I just bought this inverter with two new pylontech UP2500 batteries (24v eac).

 

The inverter is connected to a generator and solar panels which produce around 140V and 25Amp.  I´ve set the SUB in program 1, pylontech in program 5 and program 16 in SNU . As I understand the manual more changes in setting. this is off grid system.

Problem is that the inverter doesnt charge the batteries. It recognizes the volt on the generator and with the PV it reflects V and Amp. but if i go the menu of charging batteries: nothing. the light of charging is flashing but it doesnt charge anything in the batteries. However yesterday with the generator and the PV i put the inverter in the standby mode and suddenly it charged. when I put it on, it stopped charging. Someone has a clue on which setting I have to change to get the batteries charged in the on mode? Thanks in advance

15 hours ago, nicolaasP said:

I just bought this inverter with two new pylontech UP2500 batteries (24v eac).

Are the battery modules in series for a 48V inverter, or in parallel for a 24V inverter? I don't believe that you are supposed to put Pylontechs in series.

15 hours ago, nicolaasP said:

solar panels which produce around 140V and 25Amp.

That sounds too low for a VM III model. Perhaps wire all the panels in series.

Hi Coulomb,

 

Thanks for your reply. the batteries are in parallel so 24V. Regarding too low: the manual says only requirement for minimum voltage 120 nothing about amps.  

the panels are kyocera -kc130ght-2 and all already in serie. (8x 17.6V=140V). 

As said,  the inverter recognizes the panels, states voltage, amps (23.8) and watt (2.75kwh) as shown in the attached pics. If I go to the battery state it shows PV but nothing as amps or watt.  In 1 day the axpert registers 11 Kwh. 

the weird thing is that with the inverter on, it doesnt charge anything in the batteries (allthough the led on the axpert (sun symbol)  is blinking as if it charges the batteries)but the voltage in the batteries doesnt go down either, which I would expect as the inverter uses energy aswell . However the axpert in standby with generator on and Pv does charges 50amp in the batteries, but if I switch it on, directly it stops charging (even without loads connected via AC out).

On 2021/06/02 at 8:38 PM, nicolaasP said:

the panels are kyocera -kc130ght-2 and all already in serie. (8x 17.6V=140V). 

Ah. It's unusual to use 12 V nominal panels on an inverter this size. They are also unusually high current panels; often models like yours have a strict 18 A PV current limit. But you seem to be getting away with that at present.

I note that the PV startup voltage is 150±10 V, so it could be as high as 160 V. Perhaps you need an extra panel or two to get things started in battery mode.

On 2021/06/02 at 8:38 PM, nicolaasP said:

it doesnt charge anything in the batteries (allthough the led on the axpert (sun symbol)  is blinking as if it charges the batteries)

I assume that you mean the green CHG LED is flashing; that indeed means it's in bulk or absorb charging stage, and yes, it should be charging the battery. i believe that the symbol to the left of that LED isn't meant to indicate "sun", merely that the LED is on/lit.

On 2021/06/02 at 8:38 PM, nicolaasP said:

but the voltage in the batteries doesnt go down either, which I would expect as the inverter uses energy as well .

That sounds like it's charging the battery enough to balance the loads, so that the net current into/out of the battery is zero, or close to it. Sorry, I can't think why it would do that, unless it's something to do with your panel voltage being marginal. I note that from your photos above, the PV voltage must be 2750 W / 23.8 A = 116 V, which is just under the rated minimum MPPT voltage (120 V). Maybe that's confusing things.

When it switches to battery mode, perhaps the start-up condition for the PV charger is slightly different somehow, and your marginal panel voltage is now not enough, even though in standby mode it is. The "bus" voltage (the voltage at the input to the DC-AC inverter, which is also the voltage that the MPPT has to boost to) may be lower in battery mode.

So my bet would be that you just need more panels; most of the time, just one more would probably do.