Controller values fluctuating all the time after battery upgrade.

[CaptWharfRat]

Hi. I have an isunergy mppt 40 controller with 6 x 100 watt panels in series. My battery bank is 48v. I just upgraded them from 35ah to 100ah. Same type SLA gel.
After hooking the bank back up to the controller now all the values, volts, amps and pv volts are constantly fluctuating and not charging the back fully.
This is my controller
JN-MPPT-AL-40A
Panels are renorgy 100 watt x 6
Batteries are
Eaton PWHR12390W4FR 12v 100ah

I am guessing it is a setting somewhere, atleast i hope thats all.

 

[mikefitz]

Maximum solar input voltage for your controller is 100 volts. 6 panels in series exceeds that , causing erratic operation and possible damage to the controller.
Reconfigure the panels as two 3 panel strings in parallel.
The controller is also sold by Renogy as the Rover.
With high panel volts I would expect an E10 error.
Panel specification is Voc 24v, Vmp 20.4 v

It's possible there could be other issues but panel overvolts is the most likely problem and needs correcting.

Mike

 

[CaptWharfRat]

Maximum solar input voltage for your controller is 100 volts. 6 panels in series exceeds that , causing erratic operation and possible damage to the controller.
Reconfigure the panels as two 3 panel strings in parallel.
The controller is also sold by Renogy as the Rover.
With high panel volts I would expect an E10 error.
Panel specification is Voc 24v, Vmp 20.4 v

It's possible there could be other issues but panel overvolts is the most likely problem and needs correcting.

Mike

My battery bank is 48v and that puts the max volts to 145. I will try lowering the volts and see if that does it.

 

[MichaelK]

Maximum solar input voltage for your controller is 100 volts. 6 panels in series exceeds that , causing erratic operation and possible damage to the controller.
Reconfigure the panels as two 3 panel strings in parallel.
The controller is also sold by Renogy as the Rover.
With high panel volts I would expect an E10 error.
Panel specification is Voc 24v, Vmp 20.4 v

It's possible there could be other issues but panel overvolts is the most likely problem and needs correcting.

Mike

I don't think that's correct? It appears that the 100V limit is only for a 12V battery


What I would suggest doing is to first disconnect the solar, then disconnect the battery, and let the controller go stone cold for a couple of minutes. After the wait, boot up the controller on battery power ONLY. After completely booting the controller on battery only, reconnect the solar and see if it behaves more stably.

BTW, that particular battery appears to be designed for stand-by UPS service, and really isn't the best choice for off-grid, deep-cycling.

 

[mikefitz]

My apologies for my error, I assumed it was the 12/24 model controller, shoud have noted the 48 volts system.


However the specification suggests 145 volts is the maximum, input range 80 to 150 volts.
Panel Voc is 24 volts , 6 series panels is 144 volts. The Voc is at 25deg C, temp coeff typically 0.4%/degC so cool panels may exceed the maximum . From the limited data on the controller there seems to be a high degree of performance monitoring so may be able to Indicate possible faults.

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Mike

 

[MichaelK]

However the specification suggests 145 volts is the maximum, input range 80 to 150 volts.
Panel Voc is 24 volts , 6 series panels is 144 volts. The Voc is at 25deg C, temp coeff typically 0.4%/degC so cool panels may exceed the maximum .

Good call on the Voc. I was used to their older model that had a Voc of only ~21V. Actually, with a Voc of 24.3V, six panels already bumps the voltage to 145.8, and that's at room temperature.

The OP seems to have two options right now. Either remove one panel and have only 5 in series, or buy two more and wire them 4S2P.

 

[CaptWharfRat]

Where i live i have never seen the voltage go above 130v on the best days no matter the temp. I find that renorgy panels give out about 85 - 90% of what they claim. I live aboard year round and constantly monitor them. 2 yrs with no issues until now. Seems that after leaving the panel disconneted for 12hrs the controller sorted it's self out.
As far as wrong kind of batteries i use this 48v bank to run my 5kw electric motor. These work ok for that but when i can afford lithium i will switch. And i got these for $90. Canadian each. Brand new. ?