Solar PV battery options

reklamos · 18-09-2021 01:37PM

https://www.boards.ie/discussion/comment/117905566#Comment_117905566

I would not ho bellow minimum DOD set by manufacture. Actually higher DOD would help on longevity of it.

slave1 · 21-09-2021 12:17PM

Well @garo , tempted yet? I have a non-hybrid inverter so will need sofar (I think that's the name) as well as BMS etc. Must actually get a kit list together with URLs for those of us without a Hybrid Inverter

reklamos · 21-09-2021 12:53PM

There was discussion on battery temperatures, cycles, charge rates etc. Here is a videos that give good overview. It is 3 years old but the laws of physics still apply

https://www.youtube.com/watch?v=Yf9N9zBgyB8

garo · 21-09-2021 01:09PM

https://www.boards.ie/discussion/comment/117918945#Comment_117918945

Well the price went back up to 1500 a couple after I posted. So going to wait until it comes back down a bit. I got on the Seplos BMS train that @championc was driving so sorted for the BMS. And I have a hybrid inverter that can charge and discharge batteries at 3kW (66A actually) so just need to buy batteries and wires and I am all set. Also want to email the seller to confirm batteries are new.

Geeyfds53573 · 21-09-2021 09:26PM

I was really interested in this thread but hadn’t been following lately as busy out. I see $1614 so €1376 is that correct? OUIO the brand seems to be the one ye guys are looking at?

I predict I’ll have time on my hands the end of January so may wait till singles day 11/11 in China as there are always sales but this price would seem good? Might delivery take 4 months on this one?

garo · 22-09-2021 12:34AM

Most people here looking at oye store or PWOD store. I don't see the 1376. Do you have a link?

Geeyfds53573 · 22-09-2021 08:29PM

Thanks Garo - My bad it’s €1503 I was messing with delivery options - still not bad though.

championc · 22-09-2021 10:19PM

One thing about AliExpress is that they are very good for refunding you when stuff doesn't arrive.

I've taken a punt on another 16 from 1999Shop. Clearly a drop shipper. At €588.80 ex VAT, why not !!!

slave1 · 24-09-2021 07:43AM

So, in the early stages of my AE DIY battery setup and a question….

The Sofar ME3000SP has a max charge/discharge rate of 2.5kW or 3kW depending on what website you look at, is there anything else on the market that has a larger rate than this, I’ll easily be generating 4kW+ on the good days……

championc · 24-09-2021 08:22AM

Generating is totally separate from discharging. You could generate 4kW from an inverter and discharge 3kW from an ME3000, giving a potential consumption of 7kW (into an EV for instance)

unkel · 24-09-2021 08:57AM

In the spec sheet it says 60A discharge and 60A charge, but if you set it up in the menu, the ME3000SP can actually discharge at 70A so if your battery is full (say 56V) that means very close to 4kW

It can only charge at 65A, which with a lowish battery means 3.2kW max and that's exactly what I am getting with my setup

graememk · 24-09-2021 08:58AM

https://www.boards.ie/discussion/comment/117931650#Comment_117931650

It tops out at 3kw, there's not that many other, on grid storage inverters about.

Victron and Sunny do higher outputs but could end up being 2x the cost.

I've found if I'm maxing out my charging, the day will be providing more than enough to fully charge the batteries.

On the discharge side, only time I'm dipping into the grid is when I have the kettle, and oven on at the same time. - your use may be different but for the short time I'm dipping into the grid for the extra power it's not worth the extra price.

SD_DRACULA · 24-09-2021 09:24AM

https://www.boards.ie/discussion/comment/117931650#Comment_117931650

My Solis 5G 6kw hybrid does 100A charge/discharge, model number RHI-6K-48ES-5G

slave1 · 24-09-2021 09:38AM

https://www.boards.ie/discussion/comment/117931918#Comment_117931918

I already have a Solis Inverter (non-hybrid) so looking to keep that and add a Sofar. Maybe I should be thinking of changing to a hybrid.

I definitely want control over the entire system and by that I mean I want to select when the batteries are being charged e.g. I want house load first, water second, then battery third, this is because I want hot water mid and late morning, after that the batteries can charge

SD_DRACULA · 24-09-2021 09:44AM

I see. Not sure how it works for the Sofar but with the Solis you can bypass the wifi logger and connect via modbus/rs485 which will give you more control than their own apps. Could in theory set up various automations when to charge/discharge etc. Some of the guys on the forums did that :)

graememk · 24-09-2021 09:59AM

https://www.boards.ie/discussion/comment/117931960#Comment_117931960

That would be a lot easier to do with separate systems, and have a ct on the feed going to the battery system that's connected to the harvi/eddi/myenergie device

Then you can give the eddi priority over the battery in the app.

In the winter would you be going back to heating the water on night rate, and giving the battery a priority?

Not impossible to do with a hybrid, but it's not straight forward.

slave1 · 24-09-2021 10:16AM

That's that I'm thinking, I have the full MyEnergi setup so I'm thinking to have the MyE CT on the grid feed "first" so it will take excess and put to the hot water, then have the Sofar "second" with its CT and then divert to battery, when hot tank full then obviously all excess will go to battery and by the looks of things excess above house load + 3kW will go off to the Grid and there's not much I can do about that.

In Winter I will be reverting back to hot water at night rate for sure, I know from last Winter I will be generating fek all excess so I would plan to charge battery at night too.

unkel · 24-09-2021 10:48AM

I would prioritise charging the battery over heating hot water. Pretty much every unit going into the battery is worth the highest day rate (minus round trip losses) while heating hot water is worth less than the lowest night rate (if you have a gas or oil boiler)

slave1 · 24-09-2021 11:01AM

Financially that is correct, however with 3 daughters and SWMBO all long haired lassies I want hot water as PV priority after they'd had their long showers and used up all the water

unkel · 24-09-2021 11:14AM

Just heat the water with gas / oil at the same time and use the financial savings to buy an even bigger battery for even bigger future savings 🤣

On a different note, I just read that all fuel prices (electricity / gas / petrol / oil, etc.) have gone up by about 20% in this country this year so far!

slave1 · 24-09-2021 12:30PM

No oil/gas hot water heating here, immersion

unkel · 24-09-2021 12:34PM

Still immersion costs only 7-8c / kWh at the night rate (mine is less than 5c)

PV going into battery is worth about 15-17c / kWh (minus say 20% losses)

No brainer...

slave1 · 24-09-2021 12:47PM

Think you're missing it U, the tank will be full early AM (from previous day PV or night rate) but empty of hot water after the women have used it all up, therefore I need hot water during the day and want that to be PV rather than messing around "boosting" the immersion and also paying high day rate.

unkel · 24-09-2021 12:54PM

Tell me about it. Same here with 3 daughters plus wife, they empty the 360l tank in the morning and then again at night 😂

garo · 24-09-2021 09:54PM

I feel your pain guys. Same boat but a 120l tank.

unkel · 24-09-2021 10:04PM

What, you have to fill it up with hot water 6 times a day? 🤣

garo · 24-09-2021 10:07PM

Fortunately I have a gas boiler plus heating/HW controls so I just set a target temp and timer schedule and don't have to worry about it. But yeah tank is heated twice a day. Sometimes three.

slave1 · 26-09-2021 12:20AM

Folks, if looking at the 16 pack from Oye store, what Oye BMS would be required and is there anything else I’d need, just want to get one order in and be done with it….cheers

slave1 · 26-09-2021 12:24AM

…and if I was to go for 2 packs of 16 what Oye BMS please…

graememk · 26-09-2021 08:10AM

The oye bms isn't compatible with the communication with the inverters.

You would be looking at the seplos bms, that can communicate with the inverters.

For 16 cells 1 bms is needed.

For 32 you could make 2 separate strings of 16, and have 2 bms's (the seplos is stackable, like the pylontechs

Or you could pair up every cell in parallel to make a pack that's 16s2p

Solar PV battery options

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