How do I limit battery charge current, without limiting PV to Loads?

Question

question

kradenko asked Dec 26, '19

How do I limit battery charge current, without limiting PV to Loads?

Hi all,

I have gone through a few posts and am still not able to find a answer to match my question.

I have the following setup:

1 x MultiPlus-II 48/5000/70-50
1 x SmartSolar 250/100 MPPT controller
6 x 405W Canadian Solar Solar Panels (Connected 3 x 2) (Theoretical limit should be 2430W)
4 x 120Ah Deep Cycle Batteries (20A max charge current)
1 x VenusGX Controller
1 x BMV 712 Monitor

At this stage it is a pure DC solution. Mains will be connected once an electrician can be found.

My problem is this. I have set the max charge current on the MPPT to be 20A as this is the max the batteries can take. But what it is doing now is limiting the overall solar input. How do I limit the charge to the batteries but still allow excess solar to feed the load?

Multiplus-II MPPT Controllers Solar Panel

2019-12-26-2.png (42.3 KiB)

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Modifications Space

Node Red Space

Answer 1 · 2019-12-26T11:16:43Z

Matthias Lange - DE answered · Dec 26, 2019 at 11:16 AM

This is how it works.
If you set the MPPT charge current to 20A you will get max 20A from the MPPT.

I think what you want is not possible with your setup.

It should be possible if you use an AC-coupled PV-Inverter at AC-Out of the Multi and setup a max. charge current in the settings of the Multi.

Edit:
Yes, DVCC maybe can solve your problem. I'm currently looking into it myself too.

Edit2:
After a quick read through point 4.4.1. in the manual @JohnC posted, I think this will work for you.
Set the MPPT charge current to 100A, activate DVCC and "Limit charge current" and set the current to 20A.
So you will charge the batteries with max. 20A and the excess solar power will be used for your AC-loads.

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Answer 2 · 2019-12-26T11:25:15Z

JohnC answered · Dec 26, 2019 at 11:25 AM

Hi K. I think DVCC may be what you're looking for. It's described here:

https://www.victronenergy.com/live/ccgx:start

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Answer 3 · 2019-12-26T11:39:43Z

klim8skeptic answered · Dec 26, 2019 at 11:39 AM

DVCC might enable a full 20a charge, plus some inverter use. https://www.victronenergy.com/live/ccgx:start?s[]=dvcc Fully read the manual, and use at your own risk.

4 x 120ah batteries is small for such a powerful inverter.

edited by GS - also described in more detail in this Answer.

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

question