Battery discharging ...not sure why

[huminga1]

Hello,

Can anyone make sense of what is happening with our current set up?

At present we produce little or no solar due to the time of year. We are on Octopus Flux so I am charging the batteries overnight from 0200 to 0600 (lower rate of elec from 0200 to 0500) aiming to use them rather than drawing from the grid. The Oil fired heating comes on 0630 to 0830 and very little else is used , kettle boiled once, a few lights on, thats about it.

I can't understand why the battery charge drops so quickly. The batteries are now in an insulated box (after seeing the post here) and the temperature is not dropping below 10 degrees. There is nothing on in the house that would draw loads of electricity .

I would be grateful for any input because I am so frustrated with this. Could Octopus be exporting from our batteries ??

I have attached a screenshot of the Fox Ess graph
Hopefully you can see it
Many thanks
Belinda

[Dave Foster]

Can you tell us which inverter H1-5, KH7 etc.. and what batteries you have (the type HV, ECS, EP the number of packs and if you know what the battery capacity is), also what your System MinSoC and Battery Reserve (also called MinSoC on grid) are currently set to i.e. 10% ?

From the graph I can see you are charging the batteries at around 5kW for approx 2.5 hours which suggest a battery capacity of 12.5kW

But from midnight your load appears to be just over 5kW and it continues until approx 2.30 - this is very high, storage heaters, water heater, EV charging ?

Your load then continues between 1kW and 2kW until 06.30 which seems to be more than the load from a few lights on - what else is in your base load ~ fridge, chest freezer, wine cooler ?

What I can see from the graph - from approx 07:00 to 08:30 there is a substantial load in the order of 5kW reducing to a base load of approx 500 watts at 9am
From approx 9am to 1pm it continues at ~ 500 watts with a slight uplift towards 1.5kW at the end of the trace - there is no grid consumption up til then so likely your batteries are still supplying the power - from my rough reckoning you've used approx 10kW which is a substantial load - is that what you are expecting ?

There is no evidence of any export to the grid, your feed-in remains at zero

[huminga1]

Hi Dave,

Thank you so much for replying

Inverter H1-5.0-E-G2

Battery : ECS2900-2
1 Master
4 Slaves but had 2 more installed today so now 6 slaves.....not sure what total capacity that now gives ?
Min SOC is 10 %

Base load
1 small chest freezer
1 small drawer freezer
1 large American style fridge freezer
I am lucky enough to have an endless swimming pool which I don't heat as I like open water swimming but if will not allow the temperature to drop below 15 degrees C so it may be the heater kicking in from time to time.
No EV charger being used
We also have a small separate annex that has electric heaters that come on in the morning and evening and it has a fridge thats on all of the time.

Maybe with all of that lot on thats what the drawer is thats depleting the battery. It just seems too vary. Sometimes Ill look in the morning at the app and the battery will be at 90 % other times, eg this morning it was at 59%
Maybe any expectations are just too high !
Ive added a couple more images

[Dave Foster]

Hi Dave,

Thank you so much for replying

Inverter H1-5.0-E-G2

Battery : ECS2900-2
1 Master
4 Slaves but had 2 more installed today so now 6 slaves.....not sure what total capacity that now gives ?
Min SOC is 10 %

Ok, that makes sense - you had 1+4 which is 5*2.88kW=14.4kWh and at 10% minSoc you’d need to charge with 12.9kW which is what your graph suggests (I was close at 12.5kWh)

Now you have 2 more batteries once they have balanced you’ll have 20.16kW which with a 10% minSoc gives you 18.15kWh

Base load
1 small chest freezer
1 small drawer freezer
1 large American style fridge freezer
I am lucky enough to have an endless swimming pool which I don't heat as I like open water swimming but if will not allow the temperature to drop below 15 degrees C so it may be the heater kicking in from time to time.
No EV charger being used
We also have a small separate annex that has electric heaters that come on in the morning and evening and it has a fridge thats on all of the time.

Maybe with all of that lot on thats what the drawer is thats depleting the battery. It just seems too vary. Sometimes Ill look in the morning at the app and the battery will be at 90 % other times, eg this morning it was at 59%
Maybe any expectations are just too high !
Ive added a couple more images

The american fridge freezers are quite power hungry but nothing in the league of those big loads from either the swimming pool or the annex electric heaters.

I suspect the variable behaviour you are seeing is just down to lower temperatures, it only takes one of those ‘big’ heating elements to come on and you will burn through your batteries very quickly so if there’s any way you can limit them to come on between 2am and 6am it would make a big difference to your battery soc when you wake up.

With your extra batteries you won’t be able to fully charge them from flat in the 2am-5am slot, it’ll probably take that extra hour you are giving it to fully charge - but keep an eye on that, if you’re not hitting 100% by 6am you might need to extend it slightly, these batteries really need to get to 100% occasionally for them to balance properly.

[huminga1]

Hi Dave,

Thats incredibly helpful. Will keep an eye on things and accept it may take time to settle.

Best wishes
Belinda

[PhilCamb]

Hi Dave,

Thats incredibly helpful. Will keep an eye on things and accept it may take time to settle.

Best wishes
Belinda

If you have any heavy loads where you can control when they run, the other thing worth considering is switching to Octopus Go. The tariff has a longer "off peak" period and they have recently increased the "feed in" rate to 15p/hr.

I use the off peak period to charge the car, run the washing machine and dish washer and top up the battery. Even during this winter period, the battery plus what I can get from the solar panels get me through the day so, in effect, I get all my electricity at off peak rates.

Maybe you could use the off peak period to heat your pool. Doing that, it would be less likely to drop below 15C during the day and thus drain your battery. Just a thought....

[huminga1]

Hi Dave,

Thanks again for your reply , you are so helpful!
The Octopus Go would suit us better so ill see if I can switch to that .
I have covered the little pool with some insulation (looks like a giant crisp packet) Thats helping it maintain its heat at the minimum 59 degrees so stops the heater kicking in. I don't need to heat hot up any more than that as I like cold swimming

We put the dish washer and washing machine on at night now and that really helps.

The battery is below 15 degrees today despite all of my insulation bur it is -2 here today .

Thanks again and ill see if Octopus will let me switch.

Best wishes

Bel

[PhilCamb]

Hi Dave,

Thanks again for your reply , you are so helpful!
The Octopus Go would suit us better so ill see if I can switch to that .
I have covered the little pool with some insulation (looks like a giant crisp packet) Thats helping it maintain its heat at the minimum 59 degrees so stops the heater kicking in. I don't need to heat hot up any more than that as I like cold swimming

We put the dish washer and washing machine on at night now and that really helps.

The battery is below 15 degrees today despite all of my insulation bur it is -2 here today .

Thanks again and ill see if Octopus will let me switch.

Best wishes

Bel

The other difference between Octopus Go and Flux is that Octopus Go does not have a peak period. If you end up needing to draw on the grid for power early evening, you won't have to pay premium rates.

Regards
Phil

[Will]

I don't think that's correct, outside of your off peak rate with octopus go you will be on peak rate. so if you dip into power in the evening you will be charged peak rate.

Hi Dave,

Thanks again for your reply , you are so helpful!
The Octopus Go would suit us better so ill see if I can switch to that .
I have covered the little pool with some insulation (looks like a giant crisp packet) Thats helping it maintain its heat at the minimum 59 degrees so stops the heater kicking in. I don't need to heat hot up any more than that as I like cold swimming

We put the dish washer and washing machine on at night now and that really helps.

The battery is below 15 degrees today despite all of my insulation bur it is -2 here today .

Thanks again and ill see if Octopus will let me switch.

Best wishes

Bel

The other difference between Octopus Go and Flux is that Octopus Go does not have a peak period. If you end up needing to draw on the grid for power early evening, you won't have to pay premium rates.

Regards
Phil

[PhilCamb]

I don't think that's correct, outside of your off peak rate with octopus go you will be on peak rate. so if you dip into power in the evening you will be charged peak rate.

Hi Dave,

Thanks again for your reply , you are so helpful!
The Octopus Go would suit us better so ill see if I can switch to that .
I have covered the little pool with some insulation (looks like a giant crisp packet) Thats helping it maintain its heat at the minimum 59 degrees so stops the heater kicking in. I don't need to heat hot up any more than that as I like cold swimming

We put the dish washer and washing machine on at night now and that really helps.

The battery is below 15 degrees today despite all of my insulation bur it is -2 here today .

Thanks again and ill see if Octopus will let me switch.

Best wishes

Bel

The other difference between Octopus Go and Flux is that Octopus Go does not have a peak period. If you end up needing to draw on the grid for power early evening, you won't have to pay premium rates.

Regards
Phil

I have just re-checked - Octopus go has just two rates - off peak and day rate. Octopus flux has three rates - off-peak, day and peak. Octopus go is definitely cheaper than the Octopus Flux peak rate by a significant amount.

[Will]

correct, or if you have a compatible charger or car intelligent Go can give you a cheap rate whenever the car is plugged in. I get some 6 to 8 hour off peak slots every day.

[huminga1]

Hello everyone,

Many thanks again for all of your helpful replies. Im not sure Octopus will allow me to switch to GO , it doesn't give me the option on the app.
I have 2 PV systems, the original one fitted 10 plus years ago which I get a very good FIT and the deemed Export tariff. I had an additional system fitted as we had enough roof space which is the Fox Ess with a battery , Eddi and a Zappi EV charger. We don't have an EV yet but are looking to change my vehicle to one this year.

To get onto the Octopus Flux Tariff, because we cant have 2 FITs I had to agree to change our Export tariff from EON to Octopus , this will not affect the FIT payment only the export payment . Ive just had an email from Octopus saying that I need to inform EON of this change , so I have replied asking the question regarding changing to the Octopus GO......I have the car charger but not the car ...does that matter ? Is it because I would need to forfeit my good FIT payment from EON and switch this to Octopus as well?

It's all a bit confusing and I'm having to work through these problems alone as the Installers have frankly been useless at giving advice . However, I cant thank all of you enough for all the hints and tips about how to manage with batteries. Where they were installed I was told you don't need to touch or do anything!!!!! If I hadn't followed advice from this group I would probably have a set of non functional batteries by now.

Best wishes
Belinda