Adding non-Victron MPPT to system & Cerbo GX / Reporting from Victron

[WorldwideDave]

Hello.
I have victron smartshunt 500, victron smartsolar 100/20, and cerbo GX.
I have non-victron LiFePO4 battery, 12V (for now).
Kill switch between battery and fuse.
From fuse to bus bar (positive). 4 post blue sea with cover.
Also have negative bus bar. 4 post blue sea with cover.

Inverter connected to bus bars.
Cerbo GX connected to bus bars.
Solar charge controller connected to bus bars.
Battery connected to the positive bus bar via the fuse for power (mentioned above), and as a conductor going to the negative bus bar.

Everything working great.

VRM shows everything all good.

I have a lot more panels, 28 in total. Using 2s2p right now for 800W max potential (over paneled). I want to charge faster, which means more amps into the battery, that supports 100 amp charging.

Off grid - not hybrid, not grid tied.

Friend gave me a 150V 75A non-Victron MPPT. it is 150V and 80A, so about 4x what my victron is right now.

I want to connect this new MPPT to my setup, while still keeping the victron 100/20.

From MPPT, postive side go to a new standalone fuse, then to the positive bus bar. MPPT negative will go to the negative bus bar. Then I'll connect the MPPT to the combiner box to get PV to the MPPT.

Anyway, a few questions:
1.) How will the new data look in victron vrm? Will I just see more current going to the shunt and the battery, but not be able to tell from where?
2.) Will my existing victron MPPT that I'm leaving connected behave any differently?

example: let's say I do 2kWh from the victron, but now I'm doing another 8 kWh from the new MPPT. Will the VRM icon for the victron MPPT still report just what that MPPT is producing? I think the answer is yes, as there is no comms taking place to this new MPPT I'll be adding.

3.) Is it a good idea to connect the fuse for the new MPPT to one of the 4 existing bus bar connection points, and if so, should it be on the same terminal post on the bus bar as the existing MPPT, or should I connect the fuse to the post in use from the battery? Should I connect it to the same one as the inverter?

Thank you SO MUCH for reading and helping in advance!

 

[rhino]

1.) How will the new data look in victron vrm? Will I just see more current going to the shunt and the battery, but not be able to tell from where?

That's correct. It will show up as amps going into the battery from some mysterious place. Only way I know of to fix that is with a second Victron shunt and configure that shunt as a "solar charger" and then will show up as such in VRM.

2.) Will my existing victron MPPT that I'm leaving connected behave any differently?

Since the Victron MPPT and other MPPT can't talk to each other they can't synchronize what they are doing. I more or less solve this by configuring my non-Victron solar charge controller to be 0.2V below the absorb setting of the Victron one. That way the Victron controller handles when to stop aborbing and doesn't have interference with the other non-Victron controller.

 

[WorldwideDave]

That's correct. It will show up as amps going into the battery from some mysterious place. Only way I know of to fix that is with a second Victron shunt and configure that shunt as a "solar charger" and then will show up as such in VRM.

Since the Victron MPPT and other MPPT can't talk to each other they can't synchronize what they are doing. I more or less solve this by configuring my non-Victron solar charge controller to be 0.2V below the absorb setting of the Victron one. That way the Victron controller handles when to stop aborbing and doesn't have interference with the other non-Victron controller.

the absorb setting of what? New to victron - tell me where to go to set that up, I presume in either my victron MPPT or victron shunt.

I like the 'add a second shunt' idea- so I would go from non-victron SCC positive to a fuse, then from fuse to the positive bus bar; with the non-victron SCC negative I would go to a new second victron smart shunt, then to the negative bus bar, and join the shunt to the environment via VE.Direct and make a change to that shunt? Thanks. Going to go look now at settings...

For the MPPT I have some battery settings posted here:
Battery voltage - 12V
max charge current - 20A
charger enabled - on
absorption voltage 14.20V
float 13.50V

So I think what you are saying is that IF I can edit the settings in the other new non-victron solar charge controller, that I should change the absorption to be 14.00V instead of 14.20.

I don't truly understand what that will do. A brief explanation would be great. I think it prevents the victron one from sending more current when the sun is out when the battery is almost full or something? Thanks.

 

[Brucey]

What battery do you have specifically?Generally speaking a 100Ah battery may have a recommended charge rate of for example 0.5C or 50A while having a discharge rate of 1C (100A).

 

[Brucey]

Oh if you have a Cerbo you can enable "Has DC system" and it will approximate your non Victron SCCs output. Not as accurate as an additional smartshunt but if you want to save $100 that's prob the way to go.

 

[HRTKD]

Instead of spending money on a second shunt, I would buy a second Victron MPPT. Together with the Cerbo GX you'll be assured that you'll never exceed the recommended charge rate of the battery.

Save the freebie solar charge controller for some other project.

 

[WorldwideDave]

What battery do you have specifically?Generally speaking a 100Ah battery may have a recommended charge rate of for example 0.5C or 50A while having a discharge rate of 1C (100A).

Sorry for delay - it is a 200 AH 12V CHINS LiFePO4. Can't find the correct manual, but found the EnjoyBot manual which looks exactly the same as a CHINS and who knows who actually made CHINS anyway - they all look similar.

 

[WorldwideDave]

Oh if you have a Cerbo you can enable "Has DC system" and it will approximate your non Victron SCCs output. Not as accurate as an additional smartshunt but if you want to save $100 that's prob the way to go.

Did what you suggested, and looks great on VRM - just shows something is producing 1.3 A and 18W. It is in the shade, an just a single 200W panel right now. It is a Pulse Width Modulation (PWM) device, and says it supports 20A, but tried it last night with 2 panels in series (volts: 30 each; amps 7.12 each) and it would not work - threw error. I think it wishes it did 20A. It's good for a single 12V panel, but not my 30V panels.

already got a third 80A MPPT (outback FM80) to test - super excited. Waiting for fuses to arrive.

 

[WorldwideDave]

Instead of spending money on a second shunt, I would buy a second Victron MPPT. Together with the Cerbo GX you'll be assured that you'll never exceed the recommended charge rate of the battery.

Save the freebie solar charge controller for some other project.

I am heading that direction. Got an outback FM80 (80A) that will support 1000W of solar max in 12V setup. So I'm excited to try that before getting the 250/100 victron. Just want to ensure my used panels all work before investing in the more expensive stuff.
Really wish victron had an all in one that contains MPPT and charger and inverter and cerbo. We call can dream right. Sounds like maybe that RS model does, but cannot remember.
I am picking up a quattro on monday, new in box, from a friend who bought it a year ago and hoped it would fit on his sailboat (it doesn't). He bought a skinner MultiPlus II instead, and is selling it to me at half price.
I will then have to hold onto it for a while until I can afford a 48V battery.
I know everyone recommends buying it all at once at 48V the first time. I was given a lot of gear and have been playing around with it all for about 9 months. I've learned alot. The panels were a big investment of time and money - racking cost more than panels, let's put it that way. I am still recovering from the physical labor of installing the racking and putting the panels up.

 

[HRTKD]

I am picking up a quattro on monday, new in box, from a friend who bought it a year ago and hoped it would fit on his sailboat (it doesn't). He bought a skinner MultiPlus II instead, and is selling it to me at half price.

That's funny. I bought my Quattro because it fit when the Multiplus wouldn't. In my case, height was the issue. A Quattro at half price is nice!

 

[WorldwideDave]

That's funny. I bought my Quattro because it fit when the Multiplus wouldn't. In my case, height was the issue. A Quattro at half price is nice!

Thanks Jim. A bit undersized for me, but I don't have all my panels up yet. Thanks for all you do here on the forums.

 

[WorldwideDave]

Oh if you have a Cerbo you can enable "Has DC system" and it will approximate your non Victron SCCs output. Not as accurate as an additional smartshunt but if you want to save $100 that's prob the way to go.

Well, maybe not such a good idea to go that way. Works and reports great with zero loads...but once my inverter fired up and the pool pump and heater started, I don't love what it is displaying...open to suggestions.

It is showing discharge at 255W, but DC power at 512 W and current at 39.8A. someething is not right. The shunt is saying 20 amps or so discharge which would be close to 255 watts, but PV is also doing 257 w. Animation is showing that the DC power is at 512 W with it flowing towards the DC power. While I do have a battery, the purpose was to show the 2nd SCC's output. Once loads running, doesn't seem to? There is no way my tiny 20 amp PWM - which I can only get to work with just one panel that is rated at 8.6 IMP - can be handling 39.8 A of current. See photo above which shows just 1.3 A and 18 W an hour or two ago.

Thoughts?

 

[WorldwideDave]

That's correct. It will show up as amps going into the battery from some mysterious place. Only way I know of to fix that is with a second Victron shunt and configure that shunt as a "solar charger" and then will show up as such in VRM.

Since the Victron MPPT and other MPPT can't talk to each other they can't synchronize what they are doing. I more or less solve this by configuring my non-Victron solar charge controller to be 0.2V below the absorb setting of the Victron one. That way the Victron controller handles when to stop aborbing and doesn't have interference with the other non-Victron controller.

Found the manual for my 2nd PWM online at:
https://cdn.shopify.com/s/files/1/0...harge_Controller_user_manual.pdf?v=1696672221
Screen shot says 14.4 - see photo screen shot and confirm I'm reading that right for LiFePO4 battery.
If correct, you're saying to set the victron SCC to be at 14.2?
on the Victron 100/20, I can see under the battery settings that they are user defind, and absorption voltage is 14.20 V and fload voltage is 13.50 V and equalization is disabled because of the Lithium setting. Does that sound right?

 

[WorldwideDave]

for what its worth, I did try running this cheap PWM SCC for about 2 days, then ripped it out, re-did my wiring, and installed the Outback FM80 to a new victron shunt (2nd in the setup) so I can read what the MPPT is actually producing. Not great, but better than the 20 A PWM that could only handle 5-7 A max, and it was getting hot. Fire risk = garbage pile. I did program the FM80 to match the victron 100/20, so all is good there.

Along the way I have figured out how to reduce the amps flowing from the two MPPTs to the bus bar and into the battery through the fuse and kill switch: Run a load. I have a pool pump on a schedule so that when it is peak sunshine/amperage around 11 AM, I already have the pool pump running since 9:30 AM draining the battery in low sun conditions. This means that during peak sunshine, the amperage goes from the sun/PV/MPPT/Fuse/Bus Bar to the fuse/inverter/subpanel/loads, thus reducing the amps going to the battery.