Feature Request: limit total network output current of parallel running MPPT chargers

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question

clh asked Nov 12, '23

Feature Request: limit total network output current of parallel running MPPT chargers

Hi,

hope someone from Victron reads this post. :)

I am running 4 MPPT 250/100 in parallel to charge a small bank of 12V LiFePo4 batteries. Unfortunately the battery bank can handle only around 200 amps current while charging, so I had to limit each MPPTs current to 50A.

Each of the MPPTs is connected to a single string on the roof. 2 strings are oriented eastwards and 2 strings westwards giving me a nice output throughout the whole day.

It would be extremely helpful to have a setting somewhere to limit the current of all 4 MPPTs in total. With such a setting I could remove the 50A limit on my chargers and yield a lot more energy in the morning and evening hours.

I tried to implement this myself with pyhton scripts (monitor the output of the chargers and modify their individual current limits every couple of minutes)

It worked but I decided not to use the scripts anymore,because I dont know what kind of technology is used in the chargers to store settings. I assume it will be something with a limited number of write cycles…

@Victron: Can you give me some Info on this? Is it safe to constantly update charger settings?

Comments, feedback, ideas appreciated!

regards,

Chris

MPPT Controllers charge current limit

2 |3000

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Answer 1 · 2023-11-12T16:39:04Z

nickdb answered · Nov 12, 2023 at 04:39 PM

Wire them all to a GX, enable dvcc and set a charge current limit..

If its a smart battery connect that to the GX as well, if not, preferably add a shunt.

2

2 |3000

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clh commented · Nov 12, 2023 at 05:13 PM

The chargers are actually connected via MK2 interfaces to a raspberry running venus os.

So in theory I could use DVCC.. but how do I guarantee that the 200 amps are never exceeded? According to the manual:

“In all situations, the maximum charge limit configured in a device itself, i. e. the Charge current limit set with VictronConnect or VEConfigure for MPPT solar chargers or inverter/chargers will still be in effect.”

Wouldn’t that mean that I have to set the charge current limit in each charger to maximum and let DVCC handle the (total) charge current. What happens if the GX (or raspberry) is unavailable for some reason (crash, software update, etc). Won’t the chargers fall back to its regular charging algorithms and start to deliver as much power as they can?

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nickdb ♦♦ clh commented · Nov 12, 2023 at 06:20 PM

The lowest of the two is honoured.

It just works, unless you enable dc feed in.

Raise the mppt limits and let dvcc control charge.

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