Solar PV battery options

DrPhilG · 07-03-2021 12:53am

Is there a spec/model for the Heyo, to remain future proof in the event of adding more batteries?

I'm leaning towards a single pack for now but if all goes well I'll definitely go for 2 packs and perhaps 3.

DrPhilG · 07-03-2021 12:59am

championc wrote: »

There is NO inbuilt BMS in any inverter. The Pylontech sends the details to the Inverter over the comms cable link. If this cable is disconnected or miswired, it simply will not work

Ah, OK. Solis advertise it as having an inbuilt BMS but I think they're taking a bit of artistic license with the term...

unkel · 07-03-2021 1:06am

championc wrote: »

There is NO inbuilt BMS in any inverter.

I wouldn't say that now. An inverter should cover every single aspect that a BMS covers except just the one thing: cell balancing

championc · 07-03-2021 10:08am

DrPhilG wrote: »

Is there a spec/model for the Heyo, to remain future proof in the event of adding more batteries?

I'm leaning towards a single pack for now but if all goes well I'll definitely go for 2 packs and perhaps 3.

You should be looking for a "16s LiFePO4 BMS 100A". You would need one per string of 16, although you could wire 2 cells in parallel, staying all in one string, (so making each cell 3.2v x 400A), but the BMS would have no control over the two individual cells since it would see them as one cell.

I would hope, over time, that certainly Sofar will bring out firmware specifically targeted at LiFePO4's, and most specifically to prevent charging once it's sensor sees the temperature at 0°, in addition to the charging and discharging curve of LiFePO4 being so different to Lead-Acid.

sebdavis · 07-03-2021 1:01pm

SO have we all agreed that we buy in the batteries and then pay @championc to install them for us? :-)

championc · 07-03-2021 4:04pm

sebdavis wrote: »

SO have we all agreed that we buy in the batteries and then pay @championc to install them for us? :-)

I'm more than happy to advise you all, right through your installation process.

Before you do anything, make sure you have a multimeter. It's the most important tool that you will use, as you validate everything as you go along.

The most time consuming part was to extend the cables of the BMS. Watch out for the shrink tubing in Lidl. You can twist join a core of Cat5 onto the BMS lead and then use a heat gun or similar to shrink the tube on the joint.

DrPhilG · 07-03-2021 7:00pm

championc wrote: »

I'm more than happy to advise you all, right through your installation process.

You may live to regret that lol.

A question regarding the inverter. If going to a 2 inverter setup, is it better that they're the same type? With regards to export limitation etc.

Second question, with an inverter like the Solis hybrid that I have, will the batteries always be on the DC side of the conversion? Even if I change to the LiFePo4 ones that you use?

championc · 07-03-2021 7:39pm

DrPhilG wrote: »

A question regarding the inverter. If going to a 2 inverter setup, is it better that they're the same type? With regards to export limitation etc.

What is your maximum simultaneous load, both now and in the future ? That should dictate or match your planned strategy. Suppose you wanted to charge the car at 6kw at night, then that should be your target model. That would then rule out the ME3000. Mind you, if you had two sets of batteries, you could have two ME3000's. We already had the discussion on the other thread how PV inverters might / would work side by side

DrPhilG wrote: »

Second question, with an inverter like the Solis hybrid that I have, will the batteries always be on the DC side of the conversion? Even if I change to the LiFePo4 ones that you use?

The batteries ALWAYS connect to a specific DC port on an Inverter. Battery power is always DC. The main difference with a Hybrid vs standalone is that the Hybrid keeps the generated DC from the panels and puts it straight into the batteries. But as we we'll know, that is not measurable.

I have both a Sofar PV inverter and the ME3000. The menus and displays are very clear.

Deagol · 07-03-2021 7:47pm

championc wrote: »

Remember, the voltage is still only 48v DC, so it's all quite safe. Sometimes being inexperienced makes you pay more attention to what you are doing.

Just would like to clarify your point on this in case some DIY people don't get it:

Voltage doesn't kill, current does. 48vdc can be extremely hazardous, especially at the currents the solar batteries are at. If you get unlucky and contact both - and + someone will find you flat on your back and ready for a box.

Plus, if you shorted out the +/- terminals with something metal, say a screwdriver, you will turn a piece of solid metal into a gas that takes up 1000x the volume in a few milliseconds. This will have the end effect of possibly throwing you into the nearest solid object - be that a wall where you might get away with a few bruises or something sharp that will end your worries about energy forever!

Sorry to be a downer but always worry me when I see people assuming lower voltage equipment is safer than higher.

championc · 07-03-2021 9:44pm

You are spot on Deagol.

The other thing which is important is DC Disconnects MUST be part of the setup. Before working on then, they should ALWAYS be isolated.

The one thing about the AliExpress cells is that the positive and negative poles are well spaced, so there is no real reason for error, so long as you take your time.

graememk · 07-03-2021 10:13pm

DrPhilG wrote: »

You may live to regret that lol.

A question regarding the inverter. If going to a 2 inverter setup, is it better that they're the same type? With regards to export limitation etc.

The export limit would only need to be on one inverter,

So say you have 2 5kw hybrids battery on each.

Worst case is both batteries are full and both are in full sun. only 1 of them has to limit its export.

So with a storage inverter, it monitors the import export on the grid line and soaks up any excess. It also has a ct on the solar feed so it can calculate house load.

I'm 99% sure it doesnt need the solar ct, if i disconnected it, im almost sure it will still charge the batteries when there is grid export detected.

Ive noticed when the batteries are charging, It runs on a very slight grid import (only about 10w).

Also I am not sure the hybrids have a DC -DC converter in them for charging the batteries, I have a feeling that the inverter puts everthing to AC then taps off whatever is excess to the batteries through its on board charger for the batteries.

The battery section of it would have its own inverter too, to allow solar and battery power to be used simultaneously.

If that theory is the case, you could be able to generate power from one inverter and store it on a second hybrid inverter. - its detecting excess and absorbs it.

This is all theory crafting though. complete speculation.

DrPhilG · 07-03-2021 11:19pm

Thanks Graememk

I wasn't planning on having a battery on each inverter, only reason I'm looking at 2 inverters is because a single phase 10kw inverter doesn't seem to be a thing, at least not for anything like a reasonable price.

I'd be planning to have maxed out my storage plans before adding an inverter along with the additional panel capacity so would be looking at 2 if not 3 of the LiFePo4 batteries connected to my current system as a direct swap for the PylonTech.

I see what you mean about only needing 1 inverter to limit export. Since 6kw will be allowed for export, then that would mean that all of one inverter's capacity could go to the grid. The second inverter would just need to know the total export, and then limit it's own contribution accordingly?

graememk · 07-03-2021 11:23pm

DrPhilG wrote: »

Thanks Graememk

I see what you mean about only needing 1 inverter to limit export. Since 6kw will be allowed for export, then that would mean that all of one inverter's capacity could go to the grid. The second inverter would just need to know the total export, and then limit it's own contribution accordingly?

Yeah only need one to throttle.

DrPhilG · 07-03-2021 11:29pm

Those with the AliExpress cells, what physical size are they when assembled, and how many do you have?

And given the lack of fire risk with LiFePo4 cells, anyone have them in the attic?

The missus is dead against Leaf cells for fear that they'll blow the house up.

unkel · 08-03-2021 12:06am

DrPhilG wrote: »

The missus is dead against Leaf cells for fear that they'll blow the house up.

She's dead right. I don't like the idea of any lithium batteries in the house myself, apart from the ones you can't avoid like phones, tablets and laptops.

My batteries are in a heavy duty steel comms cabinet outside. Covered on three sides by brick walls.

graememk · 08-03-2021 12:27am

Each cell is (L*W*H):183*72*280mm

So a row of 16 is about 1.2 M long.

would weigh about 80-90 kg too.

championc · 08-03-2021 12:55am

DrPhilG wrote: »

Those with the AliExpress cells, what physical size are they when assembled, and how many do you have?

A set of 4 is about one and a half times the height of a large car battery, with similar length and depth. So they are quite impressive cells, but quite large too.

Deagol · 08-03-2021 1:09am

Don't take my head of with this question as maybe i'm mad but..

Could you potentially use old laptop batteries? Was looking and seeing I can still get ~50w/h from an old Dell laptop battery. 100x of them.. combo of parallel and series connections would get me to 48v... but would internal resistances etc make it unworkable?

Ubbquittious · 08-03-2021 1:11am

Are ye lads running off the grid that ye have such large batteries or is there some intricate run the gas off the electricity and the electricity off the gas to save €200 going on?

Deagol · 08-03-2021 1:16am

Ubbquittious wrote: »

Are ye lads running off the grid that ye have such large batteries or is there some intricate run the gas off the electricity and the electricity off the gas to save €200 going on?

With it likely you can get free electricty at certain times - it could be great to have a lot of battery power. Imagine in the winter time, you can charge up your battery from the grid on a Saturday and run your house off it and the little solar you might get for the week. Problem is the batteries cost more than the savings are likely to be doing that. Unless of course you can get the batteries at the right price.

Ubbquittious · 08-03-2021 1:38am

Deagol wrote: »

With it likely you can get free electricty at certain times - it could be great to have a lot of battery power. Imagine in the winter time, you can charge up your battery from the grid on a Saturday and run your house off it and the little solar you might get for the week. Problem is the batteries cost more than the savings are likely to be doing that. Unless of course you can get the batteries at the right price.

Nobody off the grid here so? This is what im really interested to find out more about. I know one dude who was off the grid but he crawled back on to it a few years ago. Not off the grid myself but this is the aim eventually and dont want to follow a similar fate

It would take a long time for me to put €2,500 worth of electricity through a battery even if I got the electricity for free I don't really see the advantage for me personally.

graememk · 08-03-2021 1:39am

Deagol wrote: »

Don't take my head of with this question as maybe i'm mad but..

Could you potentially use old laptop batteries? Was looking and seeing I can still get ~50w/h from an old Dell laptop battery. 100x of them.. combo of parallel and series connections would get me to 48v... but would internal resistances etc make it unworkable?

you mean like this?

Each one of them packs are 2.5kwh

for sure wouldn't have them in my house, that guy has them in a steel container outside.

Taking losses into account, charging at night and discharging during the day is saving about 50c/day over the winter.

If I get onto energia's new ev rate, that would push it up to nearly 80c/day

Deagol · 08-03-2021 1:49am

graememk wrote: »

you mean like this?

Each one of them packs are 2.5kwh

for sure wouldn't have them in my house, that guy has them in a steel container outside.

Taking losses into account, charging at night and discharging during the day is saving about 50c/day over the winter.

If I get onto energia's new ev rate, that would push it up to nearly 80c/day

Yeah -that's what I'm thinking of.

My partilcular issue is that my radiator pump is .385kw. During the winter I'm not making anywhere enough from the solar panels to charge the battery to supply even a fraction of what I'm using. With the signs of us getting free power on certain tarriffs etc, I'm looking at how I could charge a big enough battery to offset at least some of the running costs.

Has anyone looked into using a micro generator turbine and pump? Was thinking I have a two floor garage, wondering would it pay to put a water tank on two levels with a pump and a micro turbine. I could use the free power to lift the water up and then use the microgen to produce when needed, or even to charge the battery when empty to use the inverter as the power controller? Mad?

graememk · 08-03-2021 1:50am

Ubbquittious wrote: »

Nobody off the grid here so? This is what im really interested to find out more about. I know one dude who was off the grid but he crawled back on to it a few years ago. Not off the grid myself but this is the aim eventually and dont want to follow a similar fate

It would take a long time for me to put €2,500 worth of electricity through a battery even if I got the electricity for free I don't really see the advantage for me personally.

Would need a lot more solar to be off grid! esp when we use about 100kwh/week on the EV!

But yeah thats the main sticking point, to put 2.5k through a battery. Easier to do when you have 10kwh, but with some of the ones being sold/quoted are only 2.4kwh or 5kwh, its a much harder sell!

unkel · 08-03-2021 1:55am

Deagol wrote: »

Don't take my head of with this question as maybe i'm mad but..

Could you potentially use old laptop batteries?

Yes for sure. My first batteries were all made up from 18650 cells that I harvested out of "dead" laptop batteries that I got for free over the years.

Lot of work in that, steep learning curve, you need to test the batteries for capacity, internal resistance, self-discharge rates, etc.

If you are getting into batteries, that is a very useful learning experience though.

DrPhilG · 08-03-2021 8:07am

unkel wrote: »

She's dead right. I don't like the idea of any lithium batteries in the house myself, apart from the ones you can't avoid like phones, tablets and laptops.

Even for the LiFePo4 ones that are said to have little/no fire risk?

idc · 08-03-2021 9:02am

Deagol wrote: »

With it likely you can get free electricty at certain times - it could be great to have a lot of battery power. Imagine in the winter time, you can charge up your battery from the grid on a Saturday and run your house off it and the little solar you might get for the week. Problem is the batteries cost more than the savings are likely to be doing that. Unless of course you can get the batteries at the right price.

Just curious with these new smart tariffs like free electricity all day saturday or sunday what are the conditions? like if you did have large enough battery storage to literally fill it once a week and then use it and solar with little to no grid for the remainder of the week is that allowed or have the suppliers been smart and you need to use a certain amount from the grid the remaining days to avail of the free day?

irishchris · 08-03-2021 9:38am

idc wrote: »

Just curious with these new smart tariffs like free electricity all day saturday or sunday what are the conditions? like if you did have large enough battery storage to literally fill it once a week and then use it and solar with little to no grid for the remainder of the week is that allowed or have the suppliers been smart and you need to use a certain amount from the grid the remaining days to avail of the free day?

I noticed in the terms for free Saturday or free Sunday it says subject to normal use and that they can remove the offer during contract if not. Now what normal use is considered I'm not sure

Zardaz · 08-03-2021 9:56am

idc wrote: »

Just curious with these new smart tariffs like free electricity all day saturday or sunday what are the conditions? like if you did have large enough battery storage to literally fill it once a week and then use it and solar with little to no grid for the remainder of the week is that allowed or have the suppliers been smart and you need to use a certain amount from the grid the remaining days to avail of the free day?

I just checked Board Gais Energy website, as I am also curious on this topic.
They offer a "Free Sat" or "Free Sun" smart tariff option (9am to 5pm)

In the terms and conditions PDF, it states:

Fair Usage Cap on Free Energy units – there is a Fair Usage Cap on the monthly allowance of Free Energy units. This cap is set at 100kWh. Any excess units used above 100kWh will be charged at the Saturday or Sunday Day unit rate.

So, 100KWh free a month (or ~23KWh per 7-day-week)

Given that the average household usage per annum is in the order of 4500KWh per annum (not including widespread EV or heat pumps), which is about 12KWh per day, the best you can hope for is, with a AC coupled inverter and ~15KWh battery, is to store and carry over the equivalent of almost 1 additional "free" day per week. (so, you would get Sunday "Free" also)

Or, looked at another way, you could fully charge a ~50KWh EV for free twice a month.

Link to PDF

I didn't check the other providers, but I suspect they would have similar restrictions. (Bonkers is going to have lost of fun trying to accurately track all this stuff.)

Ubbquittious · 08-03-2021 10:13am

Zardaz wrote: »

I just checked Board Gais Energy website, as I am also curious on this topic.
They offer a "Free Sat" or "Free Sun" smart tariff option (9am to 5pm)

In the terms and conditions PDF, it states:

Fair Usage Cap on Free Energy units – there is a Fair Usage Cap on the monthly allowance of Free Energy units. This cap is set at 100kWh. Any excess units used above 100kWh will be charged at the Saturday or Sunday Day unit rate.

So, 100KWh free a month (or ~23KWh per 7-day-week)

Given that the average household usage per annum is in the order of 4500KWh per annum (not including widespread EV or heat pumps), which is about 12KWh per day, the best you can hope for is, with a AC coupled inverter and ~15KWh battery, is to store and carry over the equivalent of almost 1 additional "free" day per week. (so, you would get Sunday "Free" also)

Or, looked at another way, you could fully charge a ~50KWh EV for free twice a month.

Link to PDF

I didn't check the other providers, but I suspect they would have similar restrictions. (Bonkers is going to have lost of fun trying to accurately track all this stuff.)

There would have to be a catch, wouldn't there?

I'm still convinced the biggest way to save with all of this craic is not to spend 1000s on solar panels and batteries but to try and avoid consuming the electricity in the first place. I lived in one place where I was using <80kWh a month and another where I was being charged the low usage tarriff by ESB. Much easier to potentially give the utility companies the heave-ho at that level of usage

Somewhere in a big glass head office in New York the head boys in I squared capital are laughing at people sinking so much money into grid-tied solar setups. When everyone has them installed they'll just petition the CRU to make things less favourable for people with that kind of setup.

Ubbquittious · 08-03-2021 10:35am

sebdavis wrote: »

So your plan is not to use electricity at all? just to save a few quid. I can find a few issues with that.

No. I had a good setup, I could casually leave the lights on and had my computing machine running 24/7 and still was consuming less than 80kWh without being careful or inflicting any misery upon myself. At that level of usage it might be feasible to spend what one would spend on standing charges and PSO levies on batteries instead. But one would need a second source of power like wind or micro-hydro.

sebdavis · 08-03-2021 10:44am

Ubbquittious wrote: »

No. I had a good setup, I could casually leave the lights on and had my computing machine running 24/7 and still was consuming less than 80kWh without being careful or inflicting any misery upon myself. At that level of usage it might be feasible to spend what one would spend on standing charges and PSO levies on batteries instead. But one would need a second source of power like wind or micro-hydro.

Sorry when I looked back on post it was snotty so deleted.

I spent about 12-18 month trying to reduce electricty. I put in smart plugs etc so lights etc would turn off automatic. TV etc would shut down when not been used but still far too much electricity. I even have trained my 5 & 7 year old to use alexa to turn things on/off.....

So Solar PV made sense

graememk · 08-03-2021 11:02am

Yeah we have an outfarm and we can never switch to EI because of our low useage there.

We need the grid because we have a well for water there, also we usually get an IFA deal with bord gaia with a decent cashback that covers most of the standing charges (although now that the pso is up to 88, the cashback doesn't cover near as much!)

But at home, even now solar is starting to cover nearly all of my day useage. (Nearly hit 80kwh used in a 24 hr period!)

Granted 60ish kwh was the ev on night rate though!

Little to no day units were used in that screenshot.

DrPhilG · 08-03-2021 11:47am

I'm getting the same response as others, BSL-battery will ship to the nearest port, either Belfast or Dublin.

They don't get involved with import duty at all, so that would fall to me. In other words its not included, whereas with the AliExpress store it is.

DrPhilG · 08-03-2021 12:59pm

Also I spoke with Solis tech support and got the following advice re DIY batteries:

Solis wrote:

CANBus protocol is standard, for DIY purposes, make sure your BMS has a standard CAN Port with pin 45 is enabled in rj45 pin.

championc · 08-03-2021 3:26pm

DrPhilG wrote: »

Also I spoke with Solis tech support and got the following advice re DIY batteries:

So ask them if it will work with a DALY BMS

Sofar absolutely said they would NOT support a.n. other BMS's

DrPhilG · 08-03-2021 3:36pm

Further update from the AliExpress seller.

2 of the 16 pack was coming to €2,670 after discounts. I asked if there was any further discount available so he sent me a link for a 32 pack, for €2,691!

It pays to haggle...

Those who have purchased from these guys, a few more questions.

1 - do they deliver to your door? I know that they bring them into Poland or somewhere, clear customs and then onwards. But does that second dispatch bring it to your home address or just to the nearest port like the BSL crew?

2 - how secure is it, sending this amount of money across the world? First time buying on AliExpress so a little wary of being ripped off. Would credit card transaction still offer protection?

garo · 08-03-2021 4:46pm

I would be far more comfortable buying from AliExpress than the BSL crew. With AliExpress you can request a refund and you do get your money back - eventually - if something goes wrong and goods are not delivered.

E30M3 · 08-03-2021 5:08pm

DrPhilG wrote: »

Further update from the AliExpress seller.

2 of the 16 pack was coming to €2,670 after discounts. I asked if there was any further discount available so he sent me a link for a 32 pack, for €2,691!

It pays to haggle...

Those who have purchased from these guys, a few more questions.

1 - do they deliver to your door? I know that they bring them into Poland or somewhere, clear customs and then onwards. But does that second dispatch bring it to your home address or just to the nearest port like the BSL crew?

2 - how secure is it, sending this amount of money across the world? First time buying on AliExpress so a little wary of being ripped off. Would credit card transaction still offer protection?

I'm confused. It costs €21 extra after Haggling?

DrPhilG · 08-03-2021 5:11pm

garo wrote: »

I would be far more comfortable buying from AliExpress than the BSL crew. With AliExpress you can request a refund and you do get your money back - eventually - if something goes wrong and goods are not delivered.

Yeah that was my worry. So it's kinda like ebay. If something goes wrong you request a refund via AliExpress and they refund it.

Getting close to pulling the trigger on 2 packs. So even more questions...

1 - can the 2 packs join together to make one larger pack? I think this is answered here, but this leads me on to question 2.

championc wrote: »

You would need one per string of 16, although you could wire 2 cells in parallel, staying all in one string, (so making each cell 3.2v x 400A), but the BMS would have no control over the two individual cells since it would see them as one cell.

2 - since I currently have 1 inverter, I would be joining these 2 packs as 2 cells in parallel as above. So is the 3.2v x 400a setup described above OK? Are there disadvantages to joining the 2 packs?

3 - what else do I need to have in my shopping list to make this all complete. Busbars etc come with the cells. I need a BMS (no problem paying a little extra for the Heyo if it's worth it), and cables to connect the cells to the inverter. Anything else? Do I need a balancer if I have the BMS?

sebdavis · 08-03-2021 5:19pm

DrPhilG wrote: »

Further update from the AliExpress seller.

2 of the 16 pack was coming to €2,670 after discounts. I asked if there was any further discount available so he sent me a link for a 32 pack, for €2,691!

It pays to haggle...

Those who have purchased from these guys, a few more questions.

1 - do they deliver to your door? I know that they bring them into Poland or somewhere, clear customs and then onwards. But does that second dispatch bring it to your home address or just to the nearest port like the BSL crew?

2 - how secure is it, sending this amount of money across the world? First time buying on AliExpress so a little wary of being ripped off. Would credit card transaction still offer protection?

Who are you dealing with on Aliexpress?

DrPhilG · 08-03-2021 5:35pm

sebdavis wrote: »

Who are you dealing with on Aliexpress?

Oye store. I believe that's the same one that championc etc have dealt with?

sebdavis · 08-03-2021 5:36pm

DrPhilG wrote: »

Oye store. I believe that's the same one that championc etc have dealt with?

After you guy the 32 pack, what else do you need to buy? The BMS?

DrPhilG · 08-03-2021 5:48pm

sebdavis wrote: »

After you guy the 32 pack, what else do you need to buy? The BMS?

Well I'm buying 2 x 16s, since they're on offer and therefore cheaper than the 32.

As for what else is needed, see my previous list of questions as that's what I'm just clarifying before proceeding.

DrPhilG · 08-03-2021 5:50pm

PS where have you guys stored your batteries?

Unkel has them in an outbuilding/garage I think in a steel/brick enclosure, what about the rest of you? Are these any more or less of a risk than the PylonTech currently in my attic?

If I put them in the attic I won't need to mess with inverter location. If I have to shift them to the garage now then I'll have to move the inverter and reverse the setup, i.e. connect the house panels to the garage rather than the garage panels to the house.

If/when I double my panels then I probably will move the whole lot out but I'm not planning that in the immediate future.

graememk · 08-03-2021 6:49pm

DrPhilG wrote: »

Getting close to pulling the trigger on 2 packs. So even more questions...

1 - can the 2 packs join together to make one larger pack? I think this is answered here, but this leads me on to question 2.

So you could have 2 strings of 16 and parallel them at your breaker, but that would need 2 bms's

Or you could parallel every 2 cells together, you might need extra busbars.
but you would only have to put a balance lead on each pair of batteries.

You need 2 bus bars for every pair, so thats 32. and then another 15 to join all the pairs. 47 in total.

Remove 1 busbar for every split in the pack where you use wire, ie if you make 2 rows of 16 or 4 rows of 8.

Each cell comes with 1 bus bar. so you'll normally get 32

Draw it out and see.

3 - what else do I need to have in my shopping list to make this all complete. Busbars etc come with the cells. I need a BMS (no problem paying a little extra for the Heyo if it's worth it), and cables to connect the cells to the inverter. Anything else? Do I need a balancer if I have the BMS?

You need to get a beefy BMS able to handle at least 100amp charge.

Re the BMS, that will do the balancing, The extra features of the bms, ie low voltage cut off etc is a fail safe, it should never actually have to do that.

What you need to plan, or get
How they are stored/mounted.
Need a Fuse/DC MCB, Enclosure for that MCB you'll be looking for a 100amp one. Needs to be a DC one, Stuffing glands for said box.

Wire, Ideally black and red, and you would need 16mm2 too as you have a 5kw inverter.
Heatshrink, crimp Terminals to go on the wire and onto the battery.

DrPhilG wrote: »

Oye store. I believe that's the same one that championc etc have dealt with?

yep, thats where he got his, I have dealt with PWOD but they have the same photos in their listings. Comes via UPS.

DrPhilG wrote: »

PS where have you guys stored your batteries?

On Shelves built for them in my garage ( well a room off the garage, where a freezer used to be kept back in the day)
I have 2 rows of 8, currently surrounded in insulation to keep them warmer.

DrPhilG · 08-03-2021 7:23pm

graememk wrote: »

Or you could parallel every 2 cells together, you might need extra busbars.
but you would only have to put a balance lead on each pair of batteries.

This sounds like a decent solution. Copper busbars from the same seller are €18 for a set of 4 but I could try and haggle them into the deal.

graememk wrote: »

You need to get a beefy BMS able to handle at least 100amp charge.

That was my next query, is there a particular model in the Heyo or Daly options that will cope with the load for a doubled up battery?

graememk wrote: »

What you need to plan, or get
How they are stored/mounted.

My plan was to put them on a shelving rack in the attic. Depends on the layout though, I'm guessing they need to be end to end due to the busbar connections. Actually edit, I see you have 2 rows of 8 so I could do 2 rows of 16.

Any pics of your setup?

Also was wondering about the safety of having them in the attic but since they're probably no more of a hazard than the PylonTech I suppose it's fine. When I double up on panels and inverters I will most probably shift the lot to the garage.

graememk wrote: »

Wire, Ideally black and red, and you would need 16mm2 too as you have a 5kw inverter.
Heatshrink, crimp Terminals to go on the wire and onto the battery.

16mm2 a minimum? Or is there no harm in going higher spec?

I'll likely round up all that stuff locally. Just buy the BMS, cells and busbars from China.

graememk · 08-03-2021 9:47pm

DrPhilG wrote: »

That was my next query, is there a particular model in the Heyo or Daly options that will cope with the load for a doubled up battery?

As long as the current rating on it is higher than what your looking to draw from the battery.

Also was wondering about the safety of having them in the attic but since they're probably no more of a hazard than the PylonTech I suppose it's fine. When I double up on panels and inverters I will most probably shift the lot to the garage.

Pylontech are the same chemistry, but they are in a metal box,

16mm2 a minimum? Or is there no harm in going higher spec?

Just looked up the manual for the solis.
the max you can pull from a battery is 62.5amps (3kw) - Or put into the battery.

so a 63 amp mcb and 10mm2 wire is fine.

also the next step up from 16 is 25mm2 and its hard to work with.

sebdavis · 08-03-2021 9:54pm

DrPhilG wrote: »

Well I'm buying 2 x 16s, since they're on offer and therefore cheaper than the 32.

As for what else is needed, see my previous list of questions as that's what I'm just clarifying before proceeding.

So you end up with 20kWh new?

DrPhilG · 08-03-2021 10:04pm

sebdavis wrote: »

So you end up with 20kWh new?

Pretty much, although I think they'll be set up as 80q depth of discharge so about 16kWh usable.

Solar PV battery options

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