A ‘variable’ inaccuracy in Current Cost reading sent to PVOutput.org
6 May, 2012 - 06:19
For a few days now I’ve been monitoring my end of my ‘actual’ end of day FIT meter reading and the end of day PV Output reading so right now I don’t have a lot of data to work with however so far I’m seeing the actual FIT meter KW/h reading shows 10% to 23% more than my PV Solar output recorded on PV Output. I think this is a generally accepted problem as PV Output allow you to add a custom rule to adjust the power amount so there is a way to adjust it however the issue is that it is not out by a fixed amount on poor/cloudy generations days the difference I’ve seen is just under 10% and on a much brighter higher-output generation day I’ve seen a 22.96% difference. I don’t feel that averaging the amount and setting this as a fixed percentage will give me an accurate reading so looking to apply a more complex custom rule.
Assume other HAH users are having this same issue and I wanted to ask how you are dealing with this?
I see from the help on PVOutput.org an example rule where….
‘When power is greater than 1000W, increase by 10W, when power is greater than 1500W, decrease 10W, otherwise decrease it by 5%’
if(power > 1000) power += 10; else if(power > 1500) power -= 10; else power *= 0.95;
Also wondered if there is an easy way for me to work out how I need to adjust mine in view of a lower percentage need when less watts are being generated and a higher percentage with more watts, I have the history in PVOutput.org (and I guess pachube.com although I’m not too sure how to extract legend/history from here) can anyone suggest how I work out/construct my proposed rule?
Assume other HAH users are having this same issue and I wanted to ask how you are dealing with this?
I see from the help on PVOutput.org an example rule where….
‘When power is greater than 1000W, increase by 10W, when power is greater than 1500W, decrease 10W, otherwise decrease it by 5%’
if(power > 1000) power += 10; else if(power > 1500) power -= 10; else power *= 0.95;
Also wondered if there is an easy way for me to work out how I need to adjust mine in view of a lower percentage need when less watts are being generated and a higher percentage with more watts, I have the history in PVOutput.org (and I guess pachube.com although I’m not too sure how to extract legend/history from here) can anyone suggest how I work out/construct my proposed rule?
6 May, 2012 - 15:16
#3
Variation
I also have quite a big variation in the actual values and the ones reported by Current Cost in particular at low readings the CC significantly over-reads, so for instance when the inverter reads 10w the CC will read 150w. When I used my own script to post to PVoutput I put in some fairly large adjustments at low wattages to try and compensate.
6 May, 2012 - 15:42
#5
Not a Fiscal Meter
In CurrentCost's defence, they have never promoted their clamp based systems as fiscal meters, but as guides to typical endusers (ie not us) to enable them to manage their electricity use better
It may be that their Optismart meter reader is better beause it counts the pulses given out by your meter, but I have no personal experiences of using this sensor
kevinT
In the rules you can adjust the output.
if(power < 40) power = 0;power *= 1.02;
1.02 means it increases my output by 2% to allow for currentcost inaccuracies