Solar PV battery options

championc

DrPhilG wrote: »

Not yet. They said 6 to 9 weeks for arrival in Poland and I purchased on March 8th so technically it could be May 10th before they hit Poland.

I'd check the ups website if I was you.

DrPhilG

championc wrote: »

I'd check the ups website if I was you.

I have. Its the same as it was since the tracking number was issued - awaiting collection of the package.

slave1

Drool.......and it’s grid tied!!!! 140kWh, 135kWh usable, fed with 9.6kWp wind and 8kWp solar...good ole USA

garo

That might get the average American home - what - two hours past sundown?

slave1

garo wrote: »

That might get the average American home - what - two hours past sundown?

He's drained it in a day believe it or not, heavy AC and EV usage, was an exception but still....

garo

:eek:

unkel

garo wrote: »

That might get the average American home - what - two hours past sundown?

Average Irish home: 3.5MWh / year
Average USA home: 10MWh / year

Figures for homes with no EV

DrPhilG

OK so my batteries are due to hit Poland in the next week. So time to prep for installation.

I need to read back a bit as championc already kindly gave me a list of switches etc to get but from a quick glance, how much of that is already in place? Since the new battery will be plugged into the same ports on the inverter, shouldn't this technically be plug and play by taking the plugs off the PylonTechs and connecting the LiFePo4?

Pics below of the current setup. Thanks in advance.

graememk

DrPhilG wrote: »

OK so my batteries are due to hit Poland in the next week. So time to prep for installation.

I need to read back a bit as championc already kindly gave me a list of switches etc to get but from a quick glance, how much of that is already in place? Since the new battery will be plugged into the same ports on the inverter, shouldn't this technically be plug and play by taking the plugs off the PylonTechs and connecting the LiFePo4?

Pics below of the current setup. Thanks in advance.

Yeah I'd get new cable for the run from the batteries instead of modifying the plyontech.

But yeah that looks like a switch fuse, that can be used as the isolate the batteries from the the inverter.

championc

Very nice switch fuse / disconnect. So you possibly just need thick wire and crimp on connectors.

Will you have the whole lot of the batteries in one long row are broken into two ? Get yourself enough cable for whatever way you do it. Your simplest option might be to just buy battery cable from a motor factors - it's a once off purchase, and battery terminal cable will be perfect.

But really, you'll be looking at a cable off each end of the battery string connecting directly onto your switch fuse / disconnect.

It's possibly worth prepping your BMS cabling too. The battery dimensions should allow you to make up the entire BMS cable in advance

So all you need is cable and the connectors for both the battery leads and the BMS leads, and a crimping tool for those

DrPhilG

graememk wrote: »

Yeah I'd get new cable for the run from the batteries instead of modifying the plyontech.

Thanks, can I ask why new cable? Surely the ones connecting to the PylonTech already meet the spec in terms of guage etc?

DrPhilG

championc wrote: »

Very nice switch fuse / disconnect.

Thats a good start!

championc wrote: »

So you possibly just need thick wire and crimp on connectors

Is there a particular spec for the cables, assuming I go for new ones?

Something like this?
https://www.amazon.co.uk/dp/B0773D7V59/ref=cm_sw_r_cp_apa_glt_fabc_ET0VE53CYB5T0EMG6M3D

championc wrote: »

Will you have the whole lot of the batteries in one long row are broken into two?

I suspect it'll be 2 lines. 32 in a row would be nearly 2.4m long I think.

I had originally been looking for a good sized cabinet back when I was thinking of a Leaf cell pack, would I be OK with just a good solid shelving unit for the LiFePo4?

DrPhilG

One more thought...

Compression, yay or nay? I see people saying yes and others no.

championc

DrPhilG wrote: »

Thanks, can I ask why new cable? Surely the ones connecting to the PylonTech already meet the spec in terms of guage etc?

Are the Pylontech cables the ones which are connected into the DC fuse / disconnect switch ? If so, then the Pylontech end of those cables would need to be chopped off and re-terminated - which you don't want to be doing, as you need to keep them for selling with your Pylontechs.

If they have been joined up to tails coming from the fuse / disconnect switch, then you could connect your new cables at that point. But for the sake of a few meters of cable, I'd just contact the local motor factors for car battery cable..

graememk

Also do you have a multimeter?.

When doing the wires for the bms check, and double check they are all in the right order, if it's wrong, bye bye bms.

Also good for checking that the polarity is correct when connecting batteries together.

DrPhilG

graememk wrote: »

Also do you have a multimeter?

I think so, need to go dig it out.

DrPhilG

Sorry, just asking again for the few here who have already done a DIY.

Battery compression, necessary or not? Read arguments both ways online. My friend with the Leaf cell pack did it, but it's a different kettle of fish when you're looking at those type of cells.

Any of you guys bothered with it?

DrPhilG

And another question, I'm looking at battery cable for the batteries themselves, will also need those lugs etc and a crimping tool.

What about cable for the BMS? I thought my BMS came with cables but I thought wrong.

Any particular spec requirements etc?

graememk

DrPhilG wrote: »

Sorry, just asking again for the few here who have already done a DIY.

Battery compression, necessary or not? Read arguments both ways online. My friend with the Leaf cell pack did it, but it's a different kettle of fish when you're looking at those type of cells.

Any of you guys bothered with it?

I dont have any compression on mine.

DrPhilG wrote: »

And another question, I'm looking at battery cable for the batteries themselves, will also need those lugs etc and a crimping tool.

What about cable for the BMS? I thought my BMS came with cables but I thought wrong.

Any particular spec requirements etc?

Yeah need lugs need ones to suit the cable and have at least a 8mm hole

As for the leads for the balancer, 0.5 or 1mm2 wire would be fine, - Some ring crimp terminals for balance lead (again, at least 8mm hole)

DrPhilG

graememk wrote: »

I dont have any compression on mine.

Cheers.

Haven't got around to it, or don't think it's necessary?

graememk

DrPhilG wrote: »

Cheers.

Haven't got around to it, or don't think it's necessary?

Don't think its necessary on these cells. It seems that the prismatic ones, in the aluminium cases need it.

These batteries wont be under any stress, under max load/charge we are still chatting about 0.25C - 0.30C

(edited the other post to answer your other q!)

SD_DRACULA

Wonder if anyone got the BMW 330e batteries to run with a solar pv system.
They're only 7.6kwh but still £2000 for 15kwh sounds pretty good

championc

When people talk about Leaf batteries for solar, they are talking about using individual cells from a leaf pack.

That BMW pack could be working on a voltage of 327v DC rather than 48v to 52v which is what you want for a solar battery.

So that pack would need to be burst open and broken down into smaller cells. You could be lucky and find a YouTube video of someone doing a complete teardown of the unit.

SD_DRACULA

Yeah for sure, I meant the cells inside not just running the pack as is.
This is why I can't put anything in the boot of my car so
https://cdn.bmwblog.com/wp-content/uploads/2016/08/P90228232_highRes_production-of-electr.jpg
12kwh just sitting on my driveway not being used...

championc

So what's the voltage of each cell / module ?

For however number of of cells are needed, you'll then need a BMS, but if you can make up something around 50v, then you should be able to use them

SD_DRACULA

Yeah that's the thing not much info about them online so not sure.
Then there's the question of BMS that plays ball with Solis inverters.
Looking forward to DrPhilG's DIY build

samdeluxjones

SD_DRACULA wrote: »

Yeah that's the thing not much info about them online so not sure.
Then there's the question of BMS that plays ball with Solis inverters.
Looking forward to DrPhilG's DIY build

Yea, is he integrating his DIY battery system with his existing Pylontech system and trying to get them to behave as 1 larger unit?

championc

samdeluxjones wrote: »

Yea, is he integrating his DIY battery system with his existing Pylontech system and trying to get them to behave as 1 larger unit?

Indeed, but it's not absolutely necessary. A DIY Powerwall of LiFePO4 cells can mimic a Lead Acid setup, and the Solis (and possibly other Inverters) can be setup as though Lead-Acid's are attached, and of course, these would never have a BMS connected.

This is the way mine works

samdeluxjones

championc wrote: »

Indeed, but it's not absolutely necessary. A DIY Powerwall of LiFePO4 cells can mimic a Lead Acid setup, and the Solis (and possibly other Inverters) can be setup as though Lead-Acid's are attached, and of course, these would never have a BMS connected.

This is the way mine works

Are the LifePO4 connected in series with the Pylontech then?

DrPhilG

I'm not integrating, once the LiFePo4 cells are up and running I'll be flogging the PylonTechs.