DIY ESS - Pairing a Second Transmitter on a Wattson

I thought about this maybe a year ago and was not sure it could be done until I read more about Wattson and its capabilities: It can get signals from up to 10 (!) Transmitters

The idea here is to send Generation Power from different locations:
- First, the generation info from the Solar Installation
- Second, the DIY ESS - Energy Storage System - output generation
These two add up automatically as long as they are paired to the same Wattson display unit... => Cool !

On the pictures, you recognize the white Wattson that is already paired to my Solar Installation + ESS (off at this moment)
To be able to compare values, I brought the Silver Wattson upstairs;  It is showing Solar generation only
After pairing the second Transmitter you can see on the floor here, and plugging in a clamp/CT into the generation inlet of the Transmitter, this new "Generation" adds up to the Solar Generation, meaning we can now have a clamp + additional Transmitter directly in the DIY ESS to measure the ESS only Generation and no additional outlet to install in the Solar sub-panel / junction box - like I did with my Solar contractor -



Using Generation inlet only

For testing purpose here I am measuring a small load from few lamps - LED of course -, from my home made Easyfit Y Cable from few weeks ago

On the left, the white Wattson adds up the 2 Generation signals it receives from the 2 Transmitters,  and on the right, the Silver Wattson displays the Solar Generation only

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

Low Cost Coil Economyzer Test for Tyco Kilovac EV200A1ANA

I am still in search of an economizer for my new Tyco Kilovac EV200A1ANA

Last night, I tested different resistor values along with this 4700uF capacitor - I got for my Grid Tie Inverter repair previously - and found that the simple economizer described in this DIY Electric Car thread


seems to work . I could not find a resistor that works so I used this air dryer resistive wire again - alreday used on my mini bottom balancer - and cut a piece that was 10Ohms;

Closing the circuit bypassing the economizer, the relay closes and is using 3,5A

With the economizer, the contactor is closing and only 1A is going through the circuit - instead of 3,5A with no economizer -   

1A at 12V = 12W

I will have to try with 20Ohms and see if what it does ... The idea is to leave the relay closed using minimum current, thus minimum power

Last charge for my 3 LiFePO4 cells pack

As explained in my last post, it is time charge the 3 LiFePO4 cells pack again, but for the last time, because now I think I tested them enough and will put them for sell online

I do not know if I already wrote this, but I am using two 12V Mascot chargers in parallel to charge twice faster this pack, and, of course, I am carefully following the voltage using my Bottom Balancer for this as a voltmeter

A clear indication of the voltage

The two Mascot (Norvegian) chargers working together

Parallel charging and single cell voltage reading

Measuring my last Mottcell LiFePO4 cells

As I already wrote few weeks ago, I made a 3 LiFePO4 cells pack with them, bottom balanced them, charged, and discharged them few times by plugging in an iPhone / iPad 12V charger, which downstages voltage to 5V anyways (so it does not have to be 12V really to work, it could be 2 cells actually)

Few days ago, around diner time, I checked the voltage of each cell, because it had been more than two weeks and we had been charging our iDevices on this mostly

You can see here the benefits of bottom balancing the cells before the first pack charge: we are reaching the lower limits of the cells and they are still in balance, coming down together:

Voltage measured still under load (iPhone is plugged in as you can see)

Cell 1 = 2.94V

Cell 2 = 2.93V

Cell 3 = 2.92V

Pack  = 8.80V

=> So, no problem, and after reffilling my iPhone fully, it will be time to recharge the pack