SPF5000ES bus voltage
- Thread starter CătăDR
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MisterSandals
Participation Medalist
I guess we assume that is your battery voltage? Looks like it charges very quickly and discharges very quickly.
Without knowing anything about your system (solar and battery?), its impossible (for me) to say what is happening.
To guess, i would say either your battery(s) an nearing their end of life or they are undersized for your system (large array and large loads).
Without knowing anything about your system (solar and battery?), its impossible (for me) to say what is happening.
To guess, i would say either your battery(s) an nearing their end of life or they are undersized for your system (large array and large loads).
timselectric
If I can do it, you can do it.
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Looks fine.
As long as it stays under about 480v, I'm happy.
If it gets to 500v , you'll get an alarm. "High DC bus voltage"
As long as it stays under about 480v, I'm happy.
If it gets to 500v , you'll get an alarm. "High DC bus voltage"
I have 12 x 455w 2P 6S panels and two LiFePo Pytes batteries 5.12kwh each and I’m trying to investigate why it keeps frying the mosfets (4 times in 3 months)
MisterSandals
Participation Medalist
Do you know if its frying the mosfets while charging or running loads?
What are your charging amps and typical max load amps?
(12x 455W ) / 56V charging = 97.5A available from array.
Are you charging a 200Ah battery (2x 100Ah) at nearly 100A?
It usually fries them After the batteries are at 100% and it is not load dependent. It happened during the day in the afternoon a couple of times and one time at night when there was no significant load. Max charge current is 100amps and it is controlled by the battery bms but it never gets to that level.
MisterSandals
Participation Medalist
Well that "control" is with the mosfets. And if one BMS trips, the other battery gets all 100A.
During the last 10 days the maximum charge current was 44.9 amps and it keeps burning the Mosfets from the DC-DC converter and DC-AC inverter
MisterSandals
Participation Medalist
From what i found the max charging amps is 50A per battery. So whether its rugged enough to handle that on a daily basis, i dunno (but it appears not).
But, looking at your voltage graph, it "looks" like you charge VERY quickly and may not need to charge that aggressively everyday. I would look into charging at just enough amps to fully charge each day. I would expect that to be a lot less demanding of your BMS.
But, looking at your voltage graph, it "looks" like you charge VERY quickly and may not need to charge that aggressively everyday. I would look into charging at just enough amps to fully charge each day. I would expect that to be a lot less demanding of your BMS.
The problem is that the max charging current is controlled by the battery bms and I cannot charge it
MisterSandals
Participation Medalist
The charge controller controls the charging current. The BMS is just a safety limiter.
Does your SCC have configurable charge settings?
timselectric
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What errors are you seeing on your SPF-5000-ES?
It has but as long as the battery is communicating with the inverter it controls the charging current
‘Low bus voltage’ and ‘bus soft start failed’ but only after the mosfets are fried
timselectric
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I would do away with BMS communications.
It's nothing but trouble.
It's nothing but trouble.
timselectric
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Who is replacing the fets?
I agree with @timselectric, the bus voltage looks ok, though the BMS must be interacting poorly with the Growatt. Change setting 05 to USE, choose some conservative voltages for your constant voltage and float settings and then monitor.
I use 55.2 for CV and 54.7 float with very consistently good results.
I use 55.2 for CV and 54.7 float with very consistently good results.
I do
timselectric
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If you are replacing Fets in the SPF-5000-ES, that often. There is definitely something wrong with your system. Maybe check for a grounding problem.
I don't know why they would keep burning up.
I haven't heard of anyone having this problem with these units. If the issue wasn't repeatedly happening, I would say that it was just a bad unit. But, that doesn't seem to be the case.
