WWhy doeas the battery discharge during the "Timed Charged" period?

Not sure why this is happening, but we are on Octopus Go Faster 01:30-06:30.
Therefore, the battery is set to charge up during this period @5.5p/kWh along with other items, like water heater, washing machine, etc.
As today was predicted to be very sunny, I set the battery to charge up to 25% last night, in case it went below 25% before 01:30.
However, what happened was the battery discharged during the "Timed Charge" period down to 25% and then kept it at about that level. Which is not what I wanted.
How to you set it so that it won't discharge during the "Timed Charge" period?

Woodlands Are you saying that you set the "Charge to xx %" slider under "Timed Charge" to 25%? If so then the system did exactly what I would have expected it to.

I have read the sentence "As today was predicted to be very sunny, I set the battery to charge up to 25% last night, in case it went below 25% before 01:30" over and over and still cannot make sense of it. An explanation of when and what you set (and what you were hoping to achieve) would be of assistance.

Woodlands the battery timed charge works more as a "Keep battery at this SOC". So if there is more than, in your case, 25% it will do whatever is needed to reach 25%, in this case discharging the battery. I don't quite understand why that setting is called timed charge, as it effectively discharges if there is more than the set percentage.

Woodstock Are you saying that you set the "Charge to xx %" slider under "Timed Charge" to 25%?

Yes, that is what I did, but when the "Timed Charged" period started, the battery was already above 25%, so it discharged down to 25% before maintaining that level.

I did not expect it to drain what was left in the battery above 25%, when the items using power could have imported it from the grid @ 5.5p/kWh.

As @Huntzie says, the "Timed Charged" appears to be get the battery to the set %, even if that means discharging it first!

What is the best setting to get it not to Discharge during the Go Faster cheap period?

Woodlands If you really want to then setting "charge to xx %" to 100% will stop the battery discharging during the timed charge period but will result in less headroom in the battery to accept the next day's solar charging. An option would be setting the "charge to %" to 100% and also setting a low battery charging power, such that a limited amount of charge would be provided to the battery during the timed charge period. You would, of course, have to remember to raise the battery charging rate again the next morning. Still don't understand why you want to stop battery discharge during the timed charge period though.

Woodstock Still don't understand why you want to stop battery discharge during the timed charge period though.

EV charging is one big reason.

browellm EV charging is one big reason.

Yes, that's one of our reasons. Also, we have underfloor electric heating in our shower room & a storage radiator in a bedroom, that through the winter (and still at the moment) we heat up using the cheap Go Faster period. It is cheaper to use the electric at 5.5p/kWh, rather than gas central heating at 6p/kWh.

browellm Savings depend on where the energy stored in the battery above the "set charge to" limit came from.

If from yesterday's solar then free is cheaper than 5.5p/kWh provided the "set charge to" limit is set to retain enough charge in the battery to get through to the next start of solar production.

If from yesterday's cheap rate AC charge then yes you are suffering the round trip efficiency losses but if the energy is already in the battery you are committed to these anyway and by preventing discharge you are reducing the amount of free energy you can store next day.

Woodlands put in place a "set charge to" limit of 25% in the expectation of a sunny day so presumably thought this sufficient to cover use until solar PV took over. I don't see why he would want to prevent battery discharge down to this limit during the timed charge period; EV charging or not.

Woodstock If from yesterday's cheap rate AC charge then yes you are suffering the round trip efficiency losses but if the energy is already in the battery you are committed to these anyway

You're doing the round trip twice though.

And, if the promised solar doesn't turn up for the day, you're kinda knackered.

Woodstock Savings depend on where the energy stored in the battery above the "set charge to" limit came from.

If from yesterday's solar then free is cheaper than 5.5p/kWh provided the "set charge to" limit is set to retain enough charge in the battery to get through to the next start of solar production.

If from yesterday's cheap rate AC charge then yes you are suffering the round trip efficiency losses but if the energy is already in the battery you are committed to these anyway and by preventing discharge you are reducing the amount of free energy you can store next day.

@Woodstock Thanks for the explanation. Yes, putting it that way it does seem logical. Use up the "excess" solar PV charge from the previous day, before using cheap rate overnight if the battery already has more than you expect to need the next day.

One thing is strange though; that it goes down to 2% below what ever the % setting is and then keeps topping up & discharging 1 or 2% until the end of the "Timed Charge" period. That does not appear to be an efficient way of working.

browellm Yes, but the second round trip costs you nothing as it's expected to be solar PV. You might as well use the excess above the "set charge to" limit during the cheap rate charging period and have more capacity to accept the free energy later.

Yes, if the expected solar doesn't turn up you could have gained more by saving the energy to use later but you could also have gained by having the "set charge to" at 100% rather than 25%.

The question posed by the OP relates to a predicted sunny day, a consequent "set charge to" limit of 25% and a battery SOC of more than 25% at the start of the cheap rate timed charge period. I still do not see why they would want to prevent discharge down to 25% during the timed charge period.

Woodstock Yes, but the second round trip costs you nothing as it's expected to be solar PV

It isn't "expected" to be solar PV at all. It might be. I'm importing from the grid on Intelligent Octopus for a good 5 months a year.

It's either bugged (since it doesn't follow the same same behaviour when charging to 100%), or it's by design for some yet-to-be revealed reason.
Either way, it would be good if GivEnergy commented on why it's doing this. It's been raised before and they haven't said anything.

I was surprised by this "feature" too, that the % wins over the times. Because of this I am considering a second battery to dump more solar into the ev overnight. At the moment my % is set to 30% to get the house from 0230 through until the Sun comes out. As the nights get warmer I can reduce that even more. But yes it was not clear in my mind that the % bar wins. I thought setting the times meant the battery would not discharge during that time too.

I'm personally quite happy with the way it works at the moment but I can also see that maybe an additional setting which you could set to 'hold' the charge during a set time would be useful too. So whatever SOC you have when entering the set time period, it would leave with the same level and pull from the grid instead.

In fact, I've never tried, but wouldn't this be the same as the existing behaviour to have a timed discharge set that covers the opposite time period to where you want to hold a charge?

browellm

Woodlands As today was predicted to be very sunny, I set the battery to charge up to 25% last night

Solar PV not expected?

There are certainly scenarios where you would want to restrict battery discharge during the timed charge period. I just don't see the advantage in this case.

judgepd In fact, I've never tried, but wouldn't this be the same as the existing behaviour to have a timed discharge set that covers the opposite time period to where you want to hold a charge?

I tried that, but it then prevents the battery from being charged from excess solar PV during the day.

Since @Woodstock explained the "logic" behind the setting, I can appreciate that using up "free" excess solar PV generation from the day before is better than importing during the Go Faster 5.5p/kWh cheap period.
It is the name of the setting which is misleading.
Also the way it charges & discharges 1 or 2% during the "Timed Charge" period to maintain the % setting, rather than staying there once it has reached the agreed setting %.

Woodlands I won't bother trying it then :-)

That 1% 2% thing is really odd as if there is a largish load you can see that it is coming from the grid, so I don't know what is really causing that fluctuation away from the set percentage.

judgepd That 1% 2% thing is really odd as if there is a largish load you can see that it is coming from the grid, so I don't know what is really causing that fluctuation away from the set percentage.

Perhaps @Mickey (GivEnergy) or someone else from GivEnergy could explain why it does that.

Woodlands

I'm a bit out of the loop with this thread, do you mean a 1-2% fluctuation when charge up to % is set? The settings for that try to best keep your battery charged at that % from solar or grid. I'm assuming some form of firmware logic is causing the fluctuations to keep the battery level % like that. I'm unknowledgeable as to why it does this

https://ibb.co/BGk40kN

Example here, between 00:30 and 4:30 the timed charge was set to 40%. The graph shows the SOC going between 38% and 39% during that period with small blips where it seems to be charging and discharging. I think I queried this before and @Adam-Reynolds said that this was basically expected behaviour but we were more interested about why it would be doing that rather than just getting to the set SOC and then holding solid.

Hi - new user here! I've been trying to achieve a very similar effect; for the batter to not discharge overnight while I'm charging my EV. The battery capacity is a blip in terms of the EV's and I'm keen to not keeping running the battery empty every time I need to charge the car.

I've experimented with the timed charge function and have had the same fluctuations described above. Alternately, I've also tried to set a timed discharge from 0430-0030, although, bizarrely, this has had absolutely no effect on the battery behaviour - it continues to discharge during this period regardless (set from both the app and online portal). Any ideas as to why this might be happening? In theory could setting both the timed charge and timed discharge alleviate the fluctuation problem?

rob-f set timed charge to cover your EV charging period, Dynamic mode at all other times (assuming you have PV), check you have daylight saving time enabled.

rob-f it's worth noting that if have a Zappi and finish the charge at 0430 alongside setting the battery charge period to also end at 0430 I've seen it drain the battery due to my Zappi settings.

With the hybrid I've set the export value to keep it on 100% green but also set the charge delay timer - this seem to cling onto charge a bit longer after the end period setting.

To get around it I've just adjusted the battery charge time to end at 0435 and it stops this being an issue.

As for the charge rate settings, it's better described as a charge or discharge to value SoC. Due to the way the software works you'll see it go up and down by around 1% of that value as the battery tries to maintain that value. The only time it won't do that and lock out the battery is when you set it to 100%.

Cracking thanks that's really helpful - will give it a go!

Jesus should it really be this difficult !?

I came across this thread, (newbie user too), when looking for clarification of the setting as I'd like to set the system so that there's enough power in the battery for the morning cuppas and hair drying etc before the Sun starts to take over. Ideally, I'd like that to be left over free solar from the day before but if that's depleted, then I'd like to fill it with cheap Octopus Go lecky. So this setting seemed ideal.

I went to bed with 58% in the battery and the charge to setting set at 00:30-04:30 to 30%. Logically, I'd expect that if the battery is above 30% during that duration then nothing would happen but it it was lower then it would top of to 30%.

After reading the comments here, I was a little concerned that I would wake to to a battery that was at 30% and a system that had dumped good and free power to the grid to get there. Thankfully that was not the case. Battery level was 39% this morning so it seems to have worked as I expected.

Yorkie71 if eco mode is enabled and timed charge is set to 00:30 for 4 hours to 30%

• if there is more than 30% during time charge period / any time then any house demand will come from the battery
• if it is less than 30% during the timed charge period, it will charge to and maintain the battery at 30% from the grid.
• at the end of the timed charge period the battery will be a min of 30%
• by the time you get up any house load from the end of timed charge will come from the battery meaning the soc will be lower than 30%

locked Thanks. That's what I thought it would do and on practice, it did just that. It was that some of the posts earlier in the thread seemed to suggest that if the charge level was higher that what was set then the battery would actively discharge to get to that level which makes no sense to me.

Yorkie71 mine appeared to do a forced discharge to the target level in Feb, possibly fixed in a subsequent firmware update. Now it behaves correctly.

It would be useful if we had examples of how all the modes work. I was recently away from home for several weeks and wanted to set a timed discharge for the Agile Outgoing peak for around 90 minutes each day. At present I don't see any way to do this as I believe if timed discharge is enabled then Eco mode is disabled so after the timed discharge has ended and solar is no longer generating then the system imports until solar starts to generate again the following morning despite having sufficient SOC in the battery to last through the night.

Our Hybrid + 8.2 battery system keeps the charge in the battery if it isn't used up by various demands overnight, and it charges it up to the required charge setting % if it goes below it.

I haven't seen my system discharge down to the charge % limit unless my house was demanding it. (Unless when doing firmware update and it goes through the calibration process)

Obviously having sunny days it's a bit of fine tuning required to see what works for your individual usage, currently dropping the timed % charge limit to avoid sending out excess to the grid, equally as the days wind in it'll probably be a case of gradually winding up the lower tariff charged %.
I think we have all gotten a little complacent with being spoilt by automation of various processes but this is using prediction if it were to be fully automated process and even the weathermen have a fun time with that.

I believe that to safeguard safe capacity is to overspec' system requirements in the first place, something I am hoping to address with more Solar & Battery (When the DNO signs off on it that is!)

Martyn
I think reading through a lot of posts in the community, there is a massive amount of confusion over settings.
I had the Givenergy battery installed in late 2020, and was perfectly able to adjust the charge settings using the legacy portal and app.
Then the new portal appears looking like some sort of Fisher Price plaything but with a hopelessly unintuitive user interface. To compound that there is either no (or out of date) user manual, and the explanation of the setting functions written by someone who probably wrote the software and has no idea of plain English.
I don't want to spend hours searching the community, or experimenting with settings, I just want it to work.

The 1-2% charge/disharge thing was "winter mode" setting that seems to have now disappeared from my portal - if you click on the remote settings on your inverter on the portal is that option there?

Hello everybody. I only got my system installed this week and am trying to get my head round all of this. I have the AC coupled inverter and two 8.2 KwH batteries to complement an existing PV system. I have an EDF cheap rate tariff that provides power at 4.5p per unit between 00:00 and 05:00 GMT.

I had assumed that setting the 'timed discharge' period to be the opposite of the 'timed charge' period (ie timed discharge 05:00 to 00:00 GMT) and using the 'eco'mode to take advantage of any PV generation would achieve what I want, but setting the timed discharge mode appears to disable charging from the PVs - is that 'by design' or have I not understood (quite likely I fear).

Anyway, as a test tonight, I am leaving the timed discharge mode disabled and attempting to charge from the grid to 100% between 00:00 and 05:00 GMT. If I have understood the above posts correctly I am expecting that any house load between the times when the battery gets to 100% and 05:00 GMT should be met from the grid, which is what I want.

If this works, on subsequent nights I would expect to reduce the 'charge to' % to say 50% to allow space for solar PV to be stored the next day (in the summer anyway). Again, I would be expecting any house load between the times the battery gets to 50% and 05:00 GMT to be met from the grid.

If I have completely misunderstood this, please can somebody be so good as to let me know. Many thanks.

I guess what I am trying to do is fairly common, and I do agree that some idiots guides about how to set up such scenarios would be very helpful.

Gliderman Enable Eco mode and then set AC Charge for the period 00:00 to 05:00 and the target value you want. That's all there is to it - timed discharge disables charging from PV, so that's not what you want.

If you are also charging an EV during the cheap rate period, then the time schedule in your charge-point or car needs to align with the time schedule in the GE inverter in order to avoid draining the GE battery.
May be set the charge-point/car schedule to be slightly shorter than the GE schedule by a few minutes, to cater for the live time being a few minutes different between the 2 systems.

The GE battery will still discharge to the EV when the GE battery charge level is more than the target %age at the start of/during the AC charge period. Typically this energy will have been sourced from solar PV or during a previous cheap rate period.

Many thanks for your advice chaps - the test last night did what I expected - but of course now no room to store today's PV generation. My EV is due for delivery in October (believe that when I see it) so I will do as you say.

I suspect in the winter months the target charge will be permanently set at 100% - from the charge rate seen last night I reckon the 5 hr cheap rate slot will get from 4% to about 77% fully charged. My winter plan is to shift as much house load as possible to the cheap rate period by using the appliance delayed start timers - just got to get the family on board with that.

Hi Mates,
I just installed the Panel and Battery. Since I don't have any cheap rate tariff, how can I force the system to charge the battery by the solar panel only? and if there is no sunshine or night time, just discharge the battery as much as I can. How can I config the system? which mode should I use?

Eco mode should work for you. It aims to minimise export and impport to/from the grid whilst soalr energy is available (by charging/discharging the battery to the home), and on my own system at least, only charges the battery from solar.

Simon_C
This is one of the issues that need sorting:
So you set your Givenergy battery to charge at 00:30 from cheap rate. Yo also set your EV charger to do the same.
Both batteries start to charge as requested, probably around 10kW total.
At some point the charger is decides you are exceeding you grid allocation (not sure how this is figured) and restricts your supply to about 5kW.
ECO mode detects this, and starts to discharge your Givenergy battery into your EV battery ! How dumb is that ?
You've just charged your GE battery at 95% efficiency, then promptly discharged it at 95% efficiency to charge another battery at 95% efficiency.
Why can't you configure the GE inverter to prevent discharging during certain times ?

spark

spark At some point the charger is decides you are exceeding you grid allocation (not sure how this is figured) and restricts your supply to about 5kW.

AFAIK, the only time this would happen is if the EVSE has a CT clamp on the incoming tail and has some sort of Adaptive Fuse arrangement. For example, my EVSE is an Andersen A2 and that can be fitted with Adaptive Fuse. This will limit the current drawn to prevent the main fuse from blowing (such as when a 60A main fuse is fitted). On a 100A main fuse there should be plenty of headroom unless you have a big heatpump and are doing your baking at 3 AM!
Unless the EVSE has an equivalent of this then it will just draw the full amount needed to put 7kWh into the car.

spark Why can't you configure the GE inverter to prevent discharging during certain times ?

Timed Charge does exactly this. Set the period up and the SoC that you wish to exit the period at. The battery will reach this SoC and then maintain itself at that level. For example, I set my Timed Charge to 70% as the forecast was OK for generation today. The car charged throughout the off-peak period and the battery maintained itself at 70% SOC.

spark , not sure what device you are describing as restricting the grid supply to cause this knock on effect.
The MyEnergi Zappi EVSE with a grid CT and programmed grid limit will auto back off the EV charge rate from 7.4 kW down to a lower value so as not to exceed the grid limit (the total load of the household, the GE inverter and the EVSE). The EVSE signals to the EV to take charge at a lower rate.
As far as I know the GE inverter does not have a grid limit feature, so will continue the timed charge at the set battery charge rate.

If the GE battery SOC% at the start of the timed charge period is higher than the finishing target SOC%, then yes the EV will take that % difference but no more.

Barkster I'm with that !!!

Good Afternoon,

This is all very interesting, as the behaviour repeatedly described in this thread is exactly what I'd like to happen, but it doesn't...
I've set a timed charge to 45% between 15:00-16:00, hoping that everything would continue working as normal (ie. battery discharging to cover home load) unless it reached below 45%, at which point it would charge to and remain at that level.
Instead it seems that the battery stopped being used and we drew from the grid instead during that time. This is what the person opening this thread apparently wanted but not what I wanted and not what everyone else has explained... any ideas welcome!

Thanks all 🙂

Iainharding (probably should have started a new thread for this...)

I assume you're on a tariff with an expensive period from 4pm to 7pm, such as Flux or Agile, and want to preserve battery to ensure you can cover that period..?

What sort of inverter do you have? There is some odd behaviour on at least some firmwares where you can use discharge slots to implement a sort of timed reserve level.

Many thanks for your input DD,

My apologies, I thought I was keeping things tidy in one place.

we're running:
Inverter Model
GIV-HY-8.0-G3-HV
Software Version
D0.004-A0.004-A1030.004

The wee info sentence on timed discharge says: "This mode will trigger your battery to cover your home's electric demand only at the times you specify" which I don't think is quite what we want, but certainly worth a try as you say if it's a wee bitty quirky... will set that up for everthig except 02:00-05:00 (the cheapest charge time) and see what happens!

Have a lovely day 🙂

... sadly the timed discharge fiddle had no effect, so any other ideas would be welcome 🙂

Iainharding Ah, no, it's not the timed-discharge mechanism I was alluding to. It's a bit confusing that the feature they call timed-discharge is actually implemented by using the timed-pause feature. The app uses the name timed-export to access the underlying timed discharge registers.

Oh - "HV" - is that one of the new high-voltage inverters ? It's quite possible the firmware is completely different from the LV inverter I have, and so this may not be the same. The weird behaviour I see is that if you configure one of the timed discharge ("export") slots with a time window and a minimum SoC, but don't enable the the timed-discharge ('timed export') flag, then it still seems to honour that minimum SoC during the time window.