altitude effect on inverters ??

[chadjones99]

So here is a weird question does altitude affect the output of your inverter ? Now I'm not talking about inverter generators, I mean inverters. I will get to why I am asking and what I found and did not find.
So the back information is as follows: I have an 8 kw growatt inverter, and I'm am camped off grid in the Colorado mountains, my altitude is about 7800 ft above sea level, and a few weeks ago when I got my system online, I wanted to stress test it. I have my 50 amp Rv plugged into the 50 amp solar system plug and I proceeded to ( monitor ) add loads, 1st electric fireplace, all good ( only like 1500 watts ) then the microwave, coffee pot, and an electric water heater. total loads hit I believe 5300 ish watts and then the power dropped out , by the time I got out to the growatt inverter I did not see the code (the fault light was on and I cycled power to reset ). So I could not figure out why it tripped offline at 5300 watts. So I started searching the owners manual and found a very short note that the inverter will de-rate itself above 2000 Meters, well that's about 6500 ft above sea level, and I'm at 7800 ish feet , but what stumps me is ok I get why generators are de rated but why would solid state equipment care? I searched another growatt owners manual and it states for cooling, but it also has a temperature de rate function so why would it need an altitude de rating mode? and how can it tell what the altitude is. This got me curious so I searched my go power inverter manual and it doesn't state anything about altitude, and not all growatt manuals do either. one 8 kw inverter manual does and the other manual I found for a 8kw growatt does not.. So I wonder if this is what trip my inverter?
this was the statement I found :
The inverter uses natural convection cooling, if the installation site’s altitude is
greater than 2000 m, the inverter may trigger de-rating protection. Altitude and
output

 

[OffGridInTheCity]

Is this one of those 8,000W total (240v) but only 4,000w per 120v leg situations? Then when you got to 5000w, it could have been mostly on one leg of the 240v/120v resulting in a 4000w+ on one of the legs = overload. In other words, maybe it's regular overload and not altitude.

Just thinking out loud to try to advance the discussion...

 

[chadjones99]

Is this one of those 8,000W total (240v) but only 4,000w per 120v leg situations? Then when you got to 5000w, it could have been mostly on one leg of the 240v/120v resulting in a 4000w+ on one of the legs = overload. In other words, maybe it's regular overload and not altitude.

Just thinking out loud to try to advance the discussion...

good question, I don't believe so because it's an LF inverter with 1 big transformer inside, and the HF inverters from what I understand don't have a large transformer( so there lighter ) and use 2 inverters one for each leg, but I could be wrong and I will follow that up because that would explain it.. but its a 8kw inverter with I believe to have a 12kw surge . but that's a good lead to follow up thanks

 

[chadjones99]

the model of the inverter: Growatt 8kW Split Phase Off-Grid Inverter | SPF 8000T DVM-MPV

 

[Horsefly]

To the OP's original question: I'm not clear why altitude might matter very much, except perhaps some effect of thinner air on cooling the thing down not as well... But that doesn't seem to make much sense.

I have had a Schneider Conext CSW4024 inverter operating at our cabin (just under 9,000 ft in Colorado) for a bit over 5 years now. It has the same spec of "up to 2,000 meters above sea level" but no other explanation of what this limit means. No issues as far as I can see.

For what it's worth, we also have a propane water heater in the cabin. It is the second stock one we got from Home Depot. The two combined have worked fine for about 40 years, but if you read everything from the Inter-webs you apparently can't run a stock propane water heater above something like 6k feet elevation. Rather, you are supposed to pay some premium for water heaters that have been modified for the higher altitude. This made me think I could buy water heaters at the local Home Depot, put "high elevation" stickers on them, and sell them a few yards down the road out of a truck. Could make good money.

 

[schmism]

So here is a weird question does altitude affect the output of your inverter ? Now I'm not talking about inverter generators, I mean inverters. I will get to why I am asking and what I found and did not find.
So the back information is as follows: I have an 8 kw growatt inverter, and I'm am camped off grid in the Colorado mountains, my altitude is about 7800 ft above sea level, and a few weeks ago when I got my system online, I wanted to stress test it. I have my 50 amp Rv plugged into the 50 amp solar system plug and I proceeded to ( monitor ) add loads, 1st electric fireplace, all good ( only like 1500 watts ) then the microwave, coffee pot, and an electric water heater. total loads hit I believe 5300 ish watts and then the power dropped out , by the time I got out to the growatt inverter I did not see the code (the fault light was on and I cycled power to reset ). So I could not figure out why it tripped offline at 5300 watts. So I started searching the owners manual and found a very short note that the inverter will de-rate itself above 2000 Meters, well that's about 6500 ft above sea level, and I'm at 7800 ish feet , but what stumps me is ok I get why generators are de rated but why would solid state equipment care? I searched another growatt owners manual and it states for cooling, but it also has a temperature de rate function so why would it need an altitude de rating mode? and how can it tell what the altitude is. This got me curious so I searched my go power inverter manual and it doesn't state anything about altitude, and not all growatt manuals do either. one 8 kw inverter manual does and the other manual I found for a 8kw growatt does not.. So I wonder if this is what trip my inverter?
this was the statement I found :
The inverter uses natural convection cooling, if the installation site’s altitude is
greater than 2000 m, the inverter may trigger de-rating protection. Altitude and
output

Insufficient information.

Your battery could be undersized for that kind of load and the high current caused the voltage to sag to the point that it low-voltage-cutoff.

the easy answer here is to do the test again while standing in front of the inverter so you can see what its doing.

 

[chadjones99]

To the OP's original question: I'm not clear why altitude might matter very much, except perhaps some effect of thinner air on cooling the thing down not as well... But that doesn't seem to make much sense.

I have had a Schneider Conext CSW4024 inverter operating at our cabin (just under 9,000 ft in Colorado) for a bit over 5 years now. It has the same spec of "up to 2,000 meters above sea level" but no other explanation of what this limit means. No issues as far as I can see.

For what it's worth, we also have a propane water heater in the cabin. It is the second stock one we got from Home Depot. The two combined have worked fine for about 40 years, but if you read everything from the Inter-webs you apparently can't run a stock propane water heater above something like 6k feet elevation. Rather, you are supposed to pay some premium for water heaters that have been modified for the higher altitude. This made me think I could buy water heaters at the local Home Depot, put "high elevation" stickers on them, and sell them a few yards down the road out of a truck. Could make good money.

its funny how once you look you see things like 2000 meter de rating I never noticed before. I have a propane on-demand water heater, it kind of sucks so I bought an on-demand electric ( 3kw ) I only power up while taking a shower. i haven't had any other issues running heavy loads, just that one day I was "Testing" the system so I turned everything on that you would not normally do. As for the thinner air not cooling I believe that is their point but they also state it has a thermal de-rating if it gets too hot, so seems to me that that takes care of the heating issues regardless of why.. but thanks for the help

 

[chadjones99]

Insufficient information.

Your battery could be undersized for that kind of load and the high current caused the voltage to sag to the point that it low-voltage-cutoff.

the easy answer here is to do the test again while standing in front of the inverter so you can see what its doing.

I agree, but for other system info, the 8 kw growatt inverter is connected to ( 2 ) 48 volt 100 AH server rack batterys.( each battery is rated to 5 kw I believe) with oversized cables, it should have handled 5.3 kw but it could have been the issue. but I did not have a fault or code on the battery only the inverter which I did not capture.
the rating on the battery sellers website states: For a single 48V100E-1 battery, the charge and discharge current should be kept around 50 amps, but it can go higher up to 100 amps.
...........................................................................................................................................
So if I can go 100 amps ( x2 batterys ) 200 amps x 51 volts = 10,200 watts discharge and if I stay conservative
at 50 amps ( x2 ) 100 amps x 51 volts = 5100 watts , so I was at about 5300 watts when the system tripped
so am confused they say "should" be kept at 50 amps but" can go "100 ... So kind of a contradicting statement
I downloaded the battery manual and it list in the spec sheet : Continuous Discharge Current (A) 100 Amps

 

[time2roll]

I have read some inverters have a maximum altitude in the specifications. Doubt it matters much in an RV. Never had trouble with mine at 8,000 feet.

I am not much for a specific stress test. If it works under normal use all is good.

 

[cinergi]

Yeah only thing I can think of is reduced cooling capacity.
My heat-pump clothes dryer in my RV is a LOT less effective at high altitudes

 

[Pierre]

Electrolytic capacitors contain an electrolyte, which may freeze and destroy the capacitor at extremely low temperatures.

Also, thermal expansion is a major issue: Each material has a different thermal expansion coefficient. SInce most electronic parts consist of several materials joined together, these differences cause mechanical stress, as some materials shrink more than others while they are still glued/soldered together.

Combined with the fact that most materials get brittle at cold temperatures, this may even cause solder joints, chips and other components to fracture, destroying the device.

a Further problem is condensation caused by cooling / heating. This can cause electrical shorts in components , PC board tracks and connectors as well as rust over time.

Source: Quora

Very interesting topic indeed.

 

[chadjones99]

Electrolytic capacitors contain an electrolyte, which may freeze and destroy the capacitor at extremely low temperatures.

Also, thermal expansion is a major issue: Each material has a different thermal expansion coefficient. SInce most electronic parts consist of several materials joined together, these differences cause mechanical stress, as some materials shrink more than others while they are still glued/soldered together.

Combined with the fact that most materials get brittle at cold temperatures, this may even cause solder joints, chips and other components to fracture, destroying the device.

a Further problem is condensation caused by cooling / heating. This can cause electrical shorts in components , PC board tracks and connectors as well as rust over time.

Source: Quora

Very interesting topic indeed.

Ok its cold now... but this summer it was 75 all day long and sometimes in the 80,s at the same altitude. The inverter manual just states de rated due to altitude ... does not talk about cold temps in the same section related to altitude, other than maybe in the specs range of operating temperature. And when I did the stress test it was cold ish outside but nothing close to freezing more about low 40s

 

[chadjones99]

Yeah only thing I can think of is reduced cooling capacity.
My heat-pump clothes dryer in my RV is a LOT less effective at high altitudes

its not in a RV , its powering my RV outlet... And it is more of a house backup inverter type , but my stand alone go power IC3000 that is in the RV ( for traveling ) does not talk about issues or de-ratings due to altitude

 

[chadjones99]

I have read some inverters have a maximum altitude in the specifications. Doubt it matters much in an RV. Never had trouble with mine at 8,000 feet.

I am not much for a specific stress test. If it works under normal use all is good.

when I set up a system i wanna run it at max once ( stress test ) to make sure none of my wiring , etc get too hot and if my wife does something while I'm in town its not a fire hazard .. it was just set up ,I would not consider stress testing my system all the time, but this was basically testing to make sure everything worked. and like I said nothing fails out of the gate while my wife was home