Troubleshooting solar issues

[justamaninavan]

I have 3 100 Watt Renogy solar panels, 1 30A MPPT charge controller (Epever 3210A), and 2 100 AH universal battery AGMs. It has been hooked up since yesterday morning with nothing plugged in, and it is currently 1:37 pm and sunny. Yet my charge controller says my panels are at 20.9V and giving .4A, with my battery at 13.8V and taking .6A. 
My limited knowledge would say my solar should be generating much more electricity. Except, I have checked all connections and they seem to be connected correctly. So my question to you all is could this be a charge controller or battery issue? Or possibly something else I haven't considered?


Thank you

 

[highdesertranger]

are your batteries full? put a load on them and see what happens. highdesertranger

 

[justamaninavan]

are your batteries full?  put a load on them and see what happens.  highdesertranger

I attached my invertor to charge my phone. My charge controller says my solar panels are at 20.6V giving 1.1A and my batteries are at 13.8V taking 1.6A.

 

[justamaninavan]

I attached my invertor to charge my phone. My charge controller says my solar panels are at 20.6V giving 1.1A and my batteries are at 13.8V taking 1.6A.

And I do not know If their full.

 

[jonsun]

nearly same setup here, that's normal. It means you're full.

you're phone is WAYYY too small of a load. hook a few fans, laptop, etc up and it will go down to around 17.X and about 5A

If you dont have the MT-50 defintely get that and it will show what your daily, monthly, and total watt hours are plus lets you do user programming.

 

[John61CT]

You need to measure volts and Amps going into the bank.

The high Absorb voltage should remain until current drops to .05-3A, at which point the bank is Full.

Only then should the controller drop volts to Float.

If you want to see lots more amps coming out of the SC, put on a 5-10A load and drop the battery to 50% depleted in the middle of a sunny day.

When the bank is full and loads are low, the panel output is being wasted. Not a problem, but some like to have "opportunity" load dumps available to take advantage of the free excess power, like hot water service or ice making or. . .

 

[jonyjoe303]

Are your panels connected in parallel or in series. With 300 watts of panels you be getting at least 15 amps of charge current (if your battery is low). 

With your mppt controller you will get the 15 amps if they are connected in series, in parallel you might get less. The mppt will take the higher voltage and give you more amps.

One thing I would check is the voltage on the actual battery with a voltmeter and bounce that with what the controller is reading. If there is any voltage drop, you need to raise the bulk voltage on the controller. If the controller reads 13.8 volts, the battery also has to read 13.8 volts. If there is voltage drop, your battery will not be getting fully charge. The controller when it reads 14.4 volts will switch to float, your battery might actually only be 14 volts if there is a voltage drop. With 200 ah of batteries you don't want to undercharge them. Myself I would just raise the float voltage to 14.4 volts and keep it there all the time, agm batteries prefer to be kept at the higher voltage, they just take less amps when they are full. The only time its good to float batteries at lower voltages is when they are connected to house power 24/7 and not being used. 

Something that is suppose to happen when the battery reaches 14.4 volts, is the controller should be switching to absorb and it will hold at 14.4 volts for several hours until the amps go down to around 2 amps. Some controllers just switch to float and the battery is only 80 percent full, it needs those several hours to finish the final 20 percent.

 

[Weight]

What size, awg, are the cables to/from battery bank and solar panels to controller?

 

[tx2sturgis]

The numbers all sound pretty much in the 'ballpark' for a system in standby, waiting for a load.

 

[frater secessus]

I attached my invertor to charge my phone. My charge controller says my solar panels are at 20.6V giving 1.1A and my batteries are at 13.8V taking 1.6A.

When an MPPT controller is running the panels at higher than their peak output voltage (Vmp), it means it is limiting output on purpose because the banks don't need any more power.  The highest Vmp on any Renogy panel I know of is 18.9v for their 100W mono.  The 100W poly is 17.something.   20.6V is well above that, and strongly suggests your system is idling along. 

My take:
13.8V  is the float setpoint (Vfloat) defined for your controller.
your battery bank is fully charged and the solar setup is twiddling its thumbs, waiting.

This concern is common enough I am working on a wiki page on how to tell if one's solar is working.

 

[justamaninavan]

Are your panels connected in parallel or in series. With 300 watts of panels you be getting at least 15 amps of charge current (if your battery is low). 

With your mppt controller you will get the 15 amps if they are connected in series, in parallel you might get less. The mppt will take the higher voltage and give you more amps.

One thing I would check is the voltage on the actual battery with a voltmeter and bounce that with what the controller is reading. If there is any voltage drop, you need to raise the bulk voltage on the controller. If the controller reads 13.8 volts, the battery also has to read 13.8 volts. If there is voltage drop, your battery will not be getting fully charge. The controller when it reads 14.4 volts will switch to float, your battery might actually only be 14 volts if there is a voltage drop. With 200 ah of batteries you don't want to undercharge them. Myself I would just raise the float voltage to 14.4 volts and keep it there all the time, agm batteries prefer to be kept at the higher voltage, they just take less amps when they are full. The only time its good to float batteries at lower voltages is when they are connected to house power 24/7 and not being used. 

Something that is suppose to happen when the battery reaches 14.4 volts, is the controller should be switching to absorb and it will hold at 14.4 volts for several hours until the amps go down to around 2 amps. Some controllers just switch to float and the battery is only 80 percent full, it needs those several hours to finish the final 20 percent.

I have the MT-50, but cannot figure out how to change the float voltage to 14.4 volts.

 

[John61CT]

Is this post helpful? http://techluck.com/cgi-bin/YaBB.pl?num=1486955008

 

[frater secessus]

The controller when it reads 14.4 volts will switch to float...
...
Something that is suppose to happen when the battery reaches 14.4 volts, is the controller should be switching to absorb and it will hold at 14.4 volts for several hours until the amps go down to around 2 amps. Some controllers just switch to float and the battery is only 80 percent full, it needs those several hours to finish the final 20 percent.  [emphasis added]

I think something got crossthreaded up there, and it might confuse the OP.


His A-series tracer controller goes through the normal three-stage routine.  If it is at factory settings (sealed/AGM) it's

Bulk until Absorption voltage (Vabs) is reached
Absorption at 14.4v for 120 minutes
Float at 13.8v thereafter

which is fine for now and in line with what he has described.


OP:  to adjust the setpoints you will first need to set the profile to USER (ie, user-specified) battery type as the built-in profiles (AGM, FLA, GEL) cannot be modified.  You get to the configs by hitting the left MENU button, then down to #4 Control Parameters.  This info starts at about page 12 of the manual (pdf). 

Having said that, I do not recommend messing with it yet.  Given the data there is every chance your system is working as designed.  John absolutely nailed it earlier when he said:

If you want to see lots more amps coming out of the SC, put on a 5-10A load and drop the battery to 50% depleted in the middle of a sunny day.

He's saying if you want to observe the system making lots of power:

• stop charging
• run the battery bank down with some significant loads
• wait until you have full sun
• and start charging
• watch the system drop the hammer on those discharged batteries
• smile like a kid at christmas <-- optional but highly recommended

Until then there is nowhere for the power to go.  As the zen master pointed out, you can't pour more tea into a teacup that is already full.

 

[justamaninavan]

I think something got crossthreaded up there, and it might confuse the OP.


His A-series tracer controller goes through the normal three-stage routine.  If it is at factory settings (sealed/AGM) it's

Bulk until Absorption voltage (Vabs) is reached
Absorption at 14.4v for 120 minutes
Float at 13.8v thereafter

which is fine for now and in line with what he has described.


OP:  to adjust the setpoints you will first need to set the profile to USER (ie, user-specified) battery type as the built-in profiles (AGM, FLA, GEL) cannot be modified.  You get to the configs by hitting the left MENU button, then down to #4 Control Parameters.  This info starts at about page 12 of the manual (pdf). 

Having said that, I do not recommend messing with it yet.  Given the data there is every chance your system is working as designed.  John absolutely nailed it earlier when he said:




He's saying if you want to observe the system making lots of power:

• stop charging
• run the battery bank down with some significant loads
• wait until you have full sun
• and start charging
• watch the system drop the hammer on those discharged batteries
• smile like a kid at christmas <-- optional but highly recommended

Until then there is nowhere for the power to go.  As the zen master pointed out, you can't pour more tea into a teacup that is already full.

Last night I ran my battery bank down to 12.2V. By mid afternoon it reached 14.4V, then went down to 13.8V in float mode as you described. (Huge smile) After it reached float mode, I kept all my electrical devices unplugged. I check again at 8 o'clock tonight, and it said my batteries were at 12.4V. My question is, if my batteries have nothing to power, how can they have lost all their juice?

 

[John61CT]

Well not all, but certainly not getting to full, or not holding their charge, apparently only half way.

Simplest explanation is it needs to hold Absorb a lot longer.

The voltages you see while charging does not correspond to the battery's SoC, but the charger output.

Are you fully isolating the bank from all loads? While charging? How long?

The controller may be misconfigured or not working.

Check all the connections.

Have you got a known good tool for reading volts and amps other than the controller?

Maybe the batts are old or damaged?

Do you have a shore charger to test the bank?

A known good batt to test the charger?

 

[frater secessus]

Simplest explanation is it needs to hold Absorb a lot longer.

Agreed. 

A simple way to do this would be to set Absorb and Float voltages to the same (14.4v or close) for a few days.  Or maybe just keep it there.

 

[John61CT]

Without any loads.

Loads higher than inputs just drag SoC lower a bit more slowly.

 

[justamaninavan]

Well not all, but certainly not getting to full, or not holding their charge, apparently only half way.

Simplest explanation is it needs to hold Absorb a lot longer.

The voltages you see while charging does not correspond to the battery's SoC, but the charger output.

Are you fully isolating the bank from all loads? While charging? How long?

The controller may be misconfigured or not working.

Check all the connections.

Have you got a known good tool for reading volts and amps other than the controller?

Maybe the batts are old or damaged?

Do you have a shore charger to test the bank?

A known good batt to test the charger?

1. Yes, yesterday while charging my battery was isolated from all loads. If how long you mean charging, my guess was it took 4-6 hours. Or if you mean how long after I'd also say 4-6 hours.
2. As far as I can tell all the connections are solid.
3. I believe so, I have a Tacklife CM01A Advanced Digital Clamp Meter 4000.
4. I bought these batteries brand new, but they have been in my apartment for 2 months without a charge source.
5. I do not have a shore charger.
6. I do not have a separate good battery to test.

 

[John61CT]

OK. For testing, set Float volts to the same as Absorb, nothing connected but the batteries, recording amps, every 30 min or hourly. Confirm volts stays there throughout.

What model batts, total AH?

Use .005C to start as endAmps, keep charging until current falls to .5A per 100AH.

That defines "Full", stop charging. Record voltage. Leave isolated until the next day, record voltage again.

Report back here.

Next step, rough load test @ .05C, 5A per 100AH.

 

[justamaninavan]

OK.  For testing, set Float volts to the same as Absorb, nothing connected but the batteries, recording amps, every 30 min or hourly. Confirm volts stays there throughout.

What model batts,  total AH?

Use .005C to start as endAmps, keep charging until current falls to .5A per 100AH.

That defines "Full", stop charging. Record voltage. Leave isolated until the next day, record voltage again.

Report back here.

Next step,  rough load test @ .05C, 5A per 100AH.

I'm on it. I have 2 Universal UB121000-45978 12v 100AH Deep Cycle AGM Battery.
I am not sure what you mean by "Use .005C to start as endAmps, keep charging until current falls to .5A per 100AH."