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Juraj Nikolov avatar image
Juraj Nikolov asked

Question about sizing battery and usage the battery.

Hi I want to ask about sizing pylontech battery and using the battery with a Victron inverter/charger.

By U3000C is the discharge and charge current 37A at one pieace.
If I plug the four batteries parralel, it is possible carge and discharge it by 148A ??? or ??? Possible output up to is 1.77kw (by 37A) and 7.1kw (by 148A) . Or if I use one EasySolar 5KVA it is possible discharge up to 70A , max. output 3.36kw ? Or the output is managed byt mppt regulator ? Then max. output is up to 100A and then is the output max 4.8kw ? And what then if I use next two mppt ? Can I discharge up to summary power mppts ?

Or how to understand it ?
What is correct ?

Next question is when I want to use 4x U3000C and 1x mppt 250/100 + 2x 150/35 (that I want to use since shading places) to use 10kwp from panels, it is there some limitation for the battery ?
Or can I use 2x U3000C ? And later buy next one or two battery module, to upgrade capacity.
It is there some limitations by PVpanels that would be overchargre the battery, or ?
If would by overcharge the battery, it is for this any solution ?

Thnaks for answers.

PylontechEasySolar All-in-One
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2 Answers
Alexandra avatar image
Alexandra answered ·

@Juraj Nikolov

With the Pylontec connected to the Victron and GX as recommended, as long as you have met the minimum size requirements for the inverter, the rest is controlled by the Pylontec through communication to the GX. So there should be no worries there about overcharging. And yes the 37A is added to the system total the more batteries you add. In fact it is the way that you check that all modules are communicating with the system.

So for a 5kva inverter you would need a battery bank that can discharge at 105A continuously minimum so for the us3000 that is three and more can be added at a later date if required for more storage (but not too much later).

On a good sized solar array there should be enough to run a system at full load and charge the battery at a decent rate, so 10kw is a good start on a 5kva system.

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Juraj Nikolov avatar image Juraj Nikolov commented ·

Hi,


thanks for response.


so if I understand correctly, the 5KVA inverter will be basically discharge the battery at 4.4-4 kw at 92A-83A, so they are recommended min. three battery blocks where each has 37A = 111A in the sum ?

Am I understand it right?


And if I use only two batteries of 74A, would it be possible to use them if I did not exceed 3.5kw on a backup?


And about charging:

if I use tre regulators, one 250/100 and two 150/35 on the busbar will be 100+35+35 = 170A , but the charger will send to battery only 70A ? Or how is this working ?


Thanks a lot.

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Alexandra avatar image Alexandra ♦ Juraj Nikolov commented ·

@Juraj Nikolov

I get asked this question alot. And have had many debates over it with many people. So there is always conflict over it

The simple answer is no. Always size for a full load nominal. The reason it not for normal useage but in case of abnormal circumstances (which cannnot be planned or expected). The inverter needs the battery to be capable of supplying the full amperage to be able to shutdown in cases of overload or fault conditions.

If the battery cannot then components fail or worse a fire occurs because the surge is not enough to blow fuses or trip anything. So things get hot and bad things happen.

With DVCC forced on by the pylotec when there are data cables connected the batteries will control production and charge to themselves.

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Juraj Nikolov avatar image Juraj Nikolov Alexandra ♦ commented ·
OK thanks
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klandos avatar image
klandos answered ·

Dvcc should be enabled in your gx and then the Pylontech will Tell your mppts the max charging current, 74A for 2 modules. Beyond 90% SoC this will decrease further.

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Juraj Nikolov avatar image Juraj Nikolov commented ·

Ok then the GX mange (after setting) the charging via mppts and BMS from pylontech.

If I good understant it ?

Thanks a lot.


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