Normal temp

[southernbaja]

Hi,
What are the normal temps of fets when resting?
When resting the mngp is displaying around 59. This is 3-4 hours after the sun goes down
I am running the beta firmware. The fans are not running when resting but as soon as the sun comes up they turn on.

[offgridQLD]

When charging around 3300w this morning my fets and PCb were both around 48deg C

When idle at night I find the fets and PCB are around the same temp as well usually around 32 deg C. The battery temp is usually between 21 - 25 deg C

Ambient temperature for my location at the time was max 25 deg c day min 15 deg C night.


The question I had regarding the classics MAX rated output is cut back to 80A at 40 deg c . To me it looks as if any time the classic is charging even at low power the fet and PCB temps are over 40 deg C . So what probe is used to determine the 80A de rating temp of 40deg C?

Kurt

[southernbaja]

My temps for the pcb stays around 30c. Battery 22-25c. Temps are about 25c.
The CC is charging fine but whenever it wakes up the fans run all day. A quick look at the log shows the fet's 50-59c.

Today after the sun went down fet's showed about 49c and no lower ,PCB 30c and battery 22c. That's at idle.
I'm just concerned about longevity.

[offgridQLD]

It dose sound odd that the fets would be hotter than the PCB by 19 deg C some time after going into idle as the fets wouldn't be doing any work.

Considering the PCB temp is measured from the front panel. Once the fets heat up my thinking is they  transfer there heat to the classics aluminum case and eventually that heat will soak into the front panel readout where the PCB temp is measured .

This thinking is based on the fact that most of the time My own classic's PCB and FET temp are around the same number . The fet temp only rises above the pcb temp when there is a jump in output but the PCB slowly catches up as the heat soaks into the case. I guess the fans help to stabilize the temp and stop it going to crazy

Hope that all makes sense 

[southernbaja]

The PCB and fet's are off by 19 - 20c.
Right now I'm reading 49c(Off of the mngp) Its been at idle for at least 2 hours. Something's off.  There is no way its that hot.

[boB]

The PCB and fet's are off by 19 - 20c.
Right now I'm reading 49c(Off of the mngp) Its been at idle for at least 2 hours. Something's off.  There is no way its that hot.

When you see that 49C in the MNGP at night, is the Classic actually "Resting" when you see that ?  Or is it somehow
staying on ?  Unless it is really hot in that room, it shouldn't be 49 degrees C two hours after it goes off.

Now, the FET and/or PCB temperature can rise if it is sitting there on but not making a lot of power if the
input voltage is very high...  Like, 200 V or so maybe.

If it actually IS Resting when you see this 49C temp after sitting for quite a while, then I wonder if there might
be something fishy with that unit ?

As far as derating goes, it won't even start to derate unless the FET temperature goes somewhere into the 80C range.

The smaller internal fans turn on at a lower temperature than the external turbo fan.  Somewhere in the
50C range.

boB

[offgridQLD]

Perhaps I am reading this wrong but on the specs sheet for the classic 150 

http://www.midnitesolar.com/images/classicFrontPage/graphs.php

I read at the bottom of the page for the classic 150  D-rate current at 40deg C+  80A

I read this as it will de rate the current to 80A if the temperature is over 40deg C  .   Ambient temp?
To me that didn't sound correct but its just how I read it.

Kurt

[southernbaja]

Hi boB,

At night when the CC goes into rest, the fans do turn off, but the fet's temp never goes below 49c.
I have 4 Sunpower 235 watt panels connected 2 series 2 parallel.
Vmp 29.7
Imp 7.91
Voc 36.8
They are charging a 12v 400ah bank. In the a.m during bulk I have seen currents around 40-50 amps and 59c temps on the Fet's but the rest of the day i see  100-300 watts in float. Fet's temps remain in the high 50's.

[Halfcrazy]

What is the Ambient temp where the Classic is? I wonder if there may be a problem with the FET temp sensor. For reference at 55C FET temp the case of the Classic will be quite warm to the touch maybe what some would call almost Hot.

Ryan

[southernbaja]

That's kinda what I thought but the case is cold- ambient temps 20-22 c at night,

In the day when I see 40 or so amps all three fans are running but the case is relatively cold ( right side where the fan is located)

[Halfcrazy]

Ok send me an email ryan at midnitesolar.com and lets see about fixing this.

Ryan

[southernbaja]

Thanks Ryan. I actually sent in a tech request for form yesterday. I didn't realize you are HalfCrazy on the forum.