FYI: New Danfoss BD35/50 Control Module

[SV THIRD DAY]

Originally Posted by OzePete

Hi Doug,
I missed this post of yours so would like to ask if the current Secop motor driver modules are 'soft start' We don't have access to Secop drivers to do some tests ourselves but from what you quoted here it appears as though they are and that would solve a lot of problems. Can you confirm? Thanks.

Otherwise it would be appreciated if someone using Secop could check and verify if they are still DOL or now hopefully soft start.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

I made this post 2 Years Ago about the new compressor controllers.
Soft Start is now standard on the Danfoss Controllers and they also changed the electronics that did away with much of the heat and burn-out issues. We haven't seen any downsides yet of the new controller design.....but time is always the crucible of inadequate design!

[OzePete]

Originally Posted by SV THIRD DAY

I made this post 2 Years Ago about the new compressor controllers.
Soft Start is now standard on the Danfoss Controllers and they also changed the electronics that did away with much of the heat and burn-out issues. We haven't seen any downsides yet of the new controller design.....but time is always the crucible of inadequate design!

Thanks Rich, much as suspected. Good news. That will eliminate near all motor driver module failures specially if system manufacturers also fit a voltage clamp (Spike arrester). I guess those gurus here who claimed soft start was not needed and not a great advancement, forgot to tell Secop! Or perhaps they simply didn't understand what soft start is!

We have been using soft start motor driver modules for several years now and the failure rate has almost disappeared.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[a64pilot]

A large cause may be inadequate wiring. Seems Secop wants only a .3 V drop, and that is tough to do. For my BD80 I think they say 10 Ga wiring is only good for 5’ run? I may have that wrong, going off of memory, but I need 6 ga wire, and I don’t think that is common for most boats.

[ayates]

Originally Posted by a64pilot

A large cause may be inadequate wiring. Seems Secop wants only a .3 V drop, and that is tough to do. For my BD80 I think they say 10 Ga wiring is only good for 5’ run? I may have that wrong, going off of memory, but I need at least 8Ga wire, and I don’t think that is common for most boats.

I went a little paranoid and wired our BD35 with 6 AWG. At a guess, it was 20-25' one direction to the distribution panel.




Allan.

[a64pilot]

Originally Posted by ayates

I went a little paranoid and wired our BD35 with 6 AWG. At a guess, it was 20-25' one direction to the distribution panel.




Allan.

No, actually I just ran the numbers as a 20ft run and 15 amps and came up with 6 ga as the requirement, but that’s max amp draw for a BD80.
I changed my post to reflect 6 ga after I ran the numbers. What I’ll likely do is run 8 ga parallel with the 10 ga, that ought to get me to 6 ga and not waste the 10 ga.

I’d think 10ga is common for most boats?

[SV THIRD DAY]

The No 1 Electrical Troubleshooting call I get is the 3-LED Flash caused by....TA DA....Voltage Drop. It's so much of my troubleshooting day...I made a YouTube Video about it.....Enjoy and this applies NOT just to CoolBlue units but to all of the Danfoss Type Refrigeration Systems on the market today.

https://www.youtube.com/watch?v=r9FoE1uHzy8

[travellerw]

Originally Posted by Emmalina

Funny thing is my 2 danfoss units were the only thing to survive a big lightning hit years ago ! As one unit died this year I went on ebay and found a guy in Slovenia who sold me one of the new 212 units for 105Euro don't know what the exchange rate is but he only charged me 6 euros to ship it to Thailand ... Nice bloke.

I bought from the same fella. Controller has been installed and working for a year and a half now. No idea how he is able to sell that cheap, but glad he can.

[Typhoon]

Originally Posted by SV THIRD DAY

I made this post 2 Years Ago about the new compressor controllers.
Soft Start is now standard on the Danfoss Controllers and they also changed the electronics that did away with much of the heat and burn-out issues. We haven't seen any downsides yet of the new controller design.....but time is always the crucible of inadequate design!

Hey Rich

We use the 101N0650 . I have had this unit on my oscilloscope for the propose of detecting a soft start circuit . I did not find this function . As far as I know only the AEO controllers have the soft start function. The 101N0320 and 101N0330.

Regards John
www.coldeh.com

[ayates]

Originally Posted by a64pilot

No, actually I just ran the numbers as a 20ft run and 15 amps and came up with 6 ga as the requirement, but that’s max amp draw for a BD80.

The BD35 draws a lot less current than the BD80. From my measurements, it peaks at 6A.




Allan.

[OzePete]

Originally Posted by ColdEh Marine

Hey Rich

We use the 101N0650 . I have had this unit on my oscilloscope for the propose of detecting a soft start circuit . I did not find this function . As far as I know only the AEO controllers have the soft start function. The 101N0320 and 101N0330.

Regards John
www.coldeh.com

Hi John, do you recall what the current draw was on start up when you checked it? Did it exceed the run current?

Secop are very secretive about what is or isn't a soft start driver and hopefully they all are now.

Cheers OzePete

[Richard Kollmann]

Originally Posted by OzePete

Hi John, do you recall what the current draw was on start up when you checked it? Did it exceed the run current?

Secop are very secretive about what is or isn't a soft start driver and hopefully they all are now.

Cheers OzePete

John, On these new modules I am also interested in what you see in the milliamp load change between terminals C and T in the first ½ second during start.

[a64pilot]

Originally Posted by ColdEh Marine

As far as I know only the AEO controllers have the soft start function.

Regards John
www.coldeh.com

From the literature I have found the AEO modules are specifically stated to start in low RPM, but I haven’t seen that statement in any literature of the regular modules.

I assume what Richard is asking you to check would of course be one way to “soft start” that is use the resistance between C and T to start in low RPM, take the resistor out for start so to speak?

This is what I’m thinking, it was the old modules that were failing, not compressors? The thought is that if they were soft start, it would save the modules.
However if your redesigning a new module, it would make more sense to design it so that it can easily accept the inrush amperage of a start, as opposed to trying to reduce the inrush with a slow start?

[a64pilot]

Originally Posted by ayates

The BD35 draws a lot less current than the BD80. From my measurements, it peaks at 6A.




Allan.

Image you have attached, you measured it?
That is some kind of new O scope that you can make an image of?
That initial long pulse slightly less than 6 amps, you measured that?

[Richard Kollmann]

Originally Posted by a64pilot

From the literature I have found the AEO modules are specifically stated to start in low RPM, but I haven’t seen that statement in any literature of the regular modules.

I assume what Richard is asking you to check would of course be one way to “soft start” that is use the resistance between C and T to start in low RPM, take the resistor out for start so to speak?

This is what I’m thinking, it was the old modules that were failing, not compressors? The thought is that if they were soft start, it would save the modules.
However if your redesigning a new module, it would make more sense to design it so that it can easily accept the inrush amperage of a start, as opposed to trying to reduce the inrush with a slow start?

Module failures are not caused by an inrush of electrical power. Danfoss/Secop module failures in the past failed due to excessive refrigerant static pressures due to design or just too much refrigerant charge. Over sized expansion valves or over sized capillary tubes can cause excessive compressor starting loads.

I find the primary cause of module failures to be caused by either boats wiring allowing trenchant voltage spikes to reach module or module heat due excessive liquid refrigerant high side pressure.

There are five other 12/24 volt compressors other than Danfoss engineered so be assured my experience deals only with the Danfoss reliability.

[a64pilot]

I had wondered about the start up power being the failure, cause I have personal knowledge of a BD80 compressor using a BD35/50 module operating for an extended period. It was plagued by three flash failure to start (overamp as I understand) yet continued to operate for a long time, and was still operating when it was replaced.

Surely if hard starts killed them, that hitting it so hard that they were often not starting and shutting down with the three flash code, and continuing to restart until it finally did, over and over would kill one for sure?

Just rambling here, but I have seen a too small controller run a bigger than spec compressor, for a couple of years. I assume the only thing that kept if from being killed was very good ventilation.