Epever charge controller.

[Loveshack]

Hi I am new to this forum. I was wondering if anyone had any experience with an epever tracer a series mppt. Specifically with the advanced battery charge settings. I have changed the parameters for equalization to 15.60, but I never see the mppt actually charge at this level. Any help would be appreciated.

[sensij]

Welcome to the forum!


From the manual:

The controller will equalize the battery on 28th each month. The constant equalization period is 0~180 minutes. If the equalization isn't accomplished in
one-time, the equalization recharge time will be accumulated until the set time is finished. Equalize charge and boost charge are not carried out constantly in a full charge process to avoid too much gas precipitation or overheating of battery.

[Loveshack]

Thank you for your quick and accurate response. Am I able to force an equalization or pick a different date for equalizing? The reason for this would be to disconnect some of my 12v equipment during the equalization

[sensij]

Thank you for your quick and accurate response. Am I able to force an equalization or pick a different date for equalizing? The reason for this would be to disconnect some of my 12v equipment during the equalization

You might be able to trick it into EQ by setting the date to Aug 28. You would just need to leave it that way until the 28th actually passes, if you don't want it to EQ again.

[Loveshack]

I think part of my confusion is because I am using a ebox-wifi-01 to monitor my panels. Using this app it tells me "boost" or "equalizing " with an icon above, yet my numbers while the icon is displayed do not match my parameters I have set . Should I just ignor the icons.
Also I have my boost set to 14.8. I have also never seen this value produced.
Is there a parameter setting that you could recommend as a test to make sure that I am setting the mppt advanced parameter settings correctly.
I have replaced my batteries this year and I am trying to follow the manufacturers recommendations exactly to help prolong the batteries life.
Thanks.

[Loveshack]

IMG_7295.JPG This a picture of the app. It says it's in boost mode yet the charge value is 13.12 and not 14.8 (boost parameter I have set)

[sensij]

Look closely at the numbers. It shows the PV system is operating at 38.96 W, producing 2.43 A at 15.99 V. The charge controller is boosting the current to 2.97 A, and the battery voltage is 13.12 V... suggesting something close to 100% conversion. The controller is doing what it is supposed to do.

The first stage of the charge cycle is the bulk stage, in which the controller is pushing all of the available current to the battery. The voltage you measure during this charge stage will be OCV + (I * Ri), where OCV = the open circuit voltage of the battery, and Ri is the internal resistance of the battery. Let's say your internal resistance was 0.1 Ohm. That means that under the conditions you are observing, the OCV = 13.12 - (0.1 * 2.97) = 12.8 V.

As you put more charge into the battery, the open circuit battery voltage will climb. Once the measured voltage reaches your setpoint of 14.8 V, the controller will hold at that voltage. This is the second stage of charging, known as absorb (or boost, in some sections of their manual). Current will gradually taper off as OCV continues to rise. Taken to the extreme, current would eventually fall to a very low value necessary to match the self-discharge of the battery, and the measured voltage would be the same as the OCV.

Instead of taking it all the way to current equals zero, it drops the voltage setpoint from the boost value to the float value. For this controller, that occurs after 2 hours by default, although it is user settable from 10 min to 180 min. Better controllers don't use a timer, but actually watch for the charge current to fall to a specified rate, say 3-5% of the battery capacity in Ah.

If you are never seeing it hit the voltage you specify, that means you are not supplying enough energy to get the battery out of bulk and into absorb. If you chronically operate this way, the battery isn't going to last very long. So... more information is needed to take this further:

What is the battery capacity in Ah?
How much solar do you have (looks like it might be a 50 W panel?)
How much energy are you trying to consume each day form the battery?
How low does the voltage get before you recharge?

If your battery is FLA, you should use specific gravity to fine tune your charging plan, but it sounds like you've got a bigger mismatch problem that even SOC based on voltage is revealing.

[Loveshack]

I really appreciate your time. This has really been bothering me.
I have 6 230amp/hr FLA batteries connected in series and parallel. Giving me 690 12 v amp/hrs

i have 4 x 100watt panels. They are paired up, connected in parallel. Each pair of two goes to a separate mppt. Each mppt are connected to the battery bank. The most I have seen is about 9amps from each pair.

As as well as solar we have a generator and an alternator. We are on a boat and are trying to have solar meet our needs. If. It we can supliment our power with the other methods. So far at night our batteries have been 12.6 or better.

12.5 has been our lowest voltage yet before recharging.

[Loveshack]

Here is an example while we had sunshine today. This is from one pair of 2 pairs. Please note it says equalizing. Not sure what that means. It does this several times a day but the voltage is not 15.6 which is the parameter I have set for "equalizing. " not sure if the icon should just be ignored

[Loveshack]

The batteries are 6v

[sensij]

The short answer is that your PV system is probably too small to take care of that battery without help from other sources, especially since it sounds and looks like the panels might not be optimally oriented. Knowing more about your loads would help. Doubling to 800 W (at least) would be more aligned to a conventional C/10 charging current recommendation.

Do you have room for more panels? Replacing what you have with more efficient panels will help somewhat, even if you don't have more space. In the space of each of your 200 W pairs, you should be able to fit a 300+ W 72 cell panel. That would get you to over 600 W. With just a little more space, you could shoot for 4 x 275-290 W panels (60 cell), getting you to 1100 W or so, at which point solar-only should be realistic.

Yeah, the "equalizing" indicator doesn't make any sense, might just be a bug.

What is the output rating of each of your controllers?

[Loveshack]

Each mppt is a 20 amp controller. I was thinking of putting another 100 w panel per pair next year.
Our needs. Our needs change daily depending on what we are doing. (Sailing, or at anchor or motoring )
The lowest battery reading in the morning before sun up has been 12.5. I thought that was good for the low point of the day,and therefore the solar system was keeping up with our needs?
Am I reading the display properly that when under the battery heading it reads
Battery (normal)
13.53v, 9.6A, 129.88 w, 23.75 C

13.53 v is the charging voltage at that time
9.6 A is what the batteries are accepting ( and that this number can be higher than the solar panel amp display ?)

so getting back to my original question, if my boost charging parameter is 14.8, this number should be displayed in the battery heading. Where the picture shows 13.53 it would be 14.8 during boost?

I am am trying to figure out if it is following my charging battery parameters or not.
Thanks

[sensij]

Each mppt is a 20 amp controller. I was thinking of putting another 100 w panel per pair next year.
Our needs. Our needs change daily depending on what we are doing. (Sailing, or at anchor or motoring )
The lowest battery reading in the morning before sun up has been 12.5. I thought that was good for the low point of the day,and therefore the solar system was keeping up with our needs?
Am I reading the display properly that when under the battery heading it reads
Battery (normal)
13.53v, 9.6A, 129.88 w, 23.75 C

13.53 v is the charging voltage at that time
9.6 A is what the batteries are accepting ( and that this number can be higher than the solar panel amp display ?)

so getting back to my original question, if my boost charging parameter is 14.8, this number should be displayed in the battery heading. Where the picture shows 13.53 it would be 14.8 during boost?

I am am trying to figure out if it is following my charging battery parameters or not.
Thanks

It is following the parameters correctly. The charge controller supplies current, the voltage is the feedback. Voltage will climb as battery charge increases... a charge controller does not (and can not) simply supply a fixed 14.8 V output and instantly bring the battery to that voltage. When you are setting 14.8 V, all you are doing is telling it at what feedback voltage it should switch from constant current charging (supplying maximum available charge current, up to the rating of the controller) to constant voltage charging (holding that voltage, and allowing current to taper off as the battery continues to charge).

That you never see 14.8 V means that you're not supplying enough charge to get to 100%. If you were getting to 100%, you would see voltage at 14.8, and current tapering off to nothing.

The fact that you aren't seeing less than 12.5 V on the battery in the morning means that solar may be keeping up with your demand, or that your generator/alternator are getting enough charge into it to keep SOC from dropping too low. Your PV isn't enough to get the battery all the way through the constant voltage stage to 100% SOC.

A 690 Ah battery would ideally be getting at least C/10 of charge current... 69 A. In your latest screenshot, if both controllers look the same, you are supplying only 19.2 A. Even if you were maxing out your charge controllers, you would only be generating 40 A, still lower than most would recommend, but maybe enough to meet your demand and get the battery closer to 100%.

That you aren't discharging below 50% SOC is good, but your inability to get to 100% SOC will cause early battery death due to sulfation, if you don't add PV or other sources to get to 100% routinely.

If you haven't done it yet, measure the specific gravity at the end of the charging day. That will tell you more clearly than I can what SOC you are actually achieving.

[Loveshack]

I really appreciate your time. I am new at this but trying to get my head around it and do it properly.
I have an ac 70 amp charger. It maybe a totally different situation, or the same you can tell me.
It has a boost mode. When the batteries are low say 50% 12.2, it raises voltage to 14.4. And keeps it there until it reaches about 85% of charge. Then it backs off the voltage to say 13.5 until eventually lowering it to float voltage when above 90%. (Approximate values)
if during boost mode I check the voltage it is 14.4 Right from the start.
I thought that the solar would be the same. Set the boost voltage to 14.8 and it would boost (charge ) at that until about 85% capacity and then taper off. Not use the 14.8 boost setting as an upper limit for when to taper off?

[sensij]

I really appreciate your time. I am new at this but trying to get my head around it and do it properly.
I have an ac 70 amp charger. It maybe a totally different situation, or the same you can tell me.
It has a boost mode. When the batteries are low say 50% 12.2, it raises voltage to 14.4. And keeps it there until it reaches about 85% of charge. Then it backs off the voltage to say 13.5 until eventually lowering it to float voltage when above 90%. (Approximate values)

You are getting fooled by the internal resistance of the battery. The open circuit voltage is not immediately raised to 14.4, but the measured voltage does rise because you are pumping so much current in. If you turned off your AC charger immediately after turning it on, you would see your battery voltage fall back down and rest at something close to where it started.

Remember, Measured voltage = OCV + (I * Ri)

Since you have three pairs in parallel, let's use 0.033 ohm as Ri, and this time with 70 A of charge current.

Measured voltage = 12.2 + (0.033 * 70) = 14.5 V. In this scenario, when you have that much charge current available, it will jump immediately to the constant voltage stage of charging, as you've observed.

The algorithms it is using to set the constant voltage from there are somewhat specific to your charger.

Again, with 19.2 A of solar instead of 70 A of charging.

12.2 + (0.033 * 19.2) = 12.84 V measured.

Do you see how 12.84 V and 14.5 V measurements can both represent the exact same battery (with different charging currents), which has an open circuit voltage of 12.2 V?

This conversation would be much more anchored if you have the ability to measure specific gravity, and think about state of charge in those terms instead of in voltage.