Shoto 48V 100Ah 4.8kW batteries

[Denarius]

10 hours ago, Francois Raath said:

Does anyone know if there is a setting and or ability of the Axpert inverter so as to limit the amps drawn from the battery so as to protect it against too rapid discharge and shortening its lifespan? The recommended standard discharge rate is 0.2C and rapid discharge rate is 0.5C (0.2C for 4.8kW/48V battery is 20 Amps and 0.5C is 50 Amps)

I don't see such a setting in the manual and also don't see it listed in solar assistant:

[SuperStan]

Hi Guys,

Sorry for the side entrance, but we have a similar system as this thread/subject. 

I've installed a Axpert King 5kW inverter with 1 x Shoto 48V 100Ah as backup system for my Dad. For some reason the battery is tripping when we start the inverter up. There is no load on the inverter and also no PV. You hear the fan for a split second before all shuts down. The manual shows some kind of rectifier to activate the battery if it was dormant for more than 24 hours. Any advice will be appreciated. 

[nightbyte]

Good morning SuperStan,

I would like to suggest, as a first step to identifying the cause of the problem that you do the following: 

Disconnect the battery leads at the battery and measure (with a multi-meter) the battery voltage. It should be above 40 to 43 volts.

If not, the system will display symptoms as you describe and you will need to charge the battery.

If you do not have a solar input you will need to return the battery to the supplier to charge up or perhaps take it to a friend or a Forum member who stays near you to place on charge from their system.

If the battery will not take a charge return it to the supplier as the problem is in the BMS.

If however the battery state of charge is above the BMS cut-off voltage then the fault lies within the inverter. Check your connections to the inverter and if correct and system continues to shut down, return the inverter under guarantee to the supplier for repair.  

I am not an expert on these systems, however this is how I would approach this problem.

Please post your results to this Forum topic thread, so that we can all gain from your experience, good luck - Nightbyte.

[nightbyte]

SuperStan what is you location?

[SuperStan]

I'm in pretoria, but my Dad and the installation is on the lower south coast, Palm Beach, KZN. He has disconnected and measured the voltage as 48V. This makes sense, because this was the shut off voltage setting as we previously drew the battery down below 40V and had to send it back to the suppliers.

The tripping issue also happened on a previous occasion when the battery was fully charged, but with a few tries I got the inverter started.

[SuperStan]

Hi Nightbyte,

Okay so we got the inverter on again and it is charging up. There where two issues.

The first is that our AC supply to the inverter was on. Yip I know, not to bright from our side.

Seconly for some reason the Shoto battery we hava has a double pole breaker. You would think that you first start the battery up from the reset button (hold in for 3 seconds) and then flip the breaker up, but this was not the case. The battery would then just go into alarm mode. Seems like the preferred method is to keep the breaker up and then start the battery up with the reset button.

This breaker is not shown on the manual...

Nightbyte, thanks for you input. This forum is great and I've learnt a lot from previous chats. 

[nightbyte]

Good morning (again) SuperStan,

Ok, so it's not the battery .  Check the wiring into and out of the inverter, tightness of lugs and earth-wire battery and inverter connections. 

Also check inverter programme settings.

Has the inverter reported a specific fault on the LCD display?

Check the mains supply to the inverter and breaker on distribution board, does the mains supply have an earth leakage and does it trip?

Could you explain how you corrected it previously. The fact that you overcame it previously suggests that it could be a programme setting or external supply / demand issue.

Finally check the inverter output is not connected to something that is momentarily drawing too much power.

[SuperStan]

Does someone maybe know if/what the difference is between the Axpert King MKS lll vs VM III is?

[Coulomb]

3 hours ago, SuperStan said:

For some reason the battery is tripping when we start the inverter up.

It could be the inrush current, if you don't have any pre-charge arrangement. Any inverter larger than about 1 kW should really be started with a resistor in series, of a few ohms. That limits the in-rush current to a tolerable ≈20 A. Once the capacitors in the inverter have reached some 90% of the battery voltage, the resistor can be shorted, at which point it is safe to start taking load from the battery, or to charge it. The resistor has to be a special type capable of very high peak power, preferably about 25x its continuous rating. Usually, it will be rated for 50-200 W continuous (so 1250-5000 W of peak power). My system uses a 3.3 Ω resistor, rated at (from memory) 100 W. A small computer monitors the voltage at the inverter terminals, and turns on a contactor to short the resistor when the voltage is close enough. The contactors themselves have a large inrush current, so they are started in a staggered fashion. So my system starts up from cold with a rapid clack-clack-clack... sound (there are about 7 contactors total). These are all EV200s, capable of switching 200 A DC at lowish voltages (such as the nominally 48 V battery, or 100+ V of solar power).

You mention that you eventually got the inverter started. It's possible that each attempt left the inverter batteries with a little more voltage than before, until finally the capacitors were close enough to the battery voltage that the inrush current no longer tripped the battery's over-current protection.

My understanding is that many battery designs, including that of the Pylontechs, include MOSFETs for battery protection, and that these naturally or by design are able to limit the current out of the battery for a short period of time. The short time is because these MOSFETs would be dissipating the same energy in a short pulse of power that the pre-charge resistor would be, i.e. several kilowatts. They can withstand such power levels for a short period of time (less than a second), without needing impractically large heat-sinks. Perhaps the Shoto battery doesn't use MOSFETs, or doesn't employ them in such a fashion that they naturally provide a pre-charge or soft-start function.

[Coulomb]

1 hour ago, SuperStan said:

Does someone maybe know if/what the difference is between the Axpert King MKS lll vs VM III is?

There is no such thing as an Axpert King MKSIII; perhaps you meant three models, the King, the MKS III, and the VM III?

The King is an unusual model, in that it is the only one with dual conversion from AC-in to DC, and DC to AC-out. Thus, it can offer zero transfer time (between the loads being powered by the battery and by AC-in). It's also one of the now relatively few models that has a 145 V absolute max Solar Charge Controller (SCC). It can be paralleled.

The Axpert MKS III, also known as the PIP-MGX, is a version of the Axpert MKS II with a removable display. This model has a high voltage (450 or 500 V max) SCC. It can be paralleled.

The Axpert VM III is a "value line" machine, which can't be paralleled and has a few other minor limitations. It also has a high voltage SCC. So it's like a cheaper version of the MKS III / PIP-MGX.

All the above models come in 3 kW and 5 kW versions. A 7.2 kW and 8 kW version of the Axpert MKS III is called the Axpert MAX.

There are also the Axpert MKS models (without a II or III as part of the name). These have no removable display, have a low voltage SCC, and can be paralleled. An Axpert VM II is like an Axpert VM III without the removable display; it's a far less common model.

[SuperStan]

2 hours ago, Coulomb said:

It could be the inrush current, if you don't have any pre-charge arrangement. Any inverter larger than about 1 kW should really be started with a resistor in series, of a few ohms. That limits the in-rush current to a tolerable ≈20 A. Once the capacitors in the inverter have reached some 90% of the battery voltage, the resistor can be shorted, at which point it is safe to start taking load from the battery, or to charge it. The resistor has to be a special type capable of very high peak power, preferably about 25x its continuous rating. Usually, it will be rated for 50-200 W continuous (so 1250-5000 W of peak power). My system uses a 3.3 Ω resistor, rated at (from memory) 100 W. A small computer monitors the voltage at the inverter terminals, and turns on a contactor to short the resistor when the voltage is close enough. The contactors themselves have a large inrush current, so they are started in a staggered fashion. So my system starts up from cold with a rapid clack-clack-clack... sound (there are about 7 contactors total). These are all EV200s, capable of switching 200 A DC at lowish voltages (such as the nominally 48 V battery, or 100+ V of solar power).

You mention that you eventually got the inverter started. It's possible that each attempt left the inverter batteries with a little more voltage than before, until finally the capacitors were close enough to the battery voltage that the inrush current no longer tripped the battery's over-current protection.

My understanding is that many battery designs, including that of the Pylontechs, include MOSFETs for battery protection, and that these naturally or by design are able to limit the current out of the battery for a short period of time. The short time is because these MOSFETs would be dissipating the same energy in a short pulse of power that the pre-charge resistor would be, i.e. several kilowatts. They can withstand such power levels for a short period of time (less than a second), without needing impractically large heat-sinks. Perhaps the Shoto battery doesn't use MOSFETs, or doesn't employ them in such a fashion that they naturally provide a pre-charge or soft-start function.

Hi Coulomb,

I think you are spot on and thanks for the details explanation! With my limited electronic background I thought in the same direction by trying several time with the hopes of charging up the capacitors. I however was not sure of my trail of thought. My Dad has purchased a second battery and is adding solar, thus I hope this will solve any future frustrations. Once again thank you for sharing your knowledge. It's wonderful to have such a pool of knowledge at one's fingertips. 

[SuperStan]

Bugger this is quite confusing, but once again you are correct! I just checked again and it is the Axpert King 5kW, thus 145Vdc. We lost the small booklet hence the confusion and trying to source the right manual online. I luckily can source the correct model description from my online Takealot history.

We are going to install 12 x 365W JA solar mono panels, 4 groups of 3 x panels in series. Please let me know if you have any additional advise/comments. Reading other threads it seems there is no near future hopes of getting the battery comms to works with the inverter?

[Coulomb]

11 hours ago, SuperStan said:

We are going to install 12 x 365W JA solar mono panels, 4 groups of 3 x panels in series. Please let me know if you have any additional advise/comments.

Just make sure that the Voc of 3 panels in series is less than about 135 V (i.e. the Voc for one panel is under 45 V). Otherwise, I'd suggest wiring 2S6P.

If it's just over 45 V, you might get away with it. I've reduced my anti-3S rhetoric a little of late, as conflicting information comes out.

[SuperStan]

8 hours ago, Coulomb said:

Just make sure that the Voc of 3 panels in series is less than about 135 V (i.e. the Voc for one panel is under 45 V). Otherwise, I'd suggest wiring 2S6P.

If it's just over 45 V, you might get away with it. I've reduced my anti-3S rhetoric a little of late, as conflicting information comes out.

Yip, the Voc = 41V per panel. Thanks for the input!

[Calvin]

10 hours ago, Coulomb said:

If it's just over 45 V, you might get away with it. I've reduced my anti-3S rhetoric a little of late, as conflicting information comes out.

My 72 cell 365W Canadian Solar panels are 47.2V VOC and I had to rewire to 2S.  These fact that these 365W JA modules are 60 cell panels makes all the difference.

What has changed (I think) is that 60 cell panels were not available with such high power until recently.

[Coulomb]

On 2021/06/20 at 11:46 PM, SuperStan said:

Reading other threads it seems there is no near future hopes of getting the battery comms to works with the inverter?

I would say that there is some hope. They have partially implemented Shoto support, but it's disabled in the later firmwares. It seems like if they had no intention of implementing it, they would delete it completely. So my guess is that they intend to finish it one day, and re-enable that protocol.

I have no idea how far they got before disabling it. BMS firmware makes for slow reading.

[Coulomb]

2 hours ago, Calvin said:

What has changed (I think) is that 60 cell panels were not available with such high power until recently.

Yes, the boundary seems to keep changing.

[gav]

On 2020/12/30 at 12:17 PM, nightbyte said:

The Shoto manual that came with my batteries is identified as version V 1.0  The importers were not able to assist me with an updated version.  

Hi @nightbyte could you share the manual you have for your battery or point me in the direction of the importers please?

I never received manuals from the installer of my shoto & luxpower setup and am trying to figure it out but can't find any proper manuals online. I have the 16 cell version though but hopefully I can gain some insights and do some simple maths to get my set up working like it should. 

[SuperStan]

6 minutes ago, gav said:

Hi @nightbyte could you share the manual you have for your battery or point me in the direction of the importers please?

I never received manuals from the installer of my shoto & luxpower setup and am trying to figure it out but can't find any proper manuals online. I have the 16 cell version though but hopefully I can gain some insights and do some simple maths to get my set up working like it should. 

Hi Gav,

See attached. I think this is what you are after.

1614805_shoto_sda10_48100_manual.pdf

[gav]

yip that's what I was missing, thanks SuperStan!

[Anish]

Anyone know the difference between the Shoto M14 and the L5?

[Leonm]

Hi,

does anyone  know what the shoto 48100 20% dod is.

secondly they installed three in parallel, two are sda10-48100m14 and one sda10-48100l5.

my concern is they mixed up 15s and 16s together, and the bulk and float voltages may differ.

is there anyway to tell?

[Boetie]

Hi all. I'm strugeling for almost three mothes with my four shoto 5.12kwh batterys. I got two 5kw mpp expert inverters two of the batterys does not charge more then 50% and one 75% and the orther one 100%. What i dont understand if i charge these batterys separate thy only charge to what i just said. All i know is that the Inverter and batterys dont't communicate with each orther. Now my Quistion how can i get these batterys to charge to full capacity. Thank you so much.

 

 

[Coulomb]

It could be the premature float bugs. Assuming that you're not using the direct to BMS cable.

Edited July 16, 2021 by Coulomb

[LukeMeijsen]

Hi Guys

 

Thanks for all the info on Shoto batteries. I have a system with three Mecer/Axpert inverters setup as a 3 phase system with two 4.8 Shoto batteries. It is a system that was installed a year ago by someone else and I have to fix the mess. The batteries constantly goes into alarm mode and the inverters switch off then. I have measured the battery voltage and its 46.9vdc.

It seems that the inverters goes into bypass a lot without it being near 75% of load. Thanks