I made my own DIY Wattson EasyFit Y Cable

After taking an original one appart, I tried to make my own DIY Easyfit Y Cable

I went to a supermarket on my way back from work, and found in the HiFi/Video/Computer cables section, this simple audio headphones coupler for 6 EUR

Back home, after diner, I took a pair of pliers and cut the cable in the middle, cut off 1cm of sheaf and split the wires

Connecting the red and white of the left and right (or opposite) together and the grounds together

Connecting the female sides ground cables together

Some solder is applied to the endings


and the wires are all soldered now


and the Y cable is almost ready for a first test


a little insulating tape, and it is plugged into the Wattson Transmitter: Like yesterday with the original Easyfit, it adds up the two CTs current - BTW the two CTs/sensors are inverted here -


Then plugging it into the Transmitter input 1, 2 or 3, it displayed 37.8kW (!!), and I realized something was wrong with my wiring ...



Measuring the jack contacts, I saw that the middle one should not be connected to anything,






So I removed the tape, unsoldered the wires - first time I used my solder sucker/pump, very handy - and identified the color of the middle contact: Red
I then simply cut off all the Red wires, they will not be used at ll, and re-soldered the White ones like before, re-taped,


and re-tested: Fine !
Here all 3 CTs/sensors current, 2 on Y cable, one alone, add up : 3 x 30W = 90W


Here: 2 CTs/sensors connected in Series via the Y cable: Their current readings add up

I then now have a low cost solution to be able to Double the Current Reading on a line, and this is exactly what I need to be able to make Wattson work for USA & Canada Split Phase Electric System.

See Energeno documentation and diagram on this smart Y cable called Easifit

Solar Install continues ....

Last saturday, my contractor came to continue the Solar install started tuesday morning

Close up on the DC Breaker : 600V 20A

Wattson with EasyFit configuration photographed before unplugging the transmitter

and Easy Fit fitted back in the solar sub panel ( a bigger one here) on the Line wire going back the the main consumer panel

More wiring

Closer look at the solar sub panel and Wattson


Wattson Transmitter is temporarily plugged in and placed here

My consumer unit: See the Wattson Usage sensor is located on the Main Line wire, providing power to the whole apartment; Because the solar sub panel is wired after this, I need to use Easy Fit Y-cable

After going back on the roff the link all the Uni-Solar PVLs together as one string, DC voltage of this big string was then around 360V and the sun was not even shining because of the big white clouds

Now, after closing the SMA Sunny Boy cover panel and wiring it to earth, after switching on the DC and AC breakers, the inverter 3 LEDs blinked for one second, and then nothing ... No display, no LEDs, nothing was on ... :-( and after trying everything my contractor quickly determined that there was probably a problem with this unit ... No Luck


As my contractor advised, on sunday, in the morning sun, I measured again the DC voltage and it was showing 390V; I then tried to start the inverter gain, but still nothing ...

I also read the Sunny Boy 3000 documentation trying to find an explanation in the minimum DC voltage required and in the troubleshooting section

Later on, Mark Elliott from Energeno, Wattson maker, retweeted this pic of Wattson sensors install, with a little comment

DIY ESS - Wiring & First Test

Monday night testing after wiring all the ESS inside the metal cabinet

New GTI interconnects to link two stack of GTI

Chargers and GTIs installed

2 stacks linked

24V switched ON

Battery pack rewired and covered

Now some hot air exhaust testing with the fan at different speed levels

and it was over heating when many GTIs were ON, so I will have to fix that ...

Done - New GTI interconnects for the DIY ESS

I finally found time to make these short and clean interconnects for the Grid Tie Inverters stack and tested them (Video at the end of this post)

After cutting the 2.5mm2 electric wire to the right length, a little bending on each end, and using a good soldering iron, I could easily make the 6 pairs of 8mm lugs + wire interconnects 

A littler piece of thick paper to make a pattern for the next ones

Fits very nicely after a little adjustment  

Soldering quickly , filling solder inside the hole without have the plastic burn !

There is a good contact between the lug and the terminal after screwing the nut

Adding more inverters to the stack

BEFORE : The grid tie inverters already in use and wired

4 brand new ones received recently that will soon be part of the ESS

AFTER : The same stack with the new interconnects

DC Power is ON (GTI Mode) and the first inverter's AC side is switched ON 

Overview of the Grid Tie Inverters stack, Battery Pack, Control Board, and Wattson in the back

The whole stack is ON (DC & AC) and after long minutes of test, nothing is heating up (wires, lugs, connections) 

Net usage is low

A little video of the ESS fully using its 6 GTIs (out of 8, 2 not wired yet) going up to 1200W +



BTW, this is what I was watching on Youtube at the same time:  Daft Punk - Get Lucky



ESS overview

and this is Wattson Anywhere's Graphs for this good test sunday (click screen capture for direct link to my live graph)