Home Storage Battery

[Gadget Geek]

As we've had the first sunny weekend here in the southwest, I thought I'd just share this for anyone considering a solar PV system with battery.


We went off grid this morning at 06:55, and at 07:20 started to fill the 8kWh PowerVault. At 10:30 plugged the granny charger in to share the output. At 15:00 switched off the granny charger having put around 4kWh (7%) into the car. As of 15:30 the Powervault is still charging at 1kW and should be full at around 17:00.


With todays electricity prices and the increase imminent, if you can invest in solar, now is the time to do it.

 

[Harry]

As we've had the first sunny weekend here in the southwest, I thought I'd just share this for anyone considering a solar PV system with battery.


We went off grid this morning at 06:55, and at 07:20 started to fill the 8kWh PowerVault. At 10:30 plugged the granny charger in to share the output. At 15:00 switched off the granny charger having put around 4kWh (7%) into the car. As of 15:30 the Powervault is still charging at 1kW and should be full at around 17:00.


With todays electricity prices and the increase imminent, if you can invest in solar, now is the time to do it.

Yes, and even without solar, a battery charged overnight at cheaper rate can pay for itself quite quickly.

 

[Rob Smart]

My average usage was about 8KWh per day. Standard Price per KWh was 20p so if I consumed all power at that price it would be £1.60 per day, £584 pa (plus standing charge of about 20p per day).

I sized my battery to take almost all of my load so if it charges during off-peak @ say 5p per KWh it works out at 40p per day or £146 pa (plus standing charge of about 20p per day).

Check with Moixa that the 7.2 kWh is usable capacity and not the full battery capacity. I had an earlier Moixa battery and solar setup with a 3kWh battery (recommended at the time) which worked well but Moixa didn't tell me that they only let the battery discharge to 20% to prolongue the battery's life, and there are 10% charging and discharging losses with all battery systems, so the usable capacity was less than 2.4 kWh which is not much use for a house with 12kWh daily average use.

So I had a 13.5 kWh Tesla Powerwall installed instead which is also working well, and saving money so long as the Octopus Go tariff exists.

 

[TheRoadrunner]

We have a GivEnergy home storage system, which comprises of 2x 5.2kw batteries and a hybrid inverter. 7.2kw PV array, Zappi & an Eddi, all installed by Deege Solar. I have recently reduced our d/d with Octopus to £25/month, as we had built up a substantial credit. GivEnergy have great customer support. The system was installed May 2021, with no regrets, especially considering the recent price increases.

Just received our yearly report (bearing in mind system installed May 2021)

Total Energy Consumed 4454.20 kWh

Solar Energy Generated 3678.50 kWh

Solar Energy Consumed 2682.40 kWh

Solar Energy Exported 996.10 kWh

Consumed From Solar Directly 1700.20 kWh

Consumed From Stored Energy 1798.40 kWh

CO2 Saved 4481.22 kg

Do you have a gas supply or Is your home totally electric? What about heating system & cooking, or is the £25 per month to octopus your energy outlay in total?

 

[AussiePete]

Check with Moixa that the 7.2 kWh is usable capacity and not the full battery capacity. I had an earlier Moixa battery and solar setup with a 3kWh battery (recommended at the time) which worked well but Moixa didn't tell me that they only let the battery discharge to 20% to prolongue the battery's life, and there are 10% charging and discharging losses with all battery systems, so the usable capacity was less than 2.4 kWh which is not much use for a house with 12kWh daily average use.

So I had a 13.5 kWh Tesla Powerwall installed instead which is also working well, and saving money so long as the Octopus Go tariff exists.

The new batteries are pylontech us2000b, 2.4kWh. they do have usable of just under 2kWh based upon DOD of 80%. The Moixa AI does limit its use to prolong life, however I believe I will be ok

 

[Flat top]

Do you have a gas supply or Is your home totally electric? What about heating system & cooking, or is the £25 per month to octopus your energy outlay in total?

We do have gas supply. I've upped our monthly payments to £50. Which will build up our reserve for the impending rises. Our fixed rate with octopus ends end of August. Last week, the solar fully charged both batteries, heated the hot water cylinder & charged our GTE. Very pleased with our system (installed by Deege Solar). & that we did it.

 

[Hotlush]

Just in the process of getting quotes for solar+battery, and possibly an air source heat pump+thermal solar water heating/thermodynamic panel.

Roof should be ok with water panels but not enough room for a decent solar array so looking at an 18x10 summer house with a reinforced roof to take them.
Will have all the solar gubbins in the summer house.
Only real problems are will it give decent heat, and where to put a hot water cylinder.

 

[BarryH]

The new batteries are pylontech us2000b, 2.4kwh. they do have usable of just under 2kwh based upon DOD of 80%. The Moixa AI does limit its use to prolong life, however I believe I will be ok

It's not just a Moixa thing check out any of the battery providers and you'll find they quote nominal and Usable often expressed as DOD (Depth of Discharge).

GivEnergy I believe will state their capacity and DOD along with a guarantee period. If you want to discharge deeper then they will unlock a greater DOD but reduce your batteries guarantee. A little while ago the GivEnergy 8.2 had a DOD of something like 80% - 85% (without looking that figure up) but then began marketing it as a 100% DOD. Now you cant actually discharge and then recharge LEP batteries 100% so I asked the local installer to confirm with Tech Support my suspicion of what they had done and I was correct. GivEnergy had by using higher energy density cells increased the actual capacity to just over 10 kWh inside the same battery pack and had for marketing reasons chosen to keep the 8.2 kWh product name but label it as 8.2 kWh with an improved DOD performance of 100%. It's their choice how they market it but to keep it as 8.2 makes the product line up neater and easier to sell.

 

[enjoylife]

I have been waiting to get GivEnergy hybrid inverter and battery system installed but they are currently undergoing some serious supply issues (much like our cars!!) to the extent many well known solar PV companies have stopped using them and switched to alternative batteries where supply is better.

It is a shame as GivEnergy were doing well but they are not able to deliver now and having several months waiting time, not able to launch new products in time etc etc. so basically at this pace it will get left behind in the long run.

 

[Deleted member 2439]

As we've had the first sunny weekend here in the southwest, I thought I'd just share this for anyone considering a solar PV system with battery.


We went off grid this morning at 06:55, and at 07:20 started to fill the 8kWh PowerVault. At 10:30 plugged the granny charger in to share the output. At 15:00 switched off the granny charger having put around 4kWh (7%) into the car. As of 15:30 the Powervault is still charging at 1kW and should be full at around 17:00.


With todays electricity prices and the increase imminent, if you can invest in solar, now is the time to do it.

We had a PowervauLt 8kWh system installed three years ago. It was a total disaster & we had it removed a month later and a full refund. The unit actually worked ok, but it was VERY noisy and would not operate in a reliable way with mains voltages at the higher end of the uk spec limits so consequently produced lots of heat. It was removed and replaced with a LuxPower system and 19.2 kWh of Pylontech batteries. It was a great shame. I was also disappointed with their inability to answer straightforward questions on how the EDF aspect of the system would operate with respect to unit costs - a very specific point but fundamental to the way in which the overall EDF proposition worked. Hopefully yours has proven to be reliable & that our nightmare was not widespread.

 

[Gadget Geek]

We had a PowervauLt 8kWh system installed three years ago. It was a total disaster & we had it removed a month later and a full refund. The unit actually worked ok, but it was VERY noisy and would not operate in a reliable way with mains voltages at the higher end of the uk spec limits so consequently produced lots of heat. It was removed and replaced with a LuxPower system and 19.2 kWh of Pylontech batteries. It was a great shame. I was also disappointed with their inability to answer straightforward questions on how the EDF aspect of the system would operate with respect to unit costs - a very specific point but fundamental to the way in which the overall EDF proposition worked. Hopefully yours has proven to be reliable & that our nightmare was not widespread.

We had a few teething problems when we first had the unit installed 3 years ago (mainly due to buggy software updates. One of them needed a visit from a technician to reload the software), but on the whole, it has been very reliable.

The noise of the fans and the heat aren't a problem for us as it is out of the way in the pantry under the stairs.

We went with the EDF grid balancing option to get £2,000 off the price, and as it works in the background haven't noticed any differences in performance.

Maybe you got a duff unit as they were a newly released product at the time.

 

[Deleted member 2439]

We had a few teething problems when we first had the unit installed 3 years ago (mainly due to buggy software updates. One of them needed a visit from a technician to reload the software), but on the whole, it has been very reliable.

The noise of the fans and the heat aren't a problem for us as it is out of the way in the pantry under the stairs.

We went with the EDF grid balancing option to get £2,000 off the price, and as it works in the background haven't noticed any differences in performance.

Maybe you got a duff unit as they were a newly released product at the time.

It was the EDF offer that we signed upto as well. The issue for us was their admission that the charger/inverter unit was not specced to operate with the full possible range of UK supply voltage, ie 240 volts +/-. Our supply voltage is on the high side despite being within the DNO limits, but was higher than the unit would work with. This was despite several visits from by engineering to fix the problem- which was essentially a shortcoming in the design. The replacement system is totally silent & just works.

 

[hmadsen]

Last spring i installed a 7.2 kWh solar bank, and a 6½ kWh battery together with an inverter.

I am planning on using the "excess" power to charge the MG ZS EV, i just need a charger that has Home Assistant integration, and will accept a "sensor" in HA, that is essentially the wattage that is surplus at any given time.

If i can get a charger that can adjust the charge wattage dynamically to this sensor figure, i will be able to put max energy into the car, instead of selling it for next to nothing.

 

[biffo]

Last spring i installed a 7.2 KWh solar bank, and a 6½ KWH battery together with an inverter.

I am planning on using the "excess" power to charge the MG ZS EV, i just need a charger that has Home Assistant integration, and will accept a "sensor" in HA, that is essentially the wattage that is surplus at any given time.

If i can get a charger that can adjust the charge wattage dynamically to this sensor figure, i will be able to put max energy into the car, instead of selling it for next to nothing.

Don’t know about others, but think the Zappi can support all of this

 

[hmadsen]

Don’t know about others, but think the Zappi can support all of this

The main "problem" with the Zappi if i understand it corretly, they want you to have an amp-clamp or some other device to measure the stuff it needs to calculate the wattage.

I already have all the numbers, so no need to add any more energy measuring devices, and also, my solar panel system has a smart meter, that measures what i use combined on all 3 phases, and then it delivers back into the system what the total energy consumption is, on the one phase.

Those smart meters that the Charging people want to sell, will probably not work correctly with that setup.

All that was needed was an API that would accept stepless adjustment of the wattage, and then an integration into Home Assistant.

That being said, when i say "all that is needed" i mean...All that i need someone else to do, because i am nowhere near good enough to make this stuff myself.

In the end, i am probably going to have to just buy a charger that i can manually adjust, and then adjust it myself. The disadvantage is offcourse that they usually are not stepless, they only work in fixed intervals, and also, i need to know that my wife turned on the oven and stove and adjust or stop the charging.

 

[biffo]

The main "problem" with the Zappi if i understand it corretly, they want you to have an amp-clamp or some other device to measure the stuff it needs to calculate the wattage.

I already have all the numbers, so no need to add any more energy measuring devices, and also, my solar panel system has a smart meter, that measures what i use combined on all 3 phases, and then it delivers back into the system what the total energy consumption is, on the one phase.

Those smart meters that the Charging people want to sell, will probably not work correctly with that setup.

All that was needed was an API that would accept stepless adjustment of the wattage, and then an integration into Home Assistant.

That being said, when i say "all that is needed" i mean...All that i need someone else to do, because i am nowhere near good enough to make this stuff myself.

In the end, i am probably going to have to just buy a charger that i can manually adjust, and then adjust it myself. The disadvantage is offcourse that they usually are not stepless, they only work in fixed intervals, and also, i need to know that my wife turned on the oven and stove and adjust or stop the charging.

I don't have a Zappi, or use Home Assistant, but there are lots of threads on the MyEnergi API Forum that might have the details you're looking for.

API

myenergi-Details of the API, example projects and discussion

myenergi.info

 

[hmadsen]

I don't have a Zappi, or use Home Assistant, but there are lots of threads on the MyEnergi API Forum that might have the details you're looking for.

API

myenergi-Details of the API, example projects and discussion

myenergi.info

Tried asking on there, maybe they know for sure what is possible.

I have asked different places and most have said like you "I think product X will do this" but before shelling out a lot of money on a charger that might not actually do what i want, i wanted to be "absolutely sure" before investing.

I don't have a moneytree in the back garden, so i can not afford to buy multiple chargers just to find the one that works in my usecase

 

[BarryH]

The main "problem" with the Zappi if i understand it corretly, they want you to have an amp-clamp or some other device to measure the stuff it needs to calculate the wattage.

I already have all the numbers, so no need to add any more energy measuring devices, and also, my solar panel system has a smart meter, that measures what i use combined on all 3 phases, and then it delivers back into the system what the total energy consumption is, on the one phase.

Those smart meters that the Charging people want to sell, will probably not work correctly with that setup.

All that was needed was an API that would accept stepless adjustment of the wattage, and then an integration into Home Assistant.

That being said, when i say "all that is needed" i mean...All that i need someone else to do, because i am nowhere near good enough to make this stuff myself.

In the end, i am probably going to have to just buy a charger that i can manually adjust, and then adjust it myself. The disadvantage is offcourse that they usually are not stepless, they only work in fixed intervals, and also, i need to know that my wife turned on the oven and stove and adjust or stop the charging.

I'm not sure what your problem is with allowing Zappi to regulate its EV charging to capture surplus electricity that would have otherwise gone to the grid. Zappi has the control logic to do all you want surely and can respond to your fluctuations in your domestic load with its progressive charging. I don't believe simply steplessly adjusting the available charging current and using a regular EVSE would work. Doing so on the supply side would affect the control system electronics too and result in charging malfunctioning. Regulating the output of the EVSE could have an undesirable impact on the EV's Onboard Charging circuitry which could damage the EV and be very expensive, MyEnergi didn't develop the Zappi overnight and there are surprisingly few EVSE providers that offer any kind of charge rate dynamic control, so what does that tell you? It tells me that there is more to it than puting a high power dimmer switch!

 

[hmadsen]

I'm not sure what your problem is with allowing Zappi to regulate its EV charging to capture surplus electricity that would have otherwise gone to the grid. Zappi has the control logic to do all you want surely and can respond to your fluctuations in your domestic load with its progressive charging. I don't believe simply steplessly adjusting the available charging current and using a regular EVSE would work. Doing so on the supply side would affect the control system electronics too and result in charging malfunctioning. Regulating the output of the EVSE could have an undesirable impact on the EV's Onboard Charging circuitry which could damage the EV and be very expensive, MyEnergi didn't develop the Zappi overnight and there are surprisingly few EVSE providers that offer any kind of charge rate dynamic control, so what does that tell you? It tells me that there is more to it than puting a high power dimmer switch!

The problem with using the "amp clamp" version is that it does not take into account how much power the solar panels produce as far as i can see.

Also, my house has 3 phase power, and the smart meter will add the load on all 3 phases and then feed the same amount of power back into the grid to null out the buying of power.

I want to use only what is available up to 3600 watts but if the solar panels only make, lets say 2500 watt's and the house uses 1000 watts, i want it to charge at 1500 watts.

I know i am a bit particular, but the whole idea of solar panels and the electric car for me was to be able to charge the car, without paying anything as i fill it with my own solar power.

 

[Deleted member 2439]

The problem with using the "amp clamp" version is that it does not take into account how much power the solar panels produce as far as i can see.

Also, my house has 3 phase power, and the smart meter will add the load on all 3 phases and then feed the same amount of power back into the grid to null out the buying of power.

I want to use only what is available up to 3600 watts but if the solar panels only make, lets say 2500 watt's and the house uses 1000 watts, i want it to charge at 1500 watts.

I know i am a bit particular, but the whole idea of solar panels and the electric car for me was to be able to charge the car, without paying anything as i fill it with my own solar power.

The Zappi uses a device called a Harvi which has amp clamps (actually called current transformers, or CTs here), to measure the loads of the house, solar and battery (if fitted). They all connect wirelessly via a Hub device which is connected via Ethernet to your home network. It all works well, with the Harvi and Hub devices being very cheap also.