DIY Battery/Solar installation..

Personally i think B grade is fine in a home battery, especially if you DIY build since you can replace modules as needed. From what i've seen a lot of the factors ultimately pertain to how hard you can push your cells (ie they failed various metrics that make them unsuitable for high charge/discharge in EV's). Although different manufacturers, I think fog stars lists the B grade 280Ah at 0.5C charge/discharge and the A grade at 0.5C charge and 1C discharge. Typically what i've seen around other sites/aliexpress/alibaba is A grade should be capable of closer to the 1C and lower grades tend to be set at half to be safe.

Also supposedly the MD of fogstar uses B grade for his stuff so it can't be all doom and gloom.
 
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Freddie1980 said:
I assume the battery is going in your loft which is full of flammable materials (insulation, joists, boxes etc). What sort of safety precautions can you put in place mitigate the damage from a potential Lithium battery fire?
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Insulation shouldn’t be flammable but in any case if the battery catches fire and becomes established, your house is probably already toast regardless of where it’s located.

The mitigation is, put a suitable fire alarm in the loft. If it’s going to catch fire, better the loft than your living space which is also full of flammable material.

In reality the risk is very low, especially with LFP. The bigger risk is actually to the fire fighters if your house catches for for another reason. A heavy battery on a wooden floor that’s damaged by fire is at risk of falling on someone.
 
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I guess its all about what risk you want to take in regards the cells.
Clearly the B will be expected to fail faster, the question is do you benefit more or less before you face that challenge.

My understanding is that with these multi cell batteries the real capacity is dictated by the worst cell. Hence all the stuff people do with trying to balance cells etc.
So the battery is full when the weakest cell says it is full, and its empty when the weakest cell says it is empty. Monitored by the BMS. This BMS sounds active so it should find that and recover.
But the physical limitation will be there.

Certainly when I had an issue with my house battery the manufacturer looked at the cells. And identified 2 of my 4 modules had an issue and replaced those two.

As your running a load of cells your going to be limited by the worst one.

I just thought it was all interesting as you never really see B grade being options, they clearly go somewhere and what they get used for who knows.
Its clearly a risk, the question is is the risk worth taking.
I couldn't see anything in regards warranty, often lower graded come with reduced warranty, or much lower warranty in effect.
 
Malt_Vinegar said:
The Garage is the preference at the moment for the installation.
It's already got a load of flammable materials in there that are at least as dangerous as some batteries :D
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Best location IMO.
I would aim to build an insulated and heated cabinet for them as well.
Unless your garage is particularly warm.

Depending on the BMS control most will stop charge below a certain temp and discharge below a slightly lower one.

Doesn't have to be fancy. Just some PIR boards and a small heater such as a tube heater set to a very low thermostat temp is perfect.

You may be ok, but if it was me having had charge issues due to temp in 2022/3 winter when its cold I found they wouldn't always fully charge in a cold spell, On a few occasions they didnt charge at all.
My batteries have built in heating so when that is on they will charge fine even in cold (negative temps) (it wasn't in 22/23 as it was in the installer menu and switched off!) but they of course use more energy keeping themselves warm.

Its quite interesting to watch the difference in the temps when they are charging/discharging and inactive.
Charging uses higher voltage and they rise in temp quite quickly, discharging is lower, but when inactive the temp falls quickly.
The losses are say 5%, thats heat mainly, so you can see there isnt a lot of temp being generated at the batteries.
Insulation helps significantly to delay the speed that bleeds off.

Just thought I would mention. :)
 
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Quick Q, if you have your hybrid inverter connected to the Consumer Unit, and it's a 5kw inverter, and you demand 6kw from the house, will the load be effecrively split over the mains and battery supply, or will this overload the inverter?
I sometimes see short spikes of 8kw usage in my house and was worried that it would trip the inverter and require it to be reset.
This would make me unpopular with the wife and kids :D

Happy to move up to an 8kw, but surely people with 3.6kw systems are not always limiting load to under 3.6kw?!
 
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Malt_Vinegar said:
Quick Q, if you have your hybrid inverter connected to the Consumer Unit, and it's a 5kw inverter, and you demand 6kw from the house, will the load be effecrively split over the mains and battery supply, or will this overload the inverter?
I sometimes see short spikes of 8kw usage in my house and was worried that it would trip the inverter and require it to be reset.
This would make me unpopular with the wife and kids :D
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It draws from the grid to make up the diff. :)
 
Unless you have whole house back, and there's a power cut, then it trips the inverter if you exceed the maximum, but some inverters can cope with short spikes.

Mind you, its not often that's there's a power cut, never had one at home since I installed my system, been several in the area though and at work.
 
Ok, so I have a Sparky on-board, and doing my G99 application. Costing me £150, which I am willing to pay to ensure it is done correctly first time! I will be doing the physical installation (wall mount, etc), and he will do the final wiring once the G99 is back.

I now have to select an inverter... I am after 5kW Hybrid, with 2 solar input, supporting the 48v battery kit. with CAN communication.

So far this one looks be good:
batterygroup.co.uk

Solis 5G 5kW Hybrid Inverter with DC switch - S5-EH1P5K-L

EH1 Solis Energy Storage 5,000W Hybrid 5G Inverter with DC switch - S5-EH1P5K-L The Solis 5G 5.0kW Hybrid Inverter is a good choice for both…
batterygroup.co.uk batterygroup.co.uk

Open to suggestions :)
 
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Malt_Vinegar said:
Ok, so I have a Sparky on-board, and doing my G99 application. Costing me £150, which I am willing to pay to ensure it is done correctly first time! I will be doing the physical installation (wall mount, etc), and he will do the final wiring once the G99 is back.

I now have to select an inverter... I am after 5kW Hybrid, with 2 solar input, supporting the 48v battery kit. with CAN communication.

So far this one looks be good:
batterygroup.co.uk

Solis 5G 5kW Hybrid Inverter with DC switch - S5-EH1P5K-L

EH1 Solis Energy Storage 5,000W Hybrid 5G Inverter with DC switch - S5-EH1P5K-L The Solis 5G 5.0kW Hybrid Inverter is a good choice for both…
batterygroup.co.uk batterygroup.co.uk

Open to suggestions :)
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Have a look at the city plumbing website, they have top deals on renewables at the moment and nice discount if you use their app too
 
Malt_Vinegar said:
Ok, so I have a Sparky on-board, and doing my G99 application. Costing me £150, which I am willing to pay to ensure it is done correctly first time! I will be doing the physical installation (wall mount, etc), and he will do the final wiring once the G99 is back.

I now have to select an inverter... I am after 5kW Hybrid, with 2 solar input, supporting the 48v battery kit. with CAN communication.

So far this one looks be good:
batterygroup.co.uk

Solis 5G 5kW Hybrid Inverter with DC switch - S5-EH1P5K-L

EH1 Solis Energy Storage 5,000W Hybrid 5G Inverter with DC switch - S5-EH1P5K-L The Solis 5G 5.0kW Hybrid Inverter is a good choice for both…
batterygroup.co.uk batterygroup.co.uk

Open to suggestions :)
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First question in your scenario should be how much do you think you want to tinker, or do you want a plug n play not really go near it type system.
 
Mercenary Keyboard Warrior said:
First question in your scenario should be how much do you think you want to tinker, or do you want a plug n play not really go near it type system.
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Happy to tinker, would like to be able to see whats going on at a minimum, and perhaps set some behaviours on the fly as and when needed!

I can see a 15% discount code from CityPlumbing, so looked at this one:

Sunsynk 5.5kW Ecco Single Phase Hybrid Inverter SUN-5K-SG01LP1-EU

Sunsynk are an internationally recognised battery storage and inverter brand, who are determined to make the planet a cleaner place to live. Sunsynk offer a wide range of high quality products for on grid and off grid systems. The Sunsynk Ecco Hybrid Inverter is a multifunctional inverter...
www.cityplumbing.co.uk www.cityplumbing.co.uk

Is Sunsynk a good brand?
 
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I'm going to jump in here as I think I want to add some more panels to my system. My predecessor installed them (and I think got ripped off - well he got them under a grant, so we got ripped off) but it was just 6 panels and inverter and cost £7.5k (I have the bill). The stupid thing is that the house is fully electric and there is space on the roof for easily another 4 panels, so god knows why they only put this small array up!

I have 3 storage heaters which are essentially batteries, and they use a decent whack of power over winter (only been in there since Feb, so didn't have a full winter, but March used ~800kwh), but the house isn't using much at all currently (and we've not had a great summer) but I used 15 Jul - 15 Aug 176kwh and exported 214kwh which meant that period cost to me was only £22. Therefore, I can't see it is worth my getting a battery as one that could charge in the day off solar would need to be massive to then cover the overnight use of the radiators (and likely wouldn't be able to charge fully in winter when I need it). They are on an economy 7 circuit as well if that makes a difference, and I'm paying 11.06p overnight and 26.59 in the day.

When I was looking, I did like the look of this: https://www.fogstar.co.uk/collectio...e/products/fogstar-energy-15-5kwh-48v-battery but I cannot find anyone who would fit it...
 
Malt_Vinegar said:
Happy to tinker, would like to be able to see whats going on at a minimum, and perhaps set some behaviours on the fly as and when needed!

I can see a 15% discount code from CityPlumbing, so looked at this one:

Sunsynk 5.5kW Ecco Single Phase Hybrid Inverter SUN-5K-SG01LP1-EU

Sunsynk are an internationally recognised battery storage and inverter brand, who are determined to make the planet a cleaner place to live. Sunsynk offer a wide range of high quality products for on grid and off grid systems. The Sunsynk Ecco Hybrid Inverter is a multifunctional inverter...
www.cityplumbing.co.uk www.cityplumbing.co.uk

Is Sunsynk a good brand?
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If you want to really tinker look at Victron, it's a more complicated install and likely more expensive but prices have dropped recently. It's highly configurable, take a look at my VRM. You can run your own Node Red directly on the Victron system.

VRM Portal - Victron Energy

vrm.victronenergy.com vrm.victronenergy.com

Check the discount terms for City Plumbing, last time I checked the code was not applicable for solar products.
 
@Ron-ski - I think I am leaning more towards the Solis inverter for the now. It seems to be the best value to performance. It also is listed as compatible with the CAN for the Seplos battery kit, on the main page, so should be simple enough to get talking to each other :) They are also seemingly supported by octopus, and I think this will make stuff easier for the application. I like the backup option for maintaining critical equipment also.
It has two string for solar (as I understand it) which I like, so I can build one install, and add another later easily.
It looks like I can add Solis-cloud function later if needed, using an adaptor on the "COM" port under the unit. I think this is close to the Victron functionality (in some parts?)
- Solis cloud update video

Hopefully I am not barking up the wrong tree, but I think this should be a work-able system :D
 
@Malt_Vinegar The Victron eco system and Solis inverter are worlds apart, on the Victron VRM advanced tab, I can create my own graphs, I can go even further and create my own code to run on the Victron Cerbo (the brains of the system), create my own dashboard, my own scheduling system, anything really only limited by my own programming ability. My 8kW Quattro inverter has built in whole house back up, pretty much any 12v,24v,36v and 48v battery will work with Victron inverters one way or another. It will work directly with the Fogstar battery - it supports the Victron protocol.

Do you need all this, most probably not, most people don't and the Solis inverter will highly likely do exactly what you need for a lot less money, and a lot easier learning curve.
 
Yeah this is why I said want to tinker as opposed to can tinker.

I'm not sure how they all work, but next time I would look to see if the apps require cloud access in order to affect the inverter/system.
My solax does, so if the web is down I have to change the settings on the panel directly, real PITA and also means very limited output available should solax go pop.
Its possible to interrogate directly but if that would all easily be maintained if solax went pop I don't know. Needs api code etc.

Next time if I didn't go Victron (which I would seriously consider) I would be looking ideally for a system that had direct local access as well as routed via the cloud ideally.
 
My next major issue is knowing if I need a local earth for the inverter, or if I can just connect it to the house earth. The house uses a PME as I understand it, which is a form of TC-N-S earthing system.
So, in the event of a supply failure, the dno should have earthing points between me and the failure, which I think means I won't need an earthing rod for the property as my inverter eps should still use the PME to get an earth.

BUT I am reading that I could also add an earth rod to my existing grounding block in the meter cabinet to be sure, but this seems like a faff I would like to avoid if I could :D
 
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