HELP. PLEASE SEE ATTACHED FILE

[ask first]

Can someone who has this setup post a photo of their actual system. I'm not understanding the right side of this schematic. I'm a newbie and just trying to put the pieces together. Please start from the main positive and main negative off the battery and work your way to the DSSR20. Looks like those are shunts and breakers? What are the wire gauges. Thanks. 

[Will OBrien]

For control wiring, I grabbed a piece of stranded cat5 patch cable and stripped the main insulator off.

This is sufficient gauge for all of the control and data connections in the picture - this includes the measurement from the shunts as well as logic control wiring to your inverter, etc.

For the main feed wires - PV/Battery to Inverter, this is all dependent on your voltage and amperage requirements.

For example, My RV has a preinstalled 10Awg run from my PV panels to my solar controller. (In my case, I use a MPPT and not the electrodacus boards)

This gauge and length is the limiter of the maximum amperage - which in my case tops out around 18A and 64V or so. My MC connectors are rated for 30A each up there. I chose to arrange my panel wiring (12x 100W panels) in a 3s4p configuration to work around the limitation of the 10AWG cabling. The longer run means I have some voltage drop, but this is offset by my panels higher output voltage. 

You need to determine the maximum amperage you're running to use safe wiring.

From the battery going to the right, those are a pair of shunts, which you'll want to size for your system. I originally used a pair of 250A 75Mv shunts in my system because I could get them in time for my build. (Note that I have upgraded my load shunt to a 300A to match my new inverter fusing)

After the shunts are breakers or fuses and a disconnect of some sort. I personally use fuses and a 500a solenoid as my discharge cutoff.

My main battery is about 24V, (It's a tesla module today, soon to become a giant bank of lifepo4 cells) I used 2 AWG welding cable with copper ends for bolt positions and a bus bar for breaking out to different loads.

My Inverter is now a Victron multiplus, which is good for 3000 watts, fused at 300A with an ANL fuse and cabled with 2awg cable for the battery feed.

Since all of my cable runs are under 3-5 feet, 2AWG is the minimum wire that's sufficient for my needs. Since my victron supports dual cable runs, I'm going to double up those cables when I replace my battery pack to further reduce voltage drop.

Hope that helps.

[ask first]

Thanks. It clarified some things. But then I realized I didn't provide enough information. This project is completely off grid. 

I have ten 250w panels, one 24v 280Ah battery, SMBS0 with wifi DSSR20 with diversion. A 24v/3000w inverter and a panel 150A panel box. 

I attached another photo of what I think you're speaking of a shunt. which is what in the photo?

[ask first]

right - i am off grid build for my house as well. I used the 3rd style shunt in the picture you sent. I bought 500amp 75 mv shunts and they are working good for me at this moment. some say a smaller 300amp shunt gives better resolution but mine are working good. I have some smaller ones I may try on the next 24-volt LiFePO4 battery bank I assemble. i bought 4 DSSR20 with diversion but have not tried them -- i think you will have to use the heat side also for the DSSR20 with diversion if you have a place for the diversion to go. I am only charging the LIFePO4 battery bank at the moment but plan to try out the diversion DSSR20 on some water heater elements to begin with in 55 gallon plastic drums in the basement to store some solar energy. then later may try the resistive cable method in the concrete floor as a place to store the diversion load from the DSSR20 with diversion you do not need to hook up the diversion side of the DSSR20 if you are not yet using it.

Right now I am just using the outlets on my 6000 watt inverter (PSW LF SplitPhase to carry the heavy loads when needed). I also have a 120/240 electric panel to hook up to the inverter but not completed yet.

keep in mind the fuse and resistor needed on the positive side of the sense wire to protect the sbms0 with the extio4+, this is an important detail that you have to ferret out of all the information.

i also bought 2 dect16's so i can hook up to 40 panels 250 watts each to the sbms0. i plan to have the big array small array set up when more complete. 

right now a big uninterruptible power supply.

although a lot of people like/love circuit breakers --- i highly recommend the large class T fuse between the battery and the inverter -- a so called catastrophe fuse. many breakers simply are not dependable to the huge rush current a 560Ah LiFePO4 24 volt battery can put out.

spend the time and research it some - it will likely pay you back many times over.

The above post brought it down to my level especially with looking up the part, knowing the name and knowing its function. Let me absorb that in. I really appreciate all of you guys help. 

[Dacian Todea]

ask first,

For details on the DSSR20 with diversion and how it is connected you will need to check his dedicated user manual https://electrodacus.com/DSSR20/DSSR20.pdf

For smaller currents circuit breakers are great as they are both an overcurrent protection device and a disconnect switch in one for large currents like connecting a larger inverter is more economical to use a fuse as large current circuit breakers can get fairly expensive.

There should be no inrush current as you should precharge the inverter capacitors before connecting it.

Current shunts are nothing more than power resistors where a device like SBMS0 will measure the voltage drop across and calculate the current based on that voltage drop and knowing the resistance.

[ask first]

BY MICHAEL CLARK_NOT SURE WHY IT DIDN'T POST

yes, those are shunts. the shunts are 1st connected main positive of the LiFePO4 battery. the 1st shunt is for battery monitoring. the second shunt is for the PV monitoring. you always have a breaker or large capacity fuse between the battery and the inverter to protect the inverter. the diagram shows a breaker (I used a class t fuse in that place (400 AMP)). 

the other breaker is for the solar charge controllers (DSSR20).

i used 4/0 wire between my 2P8S LiFePO4 16 cell battery bank to the shunts. I actually connected both shunts to a copper bus bar. then from the copper bus bar to the class t fuse then to the inverter. I used 1/0 wire to the fuse and also to the 6000 watts 24-volt inverter.

I used 10 gauge PV wire to the dssr20 and from the dssr20 to the negative bus bar I used black 10 gauge PV wire. I used red PV wire 10 gauge for the positive from PV panels to the dssr20.

the sense wires from the shunts used category 5 solid strand wire. which I believe is 22 gauge. the solid strand cat 5 cable worked well for me.

i installed a 32 amp breaker between the solar panels and the dssr20 (basically a switch so I could turn off the solar panels which are wired in parallel in groups of 2). slightly different than what you see in the diagragm.

the tricky somewhat confusing part is the DSSR20 wiring.

one 22 guage sense wire(+) from the SBMS0 goes to the battery positive bus bar through a 1kohm resistor and a 1 amp fuse (not shown in diagram). the other 22 guage (-) sense wire goes from the SBMS0 to the DSSR20

the DSSR20 only has one sense wire attached to the one on it that says bat (-).

the one that says heat (on the DSSR20) is not used.

2  (a pair- 2 small strands)) (EXTIO4-/EXTIO4+) of 22 guage cat 5 (solid or stranded- i used solid) wires come out of the SBMS0 to connect and control the DSSR20's; one goes to the DSSR20 and the other goes to the thew posive bus bar through a 1 Kohm resister and the 1 amp fuse to protect it.

sorry it is confusing. I had to go take a second look to write it more correctly.

i used 2 guage wire to my pv bus bars from the main bus bars which are connected directly to the positve battery (thru 2 shunts), and from main negative bus bar to pv bus bar. i used 4/0 wire from the battery 1st.

it is blizzarding here now.

pilgrimvalley of south dakota

[ask first]

4/0 wire can carry different amperage based on whether its aluminum or copper? how many Ah is your battery?

[Dacian Todea]

Of course it will depend if it is aluminium or copper and also the type of thermal insulation and where the cable is installed like in a conduit with multiple other conductors or in free air.

This is a good basic source of information for American standard https://en.wikipedia.org/wiki/American_wire_gauge

[ask first]

FOR SOME STRANGE REASON THESE ARE NOT POSTING ON HERE MICHAEL

!ST

right - i am off grid build for my house as well. I used the 3rd style shunt in the picture you sent. I bought 500amp 75 mv shunts and they are working good for me at this moment. some say a smaller 300amp shunt gives better resolution but mine are working good. I have some smaller ones I may try on the next 24-volt LiFePO4 battery bank I assemble. i bought 4 DSSR20 with diversion but have not tried them -- i think you will have to use the heat side also for the DSSR20 with diversion if you have a place for the diversion to go. I am only charging the LIFePO4 battery bank at the moment but plan to try out the diversion DSSR20 on some water heater elements to begin with in 55 gallon plastic drums in the basement to store some solar energy. then later may try the resistive cable method in the concrete floor as a place to store the diversion load from the DSSR20 with diversion you do not need to hook up the diversion side of the DSSR20 if you are not yet using it.

Right now I am just using the outlets on my 6000 watt inverter (PSW LF SplitPhase to carry the heavy loads when needed). I also have a 120/240 electric panel to hook up to the inverter but not completed yet.

keep in mind the fuse and resistor needed on the positive side of the sense wire to protect the sbms0 with the extio4+, this is an important detail that you have to ferret out of all the information.

i also bought 2 dect16's so i can hook up to 40 panels 250 watts each to the sbms0. i plan to have the big array small array set up when more complete. 

right now a big uninterruptible power supply.

although a lot of people like/love circuit breakers --- i highly recommend the large class T fuse between the battery and the inverter -- a so called catastrophe fuse. many breakers simply are not dependable to the huge rush current a 560Ah LiFePO4 24 volt battery can put out.

spend the time and research it some - it will likely pay you back many times over.

2ND

I always use copper wire. the 4/0 copper welding cable from my 560Ah iFePO4 battery is connected to the main bus bar as are the 2 shunts on the positive side for SBMS0 to monitor the PV and charge etc. I use a 400amp class T fuse between the main bus bar and the 6000-watt inverter on the positive cables but only use 2 gauge copper welding cable from the main bus bar to the class t fuse and onto the inverter. the 2S8P configuration of the LiFePO4 24-volt battery bank has 3.2v x 272Ah x 16 cells = 13926.4 Wh capacity. I will not use that much. at the moment. but plan to use the DSSR20 with diversion in the future.

[Dacian Todea]

You do not need to connect the diversion and you can use the DSSR20 just for battery charging.

Yes a Fuse will be more cost effective and that is what many people used for connecting an inverter. The proper large circuit breakers are fairly expensive.

The 300A 75mV shunt will have less than 2x better resolution than the 500A 75mV still bot will be more than sufficiently precise.

You can read this post for details about actual resolution and how it is calculated  https://groups.google.com/g/electrodacus/c/ReL-z6vGFdw/m/vsmKm0grAQAJ

SBMS0 uses a 16bit ADC and since is a bidirectional current shunt measurement for the battery then 15bit one direction and 15bit the other direction thus the resolution smallest difference in current will be max shunt range so 500A 75mV with 90mV ADC input means 0A to 600A can be measured so 600A / 32768 = 18.3mA is the smallest detectable change in current vs the 300A 75mV that can measure up to 360A / 32768 = 11mA resolution.

[ask first]

I have 4 DSSR20 with diversion cuz I'm really interested in the hot water to heat my home. The metal 55 gallon from a better setup than the plastic which I have. Is there a way to regulate the temperature to stop it from heating? Would the drums require one for hot and one for cold with a pump if I wanted to use it for bathing? Is there a post in the in the google group with diagrams about this?

[Dacian Todea]

The plastic one should not be heated above +55C (in my experience) with metal one you can probably heat to +80C with no problem.

Yes you can add a simple bi-metal thermostat like the KDS9700 and have that in series with the Heat remote signal on the DSSR20 that way getting the normal close version of the KDS9700 with whatever temperature setting you want and when it gets to that temperature the switch will open so the Heat remote signal will be open also and heating will stop. This bimetal are maybe within 5C tolerance but you can also get an electronic thermostat and again have that disconnect the heat signal from the DSSR20 to stop heating. That signal from DEXT16 is just 9V dc and around 10mA so very easy to disconnect with any sort of thermostat.

[ask first]

is this the proper one to use(M/FFFF & F/MMMM when connecting to the main negative's that comes from the array four panels at a time?

[Dacian Todea]

Sorry I do not understand the question. All negative wires from all panels and all negative from all heating elements will all connect to a single large common negative buss bar that is also connected to battery negative.

[ask first]

https://www.amazon.com/BougeRV-Connectors-Parallel-Adapter-Panel（1/dp/B07B4ZM8Y8/?_encoding=UTF8&pd_rd_w=2FzkL&pf_rd_p=49ff6d7e-521c-4ccb-9f0a-35346bfc72eb&pf_rd_r=AMBZ3WYMW4YMNTFRSVBF&pd_rd_r=63880fe5-8458-44b0-ac42-b0910ac2b534&pd_rd_wg=y6czI&ref_=pd_gw_ci_mcx_mr_hp_d

These are M/FFFF and F/MMMM. Can I used these on the negative side if the panel or would I have to use this on both negative and positive of the panel. 

https://www.amazon.com/Signstek-Branch-Parallel-Connector-Adapter/dp/B00FWO3RAE/ref=sr_1_2?dchild=1&keywords=m%2Fff+mc4&qid=1611165912&s=lawn-garden&sr=1-2

I'm asking because according to SBMS0 diagram all the negatives forms one line that goes to the busbar whereas the positives are connected in pairs and goes into the DSSR20 before going on to a breaker then the positive busbar. 

[Dacian Todea]

What sort of solar panels do you have ? You will not be allowed to use those sort off branch connectors with 4x as those are for smaller panels that output just 5 or 6A each not the large panels.

You can parallel max 2 panels and they will just be parallel outside next to the panels then the single positive wire with 10AWG cable will go to DSSR20 and the negative wire will just go to a negative buss bar

Also this branch connectors are usually better quality than those with wires https://www.amazon.com/dp/B07HGMN7D9

[ask first]

Thanks for the product tip. Do you have a link for the busbars and breakers?

[Dacian Todea]

The breakers I use are this https://www.amazon.com/-/es/dp/B06XDYZCPZ the 32A will be ideal for two parallel panels

For busbars is a matter of preference as there are so many options. I use most stuff on din rails so I use things like this  https://www.amazon.com/-/es/Mersen-FSPDB2A-distribuci%C3%B3n-aluminio-amperios/dp/B00F5DQYKM

There are larger if you need larger current like same brand will be the FSPDB3A that is 310A

[ask first]

Those busbars are easy to work with. What should I look for on this breaker https://www.amazon.com/DZ47-63Z-1P-Mount-Miniature-Circuit-Breaker/dp/B07QS96PCB/ref=psdc_6355927011_t3_B06XDYZCPZ biz the link you sent has an available delivery of March. 

2. When is it applicable to use the 310A  with 8 ports versus 175A with 4 ports?

[Dacian Todea]

Not sure about the quality of those breakers. The one I sent link to is what I have and are high quality so will handle the rated current and not trip much sooner like is the case with some other's.

2. You need a buss bar that is enough for whatever you have as max current but if you get a buss bar with higher current rating is not a problem the larger the rating the better :)