Epever 6415AN doesn't respect my settings

jnrhome said:

I haven't experienced random controller loss of settings. They even stay when i disconnect panels and batteries.

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That’s good to know. If I learn anything more about the type of event that triggered that other member’s issue with his Epever MPPT, I’ll let you know...

I haven't seen that behavior either. That would be scary but likely not fatal. Btw, the shunt isn't going to lose you any significant voltage. Ohm's law: V = I * R. The resistance of the 75A shunt I mentioned is R = V / I or 0.0075 / 75 = 0.001 ohm's. So take that resistance and let's assume we have 50 amps flowing through our shunt. Then the voltage drop across the shunt will be 50 * 0.001 = 0.05 volts. You can lose a hell of a lot more voltage by not using the proper gauge wire for the length of run and voltage pushing it. I always recommend people search for voltage drop calculator and also DC wire gauge chart. You can see what the losses are like for your situation. The second one give you recommendations for wire gauge to prevent loss. Also don't skimp on wire. Make sure you buy good quality copper not aluminum. I'm fond of Temco welding wire for my heavy stuff.

JMH1783 said:

I haven't seen that behavior either. That would be scary but likely not fatal. Btw, the shunt isn't going to lose you any significant voltage. Ohm's law: V = I * R. The resistance of the 75A shunt I mentioned is R = V / I or 0.0075 / 75 = 0.001 ohm's. So take that resistance and let's assume we have 50 amps flowing through our shunt. Then the voltage drop across the shunt will be 50 * 0.001 = 0.05 volts. You can lose a hell of a lot more voltage by not using the proper gauge wire for the length of run and voltage pushing it. I always recommend people search for voltage drop calculator and also DC wire gauge chart. You can see what the losses are like for your situation. The second one give you recommendations for wire gauge to prevent loss. Also don't skimp on wire. Make sure you buy good quality copper not aluminum. I'm fond of Temco welding wire for my heavy stuff.

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I’m using 2 x 2/0 welders cable for the run from battery to inverter, so don’t worry, I understand about voltage drop.

I should look into the shunts to make sure I understand what voltage drop they might cost me. I can afford a loss of 5mV but not 50mV.

At 80A, 50mV corresponds to 0.625 mOhm, so if I can find a worthwhile shunt at resistance levels below that (for a current range up to 200A), I could be interested...

Heard back from Epever:

“ That presentation was made in 2018, it supports lithium battery now.

To be sure you get the new version, you can check with the vendor and ask them whether the label on the package box has
i. 12/24/36/48
or
ii 12/24/36/48/Li

The 'Li' means it supports lithium battery.’

So that puts that issue to bed - just need to make sure I get a model ending in ‘Li’..

OK, guys, I’ve finally found a configuration for my 10-panel array suffering from partial shading in the morning that will be close to optimal as far as efficiency based on using three 150V 60A MPPTs and I am studying the Epever 6415AN user manual closely.

And now that I’ve seen how they allow charge voltages to be set under user, I’m interested to understand what settings you are each using for LiFePO4 charging.

I’m assuming Equalize Time is set to ‘0’ to disable Equalize it but I don’t see any setting for Absorb Time - once the Epever AN-Series switches from bulk (CC) to absorb (CV), is there a minimum default time it will stay in Absorb or is it all voltage-based and it will return to Bulk (CC) as soon as the battery is discharged below a threshold voltage?

And essentially the same question for Float - is there any minimum time it stays in Float once it has entered that state or will it return to Bulk as soon as the battery is discharged below a voltage threshold?

Lastly, I’m interested to understand whether the AN-Series inter-MPPT communication provides anything other than simpler monitoring.

In particular, I’m interested to understand whether the communication allows multiple MPPTs to synchronize battery charging status/mode?

I’ll have one MPPT ‘waking up’ much later than the they two due to shading late into the morning and I’ve read that sometimes a late-waking MPPT can have difficulty going into Bulk (CC) charge mode because it senses the increased voltages associated with other MPPTs already charging the battery in Bulk mode and so thinks I should go into Absorb instead. Does the Epever communication provide anything to allow multiple parallel MPPTs to synchronize battery charging status to avoid this?

I heard back directly from Epever that to synchronize the charge status of multiple Tracer AN MPPTs, the PAL-ADP-50AN is needed: https://www.epsolarpv.com/upload/file/2003/EPEVER-Datasheet-PAL-ADP-50AN.pdf

It’s only about $35 so whichever of you both has a system with multiple Epever MPPTs may want to consider it.

It looks like a side benefit may be only one temperature sensor shared by all MPPTs rather than one sensor per MPPT.

User Manual: https://www.epsolarpv.com/upload/file/2003/PAL-ADP-50AN-SMS-EL-V2.1.pdf

so back to the original problem.
Here I am again. After rewiring my charge controller last night, and having it completely disconnected for hours, I would have thought that the most recent set of configuration adjustments would be honored today. I deferred reconnecting the optional load and kept the use down to minimal in an effort to push the voltage back up to max and check the fully charged voltage settings. Again, my settings are disregarded in favor of who knows what. I'm well past my current max boost voltage of 54.4v and now past the last max boost voltage of 55v with a solid, steady 2,200w+ flowing in. I don't understand what it's shooting for. Before I rewired, I felt like i was closing in on how this thing works, but i'm back to scratching my head as the theories that seemed to be firming up have now been decimated. It's really a mystery how this thing works. I've been above boost voltage for hours so the boost duration also seems useless. It's frustrating...

jnrhome said:

so back to the original problem.
Here I am again. After rewiring my charge controller last night, and having it completely disconnected for hours, I would have thought that the most recent set of configuration adjustments would be honored today. I deferred reconnecting the optional load and kept the use down to minimal in an effort to push the voltage back up to max and check the fully charged voltage settings. Again, my settings are disregarded in favor of who knows what. I'm well past my current max boost voltage of 54.4v and now past the last max boost voltage of 55v with a solid, steady 2,200w+ flowing in. I don't understand what it's shooting for. Before I rewired, I felt like i was closing in on how this thing works, but i'm back to scratching my head as the theories that seemed to be firming up have now been decimated. It's really a mystery how this thing works. I've been above boost voltage for hours so the boost duration also seems useless. It's frustrating...

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Let us know what you learn.

For what it is worth, Epever sent me their recommended settings for LiFePO4 (attached).

[EDIT: Oh, and P.S. I will not be purchasing an Epever SCC until you’ve gotten your issues worked out and are happy with the product’s performance...]

Apparently I've wiggled the configuration enough that things are working seemingly correctly. After resetting the controller to default lifepo4 settings, I spent most of the afternoon in float and adjusted to float voltage several times. Each time, the controller responded quickly and adjusted to the updated voltages. I think it was reloading the lifepo4 default settings. I'll test that next time it acts funny.

jnrhome said:

Apparently I've wiggled the configuration enough that things are working seemingly correctly. After resetting the controller to default lifepo4 settings, I spent most of the afternoon in float and adjusted to float voltage several times. Each time, the controller responded quickly and adjusted to the updated voltages. I think it was reloading the lifepo4 default settings. I'll test that next time it acts funny.

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Not understanding.

Are you using custom Lithium settings or USR settings?

Do you think the controller is overriding custom Lithium settings with Default Lithium settings or switching from USR settings to Lithium settings?

my latest theory is that maybe one of the settings i want to adjust is inadvertently changing the mode the system operates in. Boost, float and boost recon adjustments seem to hold. It may be that reducing the charge limit voltage below an undetermined threshold pushes the configuration into the next mode. Loading default lifepo4 settings, then adjusting charge limit voltage from default (58.4v) to 56v is fine, but if i reduce to 55v, it stops respecting the rest of my settings. I can't be sure yet, but the investigation continues...

jnrhome said:

my latest theory is that maybe one of the settings i want to adjust is inadvertently changing the mode the system operates in. Boost, float and boost recon adjustments seem to hold. It may be that reducing the charge limit voltage below an undetermined threshold pushes the configuration into the next mode. Loading default lifepo4 settings, then adjusting charge limit voltage from default (58.4v) to 56v is fine, but if i reduce to 55v, it stops respecting the rest of my settings. I can't be sure yet, but the investigation continues...

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I started a néw thread on how I believe these various settings control these charge controllers here: https://diysolarforum.com/threads/pros-and-cons-of-boost-voltage-for-lifepo4.19898/

Epever is my example for the ‘more complex’ charging algorithm (and settings).

I did not put anything in that discussion regarding the ‘Charge Limit Voltage’ because I do not understand it’s function.

I would have guessed it is a fail safe to stop charging whenever battery exceeds that voltage.

Can you share the full settings you are using? Does the manual state anything about the purpose of Charge Limit Voltage setting?

I checked all the documents i have. Although there are a number of references to the charge limit voltage, there are no explanations.

jnrhome said:

I checked all the documents i have. Although there are a number of references to the charge limit voltage, there are no explanations.

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The image resolution on that image is so poor I can’t read it. Perhaps you could post the most important settings.

In reading the manual for the 6415AN, I see this:

I. Over Voltage Disconnect Voltage>Over charging protection voltage(Protection Circuit Modules(BMS))+0.2V

So it looks like they want the Overvoltage Disconnect to be 0.2V above HVD of the BMS (I suppose as a fail safe in case BMS fails to disconnect).

And this:


‘II. Over Voltage Disconnect Voltage>Over Voltage Reconnect Voltage=Charging Limit Voltage ≥ Equalize Charging Voltage=Boost Charging Voltage ≥ Float Charging Voltage>Boost Reconnect Charging Voltage’

So while it’s still unclear to me what ‘Charging Limit Voltage’ setting does, they expect it to be above the Boost Charging Voltage.

I suppose the Boost Charging Voltage may be the voltage threshold where the charger switches from CC mode to CV mode and Charging Limit Voltage may be the voltage applied in CV mode.

Then after it reaches Charging Limit Voltage it switches to a passive Float mode awaiting battery voltage to drift/settle down to some level above Float Voltage.

Is that how you understand it?

The spreadsheet on the left mirrors the settings on the right. On the rare occasions that I've seen a response based on the charge limit setting, the controller briefly interrupts the charge voltage and amperage, then after a moment, voltage resumes and amperage ramps back up. I've seen no state change, nor do i know what a "passive float mode" might be. I'm unclear about the function in a number of scenarios and have attempted to approach this in a scientific manner. The results of my tests have not been consistent and i'm struggling to understand why. My supposition was that a charge limit would be the maximum voltage applied as a charge. If the voltage exceeds that, it would follow to stop charging. I think the MPPT calculations also figure into that, but I don't think float would be involved. If it were me, i would trigger a boost voltage target reducing the charge voltage to avoid overcharge based on the charge limit voltage set.

jnrhome said:

I've had this controller since 9/2019 and recently upgraded my battery bank from sealed lead acid to LiFePo4. The changeover was a bit nerve-wracking, but it all went fine after a couple of restarts.
Now, i've chosen my operating voltages, but the controller is ignoring them. I wanted the battery to top out at 90% or 53.60v so set that as boost voltage. Float is at 53.55v and boost reconnect at 53.50v. Equalisation charge is set to 54.00v and charge limit voltage to 55.00v. Boost duration is set to 30 and equalisation duration is also 30. I have the model with no load outputs so other settings are moot. I've charged for three days to get up to 53.60v. The voltage is continuing to rise, currently at 54.17v and stays in boost. Has anyone else seen this behavior? Not sure what to do...

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You don't use equalization on LiFePo4 battery, equalization setting should be 000 for time

Equalization duration is set to 0 and the EQ voltage is set by the controller to the same as boost voltage

fafrd said:

The image resolution on that image is so poor I can’t read it. Perhaps you could post the most important settings.

In reading the manual for the 6415AN, I see this:

I. Over Voltage Disconnect Voltage>Over charging protection voltage(Protection Circuit Modules(BMS))+0.2V

So it looks like they want the Overvoltage Disconnect to be 0.2V above HVD of the BMS (I suppose as a fail safe in case BMS fails to disconnect).

And this:


‘II. Over Voltage Disconnect Voltage>Over Voltage Reconnect Voltage=Charging Limit Voltage ≥ Equalize Charging Voltage=Boost Charging Voltage ≥ Float Charging Voltage>Boost Reconnect Charging Voltage’

So while it’s still unclear to me what ‘Charging Limit Voltage’ setting does, they expect it to be above the Boost Charging Voltage.

I suppose the Boost Charging Voltage may be the voltage threshold where the charger switches from CC mode to CV mode and Charging Limit Voltage may be the voltage applied in CV mode.

Then after it reaches Charging Limit Voltage it switches to a passive Float mode awaiting battery voltage to drift/settle down to some level above Float Voltage.

Is that how you understand it?

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Charging Limit Voltage is stop charging at point

jnrhome said:

Equalization duration is set to 0 and the EQ voltage is set by the controller to the same as boost voltage

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Equalization setting default is 120 mins, you change to 000 mins. Equalization is for lead acid batterys not LiFePo4. I am assuming you are using "user" as Battery type in settings

lifepo4 default settings sets eq duration to 0 and sets eq voltage the same as boost voltage

Ok, your set then. In your 1st post you said you were equalizing the battery. That threw me

i have my lithium battery boost, float and boost recon voltages lower than normal to conserve cycle life. I also use an active balancer and had experimented with using the eq setting to occasionally raise the voltage higher than my conservative settings to give the balancer a wider delta to flatten without having to run the battery so high all the time. Lithium protection being enabled defeats eq settings so could not be used in that manner.

I have same controller, but mine must be older version. In battery type I don't have LiFePo default. I have to set as "user" and set each parameter myself. I use MT 50 to set

looking better today. The voltage has ramped down to meet the float voltage once boost voltage was achieved.

looking good today. Boosted all morning, dropped into float right as the cells were close to max. Floating a little lower than expected, but between float and boost recon so within tolerance.

I saw my first boost, float, boost recon, float cycle today. It functioned correctly. The voltages tolerances were a bit wider than expected, but totally within comfort. I'm going to call this configuration successful. I will let it run as is for one more day, just to confirm everything, then back it down to the voltages i want long-term. Likely around 2.5v lower as it feels way high for my comfort. Still within acceptable, but why charge to 100% if you don't have to?