Melted wires between BMS and cells!

[Hedges]

One thing I saw in my BMS before I unplugged it safely Why is that it showed sell one voltage at around 2.6 while the rest of the cells were at 3.2.

My theory is that the wires were melting and shorting out, and that may be caused it to draw more current from the first cell in the battery pack.

Only if it shorted to busbar on other side of cell.
Otherwise, amps through any cell is identical to amps through the next.

Internal leakage could cause voltage, i.e. a bad cell.
Balancer set to operate at too low a voltage could drive imbalance, especially if not fully charged.

But is this the 2p4s battery shown later?
In that case, bad connection leaving one of two cells out of the circuit would me 1/2 the capacity, so it would drain before the other 2p groups did.

 

[WorldwideDave]

Only if it shorted to busbar on other side of cell.
Otherwise, amps through any cell is identical to amps through the next.

Internal leakage could cause voltage, i.e. a bad cell.
Balancer set to operate at too low a voltage could drive imbalance, especially if not fully charged.

But is this the 2p4s battery shown later?
In that case, bad connection leaving one of two cells out of the circuit would me 1/2 the capacity, so it would drain before the other 2p groups did.

thank you Hedges - I think what I saw was a non issue; only flashed on the screen for a second before I killed everything (MPPTs, then kill switch between battery and the bus bar). I think the actual wires were desentegrating right as I was doing that (see pics above if you care). But I appreciate your explination. Yes, it is the 2p4s battery shown later. I was litterally watching the overkill or JBS BMS right as this went down. I wish I could have remembered how to screen record but it all happened so fast. My eyes first panned to find the fire extinguisher right by me, then MPPTs off, then kill switch, like a reflex.

 

[WorldwideDave]

Just a circle back on this. Since the new conductors have been in place, they are barely warm to the touch. What I have been doing to Test is first thing in the morning I turn off my PV disconnects. Next, I am
running 150 amp load in the morning to discharge the battery to 0% state of charge. Once my inverter starts to beep, I then take a screenshots of the BMS temperature readings, the Victron VRM, temperature readings, and then I physically touch all the conductors going to and from my DIY battery pack. Including the lugs and the conductors, and the studs coming out the top of the battery., And the T class fuse, and the bus bars. Everything is as is reported by the BMS… About 93°F is as high as it gets. However, I’m running 150 A for only about 90 minutes because it is a 200 amp hour battery.I turn off the load, and turn off the inverter. I am happy with the discharge tests.

I have been trying to do charging tests. At around 12:30 or 1 PM, I get up on a ladder and look and see if all my panels are in full sun. If they are, I turn on the PV disconnects and the system starts charging at anywhere from 80 to 140 A. I just couldn’t get it to 150 A. Also, because the sun keeps going behind clouds and conditions change in the wind has been blowing, I can’t get a stable amperage from my three arrays all at the same time. I would love a consistent 150 A, but just can’t do it.

What I did rectify this was I added a 25 amp AC to DC charger. I’ve been able to reach 150 A for maybe a minute or two before the battery gets full. It just is not consistent.

So today what I did was, I added a second Victron AC to DC charger. Both of these are 25 amp chargers. At the very least I knew I would be consistently getting 50 A.

Well, today, I got a test a new feature of my BMS! Current overprotection. It triggered within about 30 seconds of turning everything onto to start charging.

I unplugged both the chargers and I’m just letting the solar charge controllers do their thing, but I am wondering if anyone has a good way to prevent the system from charging at over 150 A.

Wait a minute… I think I can set the max charging rate in the solar charge controllers. Let me go try that.

 

[WorldwideDave]

Took a minute to find it, but under the battery settings, you can control the max amperage coming out. I’ve never wanted to do that before. OK both the solar charge controllers are now set for 50 each and the other chargers are set for 25 so that’ll be a perfect 150 let me go test.

 

[Brucey]

Took a minute to find it, but under the battery settings, you can control the max amperage coming out. I’ve never wanted to do that before. OK both the solar charge controllers are now set for 50 each and the other chargers are set for 25 so that’ll be a perfect 150 let me go test.

If you have a cerbo you can enable dvcc and set a global charge limit of 150A. Leave the sccs at their max rating. The cerbo will use the shunt data to allow for your sccs to power your loads in excess of 150A, while ensuring no more than 150A is available to the batteries. Basically allows you to better utilize your available solar, versus a hard limit in the sccs. A perk of a cerbo or Venus os device.

 

[WorldwideDave]

If you have a cerbo you can enable dvcc and set a global charge limit of 150A. Leave the sccs at their max rating. The cerbo will use the shunt data to allow for your sccs to power your loads in excess of 150A, while ensuring no more than 150A is available to the batteries. Basically allows you to better utilize your available solar, versus a hard limit in the sccs. A perk of a cerbo or Venus os device.

OK, that is awesome. I just learned something new today. I just made the setting. I also reverted my charge controllers back to their maximum. I am draining my battery right now by running a load and in 15 minutes I will be able to test again. Thank you so much.

 

[WorldwideDave]

If you have a cerbo you can enable dvcc and set a global charge limit of 150A. Leave the sccs at their max rating. The cerbo will use the shunt data to allow for your sccs to power your loads in excess of 150A, while ensuring no more than 150A is available to the batteries. Basically allows you to better utilize your available solar, versus a hard limit in the sccs. A perk of a cerbo or Venus os device.

It is interesting that you can set a maximum on the charge amps and on the battery voltage, but you cannot set a maximum discharge amount through the shunt.

I believe that in my Victron Quattro, I do have the ability to set the maximum amperage… Not that I would do that.

Is that also possible in the Phoenix inverters? The ones connected with the VE direct?

 

[Brucey]

It is interesting that you can set a maximum on the charge amps and on the battery voltage, but you cannot set a maximum discharge amount through the shunt.

I believe that in my Victron Quattro, I do have the ability to set the maximum amperage… Not that I would do that.

Is that also possible in the Phoenix inverters? The ones connected with the VE direct?

Thats because the cerbo can control the sccs output for charging, while for loads it has no control over what you will place on the dc bus.

You have to understand a Victron inverter connected via ve.direct is very very basic. You can turn it on and off remotely, control the relay, and adjust the voltage set points for it to disconnect etc. It's not the same as a "real" ve.bus connected inverter. Use demo mode of victron connect to see, versus what your ve.bus inverter has available:

 

[Brucey]

What specific Phoenix are you talking about?

 

[Brucey]

There is a way to get a limited view of a second seperate ve.bus inverter using the mk3 dongle:

B

Thread 'Cerbo S with two inverters'

Oct 11, 2024

My setup includes two Victron inverters supplying separate loads (water pumps on one and house + future AC on the other) but running off the same battery bank (OPzS SOLAR 985 12v).

I can use the Victron app to see both these inverters when connected by Bluetooth.

I now want to add a Victron CERBO GX (or preferably a Victron CERBO S GX) to access this information when not present.

My question is whether the CERBO will accept two inverters. I have seen conflicting information on this. I’m not interested in the touch screen option.

Also, as I don’t want to monitor water tanks or...

• bigBW
• Replies: 4
• Forum: DIY Solar General Discussion

 

[WorldwideDave]

Thats because the cerbo can control the sccs output for charging, while for loads it has no control over what you will place on the dc bus.

You have to understand a Victron inverter connected via ve.direct is very very basic. You can turn it on and off remotely, control the relay, and adjust the voltage set points for it to disconnect etc. It's not the same as a "real" ve.bus connected inverter. Use demo mode of victron connect to see, versus what your ve.bus inverter has available:

View attachment 289534

Remember that right now all I have is a non-Victron inverter connected to my largest set up. So for me to have the ability to see you when it is inverting and see the ac load would be great. Plus, let’s not forget the fact that you have an ability to remotely turn it on and off. That is huge. The inverter that I have right now does not support a relay, and it’s not worth buying a big solenoid and a relay just to do that.

 

[WorldwideDave]

There is a way to get a limited view of a second seperate ve.bus inverter using the mk3 dongle:

B

Thread 'Cerbo S with two inverters'

Oct 11, 2024

My setup includes two Victron inverters supplying separate loads (water pumps on one and house + future AC on the other) but running off the same battery bank (OPzS SOLAR 985 12v).

I can use the Victron app to see both these inverters when connected by Bluetooth.

I now want to add a Victron CERBO GX (or preferably a Victron CERBO S GX) to access this information when not present.

My question is whether the CERBO will accept two inverters. I have seen conflicting information on this. I’m not interested in the touch screen option.

Also, as I don’t want to monitor water tanks or...

• bigBW
• Replies: 4
• Forum: DIY Solar General Discussion

That’s cool, but I am only wanting to know if it’s possible with the smaller Phoenix ones right now. I’m not sure if you answered that.

 

[WorldwideDave]

What specific Phoenix are you talking about?

250w to start with. I want a 1200w.

 

[Brucey]

Remember that right now all I have is a non-Victron inverter connected to my largest set up. So for me to have the ability to see you when it is inverting and see the ac load would be great. Plus, let’s not forget the fact that you have an ability to remotely turn it on and off. That is huge. The inverter that I have right now does not support a relay, and it’s not worth buying a big solenoid and a relay just to do that.

Yes the Pheonix 48/1200 is awesome value imo for $330.

The biggest issue for me is that its basically tapped out at 1000W.

For you with a lot of 12V batteries perhaps look at the multiplus 12/1200 units. These have ve.bus and can be paralleled for additional ac amps. And integrated transfer switch and ac charger.

 

[Brucey]

That’s cool, but I am only wanting to know if it’s possible with the smaller Phoenix ones right now. I’m not sure if you answered that.

I don't know what two 12/300s connected via ve.direct look like in vrm. But you cannot parallel their outputs together they would be seperate standalone circuits.

There's is the 12/500 and 12/800 multiplus also now available in the US or soon will be, if you want to parallel to a larger capacity.

 

[WorldwideDave]

I don't know what two 12/300s connected via ve.direct look like in vrm. But you cannot parallel their outputs together they would be seperate standalone circuits.

There's is the 12/500 and 12/800 multiplus also now available in the US or soon will be, if you want to parallel to a larger capacity.

Yeah, there is no intention to power, a panel or parallel any operations that I can think of. The little Phoenix device has a receptacle on it that I could plug to electric bike chargers into it. And the battery is full. I could tell the inverter to turn on and charge the bikes. I could use a second inverter connected to the same busbars as the other one to run LED shop lights. I could turn the inverter on and off remotely, which would be awesome. I could use another one to power POE hub and POE security cameras, which would have a very minimal draw. There would probably be extension cords running all over the place. But I have conductors, I have an extra cerbo GX, and I’ve got extra battery sitting around.

I know what these systems look like when you have them all independent of each other. I’m hoping that because I have a large bus bar that has eight positions on it, I can just attach another Phoenix inverter to it and run different stuff. I can attach four devices to my Cerbo GX. so why not experiment and learn more.

I’m gonna run out and buy two of the smaller ones just because I can. I will find out what the limitations are.

 

[Brucey]

Yeah, there is no intention to power, a panel or parallel any operations that I can think of. The little Phoenix device has a receptacle on it that I could plug to electric bike chargers into it. And the battery is full. I could tell the inverter to turn on and charge the bikes. I could use a second inverter connected to the same busbars as the other one to run LED shop lights. I could turn the inverter on and off remotely, which would be awesome. I could use another one to power POE hub and POE security cameras, which would have a very minimal draw. There would probably be extension cords running all over the place. But I have conductors, I have an extra cerbo GX, and I’ve got extra battery sitting around.

I know what these systems look like when you have them all independent of each other. I’m hoping that because I have a large bus bar that has eight positions on it, I can just attach another Phoenix inverter to it and run different stuff. I can attach four devices to my Cerbo GX. so why not experiment and learn more.

I’m gonna run out and buy two of the smaller ones just because I can. I will find out what the limitations are.

Depending on your range requirements consider the ve.direct smart dongle that you can attach to a ve.direct pheonix, will give you same control you would get thru victron connect. If you run into issues with two of them in same vrm.

 

[WorldwideDave]

Depending on your range requirements consider the ve.direct smart dongle that you can attach to a ve.direct pheonix, will give you same control you would get thru victron connect. If you run into issues with two of them in same vrm.

May need to circle back to that. I’m gonna go ahead and get two of them and see what I can find out.

 

[WorldwideDave]

If you have a cerbo you can enable dvcc and set a global charge limit of 150A. Leave the sccs at their max rating. The cerbo will use the shunt data to allow for your sccs to power your loads in excess of 150A, while ensuring no more than 150A is available to the batteries. Basically allows you to better utilize your available solar, versus a hard limit in the sccs. A perk of a cerbo or Venus os device.

OK, well, that did not work. I think that DVC might control the output of the solar charge controllers and limit them to 150, but I don’t think it prevents the shunt from sending more than 150 into the battery.

Both of my Victron chargers are 12 V 25 amp versions that do not talk to the turbo GX. They are both attached to their own fuse and to the appropriate busbars.

I hit over current protection, a second time.

Here are photos showing that I had drained the battery down to 0% state of charge and everything was turned off. And then flip on the PV disconnects, 126 A comes in through that, then I plug in the Victron chargers, one at a time And at one point I saw it hit almost 180 A.

So I think DVC is only limited to controlling the devices that are connected to the Cerbo, but the shunt itself has no way to prevent overcurrent from coming in from a different source.

I am purely guessing when I say this, but I bet that some of the newer, bigger, chargers that can connect with VE.direct, the DVC function would work as it is intended.

I also wouldn’t be surprised if it works with my Orion XS dc to dc.

 

[Brucey]

Yes my apologies I should have clarified, dvcc can only control global charge limit with victron sccs connected via ve.direct or ve.can. it can't control other random dc chargers.

 

[WorldwideDave]

Yes the Pheonix 48/1200 is awesome value imo for $330.

The biggest issue for me is that its basically tapped out at 1000W.

For you with a lot of 12V batteries perhaps look at the multiplus 12/1200 units. These have ve.bus and can be paralleled for additional ac amps. And integrated transfer switch and ac charger.

My friend got a 12 V 3000 VA multi plus available, used, it’s not the version 2. He bought it for his boat and never installed it. It is new in a box and looks great.

What is a good price I should be offering for that device? I don’t know if you can still buy them new in the US or not.

 

[Brucey]

My friend got a 12 V 3000 VA multi plus available, used, it’s not the version 2. He bought it for his boat and never installed it. It is new in a box and looks great.

What is a good price I should be offering for that device? I don’t know if you can still buy them new in the US or not.

I would look at current connected member pricing and then at the very least take 30% off for the lost tax credit as its used and not eligible?

 

[WorldwideDave]

Yes my apologies I should have clarified, dvcc can only control global charge limit with victron sccs connected via ve.direct or ve.can. it can't control other random dc chargers.

Even if that random DC charger is a Victron.

Is there a low cost AC to DC Victron charger that supports VE direct? Or VE bus? Preferably that was programmable with time of use?

I have left the DVCC settings enabled just in case we have some weird solar flare or something. Also, if I’m getting around 126 A from just the panels I have installed, once I put the next two arrays up, which is another 14 panels, I will definitely be hitting 150 A on the regular. lol.

 

[Brucey]

Even if that random DC charger is a Victron.

Is there a low cost AC to DC Victron charger that supports VE direct? Or VE bus? Preferably that was programmable with time of use?

I have left the DVCC settings enabled just in case we have some weird solar flare or something. Also, if I’m getting around 126 A from just the panels I have installed, once I put the next two arrays up, which is another 14 panels, I will definitely be hitting 150 A on the regular. lol.

Some units support dvcc, this dc to dc one for example:

Orion XS 12/12-50A DC-DC Charger

The Victron Energy Orion XS 12/12-50A DC-DC Charger redefines adaptive DC-DC battery charging in dual battery systems with an intelligent alternator.

battlebornbatteries.com

 

[WorldwideDave]

I would look at current connected member pricing and then at the very least take 30% off for the lost tax credit as its used and not eligible?

Yeah, it looks like member pricing is $930.
I take that back… Current connected only sells the newer Multiplus 2 models now.

Yeah, so around 600 bucks at the most I would say.