Have I misunderstood Wonderwatt?

jsheerin

I subscribed to Wonderwatt for two reasons.

Firstly, to overcome problems of my GivEnergy batteries discharging to my EV when Octopus allocate smart charging slots outside of core off-peak hours. This is working fine.

Secondly, so I could stop having to second guess the amount of solar energy I would generate and manually reduce the overnight charge limit on my batteries to maximise the percentage of free solar energy used, and thereby reduce the overall gross import. This does not seem to be working at all.

Despite the long hours of sunshine in recent days Wonderwatt is still instructing my batteries to charge to 100%, even when a full day of sun lies ahead. This results in much of my solar power being directly exported to the grid. I’m on a FIT tariff so don’t receive any income from this generation.

I can’t even do a manual adjustment now as presumably Wonderwatt will override this when it sets targets at 11.30 pm every night.

Am I doing something wrong?

admin

jsheerin I’m on a FIT tariff so don’t receive any income from this generation.

I thought people on a FIT tariff do receive income for their excess export? Usually more lucrative than the SEG rates.

We’ll see what we can do in terms of a smart SOC target for both IOG and Agile, related to predicted solar.

jsheerin

admin hi

admin Thanks. We receive a payment per kWh generated plus a deemed payment for export based on 50% of electricity generated. The actual amount exported is not metered. This means that I’m still saving a minimum of 7p extra for every kWh of electricity I use at home rather than export. My FIT payment is now 73p per kWh so I’m not complaining!

MrMessy

@jsheerin
Appreciate it's in your interest to self consume as much solar as possible.
Don't know if @admin has done some work on this recently but, I've tested the smart charging this week, and it appears to be working as I might have expected.

The settings used are here:
https://app.wonderwatt.com/settings

and here:
https://app.wonderwatt.com/intelli-octo

So, for reference, my battery capacity is 19kWh, and I usually have Normal usage set to 20kWh, Target 100%, smart charging off.
I don't normally bother with the predictive smart charging, as it makes more sense for me to always charge to 100% and export as much solar as possible.

Test 1:
Smart charging On
Target charge, 90%
Normal usage, 20kWh
Solar prediction, 32kWh
Result, charge to 90% ✓

Test 2:
Smart charging On
Target charge, 95%
Normal usage, 100kWh
Solar prediction, 31kWh
Result, charge to 100% ✓

Test 3;
Smart charging On
Target charge, 90%
Normal usage, 40kWh
Solar prediction, 10kWh
Result, charge to 100% ✓

In all three instances, it charged the batteries exactly as I would have expected.

I'd be interested in any feedback.

jsheerin

MrMessy Sorry, I’ve only just spotted this really helpful reply. I noticed today that the battery charge target and rate is now being adjusted for each charge period to take into account the forecast.

Unfortunately, what caused me to look at this thread again was the fact that my battery is very low today. I noted for the first time that overnight charge is being adjusted.

The reason for the under charging seems to be entirely my fault. I altered the average use figure to take into account the extra sunshine and the fact that my heat pump is using less electricity because of the warmer weather. Unfortunately I used the net consumption (ie grid consumption only, thereby substantially underestimating the amount of charge required. I’ve now increased this so fingers crossed everything will run smoothly.

Thanks for all the help.