I need to add a extra charger

DIY
, , , ,
1

Hello all!

I’ve been running my system with little to no problems whenever I’m on solar/batteries but on the (not so rare) occasions that I have to pull from the grid, the grid voltage sags a lot and I can’t have that on the load side when my pumps turn on.

I have 2x Multiplus II 48/5000 running in parallel, about 31Kw on lifepo4 cells and a 12 panel solar array (4S3P) on a 250/100 mppt smart solar.

its managed by a cerbo S GX with a 123smartBMS on the batteries.

Today I’ve pulled 11kW out of my system for a couple of moments and all running fine!

I’ve ordered another Multiplus II 48/5000 to use as a charger only: noting connected on its AC output to have a DC source without the voltage sag on the mains/grid AC (also the 3rd inverter should be my backup plan if the parallel ones somehow fail)

my question is kinda simple: can I add the inverter/charger on VE-BUS to manage it over VRM or I can only configure the charger settings and use an external relay?

I have a “spare” USB MK3 interface that I used for configuration before so if there’s no other way I could have remote control over that way but I can’t access the BMS on 2 system controllers.

I don’t need the charger to do a full 100% charge so if I don’t get any BMS communication on it I’ll run the settings to approximate do 80% SOC.

I’ll also make use of the lower cost tarif to charge when needed.

I’m not permanently grid connected due to this voltage drops my nominal voltage should be 230V and I have 118/220V on a 600W load and 187/206V on a 3000W load.

if anyone knows on how to have this on VRM please let me know. I’m a few weeks away from getting all the parts needed and the deploy time is not urgent.

3rd option, I could add a smart shunt to monitor the power input for the battery bank only on the “external” charger (but I don’t really want to add another cost here)

Details:

location: Portugal

Single phase 230V

2x MPII 47/5000
250/100 smart MPPT

123smartbms on lifepo4 31Kw 48V

2

As i keep in mind, you will have a second control panel [on, off, charger only, inverter only] for the charger MP at VRMs hamburger menue .

You need a additional MK3 for the charger MP

Details can be found in the cerbo manual, search for MK3, it is only one result

3

so its possible to add a “page” for the (inverter)charger?

I already have the MK3 that I needed for configuration on my running units so using it makes much sense.

Ive read the manual but I’ll drop my eyes on it again

4

It wont appear on the dashboard of the gx in the vrm.
You can have widgets and it is in the device list.
Is is not controlled the smae way the 'mainc system is.
You can in node red set up alot of custom control.

1 Like
5

That’s probably what you’re looking for.

ESS with MP2/3k and additional “charger” MP 800 with second MK3 interface

grafik
grafik272×974 8.95 KB

2 Likes
6

That looks exactly what I need!

I have the parts on the way and I hope to have some time to set up a stand/tripod for the charger unit. Unfortunately all my system is (? installed temporarily while I gather the money for an all new roof so there’s that…

I’ll have to get a couple more crimping terminals and a couple more fuses but that’s fine.

If I can manage do get that settings menu over vrm I’ll be delighted ^^

1 Like
7

All parts have come in and Ive put them to work!

With very little config time I have Control over the inverter/charger and I finally have a stable 230V house power since I no longer have to sink with the grid!

I’m celebrating a loss in efficiency but I can’t even care! Grid charging is only on cloudy/stormy days and somewhat temporary, I couldn’t have the voltage sag whenever grid is kinda loaded.

I plan to install a second PV array and probably double the battery capacity $$somewhere$$ down the line :slight_smile:

The information on connecting the 3rd unit over with the USB MK3 was helpful!

I’ll have some more time to deal with software and control soon. I need some automation on this since I’m doing pretty much manually (charge control)

1 Like