RFR code 6

[mofawayesu]

Writing on behalf of a friend in rural central Africa:

A couple of days ago, Classic 150 stopped charging, choosing to stay in Resting mode.  Forcing Bulk charge didn't actually do anything, nor did rebooting the Classic. Found the Wiki with the super helpful RFR chart, so went into the 'secret' screen, and it gives a code 6.  By the description it implies that the FETs are overheating.  Where to go from here? 

Or is this following the wrong trail altogether?

Thanks!

[Vic]

Hi mofawayesu,

Of course,   100 C  is about the boiling point for H20  near sea level.   This is very HOT.

What is the ambient temperature around the Cl 150?
What is the battery voltage,   and the input voltage to the Classic?

When you rebooted the Cl,  did you hear the fans run,   for a few seconds?
Did the fans run,   essentially constantly,  prior to this event

Thanks for the added detail.    Vic

[mofawayesu]

Hi Vic,

Current FET temp is 98.5, Hi FET T is 104.3, so yes, it's cooking.  He tells me the case itself isn't warm though which is odd.  The case fan (though not the top fan) is running constantly now, but this morning it wasn't he says when we got up .  As far as I understand, he didn't notice a problem until all of a sudden the batt v was low about a day ago, so don't know when it stopped charging.

Ambient temp, around 29c
Battery voltage, 23.8
Input voltage 62.7

His Outback inverter was toasted by lightning a couple weeks ago, but the Classic has been ticking along just fine since then.

[Vic]

Hi mofawayesu,

Thanks for the info.   So,  it would seem that the Classic is not really as hot,   as it is reporting.

Lightning damage can cause some delayed problems,   and intermittent behavior,   with electronics.

If the Classic has been resting for a long period (and this does seem to be the case),   then  it does seem that the reported FET temperature is in error.

What is the reported PCB temperature?

Thanks,  Vic

[boB]

ReasonForResting = 6    FETtemperature >= 98.4

He might want to turn the mode to OFF for a while and see if that FET temperature comes down a bunch.  That can help tell if it
is real or not.

If it really IS that hot, then it may have turned its current limit down automatically.

Is the Classic well ventilated ?    I suppose some sort of noise or lightning could mess up the readings.

[mofawayesu]

Because of the time difference, I'm not going to hear more from him today, but he is going to just shut it off overnight and see what the temps look like in the morning.  I passed on the request to look at the PCB temp (I'm assuming that's in the Temps menu? I used to have a Classic 150 myself, but no longer, so I'm just going by menu trees posted online). 

Yes, it's reasonably well-ventilated.  It's been in operation for 5-6 years in its current location.

Thanks to both of you for the ideas...

[boB]

It can actually run at those higher temperatures but I am curious as to why it would be that hot.

It is possible to have a bad temperature sensor or other part that might cause this though.

Oh, and it would be good to know what the PCB temperature says it is.   If the PCB temp is low, then it's more than likely a bad FET temperature sense circuit.

[DavidMH]

Hey Guy in Africa here.

I left the classic off overnight open. This morning I turned it on and it read:
FETS: 88.2
PCB: 27.7

The fan inside the bottom of the classic was running as soon as I turned it on. Everything felt cool. I put two fans on it and left it.

At 12:30 an orange light came on and it started flashing 'AMP LIMIT'. It read:
FETS: 99
PCB: 29.1

The error screen had the RFR code 6 again at this point. It is still charging for now (12:45 my time). Nothing feels hot.

Thanks for any help you can give.

UPDATE (12:52)
It went back to 'RESTING' now. RFR 6. FETS 98.0 PCB 29.3.

I still have two fans on it and I shut it off again, hoping it will cool down.

[Vic]

Hi David,   welcome to the Forum,   and thank you for the added info.

Given the PCB temperature is saying that most/all of the Classic is cool  ...

It sure seems that the FET temp sensor must be defective.   Do not know just where it is located,   but t does seem that no part of the Classic could be that HOT.   â€¦    boB  is the expert here.   

Heard that there was a Lightning event,   recently.   This might have caused some damage to parts of the Classic.    Do you have Surge Suppressors on the system?   Are they MNSPDs?    Where are they located (PV Combiner,  at the Classic PV in,  or  AC in,  AC out,  etc)?

Thanks again for the update,   Just my guesses.   Vic

[DavidMH]

*sigh*

Yes, I do have Surge Suppressors and they are MNSPDs. However, I was having a conflict in grounding with the local power company where every time the power was on (about 30% of the time) it would cause my main breaker to pop. I tried several things and the only thing that fixed it was to take up the ground that was connected to my epanel. So, then it could charge, but was no longer grounded. And then my house was struck by lightning.

So, unfortunately, I had Surge Suppressors, but they were not grounded.

My guess, from what everyone has said, is that the temp sensor is bad, maybe because of the lightning. Is that something I can replace? Or what would I need to do.

Thanks for all your help,
Dave

[Vic]

Hi Dave,

Thanks for the added info.

Lightning can cause many problems with electronics,   as you well know.  Some are intermittent,   and some will take a bit of time to appear.

MidNite does sell individual boards as service parts for the Classic.  These may be available from distributors that you deal with.

Just for reference,   MidNite sells replacement Power,   and Control boards for Classics:
http://www.midnitesolar.com/productPhoto.php?product_ID=618&productCatName=Charge%20Controllers%20-%20Classics&productCat_ID=21&sortOrder=1&act=p

The FET temp sensor is probably on the Power board,   unless it is on fly leads  …   in which case it might be easily replaced.  It is probably not on leads,   as this adds quite a bit of cost to the product.

If the problem is just the FET temp sensor,   it is probably a surface-mount part.  If so,   these can be a bit difficult to remove/replace.

boB  is the best source of info on what and where this sensor is.

It is possible that in AF or EU,  there could be a service depot for MN Classics   â€¦

Sorry,   I know nothing of the internals of the Classic.

Too bad about the Utility and the grounding issue. Sounds like you had taken every precaution that you could.

Later,   Good luck,   Vic