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I really need to program the charge function but not sure how
I really need to program the charge function but not sure how
What exactly do you need to program? Just the bulk and float voltages or the automatic charge trigger voltages with UPS or ATS?
@cali-carlos im using 24 volt 220 ah lifepo4 batteries and need to program bulk float and trigger for use on ups mode
@bobby-t Cfg, Battery/Charge:
OVP E: ~29.6 (will cause the inverter to fault and shut down at this voltage)
A: is the alarm at which it'll start beeping to notify you it's getting close to the over voltage shutdown so set this where you see fit but above the bulk charge voltage of ~29. Note that there's not much room between fully charged and over charged Lifepo4.
UVP E: The inverter and your batteries can go down to 20 however the sine wave starts getting a little flat below 22 I believe, so set it to your discretion.
Charge mode: Auto
Charge Trig: Probably around 26?
Charge Amps: I'm not sure if this setting is quite functional yet but I believe it'll be the percentage of the input amperage you want to use for charging. So if input is set to 20 amps and you have charge amps set to 25% it'll limit 5amps of the ac input for charging. Someone else might have to chime in on this one.
Bulk Volts: ~29
Float Volts: I don't believe you float Lifepo4 due to possible balancing issues but someone correct me if wrong.
Absorb tmr: I would think you could set this to 15 minutes.
Tmr Task: End Chg (unless someone recommends that you float it.
Back to the Cfg tab. A/C Input/ transfer:
Transfer: A/C UPS
240v MaxAmp: currently I believe this will only affect the charge amperage. I don't believe it'll limit the pass through amperage. Future update should change some of this.
Someone may suggest some slightly different numbers and you may want to play around with it but this should get you pretty close.
@sid-genetry-solar will the OVP kick in if the bms cuts charging input?
It will try, but (especially on 48v systems), it's possible that the voltage will go through the roof before the inverter can self-protect--BMS trips are pretty treacherous. At 24v like you are, it shouldn't be an issue.
Some time back, I added a "DC Bus Overvoltage" error that has a zero-tolerance hardcoded threshold around ~72v that will shut down the inverter mid-cycle if triggered. (This is separate from OVP error.) It seems to help protect GS inverters in the event of treacherous BMS trips--though being a zero-tolerance error, it's possible that it can cause unexpected shutdowns.
Charge Amps is functional: it sets the allowable percentage of AC input power that can be consumed by charge. (The "limit" of the AC input power is the corresponding MaxAmp setting.) In other words, if you set it to "50%", it won't pull more than 50% of the limit for charge. (If MaxAmp is set to 15A, then charge will pull no more than 7.5A.)
@bobby-t I believe you're at 48v, whereas @cali-carlos is at 24v. Scale the voltage setpoints accordingly!
@cali-carlos I float my LiFePo4 bank all day...but that's because all loads pull from it, and I don't want to be constantly microcycling the batteries. Float for me is ~56.0v (= 3.50v/cell); the batteries tend to sit nominal around 53v (= 3.31v/cell). Max spec for my Tenergy cells would be 3.65v/cell, but there's basically no further power storage to be gained at the higher voltage.
@bobby-t I believe you're at 48v, whereas @cali-carlos is at 24v. Scale the voltage setpoints accordingly!
Other way around.
@cali-carlos I float my LiFePo4 bank all day...but that's because all loads pull from it, and I don't want to be constantly microcycling the batteries. Float for me is ~56.0v (= 3.50v/cell); the batteries tend to sit nominal around 53v (= 3.31v/cell). Max spec for my Tenergy cells would be 3.65v/cell, but there's basically no further power storage to be gained at the higher voltage.
Do your balancers start balancing at 3.5? I have lead acid but I thought floating lifepo4 for to long below the balancing voltage could cause them to become out of balance?
Do your balancers start balancing at 3.5?
Approximately...they're set for ~3.55v.
Lithium batteries do not self-balance...when they're full, they stop accepting/"passing" current. This results in the voltage just going through the roof (of their limits) causing damage.
I like the maximum charge voltage setpoint to be just below the balance voltage, that way if any cells are out of balance, they can be brought back into line pretty easily.
The fast over voltage was my issue, I had it charging from GTIs and it would continue to bump up the voltage until failure
Last time I looked at the settings it had far more settings than previously and they worked well
Charge trigger should be to start charging, not stop it
Different balancers work differently
I'm running energy transfer balancers that always run so I set my charge max low enough to allow a bit of headroom between my max charge and BMS cutout as that gets messy