Solar panels and battery - any real world reccomendations?

Macro · 12 Aug 2023 at 15:50

KompuKare said:
So true off-grid which stays on when the grid is off?

Guess a separate earth makes sense for that, but I though this whole thing - power when the grid is off - was very rare in the UK? Hence why I mocked my incompetent installers having a sales pitch for it on their website; basically I suspect they don't offer this but like to get sales any which way they can.

I have the option with the cables laid and the inverter has a separate EPS output. Given I only have 10 panels and 11kWh of battery I would probably only link the EPS to a couple of essential circuits, maybe lighting and kitchen mains to keep the fridge/freezer alive. Anything else I could always use a quick extension cable for.

Having said that, although we live in a village of 400 people and we do get blackouts they tend to never last more than an hour so for me the cost doesn't justify itself yet (although i do love the idea of being to go "off grid"). If things get worse we have the option though so i'd say worth taking into account whilst any infrastructure works are being done so you have options for the future.

Ron-ski · 12 Aug 2023 at 16:46

KompuKare said:
Guess a separate earth makes sense for that, but I though this whole thing - power when the grid is off - was very rare in the UK? Hence why I mocked my incompetent installers having a sales pitch for it on their website; basically I suspect they don't offer this but like to get sales any which way they can

The only way I'd know the grid has gone off is when I get a notification on my phone

SBo · 12 Aug 2023 at 20:37

AnastieByte said:
Some guidance would be appreciated.

I have a quote for solar panels and battery. I have no idea if the specifications are good or not.

what I have been quoted is

11 X Jinko Tiger Neo 430W N-Type All Black Mono Panels

Lux Hybrid 5kW Inverter

Emlite NET Gen meter + 5x Tigo Optimisers 9.6kWh Hanchu Ess Battery Storage (100% Usable) Roof Mounting Kit

Wi-Fi Dongle for Cloud Access

Bird Protection not included

Assumed annual electrical generation from solar panels 3595kwh.

My annual electric use in 2022 was 3900

The quote for supply and installation comes in at £11,780

Does the specification look appropriate? I may get an EV in 5 years so I would want to take that into account too.

I have the Lux 5kw hybrid inverter and it is brilliant.

I would not recommend Tigo optimisers without a Tigo TAP and CCA being installed with them (~£190). https://support.tigoenergy.com/hc/en-us/articles/4770355167635-TS4-Systems-Blind-Deployment

I’ve never heard of Hanchu Ess Batteries. Maybe just me. Batteries seem to go wrong the most. See if they’ll do Pylontecs.

AnastieByte · 12 Aug 2023 at 21:15

SBo said:
I have the Lux 5kw hybrid inverter and it is brilliant.

I would not recommend Tigo optimisers without a Tigo TAP and CCA being installed with them (~£190). https://support.tigoenergy.com/hc/en-us/articles/4770355167635-TS4-Systems-Blind-Deployment

I’ve never heard of Hanchu Ess Batteries. Maybe just me. Batteries seem to go wrong the most. See if they’ll do Pylontecs.

Thanks I will speak to them bout that.

Ron-ski · 13 Aug 2023 at 09:17

This is a good video that demonstrates what can be going on in batteries, and why you don't get full capacity. The cell over voltage causes the battery to stop charging, SOC jumps to a 100% but it's not fully charged, and thus you don't get the full capacity when you discharge.

SBo · 13 Aug 2023 at 09:45

Ron-ski said:
This is a good video that demonstrates what can be going on in batteries, and why you don't get full capacity. The cell over voltage causes the battery to stop charging, SOC jumps to a 100% but it's not fully charged, and thus you don't get the full capacity when you discharge.

@KompuKare did you try changing the inverter battery charge settings (specifically voltage) to within the range I gave (per what was written in the battery spec)?

I think the BMS should override it anyway but I’m not sure.

Ron-ski · 13 Aug 2023 at 09:56

SBo said:
I think the BMS should override it anyway but I’m not sure.

In a correctly working BMS it will always use its parameters, and on most retail systems the end user won't have access to them. You can circumvent some, by setting a lower maximum charge voltage in the inverter, so in theory the pack will not charge higher, might avoid a cell going over voltage, but not sure its any benefit, as you'll still have less charge. Batteries are a very finicky technology.

KompuKare · 13 Aug 2023 at 13:53

Ron-ski said:
This is a good video that demonstrates what can be going on in batteries, and why you don't get full capacity. The cell over voltage causes the battery to stop charging, SOC jumps to a 100% but it's not fully charged, and thus you don't get the full capacity when you discharge.

Thanks for doing the hard watching again.
That too high a charge voltage could fool the BMS is an interesting thing. Now like you said, some things the BMS should not allow the inverter to override but unless the battery pack has a transformer on the incoming how could it prevent charging at what the inverter sends it?

My installer left the max charge voltage at 61.0V while Pytes want a max 57.6V. For ~48V batteries, 61.0V seems quite high so maybe the BMS is being fooled?

When I had the console cable and my laptop in the loft, the readings from the batteries all seemed to indicate that the battery's BMS thinks all is fine as the Cell count * Volts * mAh adds up the expected capacity.

Anyone know anything about BMS-Studio thing he had in the video? Not the first time I have come across that now. I tried this BmsTools when connected to the batteries but couldn't get it to work - putty was connecting at 115,200 kbps while BmsTools seem to only support 9,600 kbps. Guess BMS-Studio is some paid software or manufacturer specific? Not that I need all the information overload but in his video he was able to show lots of stuff to help with diagnostics, whereas the Pytes console commands are far more limited.

SBo said:
@KompuKare did you try changing the inverter battery charge settings (specifically voltage) to within the range I gave (and written in the battery spec)?

I think the BMS should override it anyway but I’m not sure.

I did not as that time I was all worried about the clamp meter no longer working.

But after Ron-ski's link, I think I now will.

Whether I go back to testing them all with full discharge / recharge though is another question.

Maybe let everything fully charge for a while and then do it one and also take the inverter logs of it discharging. Still feel that inverter logs discharging is a valid test even if the installer and "regulator" were keen to dismiss it. One full discharge, followed by charge from mains with the logs of the inverter charging and discharging, the octopus logs (so have to wait a day as Octopus' logs never seem to show the current days info fully) should be enough to see.

Would be nice if that fixed things - stops us having to contemplate a court case.

Ron-ski · 13 Aug 2023 at 16:24

@KompuKare You really do need to set up the voltage as per Pytes recomendations, it will cause over voltage problems otherwise. The BMS doesn't convert the voltage, it uses MOSFETS to control the flow (turn on/off) charging and discharging. The more expensive BMS's can limit current flow as well.

You'll need to see what software is compatible with the Pytes batteries, it will allow you to see what is going on in them. BMS Studio I think is new software specifically for the Seplos batteries, Andy did say it was new.

I've watched pretty much every single video of Andy's off grid garage, its basically how I learnt to build my batteries, although I am very hands on with a lot things anyway. I'm a mechanic by trade, but do welding, fabrication, pretty much all DIY at home including taking out walls etc.

Here's one of my BMS's, I can see exactly what each cell is at, and how balanced they are, amongst other things.

This is one battery, the other is also discharging at around 65 amp, when I just looked the combined discharge was 8kW or 154 amps - peak time export and the ovens on.

KompuKare · 13 Aug 2023 at 17:39

Thanks, that's a lot of info in far more digestible form than the console on my Pytes:

When	Battery Volt Curr Tempr Base State Volt. State Curr. State Temp. State Coulomb	Volt	mAh	Wh	<< bat 1 \|\| bat 2 >>	Battery Volt Curr Tempr Base State Volt. State Curr. State Temp. State Coulomb	Volt	mAh	Wh
08/08/2023 19:05	0 3314 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3314	96351	319.31		0 3313 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3313	98258	325.53
08/08/2023 19:05	1 3314 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3314	96351	319.31		1 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	2 3315 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3315	96351	319.40		2 3315 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3315	98258	325.73
08/08/2023 19:05	3 3315 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3315	96351	319.40		3 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	4 3315 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3315	96351	319.40		4 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	5 3315 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3315	96351	319.40		5 3315 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3315	98258	325.73
08/08/2023 19:05	6 3315 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3315	96351	319.40		6 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	7 3315 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3315	96351	319.40		7 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	8 3314 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3314	96351	319.31		8 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	9 3314 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3314	96351	319.31		9 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	10 3314 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3314	96351	319.31		10 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	11 3314 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3314	96351	319.31		11 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	12 3314 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3314	96351	319.31		12 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	13 3314 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3314	96351	319.31		13 3315 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3315	98258	325.73
08/08/2023 19:05	14 3314 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3314	96351	319.31		14 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
08/08/2023 19:05	15 3315 -3216 19000 Dischg Normal Normal Normal 96% 96351 mAH	3315	96351	319.40		15 3314 -2600 19000 Dischg Normal Normal Normal 98% 98258 mAH	3314	98258	325.63
09/08/2023 18:33	0 3465 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3465	99394	344.40		0 3473 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3473	99400	345.22
09/08/2023 18:33	1 3458 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3458	99394	343.70		1 3465 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3465	99400	344.42
09/08/2023 18:33	2 3462 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3462	99394	344.10		2 3460 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3460	99400	343.92
09/08/2023 18:33	3 3466 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3466	99394	344.50		3 3460 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3460	99400	343.92
09/08/2023 18:33	4 3462 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3462	99394	344.10		4 3461 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3461	99400	344.02
09/08/2023 18:33	5 3455 0 27000 Idle Normal Normal Normal 99% 99394 mAH	3455	99394	343.41		5 3462 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3462	99400	344.12
09/08/2023 18:33	6 3457 0 27000 Idle Normal Normal Normal 99% 99394 mAH	3457	99394	343.61		6 3464 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3464	99400	344.32
09/08/2023 18:33	7 3465 0 27000 Idle Normal Normal Normal 99% 99394 mAH	3465	99394	344.40		7 3465 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3465	99400	344.42
09/08/2023 18:33	8 3460 0 27000 Idle Normal Normal Normal 99% 99394 mAH	3460	99394	343.90		8 3473 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3473	99400	345.22
09/08/2023 18:33	9 3467 0 27000 Idle Normal Normal Normal 99% 99394 mAH	3467	99394	344.60		9 3457 296 26000 Charge Normal Normal Normal 100% 99400 mAH	3457	99400	343.63
09/08/2023 18:33	10 3466 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3466	99394	344.50		10 3469 296 24000 Charge Normal Normal Normal 100% 99400 mAH	3469	99400	344.82
09/08/2023 18:33	11 3466 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3466	99394	344.50		11 3461 296 24000 Charge Normal Normal Normal 100% 99400 mAH	3461	99400	344.02
09/08/2023 18:33	12 3465 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3465	99394	344.40		12 3456 296 24000 Charge Normal Normal Normal 100% 99400 mAH	3456	99400	343.53
09/08/2023 18:33	13 3463 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3463	99394	344.20		13 3467 296 24000 Charge Normal Normal Normal 100% 99400 mAH	3467	99400	344.62
09/08/2023 18:33	14 3472 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3472	99394	345.10		14 3461 296 24000 Charge Normal Normal Normal 100% 99400 mAH	3461	99400	344.02
09/08/2023 18:33	15 3457 0 26000 Idle Normal Normal Normal 99% 99394 mAH	3457	99394	343.61		15 3471 296 24000 Charge Normal Normal Normal 100% 99400 mAH	3471	99400	345.02

	Sum Ifs	bat 1	bat 2
	08/08/2023 19:05	5,109.59	5,210.23
	09/08/2023 18:33	5,507.02	5,509.25

99% and 3.45V seems low to me but I guess I am thinking of normal lithium-ions there not LifePE4 ones.

I have set the voltages to the Pytes ones.

Haven't decided whether I will try mains charging for that as well, but probably not today.

Left max charge/discharge alone.

The Afore manual seems to imply that the actual limit might be 50A:

On the other hand it says 5.4 kW, so that amps might be AC. 5,400 / 48V would be ~112 amps. Think one of the other menus on the inverter said 3,000W which at ~50V is only 60A.

Anyhow maybe in the winter when there is only a few bursts of solar and we don't want to send anything to grid then, that's when 100A vs 77A would make a difference, but for now I won't touch that.

Nathan · 13 Aug 2023 at 20:13

They are in lads! Just need to send a couple of wires from garage loft space to the house loft space, a job for Tuesday as tmw is a family day! Just under 9kw now.

IMG-2474 hosted at ImgBB

Image IMG-2474 hosted in ImgBB

ibb.co

82-D8-A1-EC-30-BF-43-F7-A12-E-F5-F944-C5-FADC hosted at ImgBB

Image 82-D8-A1-EC-30-BF-43-F7-A12-E-F5-F944-C5-FADC hosted in ImgBB

ibb.co

IMG-2490 hosted at ImgBB

Image IMG-2490 hosted in ImgBB

ibb.co

Those are the south Shropshire/Welsh hills you can see, where all this cloud comes from

JDR82 · 13 Aug 2023 at 23:22

Finalised my deal yesterday, been held up a few weeks waiting on a report from Scottish Home Energy.

13 x 405w panels for 5.2kw
5kw inverter
11.6kw batteries (2x5.8)

After a full survey installer confirmed they could get 13 panels up there (originally quoted 12), was hoping for 2 more but dormers and skylights got in the way of that.

The installer did point out as I had a ASHP I could get a £2.5k grant from home energy Scotland.

That’s half of another 5.8kw battery, but being my first install unsure if I need anymore than 11.6kw, got a lot to learn.

AnastieByte · 14 Aug 2023 at 09:29

JDR82 said:
Finalised my deal yesterday, been held up a few weeks waiting on a report from Scottish Home Energy.

13 x 405w panels for 5.2kw
5kw inverter
11.6kw batteries (2x5.8)

After a full survey installer confirmed they could get 13 panels up there (originally quoted 12), was hoping for 2 more but dormers and skylights got in the way of that.

The installer did point out as I had a ASHP I could get a £2.5k grant from home energy Scotland.

That’s half of another 5.8kw battery, but being my first install unsure if I need anymore than 11.6kw, got a lot to learn.

If you dont mind sharing the cost of the above it would help as I have one quote as per my post but no others yet

Ron-ski · 14 Aug 2023 at 10:24

JDR82 said:
That’s half of another 5.8kw battery, but being my first install unsure if I need anymore than 11.6kw, got a lot to learn

That's an awful lot for a 5.8kW battery.

£4k could buy you a 15 kWh battery with 10 year UK warranty.

48v Server Rack Batteries | Fogstar UK

Our UK designed Fogstar Energy SR51.2V Server Rack Battery comes complete with heating, several pre-loaded inverter protocols, TFT LCD touch screen, 16 Grade A EVE Cells, a DC Rated Breaker, and an 8 year warranty.

www.fogstar.co.uk

Journey · 14 Aug 2023 at 18:05

So big news in from Octopus, they will no longer require MCS for export.

Will link more later, but it is about time as I spent ages jumping through hoops to get mine added without it.

KompuKare · 14 Aug 2023 at 18:57

Since MCS are useless as a "regulator", no longer requiring them should be a good thing. Well, unless super-light touch MCS get replaced with anything goes which is always a possibility.

tonys · 14 Aug 2023 at 19:17

Does this mean we can put in diy solar panels and just need it checked over by a competent electrician or solar installer?

Tom_ed1987 · 14 Aug 2023 at 19:26

Journey said:
So big news in from Octopus, they will no longer require MCS for export.

Will link more later, but it is about time as I spent ages jumping through hoops to get mine added without it.

What are the current export rates?

Nathan · 14 Aug 2023 at 19:34

Journey said:
So big news in from Octopus, they will no longer require MCS for export.

Will link more later, but it is about time as I spent ages jumping through hoops to get mine added without it.

I’m signed up to the trial but awaiting contact, how did you get on it?

Ron-ski · 14 Aug 2023 at 19:40

tonys said:
Does this mean we can put in diy solar panels and just need it checked over by a competent electrician or solar installer?

Hopefully should mean you just need DNO approval for your export. As with any new circuits, you'd still the electrics signing off for Part P to comply with building regs. Doubt you'll find a solar installer that will 'check it over', its hard enough to find a sparky to do that, I ended up getting a sparky to do the 240v side of things, although he also run in and connected up the panels to my pre-installed DC side of things.

Tom_ed1987 said:
What are the current export rates?

It varies, but Octopus appear to pay the most at the moment, and its best to look on their website https://octopus.energy/tariffs/ as it does vary depending on where you are.