AVASS Battery order details

[doggy]

Hi All,

I have just read with fascination the details of this deal plus those of the "Home battery project". Great stuff!

I live in a place with a large number of gum trees which shade the roof periodically and in various spots. Accordingly, I have installed some low voltage solar coupled with custom UPSs to drive my CCTV system plus a variety of in-house servers and other computers. I have been developing my own MPPT solar regulators since 2004 and this has kept my deployment costs down. I also built my own vacuum tube solar HWS at very modest cost and this paid for itself in less than 5yrs (at offpeak electricity rates) and was 20% the cost of the cheapest professional quote which would have reached breakeven in 30yrs (ripoff merchants).

Installing a fuller solar PV system has always looked uneconomic because I would either have to use a lot of micro-inverters or go for a low voltage system with inverter/battery and multiple MPPTs on individual panels or small groups of panels because of the shading.

Now, if I could get my hands on some reasonably priced cells exactly like those featured here, I would have more options and could look at solar charging my Zoe and running some other things around the house and at a cost that is perhaps manageable.

So, if any of the purchasers here find that they cannot now utilise their cells or their circumstances have changed, I would dearly love to get my hands on a set of cells. I have seen how much effort and good will has gone into this project and therefore I would rather negotiate something through the AEVSA rather than outside its auspices. Of course, I would prefer the larger cells but I am sure I could do something with the smaller ones as well. Yes, I saw the eBay listing but am avoiding that.

Best Regards,
David

[jonescg]

I've just chipped in as well.
Thanks again Chris for your efforts.

Thanks David,

The final shipping bill for the transcontinental cell-swap came to $567.76. I've currently got $431.26 in the clearing account (thanks to everyone so far who has chipped in!).

So if a few more folks can chip in that would be awesome.

Cheers,
Chris

[iamlsd]

Small chip - in from me. Thanks for all your organisation with this.

[jonescg]

Thanks Damien!
Cheers,
Chris

[jonescg]

Thanks to everyone who has contributed to help sort out the final details on the shipping bill.

The cells have been shipped and everyone should have what they asked for.

Now we look forward to watching the storage systems come together!

Cheers,
Chris

[Mcdonell]

Hi Chris

I was one of the lucky ones who picked up the larger capacity batteries in Melbourne, so have sent you a bit extra to help cover the extra freight costs.

Cheers Jeff

[nuggetgalore]

Hi Chris

I was one of the lucky ones who picked up the larger capacity batteries in Melbourne, so have sent you a bit extra to help cover the extra freight costs.

Cheers Jeff

Great.
What are you going to get as a BMS?
I have the same cells, tossing up on getting a ready made one or buy the bits and use my PLC .
Maybe we in Melbourne could could exchange info and experience (lacking with LI in my case).
But for me it will be in November,I will be in Switzerland until the end of October.
Cheers

[Mcdonell]

Hi Nuggetgalore

Other posts have suggested the Batrium BMS and with a Goodwe 3600 inverter. I’m a newbie to all this so happy to learn from others.

Bryce suggested adding a monthly topic at the VIC meetings re the battery builds. Good idea I reckon.

I’m also away until mid Sept, so will start seriously thinking about it then.

Keep in touch.

Cheers Jeff

[mark_hetho]

I haven't seen any other promising options for a BMS besides Batrium. The Batrium gear seems quite comprehensive.

As far as inverters there are a few options.

In battery only inverters the Selectronic SP Pro 48V units would work, and there are the Victron Quattro units. These are fairly pricey. In hybrid inverters there is the Schneider Electric Conext XW+ 8548E, and Solax SK-TL5000E + SK-BMU5000.

All of those have about a 100A battery charger. There is also the Redback SH5000, but I think it would struggle to charge the battery during the daylight hours due to a 65A charge rate.

I'm considering the SP Pro SPMC482, because of it's surge current and additional flexibility it offers (generator start and secondary AC input, off grid and grid interactive operation) but only because it might tie into future plans.

[jonescg]

ZEVA makes a BMS which manages up to 16 cells in series, outputs CAN-Bus comms and can be configured. Pretty sure Ian is working on some protocols to talk to the Goodwe inverter, or at least have it output data like a BYD battery so any inverter can be taught to listen.

Otherwise you can use a variation of the lead acid profile - set Vmax to 56.8 volts and don't use a float feature.

[dgh853]

It is possible to use the self-define setting on the Goodwe (rather than selecting an OEM lithium battery which uses CAN or RS485 comms and the OEM battery controls voltage/SOC limits). In that setting the upper voltage limits can be set but it doesn't do this for low voltages - for that the Goodwe relies on its own SOC calculation and a depth of discharge between 10%-90% must be set.

The Goodwe self-define mode is too crude to control these Brighsun cells IMO, firstly for the reason that it uses a self-calculated SOC to limit discharge. My experience is that this calculation gets out of sync with voltage within a day or two. So that the battery can be at an idle 48V and the depth of discharge/SOC is 90%/10%. This places a very conservative lower limit on discharge. Restarting the inverter in the example above brings the calculated SOC back to around 50%. You can then run it down to lower voltages for a few hours before it gets out of sync again. That is my experience using lead acid AGM in winter, others experience may vary.

Fortunately, the upper voltage limit is good at limiting voltage on the AGM pack. Adding a BMS in there to manage individual Brighsun cell voltages means it could still work safely recognising the depth of discharge "anomaly" noted above.

As the Goodwe has DRM support it is possible to have a BMS control the Goodwe inverter through a relay to enable and disable charging and discharging.

The Goodwe SBPs support the following standard DRM functions:

DRM 0 Operate the disconnection device
DRM 1 Do not consume power
DRM 2 Do not consume at more than 50% of rated power
DRM 3 Do not consume at more than 75% of rated power
DRM 4 Increase power consumption (subject to constraints from other active DRMs)
DRM 5 Do not generate power
DRM 6 Do not generate at more than 50% of rated power
DRM 7 Do not generate at more than 75% of rated power
DRM 8 Increase power generation (subject to constraints from other active DRMs)

By having a relay close the appropriate DRM plug connections, the inverter will go into DRM 1 mode and would stop charging until the relay opens. Similarly for DRM5 mode, having a relay close the connection will stop the inverter discharging the battery (e.g. for low voltage /SOC scenarios).

If you have additional relays you could force the inverter to charge (via DRM 4) in say off-peak time of use periods when grid electricity is cheap.

As I've been successfully using the DRM commands (DRM 5 and DRM 4) for a couple of months on the AGM pack I would be able to use them to control the charging with the Goodwe set into self-define mode. Using a BMS to trigger a relay (and the relevant DRM command) is pretty standard fare for a BMS which controls a charger. While it's probably not a final solution because of the SBP's conservative depth of discharge / voltage settings it does enable a BMS to control the Goodwe inverter charging and discharging based on individual cell voltages, temperatures etc. You might only be able to access half of your pack until that anomaly that I see for the AGM depth of discharge is a still an issue. Some more testing will determine whether it is a problem with the Brighsun's as well

The CAN / OEM battery setting option is still something that I will be pursuing as the best solution as that will pass more accurate SOC from the BMS to the Goodwe inverter. That's something that I'm not familiar with yet and will take more time to test, configure and implement. Additionally I'm looking to be able to trigger the DC circuit breaker as a safeguard if various BMS limits are exceeded.

I've been fortunate that I already had the Goodwe SBP professionally installed a couple of months ago so I can readily swap out the AGM pack with the Brighsun/Batrium BMS (initially with DRM-based charging/discharging controls but hopefully in time, CAN-based control mimicing a Goodwe compatible OEM battery).

For those who are yet to jump in please be aware that getting a BMS to successfully mimic a compatible lithium battery with a Goodwe SBP has not been done to my knowledge and may not be possible. If I didn't already have the Goodwe I would be either holding off purchasing a Goodwe until there was confirmation that it works the way you would expect with your chosen BMS. Alternately there are other battery inverters - Solax, Schnieder, Victron etc that BMS makers have already integrated to successfully. If you're in a rush to get your storage working that may be a less risky approach than going down the Goodwe path right now.

You'll also need to find a qualified installer to do all the AC connection work and they must be happy with what you've done on the DC battery side from a compliance perspective as they have different responsibilities with different types of energy storage systems e.g. all-in-ones versus bespoke setup.

[jonescg]

If you went with a full off grid setup and used a Victron 150/80 solar charge controller they come with a LiFePO4 setting (the last rotary switch position). I believe it uses voltage as a crude cut off, but a half decent BMS will open a contactor before then.
@winners has one such system, working well.

[Adverse Effects]

i have heard only good things about Batrium and from what i can see its highly configurable to

this guy HBPowerwall is in Brisbane (and i think a member in here) and has worked with the developer to give the Batrium units good compatibility with Li base batterys

look through his vids on them

[dgh853]

Yep, the Victron allows for a very flexible setup, including DC-coupled PV using a charge controller and a Multigrid to minimise grid imports - see 4:45 into this video at https://www.youtube.com/watch?v=tbpQzEZTElI.

The Victron kit is a little underpowered and overpriced for AC-coupled grid-connect IMO but if you leverage the flexibility for other options then it could be worth it. The Multigrid 3000 is $2500 but you can only charge at 35A. Using a separate charge controller to feed PV into the battery largely resolves the charging limit problem. But that's not really a retrofit option for those who already have grid-connect solar unless they want to get rid of their existing solar inverter and change to a charge controller with Multigrid or modified Multiplus (to support anti-islanding requirements) to power you overnight along with a Venus GX or CCX console to manage it all and target net grid import.

Then its just a matter of living with a 3kW battery inverter overnight rather than a 5kW. Not a big issue but when you can pull 100A from these cells then it makes sense to size for that if the additional cost isn't too great. In the case of the Goodwe, it's RRP $2100 versus $1600 for the 3600. I bought the 3600 because that's all my lead acid could handle and I was looking for maximum ROI. Now I have it the Brighsun cells and I have a 5-6kW AC I'd like to be able to "net off" when the sun isn't shining, in hindsight I wish I had purchased a 5kW inverter but I really only need the 3600.

Most of us are on grid and it make sense to cut our power bills by building a grid-tie system with whatever AC/DC coupling floats your boat. Yes, you can build an off-grid system on the side but how much are you really going to save in that scenario and is it worth the hassle of having half your house circuits running from the grid and the other half off-grid.

Overall system costs

There are a number of CEC-approved battery inverters but none come close to the price and power of the Goodwe which is why I chose it for my AGM setup. While the Brighsun cells were a bargain at $1000 setting up the rest of the system is not an insignificant cost.

Here's a quick breakdown of costs based on my recent install with AGM and factoring in the Brighsun and BMS costs:

- Goodwe 3600 SBP installed with all AC connections => $3200
- Brighsun cells inc bus bars => $1100
- BMS => $1000

Total = ~$5300

That's awesome for a 23kWh lithium pack versus a Powerwall 2 at $10k say but you also need to factor in battery build time including research and learning new stuff like BMS, DRM etc. My AGM cells were used but free and required no BMS so the ROI was a lot better at just $3200 total cost albeit for less usable capacity and likely shorter cycle life.

Given those costs and the likelihood that most people won't be able to save more than $500 per year with battery backup it's a good 10% return but you need to be careful not to get carried away with higher cost solutions like Selectronic or Victron or your ROI will go out the window pretty quickly.

[mark_hetho]

I can absolutely respect a position based on ROI.

I'm interested in more economical solutions, just to see what is possible. I'm also a bit motivated to put some extra money into it as a bit of an experiment, to see how close we can get to operating grid independent or off grid. I suppose I could get a cheaper hybrid grid interactive solution for now, and monitor that first. In hindsight knowing these batteries would become available, I wouldn't have gotten a hybrid battery system in the first place. Instead I could have paired up a standard grid tie inverter with a battery inverter at this point.

In terms of ROI, I think you may need higher charge rates to get the most out of the larger battery. 22kwh over summer might be a charging rate of 2kw with longer days, but with a 5 sun-hour day it's over 4kw. Lower cycle rates would likely mean a longer calendar life, but they probably have a limit on calendar life at some point anyway? Getting more energy throughput per day would increase the ROI as far as I can see.

[dgh853]

We're fortunate to have a 10kW PV system so filling a 22kWh battery is pretty easy, even in winter as long as the inverter is sized accordingly.

The ex-accountant in me says buy the cheapest, the self-sufficient part of me says bigger and better inverter. The Selectronic and Victron are appealing but we'd need to sell an EV to find the extra cash ATM.

[mark_hetho]

I wasn't thinking so much of the amount of generation (PV panels) as the charger current capability. Some inverters seem to handle a larger amount of solar panels proportional to their charger current capability. If ones inverter only has a charge capability of 50A it would take about 10 hours to fill the battery, and you might not get that many hours of sufficient sun even on a clear day in winter. (We do also have some mountains that keep the sun for coming up for us until a bit later in the day.)

We currently export about 10kwh a day in summer, so we can soak some of that up, but I'm planning to add more solar as well, even if not immediately. We are export limited to our current system size though, so we would really want to store nearly any extra generation for it to make sense. Then again, if we had enough solar, and did some load shedding on cloudy days, we could almost certainly be grid independent with this amount of storage.

[offgridQLD]

$8,000 RRP for the 7kw 48v SP pro makes it hard to justify from a investment perspective. Particularly if you have the grid. A very isolated - remote setting where power dependability a factor in the value equation is a different story. That said I found it a bit disappointing how Selectronic stop supporting there inverter models after 8 - 10 years anyhow.


I think another aspect long term to consider when investing in components or the overall plan for your system and ROI calculations. Is think about what position you will be in next time you have to replace your battery bank. For example setting your house up to be 100% offgrid and perhaps purchasing top shelf components today with your $1000 22kwh battery is all good. Though in 8-10 years that battery replacement is $15,000. There is always talk about battery's being less expensive in the future though from what I have found they have become more expensive.


Just out of interest are the Cells new - unused or have they been sitting for some time. Has anyone performed a capacity test on there cells.?

[jonescg]

The cells were manufactured in 2015 and have never been used. I suspect the 460/220 Ah numbers are generous considering their discharge curves and cycle life charts show levelling off at about 90% original capacity.
Hoping someone can get a capacity test done soon.

[offgridQLD]

Even if they are down 10 or 15% (40-60ah) from listed spec that's ok. I found 400ah at 48v lifepo4 to more than enough capacity to be 100% offgrid even with a hungry EV in the mix. As long as you have the PV array size to support it. Any more capacity would be wasted on most homes.


It would be interesting to have some collective data on how the cells perform over time. Considering every one who has them is starting out with the same cells. Enviroment conditions hot - cold, DOD, load profile, ballancing will all most likely be different for most people using them and the end results could be the same.


Start collecting data from day one so you have a datum to measure from.

[jonescg]

It would be interesting to have some collective data on how the cells perform over time. Considering every one who has them is starting out with the same cells. Enviroment conditions hot - cold, DOD, load profile, ballancing will all most likely be different for most people using them and the end results could be the same.
Start collecting data from day one so you have a datum to measure from.

Awesome idea. Maybe a standard set of tests could be used?

[reecho]

I have scored myself a Goodwe S-BP inverter. I'm working with ZEVA to integrate their BMS. Getting protocols from known battery manufacturers has been a challenge..

[Gobopolice]

This is good news Richard, I have been looking at both the goodwe inverters, namely the SBP GW5000S-BP and the ES series GW5048-ES .
I am am very new to all this but am very keen to get my 32 batteries up and running.
I have 2 strings of PV comming in (11 panels265w on each in series) to a Fronius 5kw inverter.
My thoughts were to replace the Fronius with the ES series 5048 as it is an all in 1 unit.
Put the 32 batteries in 2 strings in parallel to make up the 48v nom.

But I have no idea how to integrate the ZEVA BMS into it, I will need help here.
Its all a bit of a gamble as there is no-one that i know of who has actually got a similar system up and running.
So when I read your post I got pretty excited LOL.
My Dad took the easy way out and installed the LG Chem to his setup which was basically plug n play, not in our case.

Do you recon I should order the ES 5048 or just AC Couple with the SBP GW5000S and leave the Fronius alone ?

Its getting exciting.

[reecho]

Do you recon I should order the ES 5048 or just AC Couple with the SBP GW5000S and leave the Fronius alone ?

Its getting exciting.

I'm inclined to leave any existing PV/Inverter in place and adding the AC coupled retrofit. I haven't found a hybrid inverter that does everything I need at a reasonable price.

[Gobopolice]

Whats the size of the Goodwe SBP you scored