The Electrodacus Solar BMS thread (SBMS0 SBMS40 SBMS120 DSSR20 and so on)

grizzzman

Some say "Why" and some say "Why not?"
Hi all, I've been designing a mobile solar system with ElectroDacus for a van build, and working my way up the learning curve. Since investing the time to figure it all out, I thought I would write up what I've learned into a Beginner's Guide to ElectroDacus to save others some of the trouble.

Seems like there are a lot of people on this thread who are knowledgeable on the subject, so if anyone feels like reading it over and giving feedback, I would appreciate it. I still have some sections to finish, and plan to add more pictures and example circuit diagrams. But please let me know if I've badly screwed anything up!

- Oberon
It has "passive" balancing. Not active.
 
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zzyzx

Apprentice Neanderthal
Hi all, I've been designing a mobile solar system with ElectroDacus for a van build, and working my way up the learning curve. Since investing the time to figure it all out, I thought I would write up what I've learned into a Beginner's Guide to ElectroDacus to save others some of the trouble.
THANK YOU for your effort! I found your writing style to be an easy read and a welcome overview to Dacian's detailed document. As I plan to use the Electrodacus for my battery builds, all help is appreciated. I'm sure any input from forum members will only improve what you have started ;) .
 

grizzzman

Some say "Why" and some say "Why not?"
It uses the ISL94203 monitor chip - is that passive? I think I'll just take the term out as it's not actually relevant. :)
It is relevant. Passive balancing burns energy from the highest voltage cell(s). Active balancing moves power from a high cell(s) to low cell(s).
 
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michael d

Solar Addict
essentially all Lishen 272Ah and Eve 280Ah cells are m6 6mm diameter(6mm studs of 20 mm length work well). so 6mm is essentially the same as 1/4 inch shrink terminals for the ribbon cable. the fortune cells had larger 3/8 inch terminal studs that Will Prowse used in his youtube video. the ribbon cable is 28 AWG (supplied with the SBMS0) so one may need to take that into account also.
 

michael d

Solar Addict
the SBMS0 uses 100mA balancing per cell while charging the battery to keep the cells in balance. and has no problem balancing 2 272Ah cells in parallel. I have 2 of the 2P8S batteries being monitored and balanced by the SBMS0. I use the DSSR20 as the solar charge controller. I believe it stands for digital solid-state relay and is rated at 20 Amps but can accept up to 24 amps -- so a little lee-way there. I have had 3 dssr20's run-up to 61 amps in the winter so slightly more than the recommended 20 amps per DSSR20.
hope I don't confuse anyone!
so 16cells x 272Ah (Lishen cells) x 3.2 volt/cell = 13,926.4 watt-hour potential capacity for the 24 volt battery. mine run 26.8 to 27.2 volts most of the time.
the problem I foresee coming is assembling a 3P8S battery using the 272Ah cells for 816 amps. try to find safe/suitable fuses/ breakers etc for higher amps without breaking the bank?
 
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grizzzman

Some say "Why" and some say "Why not?"
Anyone have the SBMS0 V03D Manuel downloaded? Dacians site is not working at the moment.
 

grizzzman

Some say "Why" and some say "Why not?"
SBMS0 V03D Manual >>>>


it opened right up for me. I likely have it downloaded but often use the website.
I copied that address from the website just now -- perhaps a typo or the internet can be quirky at times. 😎
Ya it’s working this morning. Two different devices would not download it last night. I have been downloading to my browser up to now without issue. At least now I have it on the pc.
 

Jbroscious

New Member
Hi all, I've been designing a mobile solar system with ElectroDacus for a van build, and working my way up the learning curve. Since investing the time to figure it all out, I thought I would write up what I've learned into a Beginner's Guide to ElectroDacus to save others some of the trouble.

Seems like there are a lot of people on this thread who are knowledgeable on the subject, so if anyone feels like reading it over and giving feedback, I would appreciate it. I still have some sections to finish, and plan to add more pictures and example circuit diagrams. But please let me know if I've badly screwed anything up!

- Oberon
How about some pictures of how the thing is wired? I have the SBMS0 with my 4S 12V system, 2 panels, and a 3000 watt inverter
 

Oberon

Solar Enthusiast
How about some pictures of how the thing is wired? I have the SBMS0 with my 4S 12V system, 2 panels, and a 3000 watt inverter
It would be great to have some pictures - are you volunteering? 😁

I'm about to put out a new version with a number of additions and corrections, so any contributions or collaborations are very welcome!
 

michael d

Solar Addict
It would be great to have some pictures - are you volunteering? 😁

I'm about to put out a new version with a number of additions and corrections, so any contributions or collaborations are very welcome!
I have 2 24-volt 2P8S set-ups with SBMS0 in 2 separate battery builds (an SBMS0 used for each 24-volt battery).
currently, I am working up a 4P8S battery which will be 24-volts using 32 Lishen 272Ah cells.
Is your guide going to include 24-volt?
I think Dacian says it should be annotated 8S2P and 8S4P rather than the way I have been annotating it.
my battery assemblies are stationary off-grid builds.
keep up the good work 😎
 

Oberon

Solar Enthusiast
I have 2 24-volt 2P8S set-ups with SBMS0 in 2 separate battery builds (an SBMS0 used for each 24-volt battery).
Great, would you like to share pictures of your builds (and/or circuit diagrams) for the guide?

Is your guide going to include 24-volt?
At least for now, I'm not including it - Dacian specifically recommends against using an SBMS that way. But if you (or anyone else) has experience with setting it up that way and it works well, I'm happy to hear about it, and could perhaps add it into an appendix.

I think Dacian says it should be annotated 8S2P and 8S4P rather than the way I have been annotating it.
This forum has different annotation that Dacian uses. I'm removing any of that kind of annotation to avoid confusing the issue.
 

michael d

Solar Addict
Great, would you like to share pictures of your builds (and/or circuit diagrams) for the guide?


At least for now, I'm not including it - Dacian specifically recommends against using an SBMS that way. But if you (or anyone else) has experience with setting it up that way and it works well, I'm happy to hear about it, and could perhaps add it into an appendix.


This forum has different annotation that Dacian uses. I'm removing any of that kind of annotation to avoid confusing the issue.
I have many email conversations with Dacian. my present builds include the Electrodacus SBMS0 and Electrodacus DSSR20 (with and without diversion) and Electrodacus DECT16 (are all 24-volt); so for now I will just wait until more time documenting the build correctly so as not to confuse anyone. The Electrodacus SBMS0 is designed perfectly for 12 or 24 volt systems if you match the panels with the DSSR20 that combination works as designed as well.

I am drawing/designing the 32 cell 24-volt battery build using 272Ah Lishen aluminum cased prismatic cells so still in the design phase. Currently waiting on the busbars also. This will be a 1088Ah 24-volt stationary battery.

the annotation is definitely confusing as to who has it the correct way!!!! 😎
(someone else's argument) one either agrees, disagrees, or agrees to disagree! 😢 ..... the main thing is to wire it all together safely!

Dacian is aware of the 16 cell 24-volt batteries I have assembled and I have asked his direction on parts as they are all designed to be monitored and balanced with a single SBMS0 and they are operating like a finely tuned clock as designed. I am in the process of design/build of the 32 cell 24-volt battery using the 2172Ah Lishen cells; it is also being designed to be monitored/balanced with one SBMS0.
But again it is for a stationary off-grid home/farm 24-volt solar PV system. not what you are really covering in your guide.

keep up the good work! 😎
 
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michael d

Solar Addict
I don't see any problem other than his SCC is rated for only (I believe) 20A. If you want to switch 400A then 20 of his SCC are required. If you have 10 kW of panels then a more suitable CC needs to be chosen. You don't have to use his SCC. Use a mppt controller and connect panels in series to reduce current and wire losses. The charge controller requires hardware to accept a shutdown signal from the bms.




Not necessarily, it all depends how the system is setup. The bms can be the first (primary) disconnect or the last resort disconnect. It it's used as the first disconnect then there will be lots of spikes. My system uses the bms as the primary disconnect. Should the bms fail to do its job then the mppt cc will limit charging voltage to a safe level.



That would be a problem. Perhaps with my mppt cc also. There is no backup plan when using his SCC.
the 400 amps would be pulled out of the battery through the inverter. it does not go through the SBMS0. the SBMS0 monitors the load being pulled out of the battery via shunts and tiny 23AWG cat 5 wires. the SBMS0 controls the charge going into the battery from the DSSR20's by tiny 23awg cat 5 wires. In my system, I do not have the inverter being controlled by the SBMS0 but that can be done also. the SBMS0 is being used to control the DSSR20's and when the battery is full, then it turns the DSSR20's off. charging current going into the battery stops but the inverter load continues as it is still needed from the AC side load. the SBMS0 does no switching of 400 amps. there are no big wires connected to the SBMS0 at all. sorry to rehash this, if it has already been discussed.

it would take a very hefty inverter to pull 400 amps at 24 volts.
My 8000-watt PSW LF 24-volt inverter would likely not pull that much. nor would I need to.
amps x volts = watts so 8000/24=333.33 amps. (and it is likely only 85-90 percent efficient).
so it would have to be 10,000 to 12000 watt inverter to actually get 400 amps on the AC side.

let alone the huge battery that would be required to run a 400 amp load for any length of time at all.

I have a 10,000-watt (don't quote that one as I can not see it - maybe it was only a 6000 or 8000 watt 12-volt inverter - ( it is still there)) 12-volt inverter in Bolivia South America and the battery bank was not big enough to power it. not just any little old battery will power a large inverter. so reverted to generators (gas-powered and diesel-powered - noisy darn things) for many things down there for many years (like 17years). now we have a 220volt public grid (50HZs I think) running through the valley there(the last 3 years). I was in Bolivia South America during the 9/11/2001 attacks on the twin towers and was not sure when I could return to the USA as all the airports were closed for a time. 😎
 
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Oberon

Solar Enthusiast
Here's a more updated version of the Beginner's Guide to ElectroDacus. Please use this one if you downloaded the last version — there were some errors that were corrected, as well as more detail and info added.

I think I've incorporated all of the feedback I've received. Let me know if you see anything I've missed or got wrong.

Still to do: add more pictures and diagrams, and add info on sourcing components.
 

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michael d

Solar Addict
Here's a more updated version of the Beginner's Guide to ElectroDacus. Please use this one if you downloaded the last version — there were some errors that were corrected, as well as more detail and info added.

I think I've incorporated all of the feedback I've received. Let me know if you see anything I've missed or got wrong.

Still to do: add more pictures and diagrams, and add info on sourcing components.
the DMMPT is not available as a separate module from Dacian at this time (as far as I know). but the DSSR20 with diversion will do the diversion to heat function as the newest SBMS0 has that capability built-in. you may want to check this in your "Beginner's Guide to Electrodacus". the DSSR20 is designed to handle 20 amps each but can go up to 24 amps (so it has lee-way built-in).
I have directly observed 3 dssr20 outputting over 61 amps from a 6-panel (60cell250wattPanels) array.
these are the 2 things that caught my attention. I have only read up to page 10 so far.
keep up the good work! 😎
 

michael d

Solar Addict
I have many email conversations with Dacian. my present builds include the Electrodacus SBMS0 and Electrodacus DSSR20 (with and without diversion) and Electrodacus DECT16 (are all 24-volt); so for now I will just wait until more time documenting the build correctly so as not to confuse anyone. The Electrodacus SBMS0 is designed perfectly for 12 or 24 volt systems if you match the panels with the DSSR20 that combination works as designed as well.

I am drawing/designing the 32 cell 24-volt battery build using 272Ah Lishen aluminum cased prismatic cells so still in the design phase. Currently waiting on the busbars also. This will be a 1088Ah 24-volt stationary battery.

the annotation is definitely confusing as to who has it the correct way!!!! 😎
(someone else's argument) one either agrees, disagrees, or agrees to disagree! 😢 ..... the main thing is to wire it all together safely!

Dacian is aware of the 16 cell 24-volt batteries I have assembled and I have asked his direction on parts as they are all designed to be monitored and balanced with a single SBMS0 and they are operating like a finely tuned clock as designed. I am in the process of design/build of the 32 cell 24-volt battery using the 2172Ah Lishen cells; it is also being designed to be monitored/balanced with one SBMS0.
But again it is for a stationary off-grid home/farm 24-volt solar PV system. not what you are really covering in your guide.

keep up the good work! 😎
typo above should say 272Ah not 2172Ah, a bit too late to correct the typo.
 
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