@transparent Steady on @transparent !😉

Posted by: @agentgeorge

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Biggest advantage for the planet is sodium is available from sea water, lithium is mined and causes environmental issues

And arguably even more important, sodium will be hopefully processed in more than one country... diluting excessive concentration of power.

Posted by: @agentgeorge

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no one has explained where the extra electricity will be generated from in 2030 when we have 2 million cars, 4 million trucks, hundreds of HS2 power hungry trains and thousands of local busses to charge up

Right now, when the wind blows strongly enough, a lot more could be generated than can be consumed, at least around this part of the world. But good news on that front, with the building of new "energy superhighways" (love these new names for otherwise dull infra projects..)

Posted by: @agentgeorge

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final obstacle is the grid interconnection is not capable of adding the solar farms and wind farms currently built but not cant operate as the wait is 5-10 years for some areas to get hooked up

This "lack of processing capacity" to build new grid connections seems to have been cleared to a large extent... Surely the fossil lobby will still try to appeal the unclogging of the connection queue (with lots of dormant applications by dead companies being removed).

But coming back to topic, it would be great to have a simpler way to mix use of lithium and sodium batteries and allow them to be managed by a single inverter... I assume from a safety perspective it would not be possible (or advisable) to just extend the use of modbus protocol to control operation of a mixed bank of batteries?

Posted by: @transparent

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I too had spotted the Na-ion battery and matching inverters from Eleven in Cambridge.
it's good to see a British company designing something for the obvious gap in the market.

Note that their inverters can only be used with their own Na-ion battery.
It's not a generic approach. They need to be transferring data between their own BMS and the inverter across the CAN-bus to make the system work.

 

Just continuing from a different thread.  

Eleven (that seems to be getting some coverage in the diy solar forum) offers sodium battery based systems with a 10 year warranty and that splits the components (battery and inverter). But also noted that neither is meant to be used except with each other. 

Eleven are proposing a battery pack voltage range much broader but around the lithium voltage (so it must use more than 16 cells). This should remove the potential issue with having to use very thick cables between the inverter and the batteries. 

Also I did not find any proper diagram describing the connections to the sodium batteries (even if it can be worked out from some of the photos in their brochures). 

Victron seems to have been the inverter brand with a more research focused user community (but I do not see the manufacturer getting involved). They have been configuring to use with sodium batteries, starting with 12v, from as early as 2019. The obvious need to use more cells and also thicker cables is always highlighted. Some simple high level cost comparison via this link: https://community.victronenergy.com/t/natrium-sodium-batteries/46888/11  

Posted by: @jamespa

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Apart from relative immaturity and slightly larger per unit power stored, what are the issues which lead you to say this?

The three technical issues I'm considering are:

• BMS suitability, for either ELV or 'high voltage' (above 75v DC)
• inverter functionality
• cable connections for larger batteries

Batpred mentioned Victron as a BMS supplier.
There are actually a number of possible alternative generic BMS units which allow wide-range configuration of settings.
JiKong, JBD and Batrium products would be usable in a notional 22S battery (22 Na-ion cells in series).

However they'd be less capable at two key functions which users of LFP technology tend to look for

• cell balancing current/efficiency
• reporting the SoC (State of Charge)

SoC should be easier to detect with Na-ion technology, but the BMS units were designed with Lithium chemistries in mind.

If you look at the North Sea inverters from Eleven, you'll notice that they can't (yet) offer parallel operation, despite having a pair of RJ45 sockets labelled "Link".

Designing a system which can safely/evenly share the load across 2 or more inverters isn't easy,
and the Chinese manufacturers are at least 5 years ahead of Western manufacturers for load-sharing.

Even they can't yet handle the concept of a failure of one inverter in the set.
It usually requires manual intervention to restart the remaining inverter array.

For the same reason, Eleven currently only offer single-phase inverters.

The sheer bulk of an Na-ion cell is also significant.

We're used to see a typical 4.5kWh or 5kWh battery in a rack-mounted enclosure which can be assembled by a two person team.
That restricts the lifting weight to 25Kg each (H&S rules)

But the 4.5kWh Na battery from Eleven weighs a whopping 54.5Kg.
It's 555mm deep and 150mm high.

For comparison, a 5kWh LFP battery from Pylontech would fit in the same 19"-rack frame, but would be 450mm deep and weigh 40Kg.

Commercial BESS containers seem to be using the same sort of LFP rack-mounted  units as the domestic market.
Switching to Na-cells would necessitate a larger overall container which would be heavier to transport to site.

The odds are still in favour of LFP technology.

@transparent, this is very interesting... still trying to get my head around things, so does the product from Eleven come with kit that allows them to island?

Posted by: @transparent

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But the 4.5kWh Na battery from Eleven weighs a whopping 54.5Kg.

I was told when I met the team from Midsummer Energy last year at InstallerSHOW that the Eleven sodium ion batteries were about 30% heavier than lithium ion equivalents. These seems to be significantly more though. 

Still intrigued by the batteries though. Might have to step up my exercise regime and start building bicep strength. 

Does this mean that you're intending a self-install of a storage battery?

You won't need strong biceps to run it after the installer leaves site 😉 

@transparent, terrifying prospect of me doing a self-install. Yikes! But an installer will need a hand if they weigh that much.

Posted by: @downfield

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Coincidentally I had my solar / battery installer back today to amend the wiring to allow a manual switchover to island or off-grid mode in the event of a power outage. (we get a couple a year around here usually only for an hour or so, occasionally longer).

Anyway, it's a couple of years since they installed my GivEnergy + solar system and I asked him how the market was developing.  He said they don't install GE any more as the support for installers has deteriorated.  He also didn't like the MyEnergi Libbi.

Just noticed your comment about manufacturer support for your BESS. Our inverter install is very recent and we kept everything running locally which also reduces dependency on the manufacturer. 

But since (we would hope) the equipment will last over a decade, occasionally I wonder whether it is right that, even after the warranty expires, only the manufacturer is able to update the firmware... 

Posted by: @batpred

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But since (we would hope) the equipment will last over a decade, occasionally I wonder whether it is right that, even after the warranty expires, only the manufacturer is able to update the firmware... 

I can see your point, but I think I'm inclined to explore the converse - the consequences of someone other than the manufacturer creating and applying their own firmware. Let's not forget that included in that firmware are functions for satisfying legal obligations such as disconnection from the grid if the voltage goes above or below certain limits.

What I really don't know, though, is whether or not there are any legal obligations for manufacturers to provide support for at least a certain minimum lifespan of their products. I would hope so, but at the same time I doubt it. Worth clarification, though.

@majordennisbloodnok 

The best solution is surely going to be that the manufacturers provide options to extend the support. The DNO will ultimately reach the owner in case of any issues. And we should assume the risk of owners creating and applying their own firmware to an inverter is low..

In Givenergy´s case, and going back to @downfield statement, it just seems that the quality of the support for GE installers deteriorated. 

When I researched Sodium batteries, I read from some owners that were experimenting using Victron inverters. If this required any changes to any firmware or not I have no idea, but the DC side functions being of no interest to the DNO, there is scope to make changes in that, whether it is firmware or config. 

With your Growatt, can the installer make firmware upgrades or is this reserved for Growatt?

@batpred, I agree with a lot of your points but would definitely still disagree about the firmware issue - or at least about allowing home owners to make firmware upgrades.

Posted by: @batpred

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The best solution is surely going to be that the manufacturers provide options to extend the support.

...

Absolutely. Extending support and maintenance windows to match likely hardware lifespans is the ideal and what I think we should be pushing for. It would completely sidestep any question of homeowners having to do stuff themselves.

Posted by: @batpred

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And we should assume the risk of owners creating and applying their own firmware to an inverter is low..

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I agree the risk is low but the consequences are significant. I think owners should remain detached from any amendments to firmware. An important distinction to note, though, is that I see no problem with homeowners being able to apply firmware that has been written by the manufacturer and is appropriate for that piece of kit.

Posted by: @batpred

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In Givenergy´s case, and going back to @downfield statement, it just seems that the quality of the support for GE installers deteriorated.

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This is a perennial problem and always concerning. My feeling, not that I have any clout to do any real influencing, is that this should be wrapped up in the "right to repair" legislation recently introduced - perhaps extending the scope? Even if manufacturers want to refresh their product range or even reposition themselves, I feel they should still have an obligation to provide longer term support for historical customers and their older products.

More generally, I wonder if there is a gap in the market for long term support and firmware updates to be fielded by a company or two who are specialists in doing just that. When various laptop manufacturers have decided to withdraw from a market, it's not been uncommon for them to hand over their intellectual property and bundle of spare parts over to a third party who then becomes the contact for ongoing support. If such a company could be approved as competent for applying DNO regulations correctly, there's no reason why further firmware updates couldn't be written by them instead of the original manufacturer, and such a company could provide this service for multiple brands of inverter/battery/whatever.