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Using Chargery BMS without disconnect relay

Solarfun4jim

Solar seduced :-)
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Im soon to be doing a 'capacity test' on my 8s battery bank. I wish to use my chargery BMS8T to monitor the cells but i do not have a dc relay for discharge cut off. I assume if i take the positive and negative wires from the discharge relay and simply connect them across a terminal block, then on low voltage disconnect situation, it will simply terminate the current through the block. However, at the same time, the buzzer and the warning 'led' should sound the alarm and at that point i can manually disconnect the capacity tester. I would be using the calibrated shunt supplied by chargery, so i presume no further calibration should be needed.
Anyone see any issues in monitoring my individual cell voltages this way and reacting immediately on alarm signal LVD?
 
Sounds like a workable plan, but Murphy hides around every corner. It's up to you to keep him away. I'm not very good at that.
 
Sounds like a workable plan, but Murphy hides around every corner. It's up to you to keep him away. I'm not very good at that.
Cheers snoobler...thanks for the re assurance.

You mind if i ask you a question about the remote on/off terminal H on victron products?
 
The H terminal(on a multiplus) or remote terminal on the SCC 150/45TR, just needs to see a 12v input to maintain them at the 'on position'. If i take the 12v output of the charge/discharge relay on a chargery BMS, can i simply connect the positive lead and ignore the negative. I believe when the H terminal is not needed they simply cross the left and middle terminals to switch on? The 'remote' on the SCC has a two pole connector.
So if each was supplied with 12v output from BMS relay positives only, does it really matter if the negative wires are connected anywhere?
I'm not the best at explaining, so i hope this makes sense.
Thanks

Edit....nearly 3am here, will have to catch up with the forum later. :sleep:(y)
 
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No. They indicate you short it for on, open it for off, i.e., no external power source. If it's 12V, it's coming from the unit itself, so it's looking for the open/close of the that circuit. Applying +12 from somewhere else means the circuit is still open, and nothing happens.

If you're looking for a way to shut it off, you need to either open left and middle to turn off the inverter, or short middle and right to switch to charger only mode.
 
No. They indicate you short it for on, open it for off, i.e., no external power source. If it's 12V, it's coming from the unit itself, so it's looking for the open/close of the that circuit. Applying +12 from somewhere else means the circuit is still open, and nothing happens.

If you're looking for a way to shut it off, you need to either open left and middle to turn off the inverter, or short middle and right to switch to charger only mode.
Thanks snoobler. I had thought that so long as the middle terminal was getting the required voltage it would operate. What about going through an Inverting remote on-off cable then?
Going by info on ( https://www.victronenergy.com/upload/documents/Inverting-remote-on-off-cable-EN.pdf ), in example 2 where only one connection from the 've bus' goes to the two on the inverter. Is says it can be used on Phoenix inverters rated at 3kVA and more.
Failing that, i guess i will be looking for another SSR . :(
 
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Didn't looked at the manuals or anything (I don't have the time right now) but usually when you have an input with two wires, H and L, it means high and low. In other words it means active high and active low.

So for normal activation you use L as a ground and H for the signal, the thing will be active when H is at 12 V and inactive when it is at 0 V.

For inverted activation you use H as a ground and L for the signal, the thing will be active when L is at 0 V and inactive when it is at 12 V.

If you already have the ground connected and the thing supports it you're not required to connect it and you can just send your signal on H or L.

Internally to the thing H should be default high (so 12 V) and L should be default low (so 0 V) via pull-up/down resistors so you're able to use a simple contact if needed.

I don't know if Victron follow these conventions but just shouting that in case it helps ;)
 
Didn't looked at the manuals or anything (I don't have the time right now) but usually when you have an input with two wires, H and L, it means high and low. In other words it means active high and active low.

So for normal activation you use L as a ground and H for the signal, the thing will be active when H is at 12 V and inactive when it is at 0 V.

For inverted activation you use H as a ground and L for the signal, the thing will be active when L is at 0 V and inactive when it is at 12 V.

If you already have the ground connected and the thing supports it you're not required to connect it and you can just send your signal on H or L.

Internally to the thing H should be default high (so 12 V) and L should be default low (so 0 V) via pull-up/down resistors so you're able to use a simple contact if needed.

I don't know if Victron follow these conventions but just shouting that in case it helps ;)
@BiduleOhm
Thanks BiduleOhm. Unfortunately i dont understand it enough to know if this helps me or not, but i appreciate you trying to help me. (y)

edit...
this is taken from the SCC manual
"3.5 Remote on-off
The left terminal is connected to the internal 3,3V supply, with a resistor in series for short circuit protection. The right terminal (marked as + or marked as H) will switch the controller on if >3V is applied, and will switch the controller off if <2V is applied or if the terminal is left free floating. The recommended use of the remote on-off is: a. A switch wired between the left and right terminal b. A switch wired between battery plus and the right terminal. c) A switch between the right terminal and the charge disconnect terminal of a VE.Bus BMS"
 
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Ok I have a bit more time now. What you want to do isn't 100 % clear to me so tell me if I'm wrong:

You have a Victron Multiplus inverter.
You have a Victron 150/45TR SCC.
You have a BMS8T Chargery BMS.
You want the BMS to shutdown the inverter when in LVP.
You want the BMS to shutdown the SCC when in OVP.
 
Ok I have a bit more time now. What you want to do isn't 100 % clear to me so tell me if I'm wrong:

You have a Victron Multiplus inverter.
You have a Victron 150/45TR SCC.
You have a BMS8T Chargery BMS.
You want the BMS to shutdown the inverter when in LVP.
You want the BMS to shutdown the SCC when in OVP.
Yes mate, that is what i'm trying to accomplish. The multiplus is an inv/charger. I was hoping i could split the 'charge' relay output on the chargery, with a connection to both the SCC and also to a SSR relay on the incoming grid supply, so that in the event i'm connected to campsite power and an out of parameter situation developes on a cell, it would cut the incoming power as well as the SCC power.
 
Ok, what inverter model do you have exactly?

Also why on earth Victron doesn't document their input ports properly in the manual or datasheet? I have a hard time finding the specs for the SCC one.
 
Ok, what inverter model do you have exactly?

Also why on earth Victron doesn't document their input ports properly in the manual or datasheet? I have a hard time finding the specs for the SCC one.
Cell protection disconnect layout.png

I was aiming for something along these lines for protection purposes. Inv/chg is multiplus 24/3000/70-16

Thanks
 
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The more I search and the more I'm pissed at Victron :mad: that's not what I'd expect from a company like them, especially given the price you pay their stuff...

All the manuals and datasheets don't give any info on the inputs and tell us to go see their white paper about data com which is here: https://www.victronenergy.com/uploa...unication-with-Victron-Energy-products_EN.pdf well, great, it only talks about their proprietary com but still no info about the simple on/off input...

Can someone tell me if I'm stupid and just didn't found the doc? or if it just simply doesn't exist?

@Solarfun4jim I'm sorry but right now I don't have enough info to give you a definitive answer besides this: the Chargery manual confirms page 31 the relays ouputs aren't isolated, so assuming the inputs aren't isolated on the Victron stuff too, and assuming they work in the normal sens (they're not inverted), then everything should work perfectly if you follow the last diagram you posted ;)

If they are isolated you need to connect the ground to them (like for the SSR).

If they are inverted there's several different solutions depending if there's a L input or not in addition to the H one, and how they work exactly.
 
The more I search and the more I'm pissed at Victron :mad: that's not what I'd expect from a company like them, especially given the price you pay their stuff...

All the manuals and datasheets don't give any info on the inputs and tell us to go see their white paper about data com which is here: https://www.victronenergy.com/uploa...unication-with-Victron-Energy-products_EN.pdf well, great, it only talks about their proprietary com but still no info about the simple on/off input...

Can someone tell me if I'm stupid and just didn't found the doc? or if it just simply doesn't exist?

@Solarfun4jim I'm sorry but right now I don't have enough info to give you a definitive answer besides this: the Chargery manual confirms page 31 the relays ouputs aren't isolated, so assuming the inputs aren't isolated on the Victron stuff too, and assuming they work in the normal sens (they're not inverted), then everything should work perfectly if you follow the last diagram you posted ;)

If they are isolated you need to connect the ground to them (like for the SSR).

If they are inverted there's several different solutions depending if there's a L input or not in addition to the H one, and how they work exactly.
Much appreciated BiduleOhm.
It might just be easier to slot in some more SSR's(as below) but i will go ask my supplier and the victron forum.
Thanks again for taking the time out to help me. (y)
alternative bms layout protections.png
 
Much appreciated BiduleOhm.
It might just be easier to slot in some more SSR's(as below) but i will go ask my supplier and the victron forum.
Thanks again for taking the time out to help me. (y)
View attachment 26844

This is how Victron indicates it should be done. Open circuit = off. Closed circuit = on.

Note that the SSR's on the inverter are doing the same thing. I personally wouldn't use the one on the AC output UNLESS I wanted to retain charging capability. The SSR to terminal H shuts the inverter off including generator or grid charging. A more elegant solution would be a two pole SSR that toggles the closed circuit between left and middle for inverter operation to middle and right for charger only operation.
 
This is how Victron indicates it should be done. Open circuit = off. Closed circuit = on.

Note that the SSR's on the inverter are doing the same thing. I personally wouldn't use the one on the AC output UNLESS I wanted to retain charging capability. The SSR to terminal H shuts the inverter off including generator or grid charging. A more elegant solution would be a two pole SSR that toggles the closed circuit between left and middle for inverter operation to middle and right for charger only operation.
Snoobler....it is AC input not output(for clarity).
I do not need 'charger only function', so a close/connection between the left terminal and middle terminal would suffice for me.

I need the charge relay to shut down all charging when HVD (incoming grid power and SCC power)
I need the discharge relay to shut down the inverter when LVD

I'm not electrically or electronic minded whatsoever....so please bear with me if i dont explain things very clearly.
 
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In what documentation?

Manual. Appendix A. PDF page 28. Terminal H description


Snoobler....it is AC input not output(for clarity).
I do not need 'charger only function', so a close/connection between the left terminal and middle terminal would suffice for me.

I need the charge relay to shut down all charging when HVD (incoming grid power and SCC power)
I need the discharge relay to shut down the inverter when LVD

I'm not electrically or electronic minded whatsoever....so please bear with me if i dont explain things very clearly.

You are correct. I completely misread it as output regardless of your proper documentation. :)
 
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