Help troubleshooting Pytes V5alfa 48V 5.12kWh - dead out of sudden

[miborion]

Hi,
I'm really desperate, since out of the blue, my Pytes V5alpha, died.
I have cabin in which I have an off grid solar panel setup, 3,5KW of installed PVs combined with a Growatt 3500ES and a Pytes v5a.
The system worked fine, since yesterday since last summer (august 2024), for which I have the logger logs (the Growatt inverter has a logger which monitors all the battery parameters as well).
But without any warnings, the battery just doesn't start anymore.
I found my inverter shut.
When I started my gasoline power generator, just to start the inverter (usually it works only with the PVs) the battery voltage was fluctuating: first 50V, then drops to 49V and so on until 0V (this whole time the battery indicators are dead).
The Pytes battery just doesn't start. It shows nothing on its "charge bar".
One day before It was 90% charged, without any consumers, and the last log I got from the Growatt was around 3 AM when it showed 80% on SOC.
Sorry for the long story. I just cannot understand...the Pytes just doesn't start. Since it doesn't start, the Growatt doesn't "see" it in order for me to charge it.
Is it dead? Is there anything I can do? It doesn't even have 1 year and never got it emptied below 60%.
Looking forward for any adivces,
Bogdan.

PS: I have all the proper protections implemented in the electrical panel: SPD, fuse protection, etc., therefore even a lighting should've struck, the grounding should've taken the charge.

 

[sunshine_eggo]

Hi,
I'm really desperate, since out of the blue, my Pytes V5alpha, died.
I have cabin in which I have an off grid solar panel setup, 3,5KW of installed PVs combined with a Growatt 3500ES and a Pytes v5a.
The system worked fine, since yesterday since last summer (august 2024), for which I have the logger logs (the Growatt inverter has a logger which monitors all the battery parameters as well).
But without any warnings, the battery just doesn't start anymore.
I found my inverter shut.
When I started my gasoline power generator, just to start the inverter (usually it works only with the PVs) the battery voltage was fluctuating: first 50V, then drops to 49V and so on until 0V (this whole time the battery indicators are dead).
The Pytes battery just doesn't start. It shows nothing on its "charge bar".
One day before It was 90% charged, without any consumers, and the last log I got from the Growatt was around 3 AM when it showed 80% on SOC.
Sorry for the long story. I just cannot understand...the Pytes just doesn't start. Since it doesn't start, the Growatt doesn't "see" it in order for me to charge it.
Is it dead? Is there anything I can do? It doesn't even have 1 year and never got it emptied below 60%.
Looking forward for any adivces,
Bogdan.

When you disconnect the Growatt from the , will the battery turn on?

If so, have you made the inverter connecting with a pre-charge resistor in series?

PS: I have all the proper protections implemented in the electrical panel: SPD, fuse protection, etc., therefore even a lighting should've struck, the grounding should've taken the charge.

Proper grounding is NOT protection from lightning. Lightning protection is very specific and expensive. A properly grounded system helps minimize the potential for damage from a *nearby* lightning strike, but a direct hit is likely to destroy everything.

 

[miborion]

When you disconnect the Growatt from the , will the battery turn on?

If so, have you made the inverter connecting with a pre-charge resistor in series?



Proper grounding is NOT protection from lightning. Lightning protection is very specific and expensive. A properly grounded system helps minimize the potential for damage from a *nearby* lightning strike, but a direct hit is likely to destroy everything.

Hi @sunshine_eggo,
Thanks for the quick reply.
Please take into consideration, I have all needed protections (on both AC and DC panels, since they are separated).
The grounding was tested and to be compliant with my country's regulations, it's under 4 ohm(s). The SPD should have caught the surge and discharge it to the ground.
Going back to the Pytes issue, I did try to start it without being connected to the inverter; therefore:
1) I tried starting it without being connected - on button plus soft start button - no luck; it doesn't do anything;
2) without the battery connected the Growatt was working just fine - using the gas power generator as the "line" power (utility);
3) with the battery connected - when measuring the DC voltage on the Growatt's input (from the battery), the voltage varies starting at 50V and dropping to 0 V; same thing I got on the Growatt display; in all this time the battery doesn't show anything
4) I don't have any power consumers, other that the Growatt itself (no shorts, or anything);

 

[sunshine_eggo]

Hi @sunshine_eggo,
Thanks for the quick reply.
Please take into consideration, I have all needed protections (on both AC and DC panels, since they are separated).
The grounding was tested and to be compliant with my country's regulations, it's under 4 ohm(s). The SPD should have caught the surge and discharge it to the ground.

I'm sorry. You have an incorrect view of lightning protection. If you're telling me that you have a lightning rod on the property that attracts and dissipates full lightning strikes, you are correct. If you only have a properly grounded system, you are wrong.

Again, proper grounding is NOT protection from lightning. Lightning protection is very specific and expensive. A properly grounded system helps minimize the potential for damage from a *nearby* lightning strike, but a direct hit is likely to destroy everything.

Your system is likely tolerant of nearby strikes, but a direct strike will destroy everything.

Going back to the Pytes issue, I did try to start it without being connected to the inverter; therefore:
1) I tried starting it without being connected - on button plus soft start button - no luck; it doesn't do anything;
2) without the battery connected the Growatt was working just fine - using the gas power generator as the "line" power (utility);
3) with the battery connected - when measuring the DC voltage on the Growatt's input (from the battery), the voltage varies starting at 50V and dropping to 0 V; same thing I got on the Growatt display; in all this time the battery doesn't show anything
4) I don't have any power consumers, other that the Growatt itself (no shorts, or anything);

1) I was hoping to eliminate the possibility of BMS short circuit protection due to inverter capacitor charging.

What does it measure at the battery terminals?

2) Expected. The Growatt is passing through the generator to loads.

3) LIkely varying as the charger attempts to charge but doesn't detect a battery, so it cycles on and off.

Unfortunately, it sounds like the battery or BMS has failed. I would open it up and check the voltage at the cells.

 

[miborion]

I'm sorry. You have an incorrect view of lightning protection. If you're telling me that you have a lightning rod on the property that attracts and dissipates full lightning strikes, you are correct. If you only have a properly grounded system, you are wrong.

Again, proper grounding is NOT protection from lightning. Lightning protection is very specific and expensive. A properly grounded system helps minimize the potential for damage from a *nearby* lightning strike, but a direct hit is likely to destroy everything.

Your system is likely tolerant of nearby strikes, but a direct strike will destroy everything.



1) I was hoping to eliminate the possibility of BMS short circuit protection due to inverter capacitor charging.

What does it measure at the battery terminals?

2) Expected. The Growatt is passing through the generator to loads.

3) LIkely varying as the charger attempts to charge but doesn't detect a battery, so it cycles on and off.

Unfortunately, it sounds like the battery or BMS has failed. I would open it up and check the voltage at the cells.

Thanks for the details.
Indeed, you're right and I didn't used the proper naming. I do have a proper grounding, not a lightning protection.
I do not know if I should try opening it up...I will try its warranty since it's 9 months old. But I got a feeling the seller will not reply, or do anything.

The only thing which happened was a drastic decrease in temperature. On Saturday we had 22 degrees (Celsius), sunshine, the battery was fully loaded, but on Sunday we got 0 degrees (Celsius), clouds and some snow.
Since the cabin isn't well insulated, I'm guessing maybe the Pytes heat-up system started and drained it?

 

[sunshine_eggo]

Thanks for the details.
Indeed, you're right and I didn't used the proper naming. I do have a proper grounding, not a lightning protection.
I do not know if I should try opening it up...I will try its warranty since it's 9 months old. But I got a feeling the seller will not reply, or do anything.

The only thing which happened was a drastic decrease in temperature. On Saturday we had 22 degrees (Celsius), sunshine, the battery was fully loaded, but on Sunday we got 0 degrees (Celsius), clouds and some snow.
Since the cabin isn't well insulated, I'm guessing maybe the Pytes heat-up system started and drained it?

That sounds possible. Heated batteries are only supposed to draw from a charging source to heat themselves.

 

[fnnwizard]

Hi,
I'm really desperate, since out of the blue, my Pytes V5alpha, died.
I have cabin in which I have an off grid solar panel setup, 3,5KW of installed PVs combined with a Growatt 3500ES and a Pytes v5a.
The system worked fine, since yesterday since last summer (august 2024), for which I have the logger logs (the Growatt inverter has a logger which monitors all the battery parameters as well).
But without any warnings, the battery just doesn't start anymore.
I found my inverter shut.
When I started my gasoline power generator, just to start the inverter (usually it works only with the PVs) the battery voltage was fluctuating: first 50V, then drops to 49V and so on until 0V (this whole time the battery indicators are dead).
The Pytes battery just doesn't start. It shows nothing on its "charge bar".
One day before It was 90% charged, without any consumers, and the last log I got from the Growatt was around 3 AM when it showed 80% on SOC.
Sorry for the long story. I just cannot understand...the Pytes just doesn't start. Since it doesn't start, the Growatt doesn't "see" it in order for me to charge it.
Is it dead? Is there anything I can do? It doesn't even have 1 year and never got it emptied below 60%.
Looking forward for any adivces,
Bogdan.

PS: I have all the proper protections implemented in the electrical panel: SPD, fuse protection, etc., therefore even a lighting should've struck, the grounding should've taken the charge.

Are you in closed loop?

Can you describe with time stamps at your location? Also describe temp drop over time.

The Pytes should not use battery energy to heat up. It should use either PV or gen power.

Sounds like the BMS is kicking in UVP. Battery 50V no load, connect to inverter= load from Inverter drops to <49, BMS disconnects.
And, possibly a cell severely low with repeated connections and there is not enough juice in that cell to recover.

 

[miborion]

@fnnwizard thanks for spending the time with my issue;
If I got it right, yes I have a closed loop, or off grid system, since there is no other power source (other than a gasoline power generator which I manually start, when I'm on site).
Regarding the timestamps, I wasn't at the location; I got my readings from the Growatt keylogger; Since the Growatt went offline, the last log was from Sunday, at 03:00 AM, when it registered 80% for SOC.
On Sunday (same day) I arrived at the location (since I saw the keylogger as offline) at 21:00 (local time) and everything was shutdown.
For the "BMS is kicking in UVP" I don't understand the meaning (sorry for that).
If there is anything I can try, will happily do it.

 

[sunshine_eggo]

@fnnwizard thanks for spending the time with my issue;
If I got it right, yes I have a closed loop, or off grid system, since there is no other power source (other than a gasoline power generator which I manually start, when I'm on site).
Regarding the timestamps, I wasn't at the location; I got my readings from the Growatt keylogger; Since the Growatt went offline, the last log was from Sunday, at 03:00 AM, when it registered 80% for SOC.
For the "BMS is kicking in UVP" I don't understand the meaning (sorry for that).
If there is anything I can try, will happily do it.

When you disconnected the battery from the inverter, did you also disconnect the data cable?

 

[miborion]

When you disconnected the battery from the inverter, did you also disconnect the data cable?

Yes, I disconnected the data cable as well, since even if the batter does have the on/off button it never fully shuts everything down (as far as I read)

 

[miborion]

I the very possible scenario, trying to fix it, or at least identifying the issue, should the steps be:
1) open the battery (check if any available tutorials on how to properly do it);
2) check the BSM - I saw once how it looks like, and since there should be 16 cells, I guessing there are many BMS(s) for pair of two(s) and for the pair of four(s)? For any such BSM should I check if it has lights? Voltage? Isn't shorted?
3) check each cell's voltage? in this case, if any cell would have under 3Volts, it means it's damaged? Can it be recharged? or just replaced?

Sorry for all the stupid questions, just that I would really need to get at least the steps when checking the root cause.
Regards,
Bogdan.

 

[sunshine_eggo]

I the very possible scenario, trying to fix it, or at least identifying the issue, should the steps be:
1) open the battery (check if any available tutorials on how to properly do it);

Hopefully, it's as simple as removing a couple of covers.

2) check the BSM - I saw once how it looks like, and since there should be 16 cells, I guessing there are many BMS(s) for pair of two(s) and for the pair of four(s)? For any such BSM should I check if it has lights? Voltage? Isn't shorted?

Trace the (-) battery terminal to the BMS. It will be a relatively large piece of electronics with many wires to it. Each cell should have a wire to the BMS. You might be able to disconnect the wire harness from the BMS. Disconnect/reconnect can reset some BMS.

3) check each cell's voltage? in this case, if any cell would have under 3Volts, it means it's damaged? Can it be recharged? or just replaced?

LFP cells are good down to 2.5V. If you find most cells at 2.5V or higher, the BMS has likely failed. It's also possible the BMS failed and allowed the inverter to drain the cells deeper than they should.

Sorry for all the stupid questions, just that I would really need to get at least the steps when checking the root cause.
Regards,
Bogdan.

Not stupid.

 

[fnnwizard]

Pytes are very well engineered. If you can take cover off and take pictures for us we can try and help.
I believe they use ribbon cables from balancer board to another board for the intercell connection.

I cant be 100% on this so you will have to take some pics for us.
UVP is under voktage protection.

It's at pack level and at cell level.

The simplest initial diagnostic is to measure each cell V while the ribbon connector is disconnected.

I'm on the road and hate looking at pictures on mobile... will be back in a couple hrs but if u can post pics, that would be great.