Cumulative log of solar generation

(Othel Yarwick) #1

Hi guys been using emoncms (self hosted) for about 2 months now and it is awesome. Before now I use to manually upload my usage data to pv output… Anyway to understand my question here is my setup.

I mainly use emoncms to log solar generation data. I live completely off the grid electricity wise. The data being logged are from 2 victron solar charge controllers and a victron battery monitor. (I used the Victron interfacer with emonhub)
The key feeds like real time PV voltage, power current, peak power, battery charge and discharge current all come from the charge controller and battery monitor.
I also get figures on total energy harvest for the day in kilowatt hours. It is the last figure that I want to log into a cumulative figure of total energy harvest for the week months and Year. I have not figured how best to achieve this. I have them graphed but you only see individual daily figures not cumulative. The daily energy harvest is already supplied by the charge controller so I don’t want to generate it from the emoncms from PV power log to feed and to power to kwh. I just want to log the daily harvest figure from the charge controller and make it cumulative. The figure is already in kilowatt hours. The energy yield figure starts once PV starts to generate electricity and it increases until 7pm when PV stops generating and the generated yield remains till next charge cycle.

Below is link to my dashboard

Suggestions would be highly appreciated.

1 Like
(Trystan Lea) #2

Nice dashboard, great to see emoncms used in this way! You could try the wh_accumulator processor it removes resets in a cumulative feed and could work for a daily reset as I think you describe

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(Othel Yarwick) #3

Thanks. That did the magic.

(Othel Yarwick) #4

OK when I tried this on Sunday morning it seemed to have worked. Just so happen that I had a wh accumulator process running since last month hence using the bargraph gave me a nice data of all my energy yield for close to a month.

I then setup wh accumulator for my second solar array and one for combined energy yields coming from my two solar array and one for calculating total energy consumption… This was when the log went of the chart.

I started getting very high figures… Higher than I could possibly generate in a day. This started on Sunday 15 through to today 17 July. I really don’t understand how something that was working fine just totally went off the rails

Below are how I set things up

I am suspecting that emoncms supports using wh accumulator one once in an emoncms instance. Running multiple instances for different inputs and feeds seems to have it confused. Would appreciate pointers on what I could be doing wrong.

(Othel Yarwick) #5

Link to the chart in question

(Trystan Lea) #6

There should be no issue with multiple wh_accumulator processes, its likely that the original input feed has a number of brief resets that are tripping up wh_accumulator processor leading to it registering a higher cumulative kWh consumption than your actual use. I’ve seen that happen before. If you zoom in on the original feed, do you see any resets to zero that happen apart from the expected once a day?

(Othel Yarwick) #7

I tried zooming in on the feeds and there seem to have been a spike between 9am and 17:00 a spike of 3.8 kwh which frankly is far from what that particular array generated for that day. I did not notice any reset to zero… (please direct me accordingly how to check for the zero reset)

How do you advise I fix the issue. The wh accumulator is now completely broken. Only thing I did during the time the spike happened was to configure wh accumulator to more feeds. Hence my initial question.

(Othel Yarwick) #8

I think I will file this under wh accumulator being very very unreliable. The 18th of July figure was back to normal but experienced another spike of a ghost 3kwh energy yield that never happened.(in fact spike occurred at sunset when solar output was zero), The sane figure of the 18th July happened after I deleted other wh accumulator processes. And the spike occurred when I deleted the feeds from the previously deleted processes.

As it stands my goal of having cumulative logs of energy generation is lost. I have no way of keeping record of what I generate in a year month weeks data that are very important to me. I might have to consider outputting to pvoutput… That at least does the graphing for me.

I will still be monitoring things and making observations here. It seems many don’t know much about wh accumulator or how the work hence the little help I am getting. Will try to up date this thread for future reference.

(Othel Yarwick) #9

I think I finally fixed this issue. It occurred to me the Wh accumulator was built to work with Emon power monitoring hardware and as such had a spike threshold of 25000 W or 25kW. In my case I am using emonCMS to aggregate data from my Victron charge controller, particularly the daily energy yield which is already in kwh. A 250000 W spike threshold is way too high for my use case as I rarely generate more than 5kwh a day. This meant accumulator was prone to spikes for my use case. I then took a look at the process code and changed the 25000 max_power value to 5. Hence any spike higher than 5 should be ignored. That seems to have done the trick for me. It’s been 4 days now, and I have experienced no spike and the two accumulator process now run like a clock. Just thought to throw this out there in case anyone is having a similar issue.

(Mike) #10

@bigbrovar Hi - What is the emonHub hardware that you are using with the Victron devices?
I have the BMV-712 and a 250/100 MPPT controller that I want to grab the data from and log / graph into my emoncms db…

Are you happy with the setup? Would you do anything different?

Thanks and love your dashboard!