Monitoring leccy usage

MashBag · Sep 24, 2024

I believe so, yes. One of the reasons I have not decided to play batteries.

jof · Sep 24, 2024

Yep but it still doesn't make sense not to have them when you are all electric & cover your house in panels.
(I have 10kwh batteries & 6kw inverter)
The main thing is not to let the charge drop too low, mine is set to 20% minimum. But you should also only charge to 90% to stop overcharging issues, but then you loose 30% capacity.
(My system always charges to full as it had no max charge limit until a recent update & that doesn't seem to work on my kit yet)

Agentgonzo · Sep 24, 2024

jof said:
Yep but it still doesn't make sense not to have them when you are all electric & cover your house in panels.
(I have 10kwh batteries & 6kw inverter)
The main thing is not to let the charge drop too low, mine is set to 20% minimum. But you should also only charge to 90% to stop overcharging issues, but then you loose 30% capacity.
(My system always charges to full as it had no max charge limit until a recent update & that doesn't seem to work on my kit yet)

What system do you have? I've heard different things (ie. You can charge/discharge using the full depth of charge - but it might be because the givenergy batteries have a larger capacity than they tell you to build in that over charge/undercharge protection)

MashBag · Sep 25, 2024

jof said:
Yep but it still doesn't make sense not to have them when you are all electric & cover your house in panels.
(I have 10kwh batteries & 6kw inverter)
The main thing is not to let the charge drop too low, mine is set to 20% minimum. But you should also only charge to 90% to stop overcharging issues, but then you loose 30% capacity.
(My system always charges to full as it had no max charge limit until a recent update & that doesn't seem to work on my kit yet)

I could not get the ROI to add up.

Paulus · Sep 25, 2024

Or use something like this

I have an old one for a time when I was looking to get an idea of the costs of running things around the house to see what we needed to economise on. They can be programmed with your tariff and are reasonably accurate.

jof · Sep 25, 2024

Agentgonzo said:
What system do you have? I've heard different things.

I have a solis inverter & 2*5Kwh pylontech batteries.

@MashBag If you have gas for heating/cooking, you don't get ROI, but were electric only with storage heaters and young adults at home (cooking power is as much as heating power when averaged over the year) when the energy crisis started. Overnight payback time halved to 7-8 years.

Agentgonzo · Sep 25, 2024

MashBag said:
I could not get the ROI to add up.

Them maybe it's not for you. But that doesn't mean it's not for other people.

Agentgonzo · Sep 25, 2024

jof said:
I have a solis inverter & 2*5Kwh pylontech batteries

Li-ion seena to be quite different from LiFePo4. The latter seem much more tolerant to "100% DoD" cycles.

MashBag · Sep 25, 2024

jof said:
I have a solis inverter & 2*5Kwh pylontech batteries.

@MashBag If you have gas for heating/cooking, you don't get ROI, but were electric only with storage heaters and young adults at home (cooking power is as much as heating power when averaged over the year) when the energy crisis started. Overnight payback time halved to 7-8 years.

We are 100% leccy with 23kw of generation.

The heat pump is a big draw, so unless we put a lot of battery in, no go. 3ph freezer is a not go.
That said, if I did power trading I really would reconsider.

Halving the consumption is OK if the install cost & mtbf is covered and for me that needed to be less than 5 years.

hoppyscotty · Sep 27, 2024

Paulus said:
Or use something like this

View attachment 104197 I have an old one for a time when I was looking to get an idea of the costs of running things around the house to see what we needed to economise on. They can be programmed with your tariff and are reasonably accurate.

thanks got one of those for my 3-pin run devices like pumps and chillers, but my brew kit runs off 32a commando sockets. Brewkit will use a a few fair few KW over a short time, but running a glycol chiller and a couple of fridges constantly over time will consume more over time...so wanted to monitor that over time.

jof · Sep 27, 2024

Hmm. Smart meter?
Then compare a day with & without running chiller/fridges

Its 6pm somewhere · Sep 28, 2024

I work from home a day a week and double this as a brewday once maybe twice per month, meter reading before and meter reading after the brew days and meter readings at the same times on a non brewday as a 'control' of sorts. There'll be a bit of swing but it's a good indication. If you have a dedicated brewspace/room not used for anything else then get an electrician to fit a meter to that room.

Lynx Brewery · Sep 28, 2024

I used to monitor my SmartMeter and compared a BrewDay to the average of non-BrewDays.

Average extra cost was about £2.50.

MashBag · Sep 28, 2024

I used a plug in meter (like the one above) and that was about the same.

peterpiper · Oct 2, 2024

Agentgonzo said:
My battery can export 3.6kW to the house, so brewing from the battery is no problem.
What I did find about battery/brewing is that when I set my GF to boil at 70% power, it doesnt' just reduce the load on the heater, it goes at full blast for 0.7s, then off for 0.3s. Feeding thing from the mains is fine, but batteries can't react to quick changes it load (they take several seconds). So what probably ends up happening is that the battery pumps out (say) 2kW constantly, and for the 0.7s that the GF is drawing power, that comes from the battery. But for the 0.3s that it's not drawing power, the battery is still discharging 2kW so that just goes straight into the grid.

If the load is constant, batteries are fine though

BZ gen 4, uses the same idea, to control heat by switching the on-off mark-space ratio to achieve desired power. Perhaps you need an old BZ 3.1.1, which had one switch for the 1900W element, and one for the 500W element.

Does the GF allow you to set the power control power switching period. On the BZ4, I've upped it to 40 seconds, to extend the relay life around tenfold (it uses relays for 'reliability'), as with the thermal mass of the base alone) its pointless having a very rapid switch time.
Your inverter would be able to better cope with load switching of 3s on : 9s off (or even better 9s on 27s off), than with 0.3s on : 0.7s off.

Strange that stand alone inverters (not grid connected) can't suffer same problem with varying loads - as there's nowhere else for the power to go.

Agentgonzo · Oct 2, 2024

peterpiper said:
Does the GF allow you to set the power control power switching period.

No. It seems to be a one second duty cycle, you can only set the power.

MashBag · Oct 3, 2024

peterpiper said:
Strange that stand alone inverters (not grid connected) can't suffer same problem with varying loads - as there's nowhere else for the power to go.

Is this where the dump loads come in?

Agentgonzo · Oct 3, 2024

peterpiper said:
Strange that stand alone inverters (not grid connected) can't suffer same problem with varying loads - as there's nowhere else for the power to go

Stand alone or "island" systems have their own ground spike (earth connection) as part of the installation. So if the battery and house can't take the load, the extra goes straight into the ground. So there is somewhere else for the electricity to go.

Or it could be that varying draw from the appliances results in a much greater voltage swing as the load increases/decreases.

MashBag · Oct 3, 2024

Agentgonzo said:
Stand alone or "island" systems have their own ground spike (earth connection) as part of the installation. So if the battery and house can't take the load, the extra goes straight into the ground. So there is somewhere else for the electricity to go.

Now that might be exciting with grid supplied earth.

Hmm. I am going to have to sit down and think about that.

peterpiper · Oct 6, 2024

Agentgonzo said:
Stand alone or "island" systems have their own ground spike (earth connection) as part of the installation. So if the battery and house can't take the load, the extra goes straight into the ground. So there is somewhere else for the electricity to go.

Simple installations, like motorhome/campervans; boats; a mains inverter clipped onto a battery; or a genny with a power tool plugged in, mostly operate without a ground spike.

A ground spike is needed, in more complex installations, to provide a protective earth connection. This is to prevent danger, where otherwise, a fault could make any metalwork on every connected appliance become 'live'. It can also ensure that Neutral is at or around ground potential, while Live is 230V AC. The latter is so that appliances with a single pole power switch, in the live connection, are safe when switched off.

You can't run any power through just a single wire connection, such a a ground spike. A minimum of two connections to the load is needed.

Monitoring leccy usage

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