Solar PV battery options

DrPhilG

graememk wrote: »

Yep, only disadvantage of no communication, is that the inverter has to "guess" the State of Charge. So you could see some wiggles in it when its sitting resting for a while, (ie if its full and not discharging, or at the low end and not charging.)

Gotcha. So there's no harm in connecting the BMS to the inverter either, via canbus?

graememk

DrPhilG wrote: »

Gotcha. So there's no harm in connecting the BMS to the inverter either, via canbus?

It most likely will not work, and depending on the profile set on the inverter, it might not even look for it.

championc

DrPhilG wrote: »

Gotcha. So there's no harm in connecting the BMS to the inverter either, via canbus?

As I said previously, you basically buy a Canbus model OR a bluetooth model. So if you go for the Canbus one, I have no idea as to how you read or set parameters on it. So you need to ask DALY or HEYO.

lightson

graememk wrote: »

You dont select poland, they are shipped via poland.

I ordered mine at the end of oct, and got them end of dec, just before xmas, so id budget 2 months.

Once they land in poland, its only a few days.

Thanks

Iv seen 2 options with vat etc included. one company ships from China (are you suggesting tat they go via Poland to minimise the vat etc)
The other seller there's an option to ship from Poland with much quicker shipping times but higt price (do you think this is a scam and actually its still coming from China.
links below if you check the color option gives the countries it can ship from and price etc.

from china no vat
https://www.aliexpress.com/item/1005001275656521.html?spm=a2g0o.cart.0.0.688c3c00DC9dXs&mp=1

option to send from Poland no vat more expensive but 5-18 days. although in the small print it says (Europe
UPS or FedEx
Less than 10KG- Delivery Time:12-25 Days
Exceeding 10KG Delivery Time:29-39 Days which is not what it says in the shipping method estimate box.
https://www.aliexpress.com/item/4001030205250.html?spm=a2g0o.cart.0.0.688c3c00DC9dXs&mp=1

championc

The two sellers that we have successfully used are
PWOD and OYE

Both ship with full customs clearance.

lightson

championc wrote: »

The two sellers that we have successfully used are
PWOD and OYE

Both ship with full customs clearance.

nice one thank you

irishchris

Interested to know what people think of the 48v 10kw version of this battery and shouldn't be an issue connecting i would assume with a 3.6kwp Solis hybrid inverter
https://youthpowergy.com/products/48v/YOUTHPOWER-NEW-VERSION-48V-WALL-BATTERY-.html

championc

irishchris wrote: »

Interested to know what people think of the 48v 10kw version of this battery and shouldn't be an issue connecting i would assume with a 3.6kwp Solis hybrid inverter
https://youthpowergy.com/products/48v/YOUTHPOWER-NEW-VERSION-48V-WALL-BATTERY-.html

You would need to know the parameters of the battery pack makeup. Your inverter needs to be told what voltage to charge at, and the fully charged and discharged voltage, in order to calculate the SOC.

All 3rd party battery solutions need this info to be inputted into your chosen inverter. The inverter will more than likely NEVER be able to read the details from the battery pack.

irishchris

championc wrote: »

You would need to know the parameters of the battery pack makeup. Your inverter needs to be told what voltage to charge at, and the fully charged and discharged voltage, in order to calculate the SOC.

All 3rd party battery solutions need this info to be inputted into your chosen inverter. The inverter will more than likely NEVER be able to read the details from the battery pack.

I'm on a deep learning curve here but best to start somewhere.

It states the following in the specs:
"Max charging voltage 54V
Discharge cut-off voltage 42V"

Assuming that means fully charged would be 54v and fully discharged would be 42 volts?

graememk

irishchris wrote: »

I'm on a deep learning curve here but best to start somewhere.

It states the following in the specs:
"Max charging voltage 54V
Discharge cut-off voltage 42V"

Assuming that means fully charged would be 54v and fully discharged would be 42 volts?

Yeah, 54/3.6 would mean that it is a 15s, like the pylontech batteries.

DrPhilG

graememk wrote: »

Yep, only disadvantage of no communication, is that the inverter has to "guess" the State of Charge. So you could see some wiggles in it when its sitting resting for a while, (ie if its full and not discharging, or at the low end and not charging.)

Could you expand on this? How can the battery function if the inverter doesn't know the state of charge? Does it basically try to send power to the battery and only when it isn't working, it then "knows" that it's full? And the opposite when discharging, it'll keep trying to draw power until no more is coming?

How do you guys check your SOC live?

DrPhilG

championc wrote: »

So you need to ask DALY or HEYO.

Just contacted the Heyo factory store on AliExpress. Will report back what they say.

graememk

DrPhilG wrote: »

Could you expand on this? How can the battery function if the inverter doesn't know the state of charge? Does it basically try to send power to the battery and only when it isn't working, it then "knows" that it's full? And the opposite when discharging, it'll keep trying to draw power until no more is coming?

How do you guys check your SOC live?

On the sofar, There is a empty voltage and full voltage setting.

It will calculate the SOC from a resting battery voltage (ie sitting idle for 1 hr), or when you change settings.

It then uses a form of dead reckoning going on the battery capacity.

simple example, if you start at 100%, on a 10kwh battery and you take 4kwh out. it will have 60% left.

then when it hits its minimum % it will stop discharging, and go into a standby mode. if it sits there for 1 hour it will read the voltage again and recalculate the SOC, and will keep doing that every hour until its active again, then it switches back to the dead reckoning mode.

You cannot calculate the SOC from a voltage when the battery is being charged or discharged.

DrPhilG

Thanks, makes sense.

I contacted the Heyo store folk last night on AliExpress. They are very responsive I must say, very helpful.

They said that they don't support the plan to connect sets of 2 cells in parallel, but that there is another way around it. They're going to forward on information and wiring diagrams for how to connect a 32s pack.

Also said that the Heyo can connect via canbus to the Solis but they're going to link in with their technicians for more info and come back to me.

graememk

DrPhilG wrote: »

Thanks, makes sense.

I contacted the Heyo store folk last night on AliExpress. They are very responsive I must say, very helpful.

They said that they don't support the plan to connect sets of 2 cells in parallel, but that there is another way around it. They're going to forward on information and wiring diagrams for how to connect a 32s pack.

Also said that the Heyo can connect via canbus to the Solis but they're going to link in with their technicians for more info and come back to me.

Thats going to make life a lot easier!

After discussion on the other thread I think I can put on another 4 panels on my inverter, so total of 8.64kwp

championc

DrPhilG wrote: »

Thanks, makes sense.

I contacted the Heyo store folk last night on AliExpress. They are very responsive I must say, very helpful.

They said that they don't support the plan to connect sets of 2 cells in parallel, but that there is another way around it. They're going to forward on information and wiring diagrams for how to connect a 32s pack.

Also said that the Heyo can connect via canbus to the Solis but they're going to link in with their technicians for more info and come back to me.

So if you go for the Canbus model, be sure to ask as to how it might be configured or if you can see how the cells are working and being balanced

DrPhilG

championc wrote: »

So if you go for the Canbus model, be sure to ask as to how it might be configured or if you can see how the cells are working and being balanced

Waiting now for confirmation on that from the seller. They have asked what communication protocol the Solis uses. Am I right in saying that it's modbus over RS485

I've found another seller offering a 32s Heyo BMS. €140 including Bluetooth module and Can module. They claim that both can be used.

championc

DrPhilG wrote: »

Waiting now for confirmation on that from the seller. They have asked what communication protocol the Solis uses. Am I right in saying that it's modbus over RS485

I've found another seller offering a 32s Heyo BMS. €140 including Bluetooth module and Can module. They claim that both can be used.

You better get details of the 32s setup quickly because you cannot do a conventional 32s or you will have 96v +

I still do not understand why you cannot do 16s2p. It simply means that each cell is 400A @ 3.2v. of course, the two cells would need to balance between themselves, but that's ok

DrPhilG

championc wrote: »

You better get details of the 32s setup quickly because you cannot do a conventional 32s or you will have 96v +

I still do not understand why you cannot do 16s2p. It simply means that each cell is 400A @ 3.2v. of course, the two cells would need to balance between themselves, but that's ok

I presume that's why they won't support the plan, because it means that the 2 cells have to balance rather than relying on the BMS.

So its unsupported by them as opposed to won't work.


Theres a big difference in dealing with the different suppliers. The Oye store were very helpful. Had excellent English and clear advise and support.

The Heyo factory store folk not so much. Person I had the first time was good, but didn't come back with extra info as promised. When I went back last night it was clearly a different person, as their English was shocking and they were completely unhelpful.


@championc you said that I have to use BT or canbus, not both. 2 different stores insisted that I can use both at the same time. Could they be right do you think or are they just BS-ing me to get the sale? They may be the supplier but you're the independent expert!

Also the OYE store recommend PWOD BMS that they supply.

DrPhilG

It's not just that I want the inverter to know the exact SOC, I want to know it myself so that I can turn on devices etc when the battery is full. I don't like not being able to check the % at any given time.

graememk

Looking at the photos of the bms, there seems to be a port for bluetooth and rs485/can

Tradnuts

Will Prowse on youtube says this is the best BMS he has used.
Ships from USA though

https://overkillsolar.com/product/bms-100a-16s-lifepo4/

Its available in 4s and 8s too.

DrPhilG

Tradnuts wrote: »

Will Prowse on youtube says this is the best BMS he has used.
Ships from USA though

https://overkillsolar.com/product/bms-100a-16s-lifepo4/

Its available in 4s and 8s too.

Thanks, I'll check it out.

My batteries aren't expected until May anyway.

Tradnuts

Hey DrPhil,
Reading through this thread, it would seem that we have a very similar setup.
I also have solar and 4.8kwh pylontech.
I also have the Solis 5kw hybrid.
I also want to sell my pylontech and attempt to go down the lithium iron phosphate DIY route.
I’ve no electrical experience though. Change a plug, Wire a light etc. I bought a phase tester last week!
But watching YouTube videos for the last few months I became interested.
Then I found this thread today and I’m delighted. Ye guys have come to very similar conclusions on the most part.

I’m thinking I should sell my pylontech, and spend that money, and some extra getting close to 10k-12kw lifepo4.

My solar generated 26kwh today. 6 went into and out of battery, it’s at 30 SOC now as of 7pm. 8kwh went into the solar iBoost for my immersion but I’d prefer it goes into a bigger battery setup.

Thanks to everyone on this forum so for for all the amazing patience and info.
It’s much appreciated.
The solar quotes forum was amazing for getting great deals for the initial install too.
Keep it up.
Thanks.

slave1

Solar can be addictive alright, in many respects it is nice if you have a small roof space and just room for one string, when there are more options then the fun really begins...

Tradnuts

slave1 wrote: »

Solar can be addictive alright, in many respects it is nice if you have a small roof space and just room for one string, when there are more options then the fun really begins...

Once you get locked into a serious drug collection, the tendency is to push it as far as you can.
Hunter S. Thompson.

DrPhilG

Tradnuts wrote: »

Thanks to everyone on this forum so for for all the amazing patience and info.
It’s much appreciated.

I'll second this again. Great help here.

On that note, another question...

We've discussed earlier that to add the 32 cells in a 16s format, I'll need to join sets of 2 in parallel and then link the 16 dual-cells.

Can that be expanded further? As in if I bought another 16 sometime down the line, could I join 3 together and make them into 16 x 3 packs using the same logic? Or would that take me over the limit?

DrPhilG

graememk wrote: »

Looking at the photos of the bms, there seems to be a port for bluetooth and rs485/can

2 different stores that supply the Heyo have told me that I can use Can and BT simultaneously. The DALY official store said the same about their unit.

Deagol

championc wrote: »

You better get details of the 32s setup quickly because you cannot do a conventional 32s or you will have 96v +

I still do not understand why you cannot do 16s2p. It simply means that each cell is 400A @ 3.2v. of course, the two cells would need to balance between themselves, but that's ok

Not that simple - batteries have internal impedances which are unique. Each cell will have a particular voltage that it charges it, if you connect too many eventually you will have so many imbalances the batteries will self discharge at higher and higher rates. It's beyond my engineering knowledge to confirm out but I suspect having 2x 16s will mean you potentially have 2x 'large' differences between the packs whereas with 1x 32 you have a bunch of small differences.

This is just my slightly educated guess as to why they don't like 16x2!

Deagol

DrPhilG wrote: »

I'll second this again. Great help here.

On that note, another question...

We've discussed earlier that to add the 32 cells in a 16s format, I'll need to join sets of 2 in parallel and then link the 16 dual-cells.

Can that be expanded further? As in if I bought another 16 sometime down the line, could I join 3 together and make them into 16 x 3 packs using the same logic? Or would that take me over the limit?

Whatever about the limits on the inverter, you're going to need extremely hefty cable to carry the potential current that could give out. Plus, you're running into another thing, with say 48 cells - your chances of a faulty cell is getting higher and higher (it's an exponential number calculating fault likelihoods) and if one cell goes in a pack it'll kill the whole pack until replaced.

And I don't even want to think about what would happen if a short circuit happened on a pack that size - would be one hell of a bang if the cabling isn't up to handling it

Just to explain what I mean, Lithium batteries can give a lot of their capacity out when SC'd.