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Best hybrid inverter for charging large battery (> 32kwh)

  • 05-11-2024 04:04PM
    #1
    Registered Users, Registered Users 2 Posts: 182 ✭✭


    Hi all! I have pretty much read everything in this thread and done a lot of research elsewhere too. I've decided I want to DIY some battery systems. Im thinking at least 2 x 15kwh setups, maybe more. I have a heatpump so I heat water at cheap night rate. I have no EV and dont plan on one in the near term. Currently on energia's smart data plan (11am - 8am @ 14c). Planm to change to their 4hr EV or to Pinergy 3hr EV rates. My goal is to fill the batteries during cheap EV rate, then run the house with solar & battery and dump everything back to the grid in the evening for FIT.

    My solar setup and requirement is similar to ECO_Mental. 6 kwp (south facing) and and a 6 kw Solis grid tied non-hybrid inverter (NC6 form has 6 kw export). I setup home assistant and it works great for monitoring use and FIT. My daily use is actually quite low, about 10kwh/day. It appears from my research there are 3 possible routes for me to take:

    1. Get a 6 kw solis hybrid (or similar 6kw hybrid). I'm limited to only 6 kw of EV rate charging (18kwh pinergy or 24 Energia). My other use during this time is very low, only HP runs for maybe 1 - 1.5hr @ 1.5-2kw max. This seems like a waste and limits the battery size I can get use out of. Although 2 x 15kwh system would be sufficient here (18 - 24kwh charging.
    2. Get an inverter that can be limited to 6kw feed in on the grid side but can charge the battery >6kw (maybe something that can charge batteries up to 10kw. This seems like the most straghforward from implementation & control standpoint. Thoughs here? Is this not possible or practical? Whats the best indverter to go with as I need a new one?
    3. Standard 6kw hybrid (solis or other) and supplement charging with rectifiers. This is my least preferred option.

    Please any help from the experts here would be great. To me option 2 sounds the most ideal?



Comments

  • Registered Users, Registered Users 2 Posts: 170 ✭✭darraghsherwin


    Have a look at the Sunsnyk/Deye inverters, they can do up to 290amps charge/discharge on single phase, see

    https://www.deyeinverter.com/product/hybrid-inverter-1/sun12-14-16ksg01lp1-1216kw-single-phase-3-mppt-hybrid-inverter.html

    Euromotive Energy in Carrick-On-Shannon are a distributor for Deye



  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    Amazing thanks for the info. I presume straightforward to hard limit the current on the grid export side to stay within 25amp?



  • Moderators, Home & Garden Moderators Posts: 7,102 Mod ✭✭✭✭graememk


    It is, but ESBN rules that export limit isn't allowed under nc6, it's a inverter limit not an export limit.

    Although, they don't have any way of detecting it...



  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    My PV system cannot exceed the current export limit, and I can also cap the battery’s export current at 25A, and/or only allow the battery to export 25A after sunset. This setup effectively prevents exceeding the export limitation. I understand that the NC6 limit applies to the inverter itself. Even if ESBN monitors my smart meter data, I would still remain within the set export limit.

    I would want to configure the maximum export current on the inverter’s grid side to match my existing Solis 6kW, which I believe allows up to 26.2A, or even limit it to 25A if that’s preferable.

    Am I correct in assuming that the inverter uses separate circuits for import and export currents—allowing up to 290A (on the 16k model) for import while capping export at 25A?

    My home was built 4 years ago with a 12kVA MIC, though I’ve asked ESBN about upgrading to a 16kVA MIC, and I’d consider it if the cost is reasonable.

    In my case, what would be an ideal charging power for the batteries over a 3 to 4-hour period? My current peak loads are no higher than 2–2.5kW (HP at night plus all other loads), so I believe a constant charging power of 8–10kW over those hours would be safe.

    Could you suggest an ideal inverter size for this setup?



  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    Nice it seems straigforward to set import or export power in the controls of the Deye Sun models:

    image.png


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  • Registered Users, Registered Users 2 Posts: 2,646 ✭✭✭SD_DRACULA


    It's about 2k for the 16kva upgrade and yes "big" inverters can limit export to whatever you want but I wouldn't put anything like a 16kw inverter in the attic, they make A LOT of heat and need proper cooling



  • Moderators, Home & Garden Moderators Posts: 7,102 Mod ✭✭✭✭graememk


    Also the import power limiter allows the inverter to grid limit itself to whatever you set it.

    So if the HP comes on overnight, it will slow the charging.

    The higher powered ones are noisy when the fans are running (I think the 5 kW ones are fanless)

    Low noise mode is low electronic noise. Not noise.. noise.



  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    I love this feature- Does it require putting a CT clamp on the grid feed to communicate with the Inverter? I already have CT claps that are used for Shelly 3EM/Home assistant.

    The inverter will be in my attic. I would like to keep noise and heat to a minimum as I'm planning an attic conversion to a bedroom so plan on having the inverter & battery setup in a seperate small room up there. So maybe should aim for a lower power one (maybe 8 or 10kw). Whats the best spec in that range?



  • Moderators, Home & Garden Moderators Posts: 7,102 Mod ✭✭✭✭graememk


    Hybrid inverters need a ct (or meter) to monitor the grid for normal use.

    Bear in mind, Your current wiring for the inverter would have been sized for a 6kW inverter, would be undersized for anything bigger too.



  • Registered Users, Registered Users 2 Posts: 2,646 ✭✭✭SD_DRACULA


    You will not be sleeping when the fans kick in on the big ones and will probably hear it downstairs too.

    The 8kw versions are quiet enough though, you could get two and parallel them but again you'd want decent air flow when you do max charging on them, you'd be heating whatever room they're in quite a bit through the conversion loses

    And you certainly cannot put them in the eaves if you want to convert the attic or they won't last long.



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  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    It seems that an 8kW maximum output would likely be the best choice (for less noise & heat). Relocating the inverter isn’t really feasible since the utility room is quite small. The AC-side wiring appears to be sufficient; the wires are relatively thick on the solar AC side (see attached photos). However, the 32A breaker will need to be replaced with a larger one to handle the increased load when I'm charging the battery (Likely drawing up 34 A @ 8kW on grid side). I agree Ill need to plan a decent space in the converted attic for the inverter and battery. Even if I keep the existing 6k solis, Ill need to think about how to locate it in the attic.

    My main concern now is connecting a CT clamp to the new inverter. Running a direct wire from the CT clamp at the grid feed in the consumer unit up to the attic will be challenging. Are there other options, such as a wireless connection to the clamp? Whats the easiest thing to do?

    image.png

    image.png image.png


  • Registered Users, Registered Users 2 Posts: 2,717 ✭✭✭ECO_Mental


    I think @...Ghost... going to add in just an additiionl charger to his setup like the one below because he is installing about 45 kWh of battery storage and he has if I am not mistaken a 6 kW solis Hybird. How this is added in I dont know but this might be a better option. I need to know myself as well because if I am going to get a bettery as it will be around the 30 kWh and I have a 16 kVA connection so I can really hammer it. The charger here is only about 1.6 kW but you can get bigger ones I think Ghost had a link also as well

    LiFePO4 Charger (Fogstar Energy) - 48V 35A

    image.png

    6.1kWp south facing, South of Cork City



  • Registered Users, Registered Users 2 Posts: 2,646 ✭✭✭SD_DRACULA


    I think someone on the forums has been using the wireless CTs, maybe even myenergi stuff? I don't recall who though.

    And yes technically you can do 8kw on 6mm2 cable (sunsynk manual confirms it too) but I did manage to burn out a 32a rcbo after a while of full whack charging, so I'd go for a 40a at a minimum.



  • Moderators, Home & Garden Moderators Posts: 7,102 Mod ✭✭✭✭graememk


    If you use a meter (eg Eastron) that uses a rs485 serial connection. That can be transmitted converted to either modbus tcp (to be transmitted over a network via WiFi or cable) and then back to serial at the inverter.

    There is lo-ra transceivers that do it too.

    My energi stuff is only wireless via a harvi



  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    Can you tell visually its at least 6mm2 cable, worried its only 4…. Yeah was thinking of having the exisiting 32A RCBO replaced with 40A one. Was hoping this would be as straightforward as just replacing the exisitng inverter. I imagine rewiring from the consumer unit to the inverter would be really expensive and then likely an electrician wouldnt do it



  • Registered Users, Registered Users 2, Paid Member Posts: 4,725 ✭✭✭...Ghost...


    That's right. I'll be adding an Emerson R48 (57V, 3kW) charger which will run from a timed 25A smart switch.

    I now have 46kWh with 40kWh useable storage.

    My Solis inverter is only 5kW. 8kW would do me fine for charging/discharging.

    Stay Free



  • Registered Users, Registered Users 2 Posts: 2,646 ✭✭✭SD_DRACULA


    Yeah the emerson is fine but it does sound like an airplane taking off at full whack which is fine for you when placed outside.

    Yeah on the grey sleeve it should say the size usually.

    They did put 6mm2 for me when I had the 6kw solis so maybe you have the same



  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    I think looking good for the AC wiring to the invereter. The grey sleeve shows markings for 6mm2 wires (3x6 RF):

    image.png

    So based on this, an 8kW inverter would be the max. I think I would be happy with 8kW charging capability. Other option is to get it rewired to 10mm but if 6mm is sufficient then thats fine. What the best 8kw inverter you would recommend (most functionality with lowest noise and heat production)?

    Here are some pics of the exisitng inverter install. Any thoughs on suitablilty of location and adding batteries for attic conversion? Some other option Im not thinking of maybe?

    image.png image.png


  • Registered Users, Registered Users 2 Posts: 2,646 ✭✭✭SD_DRACULA


    Either sunsynk/deye 8kw hybrid but if you box it off there it won't be good for it without some decent ventilation



  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    Yeah I figure even if I stick with the exisitng 6kW grid tied Solis inverter its going to need ventilation after conversion. Its a 97.1% efficiency so effectivily a ~174W heater when the panels are fully maxed. Assuming similar efficiency, an 8kW inverter would be ~230W heater.

    I notice there is an Ecco version of the Sunsynck 8kW hybrid. Its smaller and appears to use passive cooling so nice and quiet.



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  • Registered Users, Registered Users 2 Posts: 2,646 ✭✭✭SD_DRACULA


    The ecco does have a fan but I wasn't hearing it when it was in the attic above my bedroom and no, at 8kw grid charge you're probably looking more like 500w or so heat I'd say, standard AC to DC loses as heat.

    Not sure why but the solis was way worse for heat than the sunsynk I found



  • Registered Users, Registered Users 2 Posts: 441 ✭✭jasgrif11


    I would recommend the 8kw Deye. Great inverter with easy options to manage remotely. In fact I have two of them in parallel. They do get loud though when under load, especially when exporting. Mine are in my garage so I only notice it when im working there.
    You won’t regret purchasing a Deye.



  • Registered Users, Registered Users 2 Posts: 2,646 ✭✭✭SD_DRACULA


    Yeah the deye is louder for sure, that's why it went to the shed but the sunsynk was ok in the attic above a bedroom even at full charge so maybe they are not exactly the same.



  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    I have a 4m x 3m Adman steel shed with a concrete base, which seems ideal for setting up the inverter and batteries. The wiring distance to the house would be 20-25m max. This setup minimises noise and heat issues, and I can add solar panels to the shed later.

    I'm considering the 12kW Sunsynk inverter as it seems suitable for my needs:

    https://www.bimblesolar.com/Sunsynk12kw-single

    • My electricity supply is 12kVA

    I'd like to use 10mm² twin & earth wiring. While the Deye 12kW manual specifies 10mm², the Sunsynk manual mentions 21mm², which seems incorrect. Is 10mm² adequate?

    image.png

    Heres from the Deye manual specifying only 10mm…

    image.png

    I found the deye 12kw model for much cheaper from a spanish company. This look like good value?

    https://suministrosdelsol.com/en/hybrid-inverter/2659-monophase-hybrid-investor-deye-12kw-sun-12k-sg02lp1-eu-am3.html

    Manual specifies 21.1mmsq….

    image.png

    Can I use 10mm.sq copper twin & earth or is 16mm.sq necessary. Id consider the 10kw version maybe if it meant I can use 10mm.sq copper

    Post edited by Abromavich on


  • Registered Users, Registered Users 2, Paid Member Posts: 4,725 ✭✭✭...Ghost...


    I would err on the side of caution and go the larger gauge, especially on a longer run.

    Stay Free



  • Moderators, Sports Moderators Posts: 18,289 Mod ✭✭✭✭slave1


    …and I'm sure you know you need NC7 fee/permission for this

    My stuff on Adverts, mostly Tesla Pre Highland Model 3

    Public Profile active ads for slave1



  • Registered Users, Registered Users 2 Posts: 182 ✭✭Abromavich


    Sure, but how could esbn know if you setup an export limit...



  • Posts: 2,768 ✭✭✭ [Deleted User]




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