Hi

All the Axpert Inverter i get or i will get won't let you go under 44V to go back to grid.

This is ok when you are using lead acid battery but not with Li-Ion battery

I'm using 13S packs and with this setting, i only discharge my cells to 3.38V

3.2V should be a good setting for the li-ion cell, so i would like to apply 41.6V on my axpert but impossible !!!

I'm using 43.2kWh pack, with this setting i'm losing capacity.

I know, i should build 14S pack but at the begenning i didn't know the setting of Axpert Inverter.

I know too that with this setting i will have my pack secure in the time life.

So i ask me if it's not possible to modify the firmware or ask to axpert support to have this setting avaible ?

Thanks

 

 

 

41 minutes ago, bib60 said:

Hi

All the Axpert Inverter i get or i will get won't let you go under 44V to go back to grid.

This is ok when you are using lead acid battery but not with Li-Ion battery

I'm using 13S packs and with this setting, i only discharge my cells to 3.38V

3.2V should be a good setting for the li-ion cell, so i would like to apply 41.6V on my axpert but impossible !!!

I'm using 43.2kWh pack, with this setting i'm losing capacity.

I know, i should build 14S pack but at the begenning i didn't know the setting of Axpert Inverter.

I know too that with this setting i will have my pack secure in the time life.

So i ask me if it's not possible to modify the firmware or ask to axpert support to have this setting avaible ?

Thanks

 

 

 

Victronics  don't care about your needs. They have done the design and that's it. As lithiums gets used more in all parts of the world they surely would adjust. There are many parts of the world where having an inverter even on LAcid puts you in the upper bracket.

We is SA like to have the best around even if not always needed.

Edited July 31, 20223 yr by Scorp007

Victron ???

16 minutes ago, bib60 said:

Victron ???

Simple spell checker 🤔🤔🤔 Now corrected a few seconds before your post.

Edited July 31, 20223 yr by Scorp007

21 hours ago, bib60 said:

All the Axpert Inverter i get or i will get won't let you go under 44V to go back to grid.

All but the earliest models can't even produce a sine wave from 48.0 V, so the clipping at 44.0 V would be horrible.

There are other reasons to keep the number of options for settings like this small: they compress several settings into 8-byte CAN bus packets to send between master and slaves. So it's not just a matter of changing a few constants and recompiling.

I don't understand your answer ?

My Axpert Max 7.2kW can produce 230V correctly ( i didn't check the sinusoidal ) with 44VDC from battery before to come back to grid.

It's the material inside the inverter who can't produce 230V if voltage is under 44VDC and not only the setting inside the firmware ?

Thanks

 

Edited August 1, 20223 yr by bib60

2 hours ago, bib60 said:

My Axpert Max 7.2kW can produce 230V correctly ( i didn't check the sinusoidal ) with 44VDC from battery

See clipping.

2 hours ago, bib60 said:

It's the material inside the inverter who can't produce 230V if voltage is under 44VDC and not only the setting inside the firmware ?

Yes, it's the fact that they changed to a 1:7 turns ratio transformer. That's not something you can work around with settings. All because of Trojan flooded lead-acid batteries that almost nobody uses any more.

On 2022/08/01 at 9:59 AM, Coulomb said:

All but the earliest models can't even produce a sine wave from 48.0 V, so the clipping at 44.0 V would be horrible.

That makes me worried, it's an horrible flaw. It means that we no longer can install new Voltronic inverters with 48V batteries. But 48V is an industry standard in the telephone world, many standard battery packs are made for 48V.

And there is still another aspect to it. 48V is within the small voltage, non dangerous range. Dangerous low voltage range starts at 50V, goes up to 999V. Therefor low voltage installation regulations apply for 64V batteries. That may be more costly. If I had to go up to low voltage, I rather go for 96V, I could then use 2 standard 48V packs in series.

I have the same issue with my Aexpert. It connects to grid on 44V, but I have a Li-ion 13S, so I am losing around 20 to 40% of my capacity. My batteries have their own BMS, so I thought to put a DC-DC step up converter, so it will keep the voltage over 44V, and the BMS itself will cut the output on set voltage to keep the batteries safe.

I only found something like this in Victron Orion-Tr 48/48-8, that keeps the output voltage on 48V but the load capacity is only 8 Amps, so I need to install at least 10 units in parallel.

Does anybody know if this will work or if are alternatives with more load capacity in the market?

Hope the idea helps to find some solution to our problem.

Hi

It will be very expensive, for myself i will need 20 units !!!!!

The best way will be to add 1S Li-Ion battery with the same capacity of your battery to your pack and to change your BMS to 14S model

For myself, i will need 300 new cells and new BMS !!!

Or to find better inverter that accept to go under 44V but like Coulomb has said, at 44V it's very hard to have good sine wave

Thanks

On 2022/09/03 at 1:21 PM, vprieto said:

I have the same issue with my Aexpert. It connects to grid on 44V, but I have a Li-ion 13S, so I am losing around 20 to 40% of my capacity. My batteries have their own BMS, so I thought to put a DC-DC step up converter, so it will keep the voltage over 44V, and the BMS itself will cut the output on set voltage to keep the batteries safe.

I only found something like this in Victron Orion-Tr 48/48-8, that keeps the output voltage on 48V but the load capacity is only 8 Amps, so I need to install at least 10 units in parallel.

Does anybody know if this will work or if are alternatives with more load capacity in the market?

Hope the idea helps to find some solution to our problem.

This seems like a total mismatch of the battery bank for the inverter based on the fact that the inverter was designed with lead acid batteries in mind. One would not want lead acid to go below 11-11.5V per battery.

Converters too expensive for the currents needed. If a DIY battery then as per suggestion by bib60. If not then a more suited inverter or other battery.

Hi

What about to add  Li-Ion Battery to your pack to get 14S pack ?

Each pack is self protected.

It's 10.000mAh so for my pack (900Ah) i will need 90 cells like this, so 640 euros.

It will be less expensive for you

Is it good idea ?

Thanks

 

 

52 minutes ago, bib60 said:

It's 10.000mAh so for my pack (900Ah) i will need 90 cells like this

I would check that math a bit more closely.
90 cells in 14s6P configuration only going to give you about 60AH not sure how you get 900AH?

EDIT: Never-mind, I see what you mean. You want to add 1x90p to your existing 13s pack?

Edited September 4, 20223 yr by WannabeSolarSparky
correction

Yes you are right, just adding 1S90P to my existing pack 😀