The Electrodacus SBMS thread (SBMS0, DSSR50, etc)

[Dzl]

Yep of course, but realistically 95 % of people using the SBMS will use the DSSRs.

I suspect this is actually not the case (would be interesting to ask Dacian what the sales numbers are like though). Anecdotally there are a lot of people sold on the SBMS0, but not fully sold on Dacian's perspective on non-MPPT vs MPPT, and (acknowledging the super small sample size, and selection bias) my impression based on the systems, and planned systems, I've seen on this forum, Victron is the most popular type of SCC paired with the SBMS0. This impression could well be skewed.

I believe part or all of the reason that the current generation SBMS is separate semi-integrated components (SBMS0 + DSSR20) is because in previous generations (when the SBMS was truly a combo Charge controller + BMS in a single component) there was a lot of interest in a BMS only version.

 

[BiduleOhm]

I suspect this is actually not the case (would be interesting to ask Dacian what the sales numbers are like though). Anecdotally there are a lot of people sold on the SBMS0, but not fully sold on Dacian's perspective on non-MPPT vs MPPT, and (acknowledging the super small sample size, and selection bias) my impression based on the systems, and planned systems, I've seen on this forum, Victron is the most popular type of SCC paired with the SBMS0. This impression could well be skewed.

Interesting, I'm curious too now ^^

 

[childcarepro]

Some basics... In a parallel string, panel voltage is the dominate factor, while panel current doesn't matter. In a series string these relationships are reversed. In series, current is king. This means every panel in the series string has the exact same current. Panel voltage is a lesser factor.

In the parallel configuration one panel is at 18V and the other at 12V. The 12V panel becomes a non-factor as battery voltage is above 12V. Total power reduces from 180W to 90W.

OK let's extend this parallel thing into wiring strings. My original plan was to have a 6P (6 panels -> 3 parallel pairs -> 1 wire -> MPPT), so I bought a 100/50 SmartSolar. So with this hardware, even if I go 2S3P -> 1 wire -> MPPT, what happens to production on the parallel strings when current drops on one series pair d/t shading? It's a 40V nominal setup d/t series connecting, so it will always be above my battery voltage of 29.2, so none of the 3 strings will be completely out of play.

Am I better off wiring 2 separate 3S systems w/ 2 smaller MPPTs instead of 3 parallel strings of 2S panels into one wire? Or even 3 separate 2S systems into 3 smaller MPPTs?

 

[Cal]

You're better off with 2 parallel strings if the charge controller can operate at the higher voltage (3 * Voc).

You've seen a maximum power graph? It starts at 0W, swings up to max power at Vmp, and then quickly drops down. The MPPT controller has an algorithm to search for the maximum power point. I you have 3 parallel strings and a couple of them have some shading then there will be 3 different power points. The power graph will have 3 humps. The controller needs to find the greatest magnitude hump. I haven't done any studies on this, but believe the controller can deal with two power points better than three.

 

[childcarepro]

You're better off with 2 parallel strings if the charge controller can operate at the higher voltage (3 * Voc).

I thought it was based on Vmp. If it's Voc, I need 3 x 40.46 = 121V, so my 100/50 won't work for 3S.

Option 1: 2 3S strings MPPT
Two Victron SmartSolar 150/35's @$540 x 2 = $1080. OUCH. Now I'm seeing the light re: Dacian's $37 DSSR's!
Input: 102V 5.88A max (per 150/35)
Output: 29.2V 20.5A max (per 150/35)

Option 2: 3 2S strings MPPT
Three Victron SmartSolar 100/20 x 3, at $157 x 3 = $471, would be a bit more than my 100/50 ($323)
Input: 68V 5.88A max (per 100/20)
Output: 29.2V 13.7A max (per 100/20)

Option 3 (budget option): 3 2P strings using DSSR
Two DSSR's $37 x 2 = $74 (5.88 Imp x 6 = 35.28A)

Either way, I was planning on using that 3-input combiner box so I don't have to drill any new holes. I could simply disconnect the parallel splices and run separate lines for all 3 SAE inputs for 3 separate 2S strings, but I have to make sure the wiring is at least 14 ga, if not, will probably solder in 12 ga wire.

 

[LB3]

Now I'm seeing the light re: Dacian's $37 DSSR's!

That’s $37 CAD or ~$28 USD. There are still shipping costs but the Canuck Buck is in the toilet right now.

 

[childcarepro]

That’s $37 CAD or ~$28 USD. There are still shipping costs but the Canuck Buck is in the toilet right now.

Totally forgot. As I love to say, "Canada's on sale."

 

[lappies]

Hi @all

I can't find a detailed description of the EXT IO, I only read there are 5 types you can use. What is for example type 1 and what is type 2 etc. Is there a more detailed description somewhere?

I plan to use the sbms0 in a motorhome. Via remote ON/OFF I can switch solar and my inverter ON/OFF.
At low voltage I also would like to disconnect the connection between the battery and the built-in electrical block to prevent a deep discharge.
The built-in Elektroblock(Schaudt) cannot be switched ON/OFF remotely. I therefore plan to install a battery cut-off relay between the battery and the Elektroblock.
Which relay can you recommend for this purpose, or what is the best way to implement this?

Thanks
Lappies

 

[Airtime]

I can't find a detailed description of the EXT IO, I only read there are 5 types you can use. What is for example type 1 and what is type 2 etc. Is there a more detailed description somewhere?

Unfortunately it's not yet in the manual, it should be. Here is a description from Dacian in the Electrodacus forum. Types 1 and 2 are for normal operation charge control and discharge control. Type 5 is a safety disconnect that is set to wider limits with OV Lock and UV Lock, if either trips then it disables everything.

Type 1 (HVD - High voltage disconnect) used to control any charger that can be DSSR20, an MPPT solar charger with remote ON/OFF, a grid charger or a battery to battery charger.
Type 2 (LVD - Low voltage disconnect) used to control any load like in most case an inverter or something like a Victron BP-65 for small DC loads.
Type 3 and 4 are the same as 1 and 2 but based on SOC instead of voltage and should only be used as alarms not to control devices that is what the SOC setting is for in the EXT IO just for this type 3 and 4
Type 5 is for fault conditions when something went wrong and you get to secondary high or low voltage limits named under voltage or over voltage lock. This is not necessary but can be used as backup in case one of the chargers or loads fail to respond to remote ON/OFF control (very unlikely that will ever happen) and the you can have something like a remote triggered circuit breaker than can be tripped by this type 5 signal and manual intervention will be needed to check the fault, repair and then reset the breaker or breakers.
Type 6 is for dual PV setup where you install two PV arrays ideally one 2x larger than the other and that 2x larger PV array will be set as type 6

 

[Jdhorner8]

Type 1 (HVD - High voltage disconnect) used to control any charger that can be DSSR20, an MPPT solar charger with remote ON/OFF, a grid charger or a battery to battery charger.
Type 2 (LVD - Low voltage disconnect) used to control any load like in most case an inverter or something like a Victron BP-65 for small DC loads.
Type 3 and 4 are the same as 1 and 2 but based on SOC instead of voltage and should only be used as alarms not to control devices that is what the SOC setting is for in the EXT IO just for this type 3 and 4
Type 5 is for fault conditions when something went wrong and you get to secondary high or low voltage limits named under voltage or over voltage lock. This is not necessary but can be used as backup in case one of the chargers or loads fail to respond to remote ON/OFF control (very unlikely that will ever happen) and the you can have something like a remote triggered circuit breaker than can be tripped by this type 5 signal and manual intervention will be needed to check the fault, repair and then reset the breaker or breakers.
Type 6 is for dual PV setup where you install two PV arrays ideally one 2x larger than the other and that 2x larger PV array will be set as type 6

I assume Type 1 thru 4 go high when condition is met. Is it possible to invert these outputs?
Thanks!

 

[Airtime]

I assume Type 1 thru 4 go high when condition is met. Is it possible to invert these outputs?
Thanks!

They are optocoupler outputs with two output pins, so it depends what you connect. Outputs are connected when enabled, open when disabled. You can't invert the logic in SW in the device, which I think is your question. What would you be driving with it?

Not sure of your background or if you are familiar with optocouplers. If you just need to close a switch or energize a (small) relay when 'condition is met' i.e. charge enabled or discharge enabled, then no additional components needed.

If what you want is a logic signal that is low when enabled and high when disabled, then you can tie low side to ground, pull up high side to desired logic high voltage with a resistor, and take the output from the high side. Resistor sizing depends on input impedance of whatever you are driving.

When enabled, the optocoupler pins will be connected, pulling the output low. When disabled, the optocoupler contacts will open, and the resistor will pull the output high. You can invert that by having a pull-down resistor instead of a pull-up resistor.

 

[Jdhorner8]

They are optocoupler outputs with two output pins, so it depends what you connect. Outputs are connected when enabled, open when disabled. You can't invert the logic in SW in the device, which I think is your question. What would you be driving with it?

Yes, I was thinking in terms of software and didn’t realize both pins were available for each output. I thought they were wet contacts rather than dry.
I’m not familiar with optocouplers, my experience is in line-voltage AC controls with industrial relays.
I have a Xantrex SW3012 inverter/charger I would like to control from the SBMS0. I have a Xantrex SW remote control panel by which I can control the inverter using a 12V sense input, but can’t find a way to kill the charger other than Dacian’s suggested relay on the AC input.
I’m not particularly fond of the heat generated by SSR’s and I’ve been trying to find a way to use a latching relay on this 30A AC circuit. In lighting control we have contactors that will latch closed with control signal present, then clear the coil automatically so there is no coil heating and the contacts are mechanical so there is no heating there either. When the control signal goes low the contactor opens. Blue Sea makes a battery combiner on this principle I believe, but I’m not finding anything configured for DC in and AC out as needed for my application.
Does anyone know of a way to control the Xantrex charger directly through Xanbus or something? If not, what would you recommend for a relay on the AC input that is low loss and low heat? Thanks!

 

[childcarepro]

Hey guys, so I took a break from this project to set up equities investments. Looks like everyone else has been doing the same thing? It's been quiet in here!

I always want maximum features, but what I'm really looking for simplicity over power. I'm sticking with my Victron ecosystem because it's slick and polished and does just about everything I need including remote monitoring and control, so the SBMS0 would just be a BMS. Is Electrodacus's SBMS0 compatible with my goals? Or should I be looking at a 200A Daly for my 8S 280Ah setup? I want to like Overkill, but I have a Victron MultiPlus 24|3000 and lots of big loads (high efficiency 9KBTU 24VDC heat pump, MW/convection oven, espresso machine, 24VDC fridge, etc.) and plan on using 3000W sometimes, so would like to have 125A plus headroom, so 200A is ideal. Chargery also sounds like a good option, but again, simplicity over power.

 

[Dzl]

Hey guys, so I took a break from this project to set up equities investments. Looks like everyone else has been doing the same thing? It's been quiet in here!

I always want maximum features, but what I'm really looking for simplicity over power. I'm sticking with my Victron ecosystem because it's slick and polished and does just about everything I need including remote monitoring and control, so the SBMS0 would just be a BMS. Is Electrodacus's SBMS0 compatible with my goals? Or should I be looking at a 200A Daly for my 8S 280Ah setup? I want to like Overkill, but I have a Victron MultiPlus 24|3000 and lots of big loads (high efficiency 9KBTU 24VDC heat pump, MW/convection oven, espresso machine, 24VDC fridge, etc.) and plan on using 3000W sometimes, so would like to have 125A plus headroom, so 200A is ideal. Chargery also sounds like a good option, but again, simplicity over power.

If you want simplicity, and already have the features, monitoring, and customizability of a Victron based system, I think you have correctly judged that the SBMS0 should probably not be your first choice.

If I were in your shoes, I would:

1. Start by making a list of must have features
2. Rule out the BMSes that don't have one or more of these features
3. Select one of the simpler BMSes remaining on the list

 

[childcarepro]

If you want simplicity, and already have the features, monitoring, and customizability of a Victron based system, I think you have correctly judged that the SBMS0 should probably not be your first choice.

If I were in your shoes, I would:

1. Start by making a list of must have features
2. Rule out the BMSes that don't have one or more of these features
3. Select one of the simpler BMSes remaining on the list

1. Active balancing and 150-200A discharge current are the only MUST have features;
2. I ruled out Overkill because only 100A;
3. To my knowledge, the only ones that remain are Chargery and SBMS0

Am I missing some options? Of the two I'm aware of, I would say Chargery is simpler, but not by a whole lot? Chargery does have 1.2A balancing current, vs SBMS0's 200 mA, which is a nice bonus, though with debatable utility.

 

[Dzl]

1. Active balancing and 150-200A discharge current are the only MUST have features;

A lot of people misunderstand what active balancing means (the terms are slightly misleading). Active balancing means the BMS or Balancer transfers energy from one cell to another whereas passive balancing bleeds energy from high cells--Almost all BMSes are passive balancing. If you truly need active balancing, you rule out 90% of the BMSes (including SBMS, Charger, Daly, JBD Smart BMS (overkill solar) and Ant BMS).

If you just need a BMS that balances, than all of the above BMSes will work (passive (resistive) balancing)

2. I ruled out Overkill because only 100A;
3. To my knowledge, the only ones that remain are Chargery and SBMS0

One BMS that may meet your needs (as written) is the Heltec BMS, I don't recall if it is available for 24v or just 48v but it is a true active balancing FET based BMS and I believe is rated at 200A maybe higher. There is a thread on the forum dedicated to it. But only a few people from the forum have purchased it and most have been recent purchases.

Among high end options, there may be more choices. 123smartBMS, REC, Orion, and maybe TinyBMS are some to look into if budget allows most or all of these are $400+ one added bonus is at least a couple can integrate Victron components.

 

[childcarepro]

A lot of people misunderstand what active balancing means (the terms are slightly misleading). Active balancing means the BMS or Balancer transfers energy from one cell to another whereas passive balancing bleeds energy from high cells--Almost all BMSes are passive balancing. If you truly need active balancing, you rule out 90% of the BMSes (including SBMS, Charger, Daly, JBD Smart BMS (overkill solar) and Ant BMS).

If you just need a BMS that balances, than all of the above BMSes will work (passive (resistive) balancing)


One BMS that may meet your needs (as written) is the Heltec BMS, I don't recall if it is available for 24v or just 48v but it is a true active balancing BMS and I believe is rated at 200A maybe higher. There is a thread on the forum dedicated to it.

Among high end options, there may be more choices. 123smartBMS, REC, Orion, and maybe TinyBMS are some to look into if budget allows most or all of these are $400+ one added bonus is at least a couple can integrate Victron components.

OK sure, resistive balancing; "active" in the sense the BMS is doing something to keep the cells in balance!

I think I've saved enough on my cells that I can splurge on the BMS, though within reason. Which of the higher end options do you prefer? So far I've looked at 123 Smart and REC, the 123 Smart looks really slick, with relays per cell and individual temp monitoring.

 

[Dzl]

OK sure, resistive balancing; "active" in the sense the BMS is doing something to keep the cells in balance!

In that case every BMS I am aware of fits the bill on that point (though there are big differences in balance current)
If I got to rename the terms I would use active to mean what thought it meant, since that is more intuitive, since I can't , I just try to clarify where I can.

I think I've saved enough on my cells that I can splurge on the BMS, though within reason. Which of the higher end options do you prefer? So far I've looked at 123 Smart and REC, the 123 Smart looks really slick, with relays per cell and individual temp monitoring.

Higher end BMSes are out of my price range so I have never looked seriously at them. The one that piques my interest the most is the 123smartBMS (it is also one of the more affordably priced high end options I think) Its made by a European company, is modular, and supposedly plays nice with the Victron (but possibly requires you purchase an addon to do so, I cant remember). It is also one of the only BMSes I have ever seen that uss latching relays (if I recall correcetly).

Tiny BMS isn't exactly high end but it looks pretty cool too (priced in the ballpark of the SBMS and Chargery I think) but requires a bit more DIY'ing.

 

[childcarepro]

Higher end BMSes are out of my price range so I have never looked seriously at them. The one that piques my interest the most is the 123smartBMS (it is also one of the more affordably priced high end options I think) Its made by a European company, is modular, and supposedly plays nice with the Victron (but possibly requires you purchase an addon to do so, I cant remember).

Glad you named them first, as that's the first one I looked at. Looks like it and REC talk to Victron. I'm reaching out to 123smart, since they don't have any dealers in the US. I really like the modular approach of 123smart.

One YouTuber bought about $1000 worth of REC stuff after all the accessories; that's a lot of money in Slovenia (where REC is based).

 

[Dzl]

I'd be curious to hear more about that 24vdc heat pump you mentioned earlier