Sunny island 6048

Hedges

Photon Sorcerer
Looking at the functionality of the REC now. Annoys me these little controllers are almost $1000. Just ridiculous.
What I saw was closer to $500


Who sells REC hardware as they don't sell off their website?
 

westvandude

New Member
I think you want a lithium BMS on the CAN bus, not the rs485.

The SI6048US has CAN that the REC, Batrium, or your own BMS can talk to, if the SIs are set to Lithium mode. That is what madsci has hooked up to (read back a little more in this thread, and he has more details here https://github.com/madsci1016/SMAVenusDriver). Also further back in this thread, MurphyGuy has 2xSI6048, + ac coupled SMA sunnyboys, and lithium with REC bms on CAN bus, so that does work also.
I thought madsci was using a victron charge controller and interfacing into that. So I went back looked at page 53 and 57 of the manual https://files.sma.de/downloads/SI4548-6048-US-BE-en-21W.pdf and the COMsycIN and COMsyncOUT are supposedly CANbus? Same communication channel where SI master talks to slave(s). Interesting.

Brings me to another SMA question, interfacing the new series 41 sunny boy inverters to the 6048's....
 

madsci1016

Solar Enthusiast
Yes, the SunnyIslands expect to talk to a BMS over the CAN bus when in Li-Ion mode. They have a 485 bus, but that's for talking to SunnyBoys and SunnyWebbox

As I said before, run far away from Batrium if you have Sunny Islands. Poor electrical design (lack of proper EMI filtering) caused the shunt measurement to be off by up to 30A sometimes, causing additive SoC calculation errors. I'm a EE and actually discovered the problem with instrumentation myself, customer service was short tempered, blamed the SunnyIslands for "creating too much noise" and never owned up to the issue on their side. Made me pay shipping round trip to try another shunt even after i proved to them it was a design defect. I know of 3 other people with Batrium and Sunny Islands that all verify the same issue.

My frustration with them and unwillingness to pay $500-$1000 for another BMS solution is why I made my own solution. With a $130 shunt and a raspberry pi running Venus. I don't have cell monitoring, but with very conservative overall pack voltage limits, it being LiFEPO4 and a plan to check cell voltages monthly by hand, I'm fine with that.

At some point I'm going to design a super cheap BMS that does nothing but trip my ABB breaker if a cell gets out of range. Not in a rush for that though.

O yeah, and the Victron shunt handles all that "terrible noise" from the Sunny Islands just fine. No error in reading. Hmmm. (can you tell I'm bitter? lol)
 

westvandude

New Member
Yes, the SunnyIslands expect to talk to a BMS over the CAN bus when in Li-Ion mode. They have a 485 bus, but that's for talking to SunnyBoys and SunnyWebbox

As I said before, run fa....
So is the COMsync considered CANbus? I still have to figure out how to interface new 41 series sunny boys to my 6048’s.

thanks for heads up on batrium shunt issue. I have electronics background as well but not EE, I’m extremely surprised that the batrium hardware is so particular on how everything is hooked up in what order etc. Way to easy to fry it. Doesn’t seem very robust for the high price point. Probably an automotive specific hardware design is more appropriate given transients, noise, etc? No bms seems a perfect fit for diy lithium Setup on SI’s?

i also have an abb breaker (eBay! Cheap) 300a. 24v shunt trip.
 

madsci1016

Solar Enthusiast
So is the COMsync considered CANbus? I still have to figure out how to interface new 41 series sunny boys to my 6048’s.
You should take a look through my notes on github:


he SMA SunnyIsland 6048 has two potential communications buses. One is a CAN bus “ComSync” and the other is a RS-485 bus "ComSma" that requires an adapter card to be installed. The CAN bus is used by the SMA’s to communicate from the master to the slaves in a cluster, and to a Battery Management System (BMS) when configure in Lithium Ion mode. The RS-485 bus is required to connect to SMA grid tie inverters and to the WebBox.

thanks for heads up on batrium shunt issue. I have electronics background as well but not EE, I’m extremely surprised that the batrium hardware is so particular on how everything is hooked up in what order etc. Way to easy to fry it. Doesn’t seem very robust for the high price point. Probably an automotive specific hardware design is more appropriate given transients, noise, etc?

I work with alot of Computer Science PhDs that fancy themselves hardware designers (or think it's something easy they should be able to do) and design their own electronics, and i always see alot of the same tell-tale signs (issues) of such across their stuff that i also see in Batrium. Batirum's software is pretty good, so I suspect it's the same situation. But that's just my opinion.

No bms seems a perfect fit for diy lithium Setup on SI’s?
I came to that conclusion which is why i started spinning my own solution. Been MUCH happier with it so far.

I still have to figure out how to interface new 41 series sunny boys to my 6048’s
Can't help here. I'm all DC coupled. I will say as a high level trend SMA is not a business2consumer style business, they want to be business2business where the just make and support products that solar companies buy and install and the customer works with that solar company. As a result any support from them to us is thin at best. And they tend to only support their walled garden of products. You may have issues as these SI 6048s are now 1 or 2 generations discontinued with your modern SunnyBoys. (not sure).
 

Hedges

Photon Sorcerer
So is the COMsync considered CANbus? I still have to figure out how to interface new 41 series sunny boys to my 6048’s.

There is no interface for the -40 and -41 SB to SI 6048.
Earlier SB have RS-485 interfaces which let SI switch SB's mode between "UL 1741" and "Island" for grid-backup systems.
There is an interface for SI which is of the same species, but only supported to give status to new generation monitoring hardware.
I think the 8H series Sunny Island presently sold in Europe does support communication with -41 SB.

Previously SI 6048 and SB -41 were on the compatibility list for off-grid use together, but not grid-backup.
Latest list says, "Compatible if country data set CA Rule 21 is set"


Send an inquiry to SMA customer support, telling them which model/serial numbers and firmware revision you have and what you want to do.
If they tell you to set SB -41 for "Island" when used with Sunny Island for grid-backup, save a copy of their instructions (for CYA, because that disagrees with their published instructions.) But they may instead say to update firmware if needed or change settings to enable Rule 21. If they instruct you to use "Island" that may be easier.

If you use Rule 21, tell me how that goes.
With "island" (or older models with "Grid Backup"), Sunny Boy will remain online indefinitely as frequency moves between 61 Hz and 62 Hz to vary how much PV power is converted to AC.
As I read Rule 21, the inverter will remain online within a certain frequency range for 299 seconds, but will drop off by 300 seconds. It will then remain offline for 300 seconds before reconnecting. During that time battery will be drawn down. After SB reconnects, Sunny Island may hold frequency lower or within spec for a while before raising frequency, at which point the 299 second timer starts again.

Sunny Island with its default settings also makes excursions below grid minimum spec of 59.5 Hz, in order to make up for time at higher frequency and keep mechanical clocks/timers correct. This may be enough to knock SB offline again; if so, Sunny Island can be adjusted.
 

Hedges

Photon Sorcerer
I don't have cell monitoring, but with very conservative overall pack voltage limits, it being LiFEPO4 and a plan to check cell voltages monthly by hand, I'm fine with that.

At some point I'm going to design a super cheap BMS that does nothing but trip my ABB breaker if a cell gets out of range. Not in a rush for that though.

Operating without individual cell monitoring sounds risky to me.
I would either make an op-amp & diode circuit to find highest/lowest cell voltages, or connect a relay based DAS, and automate monitoring.

With relay I could also connect a supply for balancing.
 

madsci1016

Solar Enthusiast
Operating without individual cell monitoring sounds risky to me.
I would either make an op-amp & diode circuit to find highest/lowest cell voltages, or connect a relay based DAS, and automate monitoring.

With relay I could also connect a supply for balancing.

It's accepted risk. LiFePO4 doesn't start fires with abuse, just damages cells. I have alot of mass of cells (50kWhr) so most issues should arise slowly over time, and be caught with monthly high / low SoC manual tests. And i keep overall pack range between 51V to 56V. Cell damage doesn't occur until <2.5V and >3.8V (more to 4.0V depending on your source of data)

Again, BMS would be better, just accepting that risk of cell damage with some risk mitigation strategies in the mean time.

I've also run many months without balancing and found my cells are fairly stable even being the used BYD packs and new Sony packs, and not had to balance them yet.
 

westvandude

New Member
I’ve seen a few big kWh installs with leaf modules and they seem fairly stable voltage throughout the cells. Some people haven’t balanced in years. Also offgrid will be harder on the battery than grid backup where it mostly just floats.
I know what you mean with SMA supporting biz-to-biz which is frustrating.
My SI’s are last generation before the 6.0/8.0 came out. You’d think SMA would have some sort of interface capability with 41 SB’s as when people upgrade their systems invariably they will have some good hardware they don’t want to throw away. Why don’t they come out with a speed wire card for older SI‘s? Maybe it’s like Apple they want to make older hardware redundant?? That drives me nuts.

I was looking into arduino or raspberryPI to do serial translation on the cheap but with work and other hobbies I don’t have time to play with the stuff, and my programmer buddy is doing two jobs at the moment lol.

have to do more Research.
 

Hedges

Photon Sorcerer
Why don’t they come out with a speed wire card for older SI‘s? Maybe it’s like Apple they want to make older hardware redundant?? That drives me nuts.

I think they do have a Speedwire module, but only for data to a hub and their new monitoring system, not to support SB -41.
That would be a firmware issue. But don't know if they would ever do an update to support it.

Ideally, firmware update for SI would let it be compatible with Rule 21, and downstream SB would be told SI was handling UL-1741, so the entire system even with old SB could be Rule 21 compliant.

Or if our building codes allowed systems that were not Rule 21 if they disconnected loads as well as PV generators (switched to backup operation) outside UL-1741 limits. That is, not just disconnect PV and keep loads on line like typical grid-tie.

If you use Rule 21, tell me how that goes.
With "island" (or older models with "Grid Backup"), Sunny Boy will remain online indefinitely as frequency moves between 61 Hz and 62 Hz to vary how much PV power is converted to AC.
As I read Rule 21, the inverter will remain online within a certain frequency range for 299 seconds, but will drop off by 300 seconds. It will then remain offline for 300 seconds before reconnecting. During that time battery will be drawn down. After SB reconnects, Sunny Island may hold frequency lower or within spec for a while before raising frequency, at which point the 299 second timer starts again.

Sunny Island with its default settings also makes excursions below grid minimum spec of 59.5 Hz, in order to make up for time at higher frequency and keep mechanical clocks/timers correct. This may be enough to knock SB offline again; if so, Sunny Island can be adjusted.

Reading the fine print:


I now observe

"The Volt-Watt function is allowed as an alternative to momentary cessation in the HV1 region given agreement by the utility. Volt-Watt decreases real power as a function of increasing voltage."

"A Frequency-Watt function, which reduces real power on over frequency, is also allowed to be used given agreement by the utility."

So the mandatory disconnect by 300 seconds may only be for an inverter which doesn't reduce power output. Could be that with Volt-Watt or Frequency-Watt they are allowed to remain online indefinitely. If so this could be same/similar to "Island" or "Off Grid" mode with Sunny Island and work nicely.
 

westvandude

New Member
I suppose in a grid-down situation, since my two SB 6kw inverters are downstream of the grid they would just reboot after seeing the grid from the SI is up.... if it's too much juice I could always manually flip the main power switch on one or both if the SI isn't controlling their output very well but of course that brings dumb manual control into something that should be automatic and seamless.
Honestly, I wish SMA would show some circuit diagrams and instructions for connecting odds-ends of their hardware.... such as connecting older models of SB with newest SI, and vice versa.
I suppose pretty much any gridtie inverters downstream of the SI would function no matter what the brand as long as the SI puts the frequency over the shut down of the inverters to cut power if not needed for the battery.
 

Hedges

Photon Sorcerer
I suppose in a grid-down situation, since my two SB 6kw inverters are downstream of the grid they would just reboot after seeing the grid from the SI is up.... if it's too much juice I could always manually flip the main power switch on one or both if the SI isn't controlling their output very well but of course that brings dumb manual control into something that should be automatic and seamless.
Honestly, I wish SMA would show some circuit diagrams and instructions for connecting odds-ends of their hardware.... such as connecting older models of SB with newest SI, and vice versa.
I suppose pretty much any gridtie inverters downstream of the SI would function no matter what the brand as long as the SI puts the frequency over the shut down of the inverters to cut power if not needed for the battery.


SB do typically go offline by the time SI recognizes the failure and establishes local grid. Loads may see a 30 millisecond glitch and should remain online. SI can carry the load until SB return (up to 6 kW per SI, a bit more for a short time. 6.7 kW is the GT PV limit for grid-backup of US models. European model can work with twice that and would need SB to return real fast if 12 kW of PV was supporting loads)

Any basic UL1741 grid-tie inverter can work downstream of SI during grid failures, but only so long as 100% of its output is used either for AC loads or battery charging. If power output is excessive, SI increases frequency and knocks it offline. Loads are carried on battery, and if SI has frequency within range then after 5 minutes GT inverter comes back online. As soon as battery charge current tapers off enough that there is excessive PV generation it is knocked offline again.

Default settings of SI let it drop below 59.5 Hz and GT inverter won't connect. That setting would need to be changed for basic UL-1741 GT.
It may be that GT inverters with Rule 21 watts-Hz function would work well. Sunny Boy with compatible "backup" function do work well.

Oldest/newest SI. For US market, pretty much the same (except for really old SI4248). The SI5048 and SI6048 appear to differ only efficiency or thermal performance (different continuous wattage) and the size of lugs for battery cables.

The RS485 piggy back instructions for SI and for SB give some help. It appears the daughter card is same for most if not all, but the kit has various part numbers and comes with different sleeves etc. for wiring of various SI and SB.


The RS485 cabling plan shows wiring for the SB which have an adapter (all except newer -40 and -41; those get AC wiring only, no data cable)


What that cabling plan assumes is that you always have a Sunny Web box, Gateway, Sunny Data Control, or other device with pullup/pulldown for RS-485. Without any of those, you need to place jumpers enabling the pullup/pulldown in one Sunny Boy. At least for my short cables there was no problem leaving pullups connected in SB whether Sunny Data Control was connected or not. I put a bulkhead RJ45 socket in SI, and either plug in an RS485 terminator or else cable to my Sunny Data Control.

It will be automatic and seamless if total SB capacity is within pass-through current limits and SB is in the "backup" or "Island" mode.
I had bought 10000TLUS-12 because it is supposed to be supported, but discovered in "backup" it tolerates wider frequency but doesn't reduce power output. It remained online up to 64.5 Hz at full power, disconnected, and reconnected about when frequency dropped to about 62 Hz. SMA reviewed their firmware and acknowledged the bug. They gave me the workaround of configuring for "island" when used with Sunny Island between SB and the grid. They just updated list of supported inverters, showing this series is OK for off-grid but not backup. I've since bought SB 5000US to replace it.

It appears -40 and -41 if configured for Rule 21 should work. I assume those have watts-Hz function.
 

Pyrofx

Flux capacitor builder
Go direct. Maja@rec.com. just fired mine up. Pretty happy so far. Even the ir function is pretty accurate. Unfortunately I found out 2 of my bassen 280s have an ir of 2.1 and 1.9.
 
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