Solis 3kW AC coupled Inverter & Fogstar 5.12kWh Rack Battery ?

[rich1]

Do you have a link? Oh they are taking pre orders for the next shipment now.

Over on DIY Solar Power Forum. There's a thread where Ben at Fogstar asks for design input on a 19" rack battery.


TBH, I am contemplating building my own 14kWh battery from 280Ah cells. The trick will be convincing the hybrid inverter that its a big pylontech battery! 14kWh for £2500 would be a decent proposition. A £1500 5kw hybrid inverter on top would be a great deal. £4,000 for the whole system. A Libbi 15kWh is £11,000. So not sure what the extra £7,000 is buying me?

 

[Ronski]

I am contemplating building my own 14kWh battery from 280Ah cells

Been there, done that and next one on order

Cell's from Fogstar.

 

[rich1]

Been there, done that and next one on order

Cell's from Fogstar.

Tell me all you know... What BMS, what inverter etc etc....

 

[Ronski]

@rich1 Quite a bit is in this thread, but all of it is in this thread.

 

[Ronski]

@Oldman22 You may be interested in this thread, if you haven't already seen it.

 

[johnb2713]

Tell me all you know... What BMS, what inverter etc etc....

Seplos BMS emulates Pylontech protocol. See my battery build exactly what you’re proposing to do Here

 

[johnb2713]

For one person, yes, but two people, maybe manageable, also depends how high you need to lift it. They've sold plenty of Seplos 280 kits, and they are intended to be stacked, it would be a right pain if you had several stacked and needed to get access to the bottom one though.

Aye, two people, plenty of space either side and it still exceeds the manual lifting regulations weight of 25Kg with two people. The thought of lifting this sort of item into place in a tight spot with only one person is not a good idea.

By my calculations, my 16 cell drawer weighs about 100kg, I built it on the drawer though.

Exactly

 

[Ronski]

exceeds the manual lifting regulations weight of 25Kg

If everyone took notice of that the world would grind to a halt, I work in a commercial workshop, where a lot of things are heavier than that, part of the business is also a removals company, where a lot of items also exceed that even factoring in two people, you need to be sensible, and use the correct technique, but many years does take its toll because people aren't always sensible, or use the wrong technique.

 

[rich1]

Seplos BMS emulates Pylontech protocol. See my battery build exactly what you’re proposing to do Here

Thanks!

 

[johnb2713]

If everyone took notice of that the world would grind to a halt, I work in a commercial workshop, where a lot of things are heavier than that, part of the business is also a removals company, where a lot of items also exceed that even factoring in two people, you need to be sensible, and use the correct technique, but many years does take its toll because people aren't always sensible, or use the wrong technique.

So true, lift with your knees not you back. I always find it difficult to grip stuff with my knees

 

[Oldman22]

Its alive, No5 is alive
49% to 100% battery charged in 2hrs of sun this morning, now i'm exporting for next to no money, I need more batteries Captain.

 

[bladerunnerpv]

Cool, exciting stuff Oldman22!
Does the BMS on the Fogstar 15kWh rack actively balance the batteries / cells ?

 

[Oldman22]

Cool, exciting stuff Oldman22!
Does the BMS on the Fogstar 15kWh rack actively balance the batteries / cells ?

Well its only been running a few hours so I hope so, I charged or rather the sun did from 49% to 99% and the Battery LCD display showed the cells at that point were lowest 3.419v and highest 3.426v so just .007v difference.

 

[bladerunnerpv]

Looks promising, was wondering if the delivered manual mentioned it, I couldn't find any reference on their website. Will be interesting to see how things progress after a few weeks use, all the best.

 

[Oldman22]

Manual? what manual, no paperwork at all with it. There are some pdf's on the sales page but nothing helpful if you are new to setting one up. Dont bother emailing or phoning for help with voltage settings either. I was told to select pythontech in the Solis menu and the canbus threw a fit and alarmed with "battery name fail" so I had to use "user defined" as my battery type and with no idea what settings that sets up. I asked for help from the battery supplier as to what the correct settings should be for their battery. I'm still waiting.

 

[michael8554]

If you were thinking of adding Fogstars to your existing batteries, as I was to my Python 3000C :

"The Fogstar ESR51.2V 5.12KWH systems are not compatible with other types or models of rack battery on the market, this may be due to discrepancies in power/size of the unit, BMS or overall system compatibility. Please do not attempt to connect your Fogstar Rack Battery to any other make or model of Rack Battery on the market. If you are unsure about your set-up requirements, please contact our customer service team before making a purchase."

 

[Oldman22]

Yes I had noticed that disclaimer which btw went up on the battery sales page after they had sold out of the current batch, so you can bet your little cotton socks that some purchased expecting to marry with existing other make packs.
It was mentioned on another forum that Solis by listing battery manufacturers that were approved for use with Solis inverters with pain of loosing warranty if you fitted a non listed battery being restrictive practice.
Well I think Fogstar are also being pretty restrictive with their statement too.

 

[Ronski]

Well I think Fogstar are also being pretty restrictive with their statement too

The trouble is its a very complicated subject, if people did their research then it would be plainly obvious why different packs are not compatible with each other, some are but there are other complications. Needless to say the safest option is to say they are not compatible.

Take Pylontech, they use 15 cells and this runs at a different voltage than the Fogstar pack. It could also depend on what voltage the actual cells are as well, I believe some have a different voltage. Some packs, Fox I believe run at around 100v and those packs are possibly connected in series (add the voltage together).

Then there is communication, different makes will likely not communicate nicely together.

Now if you have different packs that run at the same voltage range you can run them together, BUT you will need an external shunt to measure and work out the SOC and that shunt will need to communicate with the inverter, you would not use the battery pack communication, this is how my Victron system works. You would also need to connect the battery packs in such a way that they all have equal cable resistance to the Inverter (same cable same length), this is why when you have multiple Fogstar batteries they tell you to connect the positive to the top battery and the negative inverter cable to the bottom (or vice versa). If you don't do this then the pack with the shortest / lowest resistance to the inverter will charge and discharge the most, the others less so.

 

[Joules]

I have a 2014 FiT solar system which is working well but dumping up to 2/3rds of its generation even at this time of year back to the grid, I would like to make use of at least some of that so I need battery storage.

Having followed several big builds on here & other forums I was champing at the bit to get started, but the costs didn't weigh up & I have come to the conclusion that a big build is not viable for me, the costs keep mounting & considering I'm not a huge kw user the payback gets too long.

But my attention was drawn to a simple solution that would have a very short payback (under 3yrs) for my situation.
One or 2 of these https://www.fogstar.co.uk/products/server-rack-battery-48v-5-12kwh? connected to one of these https://www.itstechnologies.shop/pr...-storage-ac-coupled-battery-charger-inverter? with a wifi stick https://www.itstechnologies.shop/products/solis-data-logging-stick-wifi-gen-3

That comes in at £2162 with 1 battery pack or £3512 with 2 battery packs.
OK the inverter is 3kw only but will more than take the edge off my grid demand & I will soon know if the 2nd battery is needed. Adding that is easy.
Ive not heard bad things about Solis inverters, the fogstar rack batteries seem to be a new line, I cant find any user reviews yet online so maybe the March 1st dispatch are the first ones?

A couple of isolators and 2mtr of cable and I'm done I think. Will they play nice together??

Now the only flaw in this plan is if I draw more than 3kw on a cloudy day or evening I'm going to spike & take from the grid and will it annoy me so much I will wish I had gone for a 5kw inverter? Who knows but with short payback I think I will take the risk.
The price difference between 3kw & 5kw AC coupled inverters is almost double, makes me think adding a second 3kw Solis inverter plus battery in future wouldnt be such a stupid upgrade. 2 x 3kw inverters costs near the same as one 5kw inverter, plus if they will play together if one were to fail down the line, not all your eggs are in one basket.

Comments...

Your post came up in a search for "fogstar rack battery". The issue of inverters is addressed on their blog and technically they have control of the BMS software so can modify it as required. I'm looking at Fogstar Batteries as my preferred supplier because they appear to know what they are doing and are very discerning as to what they sell. The search started with YouTube, Will Prowse makes it all look so easy. Why not call Fogstar and see what they have to say?

 

[Oldman22]

Why not call Fogstar and see what they have to say?

Its a bit late for that Joules, I'm guessing you skipped the thread to post at the end. I ordered a Fogstar rack battery which was delivered first few days of March, added an inverter and up & running by 21st March.
It was fully charged by Noon today, the house is running on it now. I have 2 more on order for late May delivery.