240vac output. The 250vdc to 120vac PWM sinewave bridge is fairly efficient in the 97-99% depending on AC output load. Charging battery is also pulled from the 250vdc HV DC nodes.

The battery to high voltage DC converter is the most inefficient of the all the power conversions. Worse for charging batteries than battery supplying HV DC supplies. Battery to HV DC in the 92 -96% range depending on load power.

All power conversions routes through the two independent HV DC nodes. (not including AC input to AC output pass through).

Best conversion efficiency is PV input to AC output when PV input voltage is close to it maximum allowed DC input voltage. (about 99% SCC x 96% intermediate DC-DC x 98% sinewave PWM = 93.1%)

Worst conversion efficiency is charging batteries from a lower voltage PV array. (about 92% SCC x 96% intermediate DC-DC x 92% HV DC to batt = 81.2%)
 
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Mine is the european model and thus I only have one 240v output. Actually, I have to note that in other threads people were discussing the deye inverter efficiency and they said that it was 96% efficient on average. The reason I am asking about the mppt efficiency is that it’s the only conversion that I can hugely influence. But now that you mention it, I should be asking about the boost converter to 500v efficiency since it will be the one most affected. Converting from 370v to 500v versus converting 210v to 500v.
 
RCinFLA said:
All in One inverter has many ways to 'game' the power conversion efficiency numbers.

Deye and SolArk have a boost converter from PV input to an intermediate 500 vdc SCC output. When PV input voltage is close to the intermediate 500vdc level the actual MPPT SCC is doing little voltage conversion, so its efficiency is close to 100%. When the PV input voltages is lower DC voltage, and the boost converter has to do more voltage conversion from a lower input PV voltage to intermediate 500vdc so its efficiency drops.
"MPPT efficiency of 99%" is meaningless as it must go through several more power conversions before it can be used to provide AC output or battery charging. Each of these additional power conversions have their own efficiency that degrade the overall efficiency to output something useful.

In order to electrically isolate and feed the two independent 120vac HF inverters for split phase 120/240vac, the PV MPPT SCC 500vdc outputs are fed into a 500vdc to 250vdc forward converter. This second stage 500vdc to 250vdc converter has about 92% to 97% conversion efficiency.

All this gets the PV power delivered to the two independent 250vdc internal high voltage DC supplies that run the two 120vac sinewave PWM bridge inverters that are connected in series for 240vac output. The 250vdc to 120vac PWM sinewave bridge is fairly efficient in the 97-99% depending on AC output load. Charging battery is also pulled from the 250vdc HV DC nodes.

The battery to high voltage DC converter is the most inefficient of the all the power conversions. Worse for charging batteries than battery supplying HV DC supplies. Battery to HV DC in the 92 -96% range depending on load power.

All power conversions routes through the two independent HV DC nodes. (not including AC input to AC output pass through).

Best conversion efficiency is PV input to AC output when PV input voltage is close to it maximum allowed DC input voltage. (about 99% SCC x 96% intermediate DC-DC x 98% sinewave PWM = 93.1%)

Worst conversion efficiency is charging batteries from a lower voltage PV array. (about 92% SCC x 96% intermediate DC-DC x 92% HV DC to batt = 81.2%)
Click to expand...
Hi this is very interesting. So if I have 12 panels (each 40V), should i connect them in series (total 480V - close to the 500V) but then in winter, they give more volts and then theres' issues (according to some threads). Should I then connect just 11 in series (total 440V)? How does one strike a balance here?
 
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