Hi guys can i use a victron mppt charge controller with a mecer 5000 kva inverter to increase my the amount of solar panels on the roof ?

39 minutes ago, vulgrim said:

Hi guys can i use a victron mppt charge controller with a mecer 5000 kva inverter to increase my the amount of solar panels on the roof ?

Yes you can, just make sure the Charge voltage settings match and remember the voltage readings between Victron and the Mecer would differ a bit, so take that into consideration when you do the settings. Both chargers must aim to achieve the same results an if the difference in readings are to big, the one charger will do all the work and the other one will just be sitting there. 

2 hours ago, vulgrim said:

Hi guys can i use a victron mppt charge controller with a mecer 5000 kva inverter to increase my the amount of solar panels on the roof ?

Many many years ago Morningstar was the first to say yes for 2, or more, controllers on the same bank BUT (and this they stressed) the two must be identical ito make and model and the settings must be identical. See here: https://www.morningstarcorp.com/parallel-charging-using-multiple-controllers-separate-pv-arrays/

So I tried two Victron MPPT's, same logic ito firmware, but different models on different facing arrays. I did not get that warm fuzzy feeling over time that the two where doing their utmost best. 🙂 

Using two different makes, I would not do that on the same bank because the firmware between the two are different, even if you can set the settings identical, so in the end it MAY affect the batteries over time. 

Ps. Thinking of the "floating bug" that Axperts have, what else is there that could be different?

That is MY opinion.

I quote a few response from Google:
Quote 1: Yes, multiple charge controllers can be used on the same battery bank.  Multiple charge controllers are used in situations where a single charge controller is not able to handle the entire output of a large solar array.  When multiple charge controllers are used, communications cables connect the charge controllers, and help them work in unison.

Quote 2: And see here for more info, this BB guy is seriously jacked: https://forum.solar-electric.com/discussion/337940/two-mppt-controllers-serving-one-battery-bank

I think that for the most part the concern about "one controller just sitting there" is overblown.

If you have two chargers on the same bank, even if they are from the same manufacturer (and barring special network capability), one will always stop charging before the other. There will always be a minute difference in calibration between two devices, and even if it is just 50mV, it means the one measuring lower will eventually (towards the end of absorption or at float) do all the work with the other one just sitting there.

I do not consider this a problem though. What does it matter if the work isn't split 50/50? The batteries are full, your loads are covered, and you are not significantly extending the life of either controller by spending all that effort to force them to split the work.

With that said, it is however true that sometimes the calibration can be significantly different. I've seen some cheap Chinese PWM controllers that are out by 0.8V! It is a good idea to carefully monitor how the split comes across, and if your larger array tends to drop out first (assuming they are not the same size), then rather up the charge voltage by 0.1V to make sure that one keeps going a bit longer.

Also adding to what tripplet said, some controllers can be networked, and then they all take their cue from the master and charge in unison. Victron Smart Solar models can do this for example (using bluetooth).

Edit: Thinking about it, there is one issue that might be a concern. Charge controllers usually time how long they are in absorb before they go to float. If the calibration difference is sufficiently different, one charger might think that absorption has been reached (and start counting down towards float) while the other one thinks it is still a little bit away from reaching that critical voltage and hasn't started counting yet. One of them will go to float sooner than the other. Again, this is not too much of a concern: At least one of the chargers has deemed the battery full enough to back off. As long as both of them are sort-of right, you're not doing any damage.

Edited June 23, 20197 yr by plonkster

11 hours ago, plonkster said:

I think that for the most part the concern about "one controller just sitting there" is overblown.

Not overblown at all sir. With my last two inverters in parallel, same make, same batch and same firmware, the one reported 0.7 volt more than the other one and that one did about one 3rd of the work and daily production. When I countered for that by increasing its bulk and float voltage settings by 0.7 volt on this unit, the work was shared a lot more equal. On the other side it was more visible under low load condition, any load that dropped the volts a bit during cloudy days for example, the second one would come to life quickly and try to add the shortfall. 

On another client installed system with 2 completely different  mppts, the client was face with a similar situation where the Victron Mppt was doing basically all the work, the other MPPT reported 1.7 Volts more than the Victron, I played around with the settings until both of them was "Indicating" bulk and float simultaneously for most of the time. It wasn't perfect but a lot closer than when i was asked to help.  

EDIT: Now that I sit and think about it, the voltage issue might not have been the only reason for what i have experienced, there is so many factors that could have played a role and how big a role the voltage thing played, will be impossible to determine now.  All that i know is compensating for the voltage difference improved the overall operation.  

15 hours ago, vulgrim said:

charge controller with a mecer 5000 kva

One question that none of us asked, and I thought about now, What battery's do you use? If it is a system that uses a BMS, I would personally not mix chargers...