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Lithium batteries discussion


Gerlach
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While we on this nice subject of Lithium batteries like the Pylontech and other brands, I think we can have a nice discussion of all the brands of lithiums that the guys are using on the forum. Like @plonkster is using Victron lithium batteries, @Youda got a massive Pylontech stack and spotted some other brands to on the forum.

I'm in the market for lithiums but spotted some problems that we have spoken on the other post, like charging volts and more stuff so now i need to make my options bigger and check what ells is there that i can run in my setup.  

The guys that are running other brands like the chine's imports and stuff, how are your findings on this brands and how is the performance of this batteries, like Narada, Shoto and more other brands. I know of the local Brands like BlueNova and MD solar and Freedom, you guys can give your inputs to on this that is using them. 

I have spotted this 48v 100amp 4.8kw that is sold locally and Probebatteries is importing there own stuff now to. 

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1 hour ago, Gerlach said:

Victron lithium batteries

They are not a very common choice, mostly because on price they don't compete too well in South Africa. I use them because I got them at what could be considered about half price.

The other "down" side is that the cycle life of these batteries are low, or more specifically, they appear low if you don't consider the full picture. They are quoted as having a mere 2500 cycles to 80% DoD and 5000 to 50% DoD, which seems terrible compared to a Pylontech, right? The specs are however determined by using a 1C discharge rate (Pylontech uses 0.5C), and the battery is deemed EOL when it has irreversibly lost 20% of its original capacity (Pylontech uses 40%). Internally it is also the same cells used by BlueNova who advertises 6000 cycles (they use a C/10 discharge rate). That is to say, the advertising material is perhaps a bit too honest for this battery 🙂

These batteries are also unmanaged. The batteries are 12.8V units with their own balancers. There are two cables on each one which you daisy-chain to the battery next to it, and then the two ends of the loop is connected to a small box called the "VE.Bus BMS", or for systems without a Multi, you'd use the mini-BMS. There is no protective FET or disconnecting contactor (though you can fit one if you want to). Instead the BMS communicates directly with the Multi to stop charge or discharge. There is no charge or discharge current control, there is merely a stop/start signal. It is in many ways a very dumb battery... but the simplicity also makes it kinda nice.

The VE.Bus BMS has dry contacts which you can use to switch off DC loads, if you have them.

The SmartLithium models have bluetooth, and you can see cell levels and temperatures using VictronConnect. The BMS will disallow charging below 5°C to prevent damage. Earlier batteries have simple passive balancing (and that works perfectly fine). Newer batteries have active balancing.

There is of course also the HE series batteries. These have a different chemistry (NMC) and a very very nice CAN-bus BMS. Completely different protocol to the others, 29-bit CAN 2.0B vs the normal 11-bit CAN 2.0A used by the others, also NMEA2000 and all that nice boat stuff. Has cooling requirements (they have cooling fans). Really nice batteries, but more suited where weight/energy density is a concern.

So that summarises that 🙂

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48 minutes ago, plonkster said:

That is to say, the advertising material is perhaps a bit too honest for this battery 🙂

The other thing that jumps out at me reading the specs etc. is that they have a short warranty. So although they are perhaps capable of the 6000 cycles, no backup. Not to say that these other battery manufactures will be around to honour the 10 year story..

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10 minutes ago, Fazil said:

Freedom Won

FreedomWon uses Sinopoly cells, Orion BMS, locally assembled and programmed. So though it is a "locally made" battery, the cells are from China (all of them are) and the BMS is from America. Has precharge as far as I know.

SolarMD uses CALB cells, or at least did in their first batteries. I think some of their later batteries used cells from somewhere else, though I am not sure. They still come from China. Don't know what BMS they use... could be locally made.

BlueNova uses Winston cells (again from China, these cells have a small amount of Yttrium doping for better heat resistance), and they build their own BMS. I like the fact that their batteries all have the precharge feature, even the lower end modules.

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The first lithium batteries for my solar were two built-to-order packs of Winston cells + BMS. With 20 kWh of the total capacity, they were able to power the whole house, including the oven and induction cooktop. I enjoyed to watch the flashing balancers in operation and liked the massive charging current that they have been able to accept. But, there was a couple of downsides too. One of them is that a single inox box with 10 kWh of LFP cells weights around 100 Kg. So it's impossible to move these boxes around by a single person. Also, how to efficiently store 3 or 4 of these, while keeping the cables as short as possible?

image.thumb.png.6407b0435343b65cb07f2e11c223d7f7.png

 

So I made a list of nice-to-have features and started looking for a replacement:

  • LFP, 48V
  • 19" rack-mountable
  • Better price per kWh - as Winstons LiFeYPo4 are one of the most expensive cells on the market
  • Price per brick around 1000 USD - so I can buy a single brick whenever I need to, without saving money a year in advance
  • With a standard LAN, RS232, RS485 or CAN BUS interface - not 3V UART
  • Weight per brick around 30 Kg - in order to handle all the install/removal operations by myself
  • Supplies must be widely in-stock all over the year - as I don't want to invest in a niche product that won't be available in the future

I did my market research and found that Pylontech US3000, while not 100% perfect, is the best fit for me. There were couple of features that I really did not like, so I poked around for some time, trying to fit something better. But I had no luck. All the alternatives had some issues. For example, SinLion batteries were cheaper per kWh, but had a very poor suply chain.

image.thumb.jpeg.18699e135abe1b80113fed201df7828b.jpeg

So far, US3000 works nicely and I feel that for me it was a good choice. Of course, there are some downsides that one has to take into account:

  • 15 cells in series architecture makes Pylontech incompatible with most of the other LFP batts that are 16S. So you can't paralel them together. It's a vendor lock-in.
  • Specsheet is a bit misleading when comes to "recommended" amps and charging voltages. Either you must have a compatible inverter with a BMS communication or be able to play with the settings a bit.
  • Supplied 25mm2 cables are bit thin. While specs allow to stack 8 bricks together, it's a lot of cable joints and resistance. In practice, it's better to split the stack in two, especially if you want to push/pull more than 120A per 592Ah stack.

 

Based on my experience, I would say that it's not just about the price per kWh, but there are other factors that come into play. For example, I would use a very different form-factor and a plastic sealed case for a yacht. Similarly, if I had to paralel the batteries with some older LFPs, I would stick to 16S.

 

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4 hours ago, Youda said:

The first lithium batteries for my solar were two built-to-order packs of Winston cells + BMS. With 20 kWh of the total capacity, they were able to power the whole house, including the oven and induction cooktop. I enjoyed to watch the flashing balancers in operation and liked the massive charging current that they have been able to accept. But, there was a couple of downsides too. One of them is that a single inox box with 10 kWh of LFP cells weights around 100 Kg. So it's impossible to move these boxes around by a single person. Also, how to efficiently store 3 or 4 of these, while keeping the cables as short as possible?

@Youda it really looks like the Blue Nova batteries inside with all the BMS's and even battery statis screen on the front looks the same. Who did the built to order for you? 

Edited by Gerlach
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Mine batteries were made here: http://www.baterioveboxy.cz/domains/baterioveboxy.cz/produkty-2/

Any similarity with BlueNova is just a coincidence for sure. Once you're using Winston cells to build your product, there's not much you can invent terms of the physical design of the box. For example, it's almost imposible to squeeze these cells in a practical rackmount package. The pack of 16 LFP cells will be always too deep, or too high. Therefore almost all the designs that I saw were similar - some kind of a closed metal box or a non-standard cabinet.

Same for the balancers - the srew terminals of LFP are ideal to fit a small PCB directly. So, many manufacturers developed a their own balancing modules with a similar look:

image.png.810e9d81292da47dc4f0c1502758a6c3.pngimage.png.2541e7cf5169ad60a12bf8ae30022887.png

 

 

Anyway, I'm convinced that Winston cells are one of the best, since I know couple of guys that are using 8yrs old 200Ah LiFeYPo4 cells from electric buses an they still have more than 80% capacity. But the brand new cells are overpriced and for me it does not make sense to use them for home solar. But that's just my personal opinion, nothing more :)

 

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I have a Voltext MKS 5KVA inverter with 12 datasafe HX400 batteries. The batteries started to burst open and the inverter started to act strange by switching off and couldnt supply our house during the evening. I swopped the batteries out with my 2nd systems batteries so all the problems stopped however they dont have enough capacity to run the house during the evening.

I want to add 2 LI batteries to replace the old batteries. This is what I have in mind 2 X 48V 3KWhP Schubart (LiFeP04)Life batteries, Currently we use 5 kwh at night.

The geyser, stove and oven are all running on gas, all bulbs are LED and appliances are new and energy efficient types.

Please comment on my decision and feel free to propose alternatives

Thank you

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  • 1 year later...
On 2019/11/19 at 1:13 PM, Youda said:

Supplied 25mm2 cables are bit thin. While specs allow to stack 8 bricks together, it's a lot of cable joints and resistance. In practice, it's better to split the stack in two, especially if you want to push/pull more than 120A per 592Ah stack.

Hi Youda

just wanted to ask about how you wired this. If I can see correctly from your picture, the comms ports on all your batteries are daisy-chained (so all run by a single master). But on the power cables, you are using 2 sets of connection cables with each set connected to 4 batteries. That way, you can push 240A of charging current into your batteries (instead of the 120A with a single set of connection cables for all). Is that correct?

I'm also looking to be able to push more than 120A into my Pylons, so would appreciate your feedback 🙂

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