Solar PV battery options

THE ALM

Just the controller and neither the inverter or battery. I suspect it will be locked down to just communicate with their own inverter or is there can/rs485 between the inverter and controller.

unkel

https://www.boards.ie/discussion/comment/119764031#Comment_119764031

Is there a need? The myenergi ecosystem caters for 3rd party inverters and the like by using their own CT clamps, connected to harvi(s)

That's how the myenergi system displays my battery, I have a myenergi clamp on my 3rd party (Sofar) battery inverter (and on my third party solar inverters - Solis and Sofar)

THE ALM

https://www.boards.ie/discussion/comment/119764273#Comment_119764273

but for a hybrid inverter it only knows what it is producing and not what the battery connected to it is doing as it only sees it as a whole

HotSwap

From the product page: https://myenergi.com/libbi/

They talk about having storage without PV and it appears that you need the control unit and inverter (which is a hybrid) and at least 5kWh of storage. And that you can add in PV later without having to buy another inverter.

Im not sure why they need the extra external control unit in addition to the hybrid inverter.

unkel

https://www.boards.ie/discussion/comment/119764292#Comment_119764292

Yes. There is nothing that myenergi can do about that though.

My third party inverter is not a hybrid inverter, it's a dedicated battery inverter. So then the clamp does the trick.

THE ALM

https://www.boards.ie/discussion/comment/119764363#Comment_119764363

Yip understand that alright and just thinking out loud about the controller unit if it would have some mechanism to connect to a third party hybrid inverter and be able to differentiate between what the inverter is producing and what the battery is doing, I suspect not and it will be all Libbi or nothing.

As @Hotswap says, you would wonder about the need for the controller unit at all.

unkel

It would be the only USP of the libbi over any third party hybrid inverter 😁

I'd say they will sell. Plenty of people buy just to greenwash or genuinely want to do the right thing, but have no idea about and no interest in pay back periods or any other financial concerns. Fair play to them. Unfortunately, I can't afford that same attitude 😂

THE ALM

Too true unkel 😀 like us we have to get the value in something before the money is spent..

Mr Q

https://www.boards.ie/discussion/comment/119764014#Comment_119764014

Even if you managed to go over the 2000kWh allowable night rate on the bi-monthly bill the rate "only" goes to 0.1481 for the excess units.

Even that is competitive compared to most plans you could sign up to today.

unkel

I'm doing mostly electric heating (gas central heating has not yet been used) so I will hit that allowable night rate ceiling and the rate above is considerably more expensive than gas per kWh of heating, so I need to be careful. I'll do as much as I can not to burn stuff, but within financial reason.

HotSwap

https://www.boards.ie/discussion/comment/119764484#Comment_119764484

I think the fact that they have a full ecosystem of products is key.

They also already have relationships with almost every wholesaler; and they are only providing their inverters in two SKU’s 3.6 and 5 kWh. So if they can ramp up manufacturing and keep them in stock I think they could do very well.

need to see what the price is going to be; I expect they won’t be a budget product. Prob in line with Huawei..

the only thing that are missing now is optimisers.

championc

So is it an AC Battery or a Hybrid Inverter ? Myenergi doesn't work with hybrids, so if it is a hybrid, I'm interested to know how they will deal with it

poker--addict

RIP the days of single digits night rate . Even night rate in the teens is tricky to find.

back on thread

idc

https://www.boards.ie/discussion/comment/119767811#Comment_119767811

From the webpage it definitely looks like a hybrid inverter. The reason it will work with this hybrid is because they have full access to what is going on in the inverter, so you want to use zappi, then eddi, then fill battery they can do that. With other inverters they would need to have an interface into different manufacturers hybrid inverters to tell the battery when to stop or start charging the battery.

The Libbi looks to be a rebadged KStar H5 https://buenergy.co.uk/products/kstar-blue-h3-h5-series-residential-ess-from-5-12kwh-capacity

But Myenergi have a an additional unit that looks a bit like an Eddi called the controller. My guess this contains custom code to interface with the KStar and control it directly either via modbus or wifi and thus can send it commands to allow charging or not!

unkel

I reckon you have hit the nail on the head there @idc

€4k for the cabinet though including just one 5kWh battery. And that's before Myenergi take their cut. And their control unit. And install costs. Extraordinarily expensive 😂

HotSwap

https://www.boards.ie/discussion/comment/119768706#Comment_119768706

It’s also a 5k PV inverter for that price. Same setup from Huawei would cost just shy of 5000 euro for the parts.

the full integration with the car charger and the hot water diversion (with the additional relays) could be very nice.

battery’s will suit some lifestyles better than others; allowing people the max out their self consumption. I know we have a decent FIT; but I’d rather consume my own energy than sell it and then have to buy it back later at an inflated price.

unkel

The trick is to sell it and then buy it back for a much lower price 😁

HotSwap

https://www.boards.ie/discussion/comment/119772540#Comment_119772540

That might still be possible now for early adopters of EV charging plans; but I don’t think it’s realistic for most people that will adopting PV now and into the future.

redmagic68

If the numbers keep going as they seem to be trending per unit and it being likely that we will all be forced into smart meters with peak rate tariffs batteries will most likely become essential I believe.

Hopefully the smart tariffs will become a bit more day/night friendly allowing greater charge times but with day unit rates likely heading toward € 0.75-1.00 before the summer, payback on shelf bought batteries will make them financially viable if not essential in a system regardless of fit.

It’s 1,350 units to reach the €200 but once there each unit is worth 7cent or there about making it substantially less than a night time unit will likely cost. I’m lucky I got the ev rate too but once we come out of that in a years time it could be Armageddon.

unkel

Yes you are both right of course. Nobody knows yet what way the tariffs are going but it is not likely the FIT will stay way higher than the night rate. It already isn't for some people. And then there are the tax implications...

I'm prepared either way. Very large PV setup, solar thermal, very large and increasing battery and working on increasing the speed at which I can discharge / charge the battery. And working on V2H.

VinLieger

Im shelving solar for the moment due to cost and potential of moving house so dont want to plow a lot into it that wont really affect the overall price. Is there any reason that just getting say a 5kw battery would be a bad idea? Specifically id be looking to fill up on the night rate smart tariff and also intend on using for an EV? Basically is a battery worth it without an Solar?

unkel

Not if you are likely to move house. I wouldn't do anything as you could bring inverters and batteries with you but the considerable install costs would be a write off.

DC999

https://www.boards.ie/discussion/comment/119774562#Comment_119774562

+1 to Unkel above. But is a good Q and one I mulled over myself. But don’t do it, not for now anyway.

Get the EV first and you’ll save a grand a year on petrol (even when you factor in cost of electricity on ~15kms milage a year). With an EV, you’ll move to a D/N meter or s smart meter on some EV tariff to get cheaper power at times. So by load-shifting other stuff in the house (washing machine, dishwasher..) you’ll save on energy costs. As in run devices at that night-rate. Few threads on good D/N or smart tariffs here. If you have an EV already, a battery can't save you money as you should charge the EV on cheapest time slot. Our EV uses as much power as our house (which is still way cheaper than petrol).

As to why not do it (bar install cost and moving to the new house), a house battery shouldn’t charge a much larger EV car battery (bar the rare times it needs a boost during expensive day rate). EV batteries are at least 30kWh and head into the 80kWh even now. House battery would be a ‘pimple’ of that. You’ve electric losses on each battery, so are paying X% more for the power for a battery to fill a battery. Plus it’s wear+tear on house battery.

So ye, it could be done. You’ll only save from €200 a year upwards (depending on how high the day rate tariffs move to). And you’ll get better savings elsewhere for the cost. So consider it after the other stuff like getting solar, EV, insulation (in no particular order)….

Btw, we’re moving house at some point and I fully intend to either sell the solar for cost we paid and get some profit. 10k is peanuts on the cost of a mortgage, for energy independence. House would sell in a flash. Or we’ll also have a sale price without it and I’ll take it down. Our installer will move from here to the new place. But it might cost me 2k (‘finger in the air’ with current labour costs) to do it – but that’s the max we’d lose. For us it was still worthwhile as we’ve no solid plans to move, but will at some point. If our installer is mad money to move it, I’ll get a sparks to turn it off and roofer to take it off. Store it for the move and do same on the other end. 

unkel

Just did a meter reading and over the last month I have used 96% of my import from the grid during night rate (7.9c / kWh). And that includes heating the house with electricity during the day. Delighted with that. Thanks to my 20kWh / 33kWh battery

DC999

https://www.boards.ie/discussion/comment/119775229#Comment_119775229

Wow. Amazing stat. That's some benchmark and shows what's possible by keep making changes and investing time. You've done a lot of diy so your time is keeping the costs down.

Brill for likes of me who is new to it all to see what's possible

unkel

Yes quite happy as family of 5 busy household and I've long given up explaining to put dryer and washing machine not on together unless very sunny. Not to run them when it's dark / raining. Completely futile any of that 😂

Battery takes care of it. Only restriction I have is that I can only charge / discharge my battery at 60A (3kW), which is inadequate for my needs. Will need upgrade soon.

Mr Q

https://www.boards.ie/discussion/comment/119775229#Comment_119775229

On your battery size, do you mean it was 20kWh and is now 33kWh?

con747

https://www.boards.ie/discussion/comment/119775674#Comment_119775674

I think the 33kWh is an EV in the driveway being used to power the house as well.

unkel

Bit of both. My home battery is 20kWh and I have a EV conversion in my drive that I can plug in for V2H that is about 13kWh

redmagic68

V2h is where it all needs to get to. Once that’s the case, panels with a very small battery should sort out your day time units.

charging the ev on the night time units and then allowing it to run the house once solar drops off and the small battery is cycled.

when that happens I’ll get an ev and borrow if necessary (hate debt not wealthy 😂) the 8kwp with 10kw battery and ev v2h should mean no more day time rates or fossil fuel required at all.

unkel

I got a rudimentary V2H going from my converted EV. Basically when my home battery is empty on a bad day, I manually connect the HV battery of my car, via a precharge circuit, directly to my PV inverter. Which then thinks the sun is shining and starts producing AC to power my house. Simple, but working great!

daughy

I don't mean to hijack this conversation but I recently had delivered two, 48 volt, 100 amp prebuilt batteries from alixpress.

I have paralleled them, and all is fine.

I have connected them by can to my solis hybrid rhi 48 5k 48ES, after I activated the batteries using user defined it showed me the soc on the hybrid screen, and it matched what the battery screen said, I boiled the kettle to check for outgoing power and the was fine, both batteries worked parallel to eachother.

My issue is using user defined mode as it uses an equalisation voltage, it has a float voltage which is fine, but there lithium batteries so I don't think they should be equalised.

I can I think set the equalisation voltage parameter to 0 amps, but I didn't have time to check that, and also the solis app didn't show the bms, or the soc of the battery..

I could switch battery type to pylontech but I think they use a 15 cells and I have 16..

Any help would be appreciated guys

championc

What type of BMS do you have ? If you went with Pylontech, are you are selecting on the internet is the language that the inverter will expect the BMS to be speaking. All parameters are passed from the BMS - so it will pass 16s.

With a BMS passing parameters to the inverter, it essentially turns the inverter into a dumb box

redmagic68

https://efficienthomesolutions.ie/product/storage-battery-sofar-15kwh-gtx-3000/

what’s the thoughts?

allinthehead

https://www.boards.ie/discussion/comment/119778234#Comment_119778234

I think that's a high voltage battery

redmagic68

Yeah missed that they’re lip instead of lifepo. Not so great after all.

bullit_dodger

https://www.boards.ie/discussion/comment/119776667#Comment_119776667

I'm torn a little bit on that one myself (the V2H bit). I mean I "get it". I get the benefits, and as any regular reader here will know, generally I'm a huge battery proponent - despite FIT, which...... incidentally I've yet to see a penny. No batteries are my friends and I love them :-)

The thing that worries me a little about V2H is the capacity depreciation on the battery which has a direct knock on effect on the range of the vehicle. Sure, for an odd V2H "cycle" that's fine, but as we know batteries have a limited number of cycles and quickening that lifetime will reduce range quicker.

it's not black/white of course. Yes, you will ultimately reduce the range in your car if you were to do this EVERY day, but then again, you are savings yourself wonga. Dunno - it's a hard one to call.

I'd be more inclinded to have a battery for the hosue and a battery in the car and if needed I'd V2H on occasion. is that the "best" way? Hard to say....

Just some musings.....

unkel

You really needn't worry. A LiFePO4 battery has thousands of cycles and can do a million km and then still has 70-80% of the original capacity. Sure if you power your house as much as your car with it, we are still talking a life of half a million km. Is that not enough for you? 😁

"I'd be more inclinded to have a battery for the hosue and a battery in the car and if needed I'd V2H on occasion. is that the "best" way? Hard to say...."

That's exactly my setup. Manually hook up the V2H (takes just a few seconds) on a bad day when my home battery is empty early

the_amazing_raisin

https://www.boards.ie/discussion/comment/119786763#Comment_119786763

It's worth remembering that the typical discharge from an EV battery is a lot higher than what your house would consume. You're talking ~20kW from cruising along on a motorway, or 150kW of you're flooring it

By comparison, everything running in your house might just top 10kW, and typical load would probably be less than 5kW.

And you're limited in how much you can take out of the battery for V2H anyway. The most powerful one I've seen is 22kW, but I'm pretty sure that's 3 phase. So 7kW max is probably all you'll get

The degradation of a battery is partly dependant on the discharge power and depth of discharge

So cycling an EV battery for V2H will degrade it a bit, but the vast majority will be from driving around.

I think the best way to use them is as a supplement to a smaller house battery. You can use the car to store up a load of excess solar for a day or two and if the sun isn't shining for the next couple of days you can use the car to supplement this

noc231073

https://www.boards.ie/discussion/comment/119744349#Comment_119744349

How much are u paying for the 5kwh battery ? And are u buying direct ?

Bif

https://www.boards.ie/discussion/comment/119789890#Comment_119789890

Got my first one with my original install and got my second one from a person who had replaced their Puredrive with a different battery setup.

Midlakelands

https://www.boards.ie/discussion/comment/119790008#Comment_119790008

Hi @Bif

Did you go with the wiring configuration recommended by jonathan earlier? Will change mine to that but first I sent a support message to puredrive just in case there's some weird reason they prefer the one in their documentation.

SchrodingersCat

https://www.boards.ie/discussion/comment/119788687#Comment_119788687

Dont most EV's have a lipo battery, not lifepo, which has a much smaller number of charge cycles compared to lifepo?

Lifepo are typically 5000 cycles whereas lipo in cars is ~1200 cycles. Worst case scenario, if you were using VFH daily you would reduce the lifespan of your cars battery to 3 years, which doesnt even include the additional cycles due to driving the yoke?

Unless im missing something here.

Bif

Hi @Midlakelands. Yip, went with Jonathan’s wiring schematic. Like you I had some doubts based on Puredrive documents and some online videos but speaking to a few people, all confirmed Jonathan’s plan.

bullit_dodger

https://www.boards.ie/discussion/comment/119788798#Comment_119788798

Ahh - I'd be fairly well clued in with the chemistry here. All what you said is true, and I'd also add that it depends a little on the temperature of the battery, where in the SOC that you're discharging/charging from, etc.

No all good points along with unkel's comment about 5000-10000 cycles. What I'm saying is that for fully day-to-day usage, I'm not sure I'd be totally bought into using the car as the storage for the house. Sure, the occasional use (let's put a number on it 2-3 times a month) yeah makes sense. Good thing to do.

The reason I'd personally be slow to use it fully for everyday, is that range of the car is important to me. My old 50Liter Honda Civic I know I could get 319 miles out a fill tank. Less of course if I drove it like the lunatic I was back in my 20's/30's :-) If your using the car everyday, then you will probably reduce range, what 1-2% a year? Sounds about right with 20% reduction in 10 years? That would irk me. I know it would. Illogical? Yes, but it would irk me :-)

That's just me of course - people would be perfectly right of course to use a V2H everyday.

unkel

https://www.boards.ie/discussion/comment/119790910#Comment_119790910

Yes true (lithium ion, not lipo though), but most new EVs coming from China will have LiFePO4 batteries. Also you are overly pessimistic about the life of a lithium ion battery. 1200 cycles does not equal one cycle a day, so a life of just 4-5 years. This cycle figure is down to typically 10% from near full and then at the end of the cycle life, the battery typically still has 70-80% of the original capacity. With average Irish driving mileage this gives a life of about a week per one cycle. Also a home in Ireland uses about 10kWh per day, so even if you got all of that out of the car with say a 60kWh battery, you'd only have a bit over a cycle per week from V2H, both will barely make a dent in the life of the battery really

the_amazing_raisin

https://www.boards.ie/discussion/comment/119790992#Comment_119790992

I don't think you'd be looking at 20% over 10 years from V2H, that would be fairly outrageous

I mean, the old Leafs which are 10 years old now had a worse battery chemistry and almost no battery care and they're only around the 20% degradation mark.

Newer cars have much better battery management, so I wouldn't be concerned about that.

They also generally have controls that won't let you discharge the battery below a certain amount, so unless you're doing 500km per day then range shouldn't be an issue

The other thing to remember is that the buffers on EV batteries are massive. The ID.4 for example has an 82kWh gross capacity, but only 77kWh is available (in fact it's more like 72kWh, the battery reads 0% when there's a few kWh left)

These buffers help absorb any degradation during the lifetime of the battery

You will see degradation, but I still think that 90% of it would be from actually driving the car rather than from using it as a house battery

10-10-20

https://www.boards.ie/discussion/comment/119777305#Comment_119777305

Back to the elephant hiding in the short grass - "I manually connect the HV battery of my car, via a precharge circuit, directly to my PV inverter.".

So how does that circuit look? Where do you link into the main battery DC (800v DC?) and what is a precharge circuit and how is this made safe?

I presume you're starting the vehicle's ignition and then taking a feed off somewhere, but I'm curious as to whether you're going battery DC -> AC 230v -> DC -> inverter MTTP-in to simulate a bank of cells? Or am I overthinking it?

bullit_dodger

You will see degradation, but I still think that 90% of it would be from actually driving the car rather than from using it as a house battery

True again mate - course that's a little dependent on how much you drive. With the WFH these days, I've had my current Beemer reporting that the battery needs charging as it can be 1-2 weeks before I fire it up. So if practically all of your usage of the battery is the house, then it's not going to be driving that's depleting it. Remember here that I'm 30-35Kwh/day in the house, so not your average consumer.

To me it makes sense to differentiate the two. If you need a battery for the house, get a battery for the house. A good 20Kwh DIY jobbie would see you right.

Again, all good well reasoned points, but if I have an EV (and the plan is to get a 4-series once they come out with a coupé)....I know I'll curse the day that the range drops from 500Km to 499Km.

CURSE THE DAY! LOL

graememk

https://www.boards.ie/discussion/comment/119791204#Comment_119791204

It's the red arrow, bmw conversion, 15ish kwh.

DC batteries in that is about 200v, straight into the inverter.