Safest, best method to install the many resistors needed for multiple IO circuits to and from SBMS0?

[Barry Timm]

I need help from the electronics experts on what is the BEST, SAFEST, most RELIABLE method to install the many, many different resistors required for driving multiple charge and load devices to and from the SBMS0.

As I could have three different charging methods (Multiplus inverter-CHARGER, DSSR50 and possibly a 24v DC-DC charger from a vehicle alternator, and three different LOAD circuits - an Orion 24-12v 70 amp to feed my 12v circuits and some kind of protection device to switch my high-current 24v DC loads (DC air-conditioner), and the Multiplus INVERTER-charger for my 120v loads.

All of these would require at least one multi-circuit opto-isiloate module to provide the number of additional IO ports to be managed by the SBMS0, and that, in turn appears to require potentially even more resistors to manage both the pre- and post-isolator circuits.

This large number of different resistors makes me very nervous as I had a very bad experience with such a setup in the past, and do not want to repeat that experience!

Any help would be very much appreciated with how to best install all these resistors in a safe and fireproof manner!

Thanks!

[Dacian Todea (electrodacus)]

Barry,

If you can wait a bit (guessing before the end of the year) the new DEXT will be available.

On top you see:

3pin connector for power (battery voltage)

4pin for I2C supply if DMPPT100 are used.

Bottom:

Two 4 pin connectors for EXT IO3, IO4, IO5 and IO6 (that is where those connect directly to SBMS0)

Left side:

3 pin connector to connect directly to a trip coil if you have a main breaker to disconnect the battery in case of fault and it is controlled by EXT IO6 set as type 5 capable of up to 6A peak coil current

4 pin connectors from bottom you have EXT IO3 x 2 so you can control an inverter with one and something like Victron BP for DC loads each of this capable of max 500mA 60vdc

4 pin connector above will have an inverted EXT IO4 to control diversion charging and inverted EXT IO5 also for diversion in case of dual PV array setup.

Right side

4 pin connector bottom right are two EXT IO4 500mA 60V

4 pin connector on top another EXT IO4 50mA 400V to control DSSR20 or DSSR50 PV array 1 and EXT IO5 also 50mA 400V to control a second array if needed or can be programed as any type if you do not have a dual PV array.

[Dacian Todea (electrodacus)]

So to simplify you will have

2x EXT IO3

3x EXT IO4

1x EXT IO5

1x EXT IO6 (6A for shunt trip coil)

1x inverted EXT IO4

1x inverted EXT IO5

[Barry Timm]

Wow, that sounds EXACTLY what I was hoping for! This appears to be exactly the type of quality interface that would make the Electrodacus system a properly viable system for guys like myself with less electronics DYI experience, and hopefully avoid having to use cheap, crappy optoisolators and also avoid cludging together some concoction of resistors, in order to switch on/off various types of charging and loads equipment.

PLEASE put me on your wait list for the new DEXT!!!

Thank you!

[Chris R8]

I just soldered the resistor inline into the cable and the isolated with shrink tube 4:1 with glue inside, means shrinked resistor+connection is completely isolated. The shrink tube gives extra stability and used oversized 2W resistors because they are inside shrink tube.
I have each one 4 channel 718 optocoupler per EXTIO and a resistor inline. This is also visually good to track issues because you can see quickly see red light means that channel is on. Means then all victron equipment connects to the screw terminals of the 718 optocoupler.

[Chris R8]

@dacian: I suggest you also change the connector at the SBMS and also this board to Wago 221 style. The current ones are really small and fiddely.  and eg in marine and also RV environments we need to use stranded cat 5 or 6 cables and then ferrules to comply with ISO or ABYC standards. Needed to order 6 different ferrules till I got one that was tiny to go in and then long enough to fit/lock. Standard size in diameter is too short in length so the locking mechanism holds properly. 

[Dacian Todea (electrodacus)]

There are 16 connections on the SBMS0 and so the pin pitch needs to be 2.5mm else they will not fit. And internal construction for the Phoenix connector on the SBMS0 is also spring loaded contact same as the Wago 221.

The connectors on this board are different than the ones on SBMS0 and they are the same as on the DSSR50 that are plug-able and larger 3.5mm pin pitch. So you can screw the wire in then plug the connector.

[Marinepower]

This new DEXT looks like just what I need to clean up the rat's nest of relays i have coming off my SBMS0.  For what ever reason, I have a number of relays to control (inverter load remote, general panel load relay, alternator regulator, DC-DC charger, SCC, main charge-bus type 5) and many of these relays are pushing the 50ma max of the SBMS.

Dacian, when you say that two of the type 4 relays are "inverted" do you mean they are "normally closed?"

I'm sure it's too late for requests for this DEXT iteration, but I would like to the see two "normally closed" relays off the SBMS for the purpose of audible allarms.  One for LVC and one for Type 5 over voltage lock out.  These are two events that you want to be alerted to as soon as they occur.

MP

[Dacian Todea (electrodacus)]

MP,

I just finalized yesterday the design for the second version of DEXT will order the PCB this weekend just need to double check it.

As you see in the 3D render of the PCB there are quite a few more connectors as I added a 16pin (2x8) connector at the bottom that is the same pin-out as the 1x16 pins on the SBMS0 so that all signals from SBMS0 go to this board making removing the SBMS0 from the installation simpler.

So I also added two 4pin plugable connectors one for the two shunts and one for the two ADC and temperature sensor that way all signals have plugable connectors to keep things more organized.

I needed to move all connectors on the other side of the board else it was not going to fit so I also needed to change the LED's for the type that illuminate trough the board and I needed to change the mosfet that triggers the shunt trip on breaker as the two smaller ones I tested on first version where not capable of tripping the larger 300A barkers I have as they need 6A and voltage will drop to much on those two mosfets so I replaced them with a single larger one.

Those depletion type mosfets are super expensive and there is basically a single source for them so there is not much to chose from.

The EXT IOx is the same as last time

EXT IO3  2x normally open

EXT IO4  3x normally open  + 1x normally closed

EXT IO5  1x normally open  + 1x normally closed

EXT IO6  1x normally closed but high current (6A) so will be set as type 5 and designed to directly trip a large circuit breaker.

So an example of using all EXT IOx will be a large setup with dual PV array and diversion to heating then things will be used this way

EXT IO3 (type 2)

- ON/OFF Power inverter

- ON/OFF DC loads (maybe a Victron BP65)

EXT IO4 (type 1)

- DSSR50's small PV array  and  1x normally closed for excess energy diversion.

- DC-DC charger (car alternator)

- Grid charger

EXT IO5 (type 6)

- DSSR50 larger PV array and 1x normally closed for excess energy diversion.

EXT IO6 (type 5)

- shunt trip circuit Breaker.

If you do not use a dual PV array then EXT IO5 that has a normally open and normal close output can be used for something else.

 

[Tony Doust]

Giday Dacian

As always extremely well thought out board & excellent workmanship. Congrats keep up the excellent work

May i suggest in your next revision that you consider 3 N/O for IO3: because some people like my self have Victron BPxx for 24VDC  loads as well as Dual Victron Inverters with separate 2 wire control for each inverter & running inverters in parallel synced to share the 240VAC loads.

By having the additional IO3: output negates the need to install additional external hardware to increase the number of IOs for controlling Loads.

[Dacian Todea (electrodacus)]

Tony,

But if the inverters are in parallel is there not a master inverter that will turn ON/OFF both of them ?

I think Victron uses the same strategy as all other inverters I seen where you only need to control ON/OFF the master inverter and both will turn ON or OFF.

[Dacian Todea (electrodacus)]

Here is the front panel. Any feedback is appreciated. Hope it looks intuitive.

There will be 5 LED's  one for each of the 4 EXT IOx and one under the Electrodacus logo showing that 3.3V for I2C is working.

There are multiple side points to secure wires using zipties.

There are a total of 50 connections and only two of those are no used shown as NC (not connected). Those NC are on the two 3pin connectors so that there is no damage in case connectors are inserted in the wrong one by mistake. One of them is for power GND and Batt+ (10 to 32V) and the other is GND and TRIP where to connect the circuit breaker trip coil up to 6A trip coil current is supported so should be able to handle most trip coils.

[Barry Timm]

Looking forward to this being available for my next build. Am SO VERY HAPPY to not have to deal with all those resistors and cheap crappy opto-isolators with the fire risk associated with all of that, any longer!!!