Wiring confirmation

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Dan Karau

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Jul 25, 2021, 11:12:01 AMJul 25
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I just received by SBMS0 and 4 x DSSR20 with Diversion.

I have no current plans to use the diversion.

I'm I correct in thinking that the negative output on the DSSR20 is left blank with no Diversion?

Do the control wires need a resistor when not using diversion?

My plan is to use  4 x DC Circuit Breakers between the panels and the DSSR20s as a means of disconnect...is the OK or does the disconnect "need" to go after the DSSR20's as shown in the manuals.   The advantage of using before the DSSR20's is you can disconnect both positive and negative on a double pole breaker. (now code in the US when using a traditional Charge Controller)

I know that the main shunt needs to go immediately off of the battery followed by the main fuse.  Does the solar shunt have the same requirement or can it go to the battery positive bus bar located after the main fuse?

Dacian Todea

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Jul 25, 2021, 2:55:41 PMJul 25
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The DSSR20 with diversion can be used exactly like the one without diversion.
But Battery negative connection is always used. The two connections that will not be used will be Heat+ (large connector) and the Heat (small grey connector).
Yes you need a resistor between the Battery+ and EXT IO4+ and then EXT IO4- will connect to Batt (small grey connector).
It is OK to add breakers for disconnect purpose between the Panels and DSSR20  but you may still need either a breaker or a fuse between Battery+ and DSSR20 close to Battery+ as that will protect that cable in case of a short circuit on that cable.
PV panels can not output higher current than working current so no over current protection is needed but the battery can output any current so cables need to be protected by a fuse or breaker.
That is why in my manual I how a breaker between the Battery+ and DSSR20 as that cable will need to be protected if a sort circuit is possible there.

Dan Karau

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Jul 25, 2021, 5:44:38 PMJul 25
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Yes I have a fuse on the output of the solar between the shunt and the DSSR20s!

So just to confirm, the negative battery bus bar will have the four 10 gauge wires from the panels (in my case from the DC Circuit Breakers) and four more 10 gauge wires from the negative side of the DSSR20s?   

EXT4- is a single wire from the SBMS0 to the small grey "Batt" on the first DSSR20 then daisy chained to the rest of the DSSR20s
EXT4+ is a single wire to the positive bus bar with a resistor (should this be to the most positive bus bar of the battery pack or is the positive bus bar OK?)...not a twisted pair with the EXT4-

PVn and PVp are a twisted pair to the PV Shunt
ADC1n and ADCp are a twisted pair to the Primary Shunt

I will have a Victron 24v 3000w Multiplus and a Victron 24 v to 12v DC to DC 70a Buck Converter.    Do these get connected to the EXTIO3 or EXTIO4 for controlling charge and loads?  Can they be connected directly or do I need a Victron Battery Protect too?

Dacian Todea

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Jul 25, 2021, 5:56:36 PMJul 25
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You do not need 10AWG from DSSR20 to negative even 18AWG will be enough as there will not be much current there is mostly for DSSR20 self consumption and a bit of protection.
Just see page 7 figure b) for the EXT IO4 connection https://electrodacus.com/DSSR20/DSSR20.pdf
You want the EXT IO4+ to be connected to Battery+ as close to Battery+ as possible so you do not want this after a switch like say a Victron BP65 since you want to be able to charge even if Loads are disconnected maybe due to fully discharged battery.
Yes PVp/PVn and ADC1p/ADC1n will be twisted pairs.
Yes SBMS0 needs to control all charge sources and separately all Loads  so yes both the Multiplus and the Buck converter will need to have the remote ON/OFF controlled by SBMS0
For multiplus see this document https://www.victronenergy.com/upload/documents/Manual-Connecting-other-lithium-battery-systems-to-Multis-and-Quattros-EN.pdf  so separate charge and discharge remote ON/OFF will be used if you will be using the grid charger and all settings as in that document except the last two where you will select disable charger.
So both the multiplus and the Buck converter have tier own remote ON/OFF thus the Victron BP is not needed for them as they can be controlled directly by SBMS0.
You may need to use IO5 and or IO6 or have some external optoisolators to multiply the amount of devices that can be controlled by EXT IO3 and IO4. 


Dan Karau

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Jul 25, 2021, 6:14:27 PMJul 25
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Thanks

The one thing I still am not clear on is where to connect the PV Shunt...can it go to the Positive Bus Bar after the main fuse and switch or does it need to go before the fuse and switch?

Dacian Todea

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Jul 25, 2021, 6:37:44 PMJul 25
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See page 3 in the user manual  https://electrodacus.com/SBMS0/SBMS0v03d.pdf  you will have the battery shunt ADC1 and then the PV shunt and there will be no switch or fuse between the shunts and battery+ all those are after the shunts.


Dan Karau

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Jul 26, 2021, 11:51:41 AMJul 26
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Would this resistor be appropriate for a 24v 580 AH battery  (16 x 280 ah EVE Cells)?


Would this Thermistor work as the battery temp or is there a better option?

Dacian Todea

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Jul 26, 2021, 2:53:55 PMJul 26
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You mean the resistor to use for EXT IO4 to control the DSSR20 then yes that will be perfectly fine.
Yes the thermistor is fine many people use that model. 


Dan Karau

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Jul 26, 2021, 4:43:57 PMJul 26
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So with a ton of help from Dacian...here is the current plan!   Anything look out of place?
SBMS0 Wiring Schematic.pdf

Dacian Todea

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Jul 27, 2021, 4:07:52 PMJul 27
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All looks good but please leave the EXT IO3 as default type 2 for discharging and just set the EXT IO5 as type 1
Also after you do all this EXT IOx settings and the current shunt settings go to Device settings and push the Save device settings button so all this are saved permanently.
If you ever push the reset to factory button then EXT IO3 will default to type 2 that is why is not a good idea to change the EXT IO3 from type 2 and EXT IO4 as type 1 as those are the defaults. 

Dan Karau

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Jul 27, 2021, 5:33:50 PMJul 27
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Perfect...thanks Dacian, that is an easy change!   Now to figure out how to mount this all nice and neat!   

Dan Karau

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Sep 12, 2021, 3:53:02 PM (9 days ago) Sep 12
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Dacian

How much heat will a DSSR20 produce?  Just wondering for how I will mount them, do they need to be able to dissipate heat from the base?

Dacian Todea

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Sep 12, 2021, 4:07:56 PM (9 days ago) Sep 12
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No need to worry about DSSR20 heat. It will be 1.6W of heat at 20A charge current and that can easily be dissipated by the DSSR20 no matter what the DSSR20 is installed to.
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