I have 30kw pv. I have 16 units of US3000C Pylontech batteries total of 56kwh.

I have a three phase AC installation.

The system is OFF-GRID. NO feed into the grid.

I am in doubt if I should buy two units of the MPI-10kw or 4 units of the PIP-8048MAX.

I am sure that both of the models can do what I want, but I am in doubt if you guys have some recommendation or experiences that you can share.

Thank you.

Jesper Friis
St. Vincent and the Grenadines
 

9 hours ago, Jesper said:

I am in doubt if I should buy two units of the MPI-10kw or...

? Why buy grid tie inverters if you don't have a grid?

Also, the reliability of the hybrid (Infini / MPI) seems lower than that of the off-grid models, without researching it thoroughly.

Of course, the Axpert/PIP MAX are a fairly new model, so there are likely to be teething issues.

The MPI can do off-grid and feed into the grid and the PIP-Max can be off-grid but not feed into the grid, so yes I don;t need the function from the MPI to feed into the grid, but beside this extra feature from MPI are there other advance with this inverter vs the PIP-Max?

You say that the PIP-Max is a newer inverter model and therefor could have more issues. Do somebody know about such issues?

But you also say that the MPI has reliability issues compared to the off-grids models. Dos that include the PIP-Max's? Does anybody knows more about these reliability issues?

The prices on two MPI10kw is about the same as four PIP 8048MAX. Also both models as direct BMS communication with Pylontech.

Anybody else has advice or experiences with these two modes or input which of the two models I should go for?

Thanks

Jesper

On 2020/12/16 at 11:06 AM, Jesper said:

You say that the PIP-Max is a newer inverter model and therefor could have more issues. Do somebody know about such issues?

I'm not aware of any problems other than needing to update firmware to fix niggling bugs. Just that in general, "version one" of anything tends to be less reliable than the same thing with most of the bugs worked out of it.

2 minutes ago, Coulomb said:

I'm not aware of any problems other than needing to update firmware to fix niggling bugs. Just that in general, "version one" of anything tends to be less reliable than the same thing with most of the bugs worked out of it.

Okay, thanks for your input!

Jesper

I have the PIP7248MAX and the PV input is the same as the 8048 (2 x 4000W) with the same voltage range for MPPT and it work better than for exemple the PIP5048GK it begin to work with 80V from PV the only problem is that feedin power to the grid 

You say it feeding power into the grid! Is that the 7248 model?

That is dangerous for the utility line people!!

How can an off grid inverter feed power into the grid? Is it not an automatic transfer switch/relay, which open/close the connection to the AC input? That must be a fundamental design fault!

Jesper

1 hour ago, Jesper said:

How can an off grid inverter feed power into the grid?

They synchronise the AC-out to AC-in, and configure the inverter as a battery charger (operate the inverter in reverse) for utility charging. AC-in is connected to AC-out in this mode, and so the inverter's output is in parallel with the utility. In this mode, it's possible to accidentally push a little energy into the utility, especially when the required battery charge power drops suddenly.

Some models actually attempt to blend AC-in and PV power; again, when a load drops off, too much power is sent briefly to AC-out, and there is nowhere for that power to go except back into the utility. These models may send higher power (but again only briefly) to the utility.

it not only briefly sending power to the utility it was peaking at over 1kw and constantly between 250-350 watts with a battery not fully charged, i only use it for 3 months in battery mode only (SUB mode) because inverter need big VA (1560 VA) if not enough power from solar.

If the utility is down inverter switch to battery mode (from SBU to SUB)

Edited December 19, 20205 yr by KJM

45 minutes ago, KJM said:

it not only briefly sending power to the utility it was peaking at over 1kw and constantly between 250-350 watts with a battery not fully charged, i only use it for 3 months in battery mode only (SUB mode) because inverter need big VA (1560 VA) if not enough power from solar.

If the utility is down inverter switch to battery mode (from SBU to SUB)

What do you mean that the inverter needs big VA (1560 VA)?

Please explain the SBU and SUB mode?

Thanks

Jesper

In france whe have the neew utility meter (LINKY) and it display not the Watts but KVA and it count a part of KVA and add it to watts used.

SBU mode is solar and battery and if not enougth solar  and battery is to low it switch to utility.

SUB mode is solar + (utility if not enougth solar) and switch to battery if no solar and no utility.

Inverter is disconnected from utility and I use it only with solar and battery

Edited December 19, 20205 yr by KJM

I did't get this about that the Inverter needs 1.560 KVA. (Kilo Volt Amp)

Thanks for the SUB and SBU mode explanation.

Jesper

23 hours ago, Coulomb said:

They synchronise the AC-out to AC-in, and configure the inverter as a battery charger (operate the inverter in reverse) for utility charging. AC-in is connected to AC-out in this mode, and so the inverter's output is in parallel with the utility. In this mode, it's possible to accidentally push a little energy into the utility, especially when the required battery charge power drops suddenly.

Some models actually attempt to blend AC-in and PV power; again, when a load drops off, too much power is sent briefly to AC-out, and there is nowhere for that power to go except back into the utility. These models may send higher power (but again only briefly) to the utility.

Should I understand that it is only in the SUB mode that the problem with the feed in to grid problem occurs, meaning that if the inverter is configured in SBU mode, this will not happen?

Jesper

13 hours ago, Jesper said:

Should I understand that it is only in the SUB mode that the problem with the feed in to grid problem occurs, meaning that if the inverter is configured in SBU mode, this will not happen?

I don't have one of these inverters, and this part of the firmware isn't clear to me, but yes it is my understanding that blending of PV and AC-in only happens in SUB mode, so the larger amounts of feed-in will happen only in SUB mode.

Having said that, I believe that if you have a really strict, trigger happy meter that won't stand for more than a tiny amount of feed-in, you could still trip it in SBU mode.