Complete specs for their RS485 protocol are at:
See the Draft 4 and corresponding spreadsheet
See the Draft 4 and corresponding spreadsheet
Long post - apologies but will try and cover a few things - for those who already understand BMS/CAN etc - please skip over most of it.Need to wake you up again @Haugen
Im doing some numbers to decide either between some pylontech batteries or a DIY one with the Heltec BMS.. same as yourself.
Fits of all, what would be the main advantages of the inverter communicating with the battery?.
Do you know if the CAN compatibility with generic BMS's its an special implementation from Sol-Ark?. I was considering a Deye / Sunsynk but maybe they wont provide that.. so that could steer things to the SolArk Again. Al tough, seeing the guys that are reverse engineered the communication protocol with the web monitoring, and if thats suposed to work with the 3 brands, it would mean that the Sol-Ark doesn't have an special firmware and the Heltec BMS could work also with the sunynk's and deye's.
- Being able to cut the charge / discharge depending of SOC, without a hard turnoff from an external BMS
- Maybe read SOC? (Altough you mention before that Sol-Ark can calculate this even with "dumb" batteries.
And when you are building your DIY battery?, im very interested in your experiment.
Great info!.... I ended up getting a pylontech battery, its suposed to be able to talk with the Deye, will testLong post - apologies but will try and cover a few things - for those who already understand BMS/CAN etc - please skip over most of it.
One of the big advantages of CAN is accurate SOC, and control for the charge/discharge are now handled by the BMS.
An issue with SOC determination using V is a drop when under load which affects it - some inverters are better, some standalone shunts etc also "learn" but the inverter still looks at the V rating. To use an example - your lithium bank might be sitting at 51V idling, and the SOC (varies on all batteries) would be roughly 80% (just an example on a 48V nominal battery) - it's not linear - so 49V might be close to 20% SOC, 50V 50% etc. When you add substantial load (couple of kW) you will experience a drop in V - sometimes 1.5-2V depending on load -this is normal - so the inverter suddenly see's the battery drop from 80% to 20% - and depending on your settings might switch to utility. Remove the load - it recovers back to 51V - this switching causes inaccurate SOC readings, and not very efficient. You would see this on battery SOC graphs as big steps in %. Also means you have to set the V levels as an estimate for cutoff/low - recharge/full etc - all in V (The Sol-Ark has a % estimate that tries to match V - but it's still estimate) - if you use CAN or RS485 (different protocols but the same end result) - you are are measuring accurate V per cell direct from the BMS- regardless of load. So the inverter gets "told" what the correct SOC level is by the BMS. Also makes the programming much easier for levels - you simply choose "low battery = 20%"- or "keep it between 40% and 80% during X time of the day." as an example. The BMS also controls charging/discharging etc - so no need to program the values - keeps it within the recommended parameters of the cells. Using an external shunt, running it through the learning process will of course work, but it's another component, something else to buy, and only does 1 thing - gives you SOC - something which the BMS already does.
There are PHD papers on the web trying to explain the determinations of SOC in Lithium cells - it's complicated math.
With regards to @Craig's post question "why is it complicated" - it isn't on paper, but can you just buy any DIY BMS, hook up a network cable and it works - absolutely not. There are many details and technicalities around al the different cells, charge curves, all sorts of math around when to start throttling charging, how to calculate SOC etc - and every bms out there and every cell is different. That's part of what you pay extra for when going for a branded battery - they have engineered both hardware and software to match perfectly, and spend many hours making sure THEIR BMS talks to the inverter - probably paid some fee's also for inverter manufacturers to develop code, certify their battery etc. This is why often firmware upgrades add more batteries to the list of supported ones for CAN/RS485.
It is changing though - so BMS companies are trying to make it easier - the trick is to know which ones.
Another issue not mentioned is connecting multiple batteries in parallel. How does CAN then work? In the branded battery world you often have little dip switches to indicate which battery in the stack is "master" and then slaves, as well as ID them say battery 0,1,2,3 - for example a 4x 48V 100A Dyness pack (so 400A @ 48V) - each battery has a BMS that controls it's own cells - your inverter now needs to understand there are 4x packs each with potentially 12-16 Cells, and each to be managed separately. In the DIY space this sometimes worked using RS485 as a protocol and then a small little hub to broadcast all RS485 info - but CAN is much better - no hubs needed. This is important if you want to build out larger banks. Without intelligence you will run into many issues with parallel banks where BMS's now fight each other, require buzzbars etc.
Tried a few brands of BMS with the Sunsynk - none of them with success - and finally (after searching for months) found one that seems to do it all - talks direct with Deye/Sol-Ark/SunSynk/Ohm (all from the same factory - rebranded), have master/slave ports built in to build out larger banks etc. Have ordered and waiting for stock to test it out.
For those that are keen : Seplos is the brand. They have a very active youtube channel, of course they also make and sell their own DIY kits - very impressive stuff - (and priced accordingly!) - but they do sell the BMS on it's own - so for those that are keen to give it a go - https://www.seplos.com/ Last time I checked they were around $150 for a single 100A 48V BMS (unsure of min order limit) + shipping.
I found another post this forum where the manual was uploaded - so maybe worth a read - but for this use case - they do seem to talk to Sol-Ark fine on CAN. https://diysolarforum.com/resources/seplos-48v-100a-bms-specification.77/history
The specific BMS I'm referring to is the 100A 48V one in the download link - unsure what other size and configurations they have.
If you prefer something that "just works" and is "plug & play" - then branded batteries is the way to go - does not have to be the most expensive ones, there are very good 2nd life ones out there that already work over CAN with many inverter brands - but yes it will be more expensive than a full DIY - but many of us like to fiddle and make it work over time
Alternatively setup your battery as AGM-V/% - set you levels accordingly and accept 20%-30% less usable capacity (which in the long run will make your cells last longer anyways). Your BMS will still offer protection for low cutoff, overcharge, temperature etc (if those are features of your BMS).
New to solar but this makes sense. The BMS in most other types of battery just need to present a dumb two-terminal device externally and limit conditions in the pack. As long as the charger runs a proper CC/CV cycle for that battery, any communications should just be for optimization and asset health monitoring.I also verified with Sol-Ark tech support that the BMS doesn't have to communicate to the Sol-Ark.
Haugen, when do you think you system will be up and running?
What DEYE version did you get & where? I'd be interested in your setup since I have the Sol-Ark 12k already for our house but at the cabin we just bought I am thinking on the 5k DEYE version. Have a Alibaba vendor who wants to sell me one.Great info!.... I ended up getting a pylontech battery, its suposed to be able to talk with the Deye, will test
What DEYE version did you get & where? I'd be interested in your setup since I have the Sol-Ark 12k already for our house but at the cabin we just bought I am thinking on the 5k DEYE version. Have a Alibaba vendor who wants to sell me one.
Yes definitely talks to the Deye 100%. Did you go single Pylon or a stack of multiples? (2.4 or 3.6) - just be aware of the max discharge rates - around 50A (think the 3.6 bursts to 75A) - so essentially 2.4kW max if you have a single.Great info!.... I ended up getting a pylontech battery, its suposed to be able to talk with the Deye, will test
Yes definitely talks to the Deye 100%. Did you go single Pylon or a stack of multiples? (2.4 or 3.6) - just be aware of the max discharge rates - around 50A (think the 3.6 bursts to 75A) - so essentially 2.4kW max if you have a single.
Very good information! Thanks for sharing your experience. I have been searching for this myself.Another issue not mentioned is connecting multiple batteries in parallel. How does CAN then work? In the branded battery world you often have little dip switches to indicate which battery in the stack is "master" and then slaves, as well as ID them say battery 0,1,2,3 - for example a 4x 48V 100A Dyness pack (so 400A @ 48V) - each battery has a BMS that controls it's own cells - your inverter now needs to understand there are 4x packs each with potentially 12-16 Cells, and each to be managed separately. In the DIY space this sometimes worked using RS485 as a protocol and then a small little hub to broadcast all RS485 info - but CAN is much better - no hubs needed. This is important if you want to build out larger banks. Without intelligence you will run into many issues with parallel banks where BMS's now fight each other, require buzzbars etc.
Tried a few brands of BMS with the Sunsynk - none of them with success - and finally (after searching for months) found one that seems to do it all - talks direct with Deye/Sol-Ark/SunSynk/Ohm (all from the same factory - rebranded), have master/slave ports built in to build out larger banks etc. Have ordered and waiting for stock to test it out.
For those that are keen : Seplos is the brand. They have a very active youtube channel, of course they also make and sell their own DIY kits - very impressive stuff - (and priced accordingly!) - but they do sell the BMS on it's own - so for those that are keen to give it a go - https://www.seplos.com/ Last time I checked they were around $150 for a single 100A 48V BMS (unsure of min order limit) + shipping.
I found another post this forum where the manual was uploaded - so maybe worth a read - but for this use case - they do seem to talk to Sol-Ark fine on CAN. https://diysolarforum.com/resources/seplos-48v-100a-bms-specification.77/history
The specific BMS I'm referring to is the 100A 48V one in the download link - unsure what other size and configurations they have.
They sell them on AlibabaLong post - apologies but will try and cover a few things - for those who already understand BMS/CAN etc - please skip over most of it.
One of the big advantages of CAN is accurate SOC, and control for the charge/discharge are now handled by the BMS.
An issue with SOC determination using V is a drop when under load which affects it - some inverters are better, some standalone shunts etc also "learn" but the inverter still looks at the V rating. To use an example - your lithium bank might be sitting at 51V idling, and the SOC (varies on all batteries) would be roughly 80% (just an example on a 48V nominal battery) - it's not linear - so 49V might be close to 20% SOC, 50V 50% etc. When you add substantial load (couple of kW) you will experience a drop in V - sometimes 1.5-2V depending on load -this is normal - so the inverter suddenly see's the battery drop from 80% to 20% - and depending on your settings might switch to utility. Remove the load - it recovers back to 51V - this switching causes inaccurate SOC readings, and not very efficient. You would see this on battery SOC graphs as big steps in %. Also means you have to set the V levels as an estimate for cutoff/low - recharge/full etc - all in V (The Sol-Ark has a % estimate that tries to match V - but it's still estimate) - if you use CAN or RS485 (different protocols but the same end result) - you are are measuring accurate V per cell direct from the BMS- regardless of load. So the inverter gets "told" what the correct SOC level is by the BMS. Also makes the programming much easier for levels - you simply choose "low battery = 20%"- or "keep it between 40% and 80% during X time of the day." as an example. The BMS also controls charging/discharging etc - so no need to program the values - keeps it within the recommended parameters of the cells. Using an external shunt, running it through the learning process will of course work, but it's another component, something else to buy, and only does 1 thing - gives you SOC - something which the BMS already does.
There are PHD papers on the web trying to explain the determinations of SOC in Lithium cells - it's complicated math.
With regards to @Craig's post question "why is it complicated" - it isn't on paper, but can you just buy any DIY BMS, hook up a network cable and it works - absolutely not. There are many details and technicalities around al the different cells, charge curves, all sorts of math around when to start throttling charging, how to calculate SOC etc - and every bms out there and every cell is different. That's part of what you pay extra for when going for a branded battery - they have engineered both hardware and software to match perfectly, and spend many hours making sure THEIR BMS talks to the inverter - probably paid some fee's also for inverter manufacturers to develop code, certify their battery etc. This is why often firmware upgrades add more batteries to the list of supported ones for CAN/RS485.
It is changing though - so BMS companies are trying to make it easier - the trick is to know which ones.
Another issue not mentioned is connecting multiple batteries in parallel. How does CAN then work? In the branded battery world you often have little dip switches to indicate which battery in the stack is "master" and then slaves, as well as ID them say battery 0,1,2,3 - for example a 4x 48V 100A Dyness pack (so 400A @ 48V) - each battery has a BMS that controls it's own cells - your inverter now needs to understand there are 4x packs each with potentially 12-16 Cells, and each to be managed separately. In the DIY space this sometimes worked using RS485 as a protocol and then a small little hub to broadcast all RS485 info - but CAN is much better - no hubs needed. This is important if you want to build out larger banks. Without intelligence you will run into many issues with parallel banks where BMS's now fight each other, require buzzbars etc.
Tried a few brands of BMS with the Sunsynk - none of them with success - and finally (after searching for months) found one that seems to do it all - talks direct with Deye/Sol-Ark/SunSynk/Ohm (all from the same factory - rebranded), have master/slave ports built in to build out larger banks etc. Have ordered and waiting for stock to test it out.
For those that are keen : Seplos is the brand. They have a very active youtube channel, of course they also make and sell their own DIY kits - very impressive stuff - (and priced accordingly!) - but they do sell the BMS on it's own - so for those that are keen to give it a go - https://www.seplos.com/ Last time I checked they were around $150 for a single 100A 48V BMS (unsure of min order limit) + shipping.
I found another post this forum where the manual was uploaded - so maybe worth a read - but for this use case - they do seem to talk to Sol-Ark fine on CAN. https://diysolarforum.com/resources/seplos-48v-100a-bms-specification.77/history
The specific BMS I'm referring to is the 100A 48V one in the download link - unsure what other size and configurations they have.
If you prefer something that "just works" and is "plug & play" - then branded batteries is the way to go - does not have to be the most expensive ones, there are very good 2nd life ones out there that already work over CAN with many inverter brands - but yes it will be more expensive than a full DIY - but many of us like to fiddle and make it work over time
Alternatively setup your battery as AGM-V/% - set you levels accordingly and accept 20%-30% less usable capacity (which in the long run will make your cells last longer anyways). Your BMS will still offer protection for low cutoff, overcharge, temperature etc (if those are features of your BMS).
I have done a fair amount of research, looking at many BMS's for LiFePo4 battery banks. Unless things change between now and the time I'm ready for a full battery bank, (6-9 months, under construction) I'm going to spend the money and go with Batrium. I feel it suits my needs the best but may not be the best for someone else. Of course things change so fast with technology these days, so who knows.So I'm in the planning stage of switching my inverter to Sol-Ark. I've read so many good feedbacks, but I'm stuck with a BMS to use with a DIY 272Ah 48v battery setup. I'm planning to do a 4p16s or 16sp4, but I'm curious what others who have DIY Lifepo4 batteries hooked up to their Sol-Ark inverter.
I did contact Sol-Ark and Orion BMS, and the Orion BMS Jr has a close loop support through CAN. The problem that I have is the Orion BMS Jr seems very complicated compared to the other BMS' that I've look at. Also in their manual(s), they are strongly against parallel strings.
So, what BMS are you all using with Sol-Ark inverters?
I like Batrium as there are more videos that I can learn, their literature is much better, and awesome interface. How do you plan on connecting to the Sol-Ark inverter?I have done a fair amount of research, looking at many BMS's for LiFePo4 battery banks. Unless things change between now and the time I'm ready for a full battery bank, (6-9 months, under construction) I'm going to spend the money and go with Batrium. I feel it suits my needs the best but may not be the best for someone else. Of course things change so fast with technology these days, so who knows.
As a follow up to several of my previous posts in this thread. The data communication between Sol-Arks' cloud service and Power View desktop/app is encrypted. No way that I can find to capture and read the data without the encryption being removed or a way to decrypted it.
Some of you may have known this already, but I figured it out the hard way. So at this point, persuading Sol-Ark to give open source data access will be the only way for off grid folks to monitor their inverters data output.
Kind of funny that an American, VETERAN owned company, is the only inverter that requires a "Big Brother" style, control "permission" to see your own inverter data, huh?
I don’t. There’s currently no way to make Batrium & Sol-Ark communication work. The parameters will need to be set accordingly on each device. This way I can at least monitor/log my battery banks data in real time.I like Batrium as there are more videos that I can learn, their literature is much better, and awesome interface. How do you plan on connecting to the Sol-Ark inverter?
I don't think I would label using the cloud (internet based) data stream can be construed as "Big Brother". Maybe you need to read 1984 again.I have done a fair amount of research, looking at many BMS's for LiFePo4 battery banks. Unless things change between now and the time I'm ready for a full battery bank, (6-9 months, under construction) I'm going to spend the money and go with Batrium. I feel it suits my needs the best but may not be the best for someone else. Of course things change so fast with technology these days, so who knows.
As a follow up to several of my previous posts in this thread. The data communication between Sol-Arks' cloud service and Power View desktop/app is encrypted. No way that I can find to capture and read the data without the encryption being removed or a way to decrypted it.
Some of you may have known this already, but I figured it out the hard way. So at this point, persuading Sol-Ark to give open source data access will be the only way for off grid folks to monitor their inverters data output.
Kind of funny that an American, VETERAN owned company, is the only inverter that requires a "Big Brother" style, control "permission" to see your own inverter data, huh?
Understand but if the data wasn’t transmitted out it wouldn’t need encryption. If you wanted to transmit data, then enable encryption. The 1984 reference on my part my have been a stretch but being forced to use their service was my point.I don't think I would label using the cloud (internet based) data stream can be construed as "Big Brother". Maybe you need to read 1984 again.
Encryption means that your data is yours and cannot be taken from you for any reason. Not even SolArk could break it.
It's not nefarious, just convenient. Even living off grid, you can have internet. Get an old wireless phone and share a data plan to connect.
I get your point that you want to own every bit of data produced. The fact is, after a couple months, I don't even look at the data every day. I'm certainly not going to waste my time checking in on my system second by second.
Yes, I have shading issues from trees in neighboring lots. I see a dip in power out; I look up, probably a cloud. Nothing I can do about it.