Project Pay it Forward : The Classic 150SL repair

Started by DMJ72, January 22, 2023, 02:15:25 PM

Previous topic - Next topic

DMJ72

Hey all,

This is a journey that started a few weeks ago, when I sold my Conext SW and Midnite E-Panel to a very nice couple on the south coast of Jamaica (where I live). Electricity costs are 5x more expensive / KWH than they are in the average US state. Just like everywhere else, you have the folks that can put down US$20,000+ on a solar system in one go, others can not and either have to take a loan or piece together something that can offset the light bill from an electricity company that is a monopoly.

One of their neighbours gifted them 8 ROLLS  flooded batteries and a used Classic 150SL that was "not working" and judging by the dust in the unit, it was in production for sometime. I could not find out a history of what happened to the unit, but I suspect too much voltage was applied to the PV at some stage or the other.

My initial inspection:
  • The fans spin up using the sorting of the temp sensor trick.
  • The MNGP turns on and I can save settings. It shows the appropriate voltage.
  • The Turbo Fan's shroud side piece needs replacing. I see midnite sells that!
  • The unit does not register voltage applied to the pv inputs.
  • There is no dead short between the PV +ve and PV -ve inputs.

Opening up the unit:
  • Two of the power-board's 3 big capacitors are swollen at the top. I suspect this is NOT a good sign..
  • One of the MOSFETs has a short between the Drain and the Gate (DISCLAIMER : I am not an electronics repair expert)

Unfortunately the funds to replace the power-board are not available, and the couple aims to put future funds towards another classic to complete the pair and of course solar panels.

So my plan of action is to replace the mosfets with these:
https://www.infineon.com/dgdl/Infineon-IRFB4115-DataSheet-v01_01-EN.pdf?fileId=5546d462533600a401535615ba6a1e0f

and to replace the two swollen capacitors (still trying to find a source for them).

I will be journalling the attempt at the repair here. I remember the early days when I had no RE system, and received help and motivation from others. Time to pay that back.

Wish me luck!

(System 1) To be updated ...  @ Jamaica, West Indies.
(System 2-mom's) 6 Wuxi My-Solar 200w Mono panels, Conext SW Inverter, Classic 150, 8 Trojan T-105RE batteries, Trimetric.

DMJ72

Some photos from the initial powerup of the unit (using a laptop 19V power brick).
(System 1) To be updated ...  @ Jamaica, West Indies.
(System 2-mom's) 6 Wuxi My-Solar 200w Mono panels, Conext SW Inverter, Classic 150, 8 Trojan T-105RE batteries, Trimetric.

wagreg


ClassicCrazy

#3
Contact Midnite. I am sure they have the parts you need and then you will know you get the correct ones.
Besides the capacitors and all the FET's , you will want to replace the fans too - the main and turbo fans. 
Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 , Hawkes Bay , 5s 135 watt Kyocero , Jakiper 48v LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batteries

DMJ72

Quote from: ClassicCrazy on January 22, 2023, 05:53:12 PMContact Midnite. I am sure they have the parts you need and then you will know you get the correct ones.
Besides the capacitors and all the FET's , you will want to replace the fans too - the main and turbo fans. 
Larry

Hey, good morning Larry. That is a good point, I did not think of that being possible for the FETS and the Capacitors. I know they sell the entire powerboard, and our local distributor has the fan kits in stock.

Maybe this thread might catch the eye of @Bob or @Robin Gudgel and they would be able to confirm. Come to think of it, when I get the time today, I will email support to see if they would sell me the components themselves.

Thanks.
David
(System 1) To be updated ...  @ Jamaica, West Indies.
(System 2-mom's) 6 Wuxi My-Solar 200w Mono panels, Conext SW Inverter, Classic 150, 8 Trojan T-105RE batteries, Trimetric.

DMJ72

(System 1) To be updated ...  @ Jamaica, West Indies.
(System 2-mom's) 6 Wuxi My-Solar 200w Mono panels, Conext SW Inverter, Classic 150, 8 Trojan T-105RE batteries, Trimetric.

ClassicCrazy

If I had to use a vendor I think I would go with Digikey because you know you are getting the real thing and they are a good company.
https://www.digikey.com/en/products/detail/infineon-technologies/IRFB4115PBF/2096589?s=N4IgTCBcDaIJICUBiAhALARgwVgAoqRAF0BfI

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 , Hawkes Bay , 5s 135 watt Kyocero , Jakiper 48v LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batteries

FNG

If you run into issues sourcing let me know ryan@midnitesolar.com I can probably assist some if needed

boB

Those FETs, the IRFB4115s look good.  There are 4 FETs per "cylinder" (the power section is split into 2 halves), 2 buck converters each with 4 FETs...

If the Classic has been running continuously in a warm/hot environment, then that could age the capacitors faster than normal.

Yes, let's see what support says. Just one FET being shorted should not make the PV input read zero though.  I suspect there may be more than one FET shorted ?  They do not have to be in the same cylinder though.  A cylinder is one buck converter BTW.

It sounds  like you pretty much know what you are doing !  Those FETs can be difficult to replace though.  Only because there is so much copper in that PCB.  It is 4 layers.

I also notice from looking at the serial number that is appears to be "unprogrammed".  That serial number is an unprogrammed 32 bit number around 4 billion.  Not sure why that would be ?

But things light up and the fans turn on etc so that is a good thing to start with !

How I like to replace FETs is to take one larger iron that can straddle all 3 pins and pull it out.  Then, while that area is hot, re-insert the newer FET.

Also check the gate resistors which should be around 10 Ohms.

Keep us posted please

boB

K7IQ 🌛  He/She/Me

FNG

Serial # makes sense, this is an SL and Midnite does not burn the serial # into the memory on the SLs

boB

Quote from: FNG on January 24, 2023, 07:17:01 AMSerial # makes sense, this is an SL and Midnite does not burn the serial # into the memory on the SLs

Oh yeah.  Forgot.  No Ethernet on SL.  They COULD still burn a serial number into an SL but it is harder to do.

K7IQ 🌛  He/She/Me

DMJ72

Sorry for the late reply!

Thank you all very much for the words of encouragement on this thread. I am going to get down to ordering the parts starting with the FETs from the retailer classicCrazy suggested!

I will post updates as soon as I have them... :D
DMJ
(System 1) To be updated ...  @ Jamaica, West Indies.
(System 2-mom's) 6 Wuxi My-Solar 200w Mono panels, Conext SW Inverter, Classic 150, 8 Trojan T-105RE batteries, Trimetric.

Wizbandit

Shorted FET's on the Classic usually damage the FET DRIVER IC's as well.  Putting in new FET's without replacing the drivers you will probably end up with another bunch of shorted FET's...
Going from memory I think they are ONSEMI FOD3120 chips but don't hold me to that...

boB

Quote from: Wizbandit on January 27, 2023, 07:53:04 AMShorted FET's on the Classic usually damage the FET DRIVER IC's as well.  Putting in new FET's without replacing the drivers you will probably end up with another bunch of shorted FET's...
Going from memory I think they are ONSEMI FOD3120 chips but don't hold me to that...

Yes, the 3120 from On Semi or Fairchild.  On Semi bought Fairchild a few years ago.

Originally this driver was the HP or Avago  HCPL3120.   It is an opto-coupled part with an LED inside.

This part has been used a LOT in all sorts of inverters and charge controllers over the years.

The driver does not always break when the FETs go though.  Good idea to check though.

Also, don't forget to check the gate resistor.  Somewhere around 10 Ohms

boB
K7IQ 🌛  He/She/Me