Is my Epsolar Tracer MPPT charge controller Broken?

[t1m]

Got an Epever Tracer 1215n in my motorhome. The lifepo4 battery doesn't get charged under load anymore. Nor does it get charged past 13.1v. With a multimeter at the "solar terminal" I see that 13.8v is incoming from the solar panels into the Epever charge controller.

The output measured with multimeter on the Tracer's "battery terminal" is only 13.1 v. Does this mean the Tracer doesn't put out anymore or could it also be an issue further down the line such as the shunt, a connection, the BMS, the battery that causes the charge controller to only put out 13.1v at the "battery terminal"?

Trying to understand how this all works. Any input is greatly appreciated.

 

[MisterSandals]

With a multimeter at the "solar terminal" I see that 13.8v is incoming from the solar panels into the Epever charge controller.

Normally, SCCs require solar input 5V higher than battery voltage before they start charging.

 

[t1m]

The SCC is set to go to float (13,8v) after 3 hours bulk charging. 3 hours is the max in the Tracer's settings. It does charge with higher voltage and current before that. But not to 100% or near that SOC. I also see a different current on the BM1 monitor versus the amps drawn according to the BMS smartphone app. This discrepancy must have something to do with the issue, it seems

 

[MisterSandals]

What does your array look like? My gut feel is your array is too low voltage.

 

[mikefitz]

I

could it also be an issue further down the line such as the shunt, a connection, the BMS, the battery that causes the charge controller to only put out 13.1v at the "battery terminal"?

Its possible. More information about the system would be useful.
Does the battery charge with alternative chargers? Does the battery deliver current to loads?
It seems you have BMS data, is the BMS entering protection mode? What battery?
How are you determining SOC?
Have you measured panel OC volts and SC current disconnected from the controller?

Mike

 

[t1m]

What does your array look like? My gut feel is your array is too low voltage.

3x 150 watt panels
Epsolar Tracer 1215 TN SCC (30A)
MT50 SCC monitor
100A shunt
Nasa BM1 battery monitor
80 Ah EVE cells lithium battery nominal capacity: 72Ah, cycle capacity: 57.6Ah
Single full voltage 3.35 volt
Victron Multiplus Compact 12 800 35

 

[t1m]

I
Its possible. More information about the system would be useful.
Does the battery charge with alternative chargers? Does the battery deliver current to loads?
It seems you have BMS data, is the BMS entering protection mode? What battery?
How are you determining SOC?
Have you measured panel OC volts and SC current disconnected from the controller?

Mike

Today when the battery was probably about fully charged, the BMS went into cell voltage overload protection. One cell reached (almost?) 3.65v
This made me think bulk charge at 14.2V is set too high in the Epsolar Tracer. I have lowered it to 14v. (float at 13.8v)
Today the battery was charged properly so it seems. From 5 to 8 A in the morning up to 20A towards noon and after.
Panel voltage ranged from 17volt up to temporarily 21.5volt.

Since yesterday I noticed there was hardly any charging, after drawing approx. 30Ah in the evening both the Nasa BM1 as well as the BMS app showed a battery voltage of 12.6V yesterday night and early this morning, which I understand is roughly 15% SOC.

I determine SOC by aforementioned and by counting how much I used in the evening and how much I see getting in the next day.
Yesterday and today I did not let the battery draw any loads. In other words, the Victron Multiplus was kept off
No I haven't measured panel OC volts and SC current disconnected from the controller.

What I'd like to understand is why the system doesn't seem to properly charge the battery at some days whereas today it seemingly did. Could this simply be a matter of inappropriate float and bulk charge settings in the MT50 SCC monitor? (currently 13.8v and 14v resp.)

 

[MisterSandals]

3x 150 watt panels
Epsolar Tracer 1215 TN SCC (30A)

Is the max input voltage high enough to handle these 3 panels in series? If so, that would GREATLY increase the voltage and charge earlier, later and in low light conditions.

 

[mikefitz]

system doesn't seem to properly charge the battery at some days whereas today it seemingly did. Could this simply be a matter of inappropriate float and bulk charge settings in the MT50 SCC monitor? (currently 13.8v and 14v resp.)

Some Epever users have symptoms where the controller seems to enter a low charge state. Disconnecting and reconnecting the panels often restores full charge rate.
Your charge voltages, 14.0, 13.8 should not be the problem.
Your battery at 72Ah with 80Ah cells sounds that the cells may be used cells and perhaps unbalanced, when you have a successful charge is there a large difference in cell volts?

Single full voltage 3.35 volt

That's resionable for a rested battery, under charge I would expect the cell to reach over 3.45 volts.

The 150 watt panels will have a Voc around 22 volts, so connecting in series is possible as suggested. Worth trying if practical.

Mike

 

[t1m]

Is the max input voltage high enough to handle these 3 panels in series? If so, that would GREATLY increase the voltage and charge earlier, later and in low light conditions.

That would be the 30A that the Epsolar Tracer is supposed to be able to charge with, right? Well, I've never seen a charge of 30A. 20 something amps at most.

 

[t1m]

Some Epever users have symptoms where the controller seems to enter a low charge state. Disconnecting and reconnecting the panels often restores full charge rate.
Your charge voltages, 14.0, 13.8 should not be the problem.
Your battery at 72Ah with 80Ah cells sounds that the cells may be used cells and perhaps unbalanced, when you have a successful charge is there a large difference in cell volts?

That's resionable for a rested battery, under charge I would expect the cell to reach over 3.45 volts.

The 150 watt panels will have a Voc around 22 volts, so connecting in series is possible as suggested. Worth trying if practical.

Mike

No the BMS balances and there's generally very little difference in single cell voltage.
The panel voltages on the MT50 monitor did touch 22v today a few times but were reduced down to 17v ish soon thereafter.
The seller said he balanced the cells before I picked them up. Didn't say anything about B grade or used cells though.
Gonna try to dis- and reconnect the panels next time there's low charge rate

 

[MisterSandals]

That would be the 30A that the Epsolar Tracer is supposed to be able to charge with, right? Well, I've never seen a charge of 30A. 20 something amps at most.

No, its the max input voltage of your SCC. What does your manual say this voltage is? And what are the specs of your panels? (mainly the Voc).

 

[t1m]

No, its the max input voltage of your SCC. What does your manual say this voltage is? And what are the specs of your panels? (mainly the Voc).

Can't find the manual right now. It's the EPSolar Tracer 4215BN 12V / 24V 40A MPPT LDR.

Maximum battery voltage	32V
Max. solar input voltage	150VDC

Max. PV input power

Tracer4215BN 520W(12V);1014W(24V)

I don't remember the VoC of the panels but if I'm correct they were able to put out roughly 8 amps each, so 24 amps in total. If that makes sense for 150 watt panels.

 

[MisterSandals]

Epsolar Tracer 1215 TN SCC (30A)

EPSolar Tracer 4215BN

Which is it?

150W / 8A = 18.75V

If your SCC accepts 150V input then you should definitely put your 3 panels in series. I suspect this will solve your charging issues.

 

[t1m]

Which is it?

150W / 8A = 18.75V

If your SCC accepts 150V input then you should definitely put your 3 panels in series. I suspect this will solve your charging issues.

It's the EPSolar Tracer 4215BN 12V / 24V 40A MPPT LDR

With 150W / 8A = 18.75V you mean that the solar panel voltage will reach 18.75V while charging?

 

[MisterSandals]

With 150W / 8A = 18.75V you mean that the solar panel voltage will reach 18.75V while charging?

This 18.75V is what each panel provides to the MPPT. 3 panels in parallel like you have them will supply this voltage but with the sum of the amps of the 3 panels (24A).
Connecting in series, sums the volts (3x 18.75V = 56.25V) to the MPPT.

Your MPPT is designed specifically to convert higher array voltage to your charging voltage (you probably have it set to about 14V).

As was stated earlier, MPPTs normally require your battery voltage (~13V) plus 5V before they start charging.
In low light, your array with all 3 panels in parallel (~18.75V best case!) will struggle to reach the starting voltage. With all 3 in series, the 3 panels together will reach charging voltage far earlier in the day, later in the afternoon and in low light conditions.

 

[t1m]

This 18.75V is what each panel provides to the MPPT. 3 panels in parallel like you have them will supply this voltage but with the sum of the amps of the 3 panels (24A).
Connecting in series, sums the volts (3x 18.75V = 56.25V) to the MPPT.

Your MPPT is designed specifically to convert higher array voltage to your charging voltage (you probably have it set to about 14V).

As was stated earlier, MPPTs normally require your battery voltage (~13V) plus 5V before they start charging.
In low light, your array with all 3 panels in parallel (~18.75V best case!) will struggle to reach the starting voltage. With all 3 in series, the 3 panels together will reach charging voltage far earlier in the day, later in the afternoon and in low light conditions.

To be sure I understand what's exactly a starting voltage.... this morning at 9AM when the sun just had risen, the panels were at 17.4V and the MPPT charged during the hour with 3A to 6A at 13.5V.

Then from 10AM till 11Am the panel voltage was 16.9V and dropped to 16.2V when it became a bit cloudy. Charge ranged from 8A to 11A at 13.8V and halted momentarily there because of the clouds.

So do you mean with starting voltage that if the panels were in series, the panel voltage would be much higher from the get go and the MPPT could charge basically as soon as the sun has risen with 13.8V (float) or even with 14V (bulk)?

Or do you mean that normally there is a panel voltage threshold (~5V > battery voltage) and if that isn't met there will be no charging at all?

 

[MisterSandals]

So do you mean with starting voltage that if the panels were in series, the panel voltage would be much higher from the get go and the MPPT could charge basically as soon as the sun has risen with 13.8V (float) or even with 14V (bulk)?

Exactly this.

Or do you mean that normally there is a panel voltage threshold (~5V > battery voltage) and if that isn't met there will be no charging at all?

This is usually the case. Your array low voltage has to be very close to this threshold to "start". There is a point a little lower voltage where it stops (like when you got clouds).

You definitely should put your 3 panels in series.

 

[t1m]

Exactly this.

This is usually the case. Your array low voltage has to be very close to this threshold to "start". There is a point a little lower voltage where it stops (like when you got clouds).

You definitely should put your 3 panels in series.

Got it, thanks a lot. Will the amperage with which it charges stay the same if the panels are in series?

 

[MisterSandals]

Got it, thanks a lot. Will the amperage with which it charges stay the same if the panels are in series?

Yes if the SCC is getting the same number of watts... (which it should but at a more useable voltage).

Either way you are supplying 450W to the SCC and its job is to turn that into your charging volts (14V?) with as many amps as it can.
450W solar / 14V charging = 32A charging (operating at 100%... which never happens)