Advice AC coupled charger/inverter, charge from surplus solar and TOU tariff.

chuckp

chuckp

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Jul 29, 2018
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Hi guys

Chuck from the UK here.

Sorry If this have all been asked before, please could someone point me in the right direction to any appropriate threads.

Ok I have an 6kWp solar array (also enough panels to potentially fit an additional 3kWp),APS YC500I micro-inverters giving me a 240V A.C. supply from the panels sited away from the house.
I also have a TOU tariff, (economy 10) 10hrs off peak. 4hrs morning, 2hrs midday and 4hrs evening, tariff is0.07p/unit, off peak rate and 0.21p/unit peak.

My typical home usage is between 500Wh and 1kWh increasing to around 4-5kWh when the hot tub kicks in etc.
During the day I export between 2kWh to 4kWh (5kWh to15kWh per day)depending on available solar, cloudy/rainy days are much lower.

I have started on my Powerwall packs, 18650's, 14s100p. I want to use aBatrium bms. At a later date i would like to add additional 14s100p to increase available storagecapacity.

Questions are:

1. What bidirectional A.C. coupledcharger/inverter would you guys recommendto charge my batteries from the surplus solar energy (240V A.C.) and also fromthe TOU tariff so that I can use the batteries to supply my house during peak hours?
2. Could I use a CT clamp and controller of some sort onmy incoming meter tails to allow charging during surplus export?
3.Could I do the same as above on a supply to an unused off peak distribution board to change from TOU tariff?I would obviously put a load on the board so that the CT clamp had something to measure.
4. Best way to prevent power from feeding back into the grid in the event of a grid supply failure/power cut? Anti-islanding.
5. When adding additional packs to the Batrium bms is it best to wait until I have built all 14 additional packs orcan i add them as I go along?


Thanks guys and apologies as I'm sure this has all been asked before.
 
Regarding #4:

This feature is built into the micro-inverters. If yours don't have it then you're using a model that isn't necessarily worth a recommendation and possibly even illegal. It depends on your local laws and regulations. Here in Germany it took us a while to permit the operation of solar panels with micro-inverters but it seems that we got it now. The inverters are required to have a so called "ENS" which stands for "Einrichtung zur Netzberwachung mit zugeordneten Schaltorganen". Don't even try to translate it, it's just a red tape terminology and describes an Anti-Islanding functionality according to our local regulation VDE-AR-N 4105. I'm not familar with the regulations in the UK but I guess you will have something similar and using inverters without it is illegal. Several micro-inverters compliant to this regulation are available.
For example the EVT248 which is compliant to these regulations: VDE-AR-N-4105, VDE 0126-1-1, G83/2, UTE C15-712-1, AS4777, EN50438, EN62109, EN61000
Maybe one of these is valid for the UK.
 
DarkRaven said:
Regarding #4:

This feature is built into the micro-inverters. If yours don't have it then you're using a model that isn't necessarily worth a recommendation and possibly even illegal. It depends on your local laws and regulations. Here in Germany it took us a while to permit the operation of solar panels with micro-inverters but it seems that we got it now. The inverters are required to have a so called "ENS" which stands for "Einrichtung zur Netzberwachung mit zugeordneten Schaltorganen". Don't even try to translate it, it's just a red tape terminology and describes an Anti-Islanding functionality according to our local regulation VDE-AR-N 4105. I'm not familar with the regulations in the UK but I guess you will have something similar and using inverters without it is illegal. Several micro-inverters compliant to this regulation are available.
For example the EVT248 which is compliant to these regulations: VDE-AR-N-4105, VDE 0126-1-1, G83/2, UTE C15-712-1, AS4777, EN50438, EN62109, EN61000
Maybe one of these is valid for the UK.
Click to expand...

Thanks for your reply.
Yes my micro-inverters do have anti-islanding built in,
The questionwas withreferenceto what bi?directionalcharger/inverter I should use in order to prevent the batteries from supplying the house asan island.
Sorry I could have been a bit clearer.
 
Im doing a similar setup as our Solar is microinverter basedbecause of a weird roof shape and shading.
Im using a Victron Multiplus, itll charge before exporting if youre generating surplus, provide backfeed protection in a grid outage but still provide power to your home and communicate with the Batrium BMS.

When adding additional packs you need to add them all at the same time.
 
floydR said:
https://enphase.com/sites/default/f...ion-Note_AC-Coupled-Battery-Based-Systems.pdf
in the pdf they describe both off grid/mircointerter usage and grid tie with battery backup using micro grid tie inverters
might be something in there you can use

later floyd
Click to expand...

Thanks I'll take a look.

KtB said:
I am in the UK and have been using this http://www.sofarsolar.com/product-detail/323/ME-3000SP
for the last year. It has worked very well.
Click to expand...

Hi KtB

I've been looking at that same unit for some time know,

I spoke to SoFar tech support,but they wont give me any informationregarding the Canbus communications protocol, so I don't knowif it would be compatible with the Batrium bms coms.
I know both havean RS458 communications port, what i could potentially use to control the Sofar from the Batrium Modbus?
Itwould then be a case of setting up the charge/discharge perameters on the MB300SP to suit my needs.
Are you using the 48VBatrium to control the charge current? If so would the settings be similar for my 48V 18650 batteries as your 48V lifep04 batteries?

The SoFar tech support were only interested in helping if I wanted to buy the Pylon 2.4 kWh batteries at 820 someodd a piece.
 
Jon said:
Im doing a similar setup as our Solar is microinverter basedbecause of a weird roof shape and shading.
Im using a Victron Multiplus, itll charge before exporting if youre generating surplus, provide backfeed protection in a grid outage but still provide power to your home and communicate with the Batrium BMS.

When adding additional packs you need to add them all at the same time.
Click to expand...

Thanks

I too have a problem with shading, between around 09:30 until about 12:00 i have 4 panels that are affected, witha string inverter i would be losing out on loads of power. Howeverthis wasn't the original reason I went down the micro inverter routeas the shading has only been an issue this year since the neighbours trees have grown higher. I usedmicro inverters because i needed to install my panels over a long period of time and thought that would be the best way of gaining energy from the start.

I just seen a video (i can't seem to find it now to post a link)for the Batrium. This guy was showing how to setup the additional cell packsin a multi string parallel system. Very interesting if I find it again I will post a link.
 
chuckp said:
floydR said:
https://enphase.com/sites/default/f...ion-Note_AC-Coupled-Battery-Based-Systems.pdf
in the pdf they describe both off grid/mircointerter usage and grid tie with battery backup using micro grid tie inverters
might be something in there you can use

later floyd
Click to expand...

Thanks I'll take a look.

KtB said:
I am in the UK and have been using this http://www.sofarsolar.com/product-detail/323/ME-3000SP
for the last year. It has worked very well.
Click to expand...

Hi KtB

I've been looking at that same unit for some time know,

I spoke to SoFar tech support,but they wont give me any informationregarding the Canbus communications protocol, so I don't knowif it would be compatible with the Batrium bms coms.
I know both havean RS458 communications port, what i could potentially use to control the Sofar from the Batrium Modbus?
Itwould then be a case of setting up the charge/discharge perameters on the MB300SP to suit my needs.
Are you using the 48VBatrium to control the charge current? If so would the settings be similar for my 48V 18650 batteries as your 48V lifep04 batteries?

The SoFar tech support were only interested in helping if I wanted to buy the Pylon 2.4 kWh batteries at 820 someodd a piece.
Click to expand...


It does work with the batrium bms ( Thats what Ihave)over can bus using one of the project profiles and controls charging and cutoff voltages ok
I was hoping for official support for the sofar in a future update but there have been none for quite a while.
You can set any voltages etc you want within reason on the batrium and it then controls the sofar and manages state of charge
 
It does work with the batrium bms ( Thats what Ihave)over can bus using one of the project profiles and controls charging and cutoff voltages ok
I was hoping for official support for the sofar in a future update but there have been none for quite a while.You can set any voltages etc you want within reason on the batrium and it then controls the sofar and manages state of charge

That's great, what profile do you use. In the manual i see it lists three options:

1.DARFON DARFON EAA01 2.7KWH
DARFON EIA02 5KWH
2.PYLON PYLONTECH US2000B
(BMS firmware should be B63 or newer)
3.TELE TELELEAD CRYSTAL

Obviously not option 3, am I correctin thinking that the Pylontech batteries are Lifp04?, So I guess that it would be the option 1, Darfon batteries, I've not familiar with these batteries but I guessing they will be style of Lithium batyery.

From all the threads I'mreading Ithink I will have a pretty good idea of his to set it up,

Sorry I have one more question, if using the time of use grid charging feature, would you know if it can charge from economy 10, ie: 3 separate charging periods?

Thanks
 

KtB said:
There are more options standard lithium and lead acid i have used both the pylon tech one and I am now using the standard lithium option they both work for managing charging and state of charge
Don't have economy 10 but will have a look in the options for forced charge
Click to expand...

Ok Had a look, there seemsto be 4 periods a day you can set i have attached a pic. This is using the latest 1.8 firmware for the sofar.


image_enhyrc.jpg
 
KtB said:

KtB said:
There are more options standard lithium and lead acid i have used both the pylon tech one and I am now using the standard lithium option they both work for managing charging and state of charge
Don't have economy 10 but will have a look in the options for forced charge
Click to expand...

Ok Had a look, there seemsto be 4 periods a day you can set i have attached a pic. This is using the latest 1.8 firmware for the sofar.


image_enhyrc.jpg

Click to expand...


Thanks buddy

That's great i think I'm going to be placing an order for it as soon as I have completed enough packs.
 
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