driving via canbus Eltek 2kW Flatpack2 supplies


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poida

Guru

Joined: 02/02/2017
Location: Australia
Posts: 1117
Posted: 03:19am 18 Nov 2020      

I received another 48/2000 HE, identical to the first one used above.

It works fine, needing only one change to the above code, where
the 8 byte login string is constructed. I needed to change it to suit
the new unit's serial number.

Now it's time to look at using 2 units.

When in parallel, the 2 units share a common ground, tied to the DC output negative.
This is good since I need to communicate via canbus to both and so both canbus to SPI modules will work fine with shared 5V supply, common logic grounds etc.
I suspect I will have to use a nano plus the canbus module per unit, and then use another microcontroller to supervise the nanos. I am not sure the Arduino canbus software permits multiple instances. Maybe it does, I need to read a few working examples of this.

When in series one unit will be 50V above the ground of the other.
I will need some sort of isolated TTL level transceiver for the SPI bus. And an isolated 5V supply to drive the canbus to spi and iso-trans.

Two units means 4000W with voltages from 43V to 114V. This is looking to be a bit of a beast.

Also, I bought a Eltek DC-DC converter, 18-75V IN, 53V/25A out.
I could not get it work. When powered, the fan runs but zero output.
And in the spirit of the EEBLOG (waves to Dave!) I opened the cases up before
I turned them on.

First, the 48/2000 HE









next is the DC-DC converter

I think there was a repair made to it. Whether the repair was successful is an open question.






a closeup of the repair. I think things got very hot here.
Also, the PCB is 4 layer to my eyes.



All the soldering looks as new, except on the 2 common mode choke terminals
and the very average reworked 3 terminal device. Things got hot there and I doubt
it got hot during soldering. 99% Tin solder is used throughout so the rework temps
will be high...
This area corresponds to the multiple fuse array protecting the output.
There are 2 x 3 fuses in parallel under the black plastic box. I wonder if some are blown.


Anyway, it only owes me $50 so I will not worry too much.