Bulk Charge Troubleshooting

apple036

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Background: 8 months without issues, 2x 150w panels & 1x 100w panel in series, 40a MPPT charge controller, down to 4x 100ah gel batteries in parallel.

Was diagnosing why my battery isolator wasn’t working when I was driving, so I had disconnected batteries, etc, looking at voltages at various points in the system. Cleaned off terminals, hooked everything back up. Now it seems like the highest voltage the batteries display while charging is ~13.3v (~7a), compared to previously, when they’d show ~14.2v.

Solar output seems the same (ballpark of 51v, 2.X amps). This happened just a couple days ago. Gel setting on controller hasn’t changed.

Any ideas for what to troubleshoot? Voltage at controller and battery terminals is the same.
 

sunshine_eggo

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It sounds like a charge controller failure, unless they were deeply discharged while disconnected. The power you're seeing (51V/2.XA) is only about 100W. That means you're charging at about 7-8A. At 7-8A, it would take 53 hours to charge your bank.

I would confirm the batteries can be charged to ~14.0V with an alternate method.

Additionally, you may have crippled your array in the 3S configuration.

For 150W panels, what is Vmp/Imp?
For 100W panel, what is Vmp/Imp?
 

HRTKD

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I would dig into the charge profile of the solar charge controller and see what the parameters are. Sounds like something is off there.

Mismatched panels like you have often doesn't work optimally. Three panels of the same specs would work better.
 

smoothJoey

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Connected to is probably more appropriate. No battery monitor.
A shunt based battery monitor will tell you whether current is going into or out of the battery.
It could be that your solar charge controller and panels are not delivering or it could be that you have a sneaky load.
 

apple036

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It sounds like a charge controller failure, unless they were deeply discharged while disconnected. The power you're seeing (51V/2.XA) is only about 100W. That means you're charging at about 7-8A. At 7-8A, it would take 53 hours to charge your bank.

I would confirm the batteries can be charged to ~14.0V with an alternate method.

Additionally, you may have crippled your array in the 3S configuration.

For 150W panels, what is Vmp/Imp?
For 100W panel, what is Vmp/Imp?
They were discharged to around 50% while disconnected. I was thinking of doing that next, connecting them to a charger to make sure they can get to 14V.

150W: 17.0V/8.28A
100W: 16.77V/6.26A
 

sunshine_eggo

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They were discharged to around 50% while disconnected. I was thinking of doing that next, connecting them to a charger to make sure they can get to 14V.

then they need AT LEAST 26 hours of charging WITH NO POWER USAGE AT ALL.

150W: 17.0V/8.28A
100W: 16.77V/6.26A

Your array is compromised. In series, the 150W panels are forced to operate at 6.26A, so you're losing 25% of each of those panels.

You need to parallel them to use their full power.
 

apple036

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I would dig into the charge profile of the solar charge controller and see what the parameters are. Sounds like something is off there.

Mismatched panels like you have often doesn't work optimally. Three panels of the same specs would work better.
It’s an EPEVER Tracer. Specs from user manual:

Gel
Over Voltage Disconnect Voltage 16.0V
Charging Limit Voltage 15.0V
Over Voltage Reconnect Voltage 15.0V
Equalize Charging Voltage ——
Boost Charging Voltage 14.2V
Float Charging Voltage 13.8V
Boost Reconnect Charging Voltage 13.2V
Low Voltage Reconnect Voltage 12.6V
Under Voltage Warning Reconnect Voltage 12.2V
Under Voltage Warning Voltage 12.0V
Low Voltage Disconnect Voltage 11.1V
Discharging Limit Voltage 10.6V
Equalize Duration ——
Boost Duration 120 min
 

apple036

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then they need AT LEAST 26 hours of charging WITH NO POWER USAGE AT ALL.



Your array is compromised. In series, the 150W panels are forced to operate at 6.26A, so you're losing 25% of each of those panels.

You need to parallel them to use their full power.
Thanks for the feedback. So, this system is in my van, which I live & work in. Is my best bang for buck here to order connectors & wire in parallel? And then also pull the batteries, get them fully charged. Other option I see would be getting a matching 3rd 150W panel (which is more expensive/more time to install).
 

HRTKD

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I can't speak to your gel batteries, but my AGM batteries weren't getting a proper AGM charge and I had to perform a reconditioning process to bring them back to proper working order. My lead acid charger simply wasn't giving them a high enough charge.

I would get a third 150 watt panel, but verify that it won't put you over the Max PV Input Voltage amount.

The parameters I would like to see are what the solar charge controller is currently operating off of, not what the manual says it's supposed to be.
 

sunshine_eggo

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Thanks for the feedback. So, this system is in my van, which I live & work in. Is my best bang for buck here to order connectors & wire in parallel?

Yes. A set of parallel connectors will probably run you ~$20.

And then also pull the batteries, get them fully charged. Other option I see would be getting a matching 3rd 150W panel (which is more expensive/more time to install).

I would work towards a minimum effort solution ('cause I'm lazy). Is there any way you can charge the batteries in place? An automotive 12V charger connected to AC power?
 
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