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Solis Hybrid - charge battery using Night rate



  • Moderators Posts: 12,155 ✭✭✭✭ Black_Knight

    That did it for me. Thanks all! Now where's the sun?

  • Registered Users Posts: 2,625 ✭✭✭ yankinlk

    thats just the way solis cloud displays the data. Its a pain and there is no fix for that unfortunately. We have talked about this problem in a few threads around here - hoping solis will fix it eventually.

  • Moderators Posts: 12,155 ✭✭✭✭ Black_Knight

    Curious one. My inverter display shows X going out from the battery, but much less going into the house. What's that about?

  • Moderators, Education Moderators, Home & Garden Moderators Posts: 7,587 Mod ✭✭✭✭ Jonathan

  • Registered Users Posts: 1,497 ✭✭✭ Manion

    That seems huge, could that be right?

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  • Registered Users Posts: 1,288 ✭✭✭ Big Lar

    From my reckoning the inverter is 130w just to run then conversion losses after that

  • Registered Users Posts: 1,497 ✭✭✭ Manion

    That seems consistent

    i had assumed inverter load was in the house stat but maybe not. That's not so bad so.

  • Registered Users Posts: 19,359 ✭✭✭✭ ELM327

    Yup,mine is similar. There are a fair amount of losses to run the inverter and to invert from DC to AC. You'll see less losses if running direct on solar.

  • Registered Users Posts: 3,512 ✭✭✭ graememk

    I wonder would you just not see that power.

    Eg, inverter uses 100w to stay on.

    When running from solar, inverter gets "first dibs" and you never see that power.

  • Registered Users Posts: 1,497 ✭✭✭ Manion

    Maybe that's exactly whats happening? The battery discharge I think is coming from the battery itself and the house consumption is coming from the power meter at the consumer unit, so the difference would be what the inverter is using and loosing? Makes a little more sense now.

    Has anyone had any luck tapping into the power meter at the CU? I've a Eastron SD120CT. Been thinking about trying to get direct access to to the data coming back from that.

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  • Registered Users Posts: 19,359 ✭✭✭✭ ELM327

    There's two separate things.

    Power to run inverter - yes you may not see it if the inverter is running on solar

    DC to AC inverter losses - I get the feeling that the solis (the only inverter I have with a OSD) experiences more losses going from battery DC to grid AC, as opposed to Solar DC to immediate grid AC.

  • Registered Users Posts: 20 aleesi

    While not mentioned in the datasheet the inverter also needs power to run. I've observed 100-150Wh needed to run the Solis depending on house load. But it could take much more if for instance charging the battery from the grid at 100A, as the efficiency is 95-99% (DC-AC efficiency), if you take the 95% for the worse case scenario (charging at 100A or putting 5kWh in the battery) you have to add an extra 250Wh to the 100-125Wh so the Solis could take 350-400Wh while working at full blast (from / to the battery).

    If we talk about Solar PV (tipically 300-400V DC) to 230AC, the efficiency is much better as the DC coming from the panels is typically 300-400VDC, conversion from DC to AC are much more efficient when the DC voltage is much higher than the AC (400DC vs 230AC), for the battery we start with 50VDC much lower than 230AC and therefore not as efficient.

  • Moderators Posts: 12,155 ✭✭✭✭ Black_Knight

    Thanks! Certainly seeing a couple of hundred W more drawn from the battery than is being consumed by the house. Currently 233W drawn, but the battery is supplying 448W.

  • Registered Users Posts: 2,874 ✭✭✭ con747

    That's the way it is, I have a house load now @ 162w but 278w coming from the battery. That's real time, not via the app because my inverter is beside my kitchen.

  • Moderators Posts: 12,155 ✭✭✭✭ Black_Knight

    Thanks for confirming. This is making creating a nice representation in home assistant a touch difficult. Using the "tesla style solar power card". Calculating my "solar to grid" power is a bit difficult, because Solar generated - house consumption - battery output is currently saying a couple of hundred W going out, when in reality it's just being used by the inverter itself.

    Thanks though, i'll figure it out eventually.

  • Registered Users Posts: 3,512 ✭✭✭ graememk

    Are you using the pysolarman in home assistant?

    I'll need to dig up the register, I don't think it's in the default config but there is another value, BMS Volt/ Current /Power. And this value is supplied by the battery over the CAN bus.

    I'm not logging the inverter AC power.. but I am monitoring the Volt and current, so that can be calculated.

    I trust the BMS value as Ive verified it on my BMS with a clamp meter.

    BMS Power : 893w

    Battery power according to Solis : 973w

    Solis AC power : 780w.

    Yeah.. i dont know where solis is picking up its battery power

    (all this data pulled from the inverter using the pysolarmanv5 every 10ish seconds.)

    There is also a DC Power which is the Solar only output.

  • Registered Users Posts: 441 ✭✭ alan kelly

    Hey Folks,

    On reviewing some of the comments I looked at my battery settings and the times set by the engineer.

    Im on the Electric Ireland night rate, 12p from 2-4am and 20p from 11pm to 8am.

    My original settings are below along with what the engineer set it at. It doesn't make sense to me so I changed the times for the battery to charge from 2am to 8am. Am I correct or was the Engineer correct ?

  • Registered Users Posts: 3,512 ✭✭✭ graememk

    The discharge time should be set to 00:00 to 00:00.

    What you set it to is fine

  • Registered Users Posts: 441 ✭✭ alan kelly

    Thanks, does the charge and discharge limits look ok ?

  • Registered Users Posts: 752 ✭✭✭ DC999

    I didn’t notice the size of your battery. If you’re starting when the night rate kicks in (11pm you said), check it’s not charged before the cheap 2-4am slot. If it is, you’ve overpaying. So could start at 2am (to get 12c). Then stop when night rate ends (which is remainder at 20c). 

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  • Registered Users Posts: 3,512 ✭✭✭ graememk

    If your battery is 5kwh, I'd leave it be,

    Discharge limit doesn't matter, it won't be used. (Discharge times will force discharge the battery at them times, no matter the load)

    Setting it to go from 2-8 is a good idea, battery should get charged on the cheapest rate, it will also prevent discharge on night rate.

    As the battery will likely be empty by 11pm you don't have to worry about blocking out that time.

  • Registered Users Posts: 38 brendandonlon

    Hello to all on this thread - I'm trying to work out what sort of battery capacity I can get fully charged in the two hour super-cheap slot between 2am and 4am.

    So I've currently got a 3.5kw Pylontech, and I'm looking to add one or two additional 4.8kw Pylontech batteries to get our total battery storage close to our above our average daily use, which is approx 12kwh.

    But looking at this charge time calculator, it looks like the limits of how fast I can charge the smaller capacity battery is going to really constrain how much power I can put into the total battery capacity during that two hour slot.

    Am I right in my understanding that the 37Ah charging rate for the Pylontech 3000 means it would take nearly 8 hours to fill up all three batteries? Or have I got the maths wrong?

    Or does anybody else have experience of setting the charge rate when you're dealing with a mixed group of batteries?

    Thanks in advance!

  • Registered Users Posts: 19,359 ✭✭✭✭ ELM327

    You won't have a mixed group of batteries, once you parallel them it will be one big battery. Once the bms realises that then the charge rate would increase accordingly.

  • Registered Users Posts: 38 brendandonlon

    Thanks - but what charge limit would I select in the Solis Inverter settings? The default is 050.0A (50 amps, I presume) - and the smaller battery spec sheet says it's charge rate maxes out at 37Ah but the larger has a higher charging rate limit of 80Ah…

    Are you saying I just leave the Solis cranking away at 50 amps and let the batteries manage how much power they accept?

    Given that, how much of the approx 13kWh in the batteries will be charged in two hours?

    (I'm getting maths exam anxiety flashbacks at this point…)

  • Registered Users Posts: 752 ✭✭✭ DC999

    Would you not be better on a D/N meter? No charge to swap out the smart meter. They have something like 9 hours night rate. Afaik its’s 11pm to morning. Energia D/N night rate is somewhere around 13.5C maybe. Until solar deemed export disappears, I don’t see the downside of moving to a D/N from a smart meter. And with batteries, you’ll export less so getting deemed export is to your advantage. I’ll be moving to a D/N once I get offered a smart meter (I’ve reasons to stay on current 24hr meter).

    For people filling a battery (in winter), and charging an EV and load shifting…. 9 hours is so much easier than 2. 2 hour window means everything has to start at the exact same time and go flat out.

    With a D/N, you could even plug in electric rads to be on a timer to heat parts of the house on night-rate just before ye get up. Cost less than gas + oil some here suggest.

    Our EV only charges at 3.6kW (old Leaf) so 2 hour slot won’t even fill ours.  

  • Registered Users Posts: 38 brendandonlon

    I looked into this last year (also to charge EV) and I was told it's no longer possible to replace Smart Meter for a Day Night meter.

    Initially (in Feb 2022) I was told it was an option, but with a much larger standing charge and a significant installation fee - and an even larger replacement fee if we ever reverted to Smart Meter.

    But when I looked to action this later in the year - as I had done the maths and figured it was worth doing - I was told it wasn't possible any more. Didn't pursue why, but it was just after we had our solar PV installed, so I presume that may have triggered something on our account.

  • Registered Users Posts: 19,359 ✭✭✭✭ ELM327

    Yes the default is 50a. assuming you have the 6kW inverter I would set the max to 100a and let the battery bms sync and decide what it can take. Thats what I do. Set it to 100 in the charge timer screen.

  • Registered Users Posts: 38 brendandonlon

    So if I've got my calculations right here, that gives me a charge time for a 13kw battery of 2.9 hours - does that sound right?

  • Registered Users Posts: 19,359 ✭✭✭✭ ELM327

    So if you're using a solis 6kW inverter it will drop down to 75A from 100A after 15 minutes. 100A is about 5kW, 50A is about 2.5kW and 75A is about 3.75kW.

    I'd base my estimates off 75A or 3.75kW. 13kWh to be added at 3.75kW would take approx 4 hours, allowing for speed tapering at the top end.

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  • Registered Users Posts: 752 ✭✭✭ DC999

    Ah, I was told there is no charge from a 24hr meter to a D/N.