Did Victron BlueSolar Kill My Batteries?

[zstine]

I installed a Victron BVM-700 battery monitor, a Victron BlueSolar 100v/50a MPPT controller and 530W of panels 2 years ago. They worked fine last year and I haven't payed much attention to the system this season. Last Saturday I noticed my battery voltage was kind of low 12V, even though the monitor said I had a SOC of like 95%. I also saw the charger was on Float charge. I disconnected the panels and opened the controller-battery breaker and then reconnected everything and it went to bulk charge so I walked away fat-dumb-happy. That night I was woken up by a low voltage alarm on my inverter. 10.9V! I shut everything off and dealt with it in the morning. What I found is 2 separate issues. First the SOC is wrong because the monitor auto-synchs incorrectly with a solar charger and this is discussed in the monitor manual. That should not affect the charge controller as the 2 units do not communicate. What I found is the BlueSolar controller is reading a much higher voltage than true. As seen in the attached photo, my correct voltage is 11.8, while the controller is thinking it is 14.4V and only charging at 2.8Amps. I forced it into equalize and it jumped to 25+amps of charge, which it should have been at with 11.8V. I could not find any tech support on Victron's web page. This has been going on for a bit and my batteries are toast from undercharging.
Can you help? How do I fix the Charge controller's erroneous voltage reading? I just bought 3 more expensive batteries and I don't want to toast them too.
Thanks,
Zach

[Simi 60]

Might be worth asking the question on the victron blog as well.
I had my issues sorted fast.

[zstine]

Originally Posted by Simi 60

Might be worth asking the question on the victron blog as well.
I had my issues sorted fast.

Done.. hope CF comes through.

[fallingeggs]

I have both the solar controllers and monitor. They are a tenth or two different generally, so something is up with yours.

Have you confirmed which reading is correct with a Multimeter?

Maybe the current wires from the controller to batteries are corroded or loose? Can you change out these wires for some new 10 gauge? Anything else between the controller and batteries that could cause resistance / voltage drop (loose busbar, bad lug)?

Victron has great service, so I am sure they can figure out the answer. Would be grateful if you post it here just in case it happens to me!

[Scott Berg]

Call Victron directly
Great tech support

[zboss]

Are you sure that the 14.4 shown on the iPhone isn’t the absorption charge voltage and the 11.84 the actual battery voltage? If you are using the batteries it will pull down the voltage on the battery, so first try and switch off everything using the batteries. Maybe you have a bad piece of equipment, like a bad fridge compressor or maybe a loose cable that is pulling the voltage down more than it should. The panel is only showing that it’s producing 41 watts so maybe the panel is bad.

Just some ideas.

[fallingeggs]

Originally Posted by zboss

Are you sure that the 14.4 shown on the iPhone isn’t the absorption charge voltage and the 11.84 the actual battery voltage? If you are using the batteries it will pull down the voltage on the battery, so first try and switch off everything using the batteries. Maybe you have a bad piece of equipment, like a bad fridge compressor or maybe a loose cable that is pulling the voltage down more than it should. The panel is only showing that it’s producing 41 watts so maybe the panel is bad.

Just some ideas.

The solar controller has a set absorption voltage of 14.4, which it thinks has been reached, switching itself to absorption mode from bulk.

The batteries are also only accepting 41 watts, which wouldn't be unusual if they were near 100% SOC. But if the monitor is to be believe, they aren't even being charged!

Mystery.

[Captain Bill]

First thing you need to do is get a proper volt meter and determine the real battery voltage measured at the battery posts. Given the low voltage alarm on the inverter it is likely the battery monitor is correct. Then you need to measure the voltage at the output of the solar controller. If it is really at 14.4 then you have a problem with the wiring between the solar controller and the batteries. If the voltage at the posts reads the same as the batteries then you have a controller problem. Remember to measure the voltage on the output posts, not the lug on the cable. The problem may simply be a poor connection as suggested previously.

[Maine Sail]

How is the system physically wired?

[Mike OReilly]

I have the same arrangement and also see the voltage within 0.2 v of each other. My solar controller is only one year old though (100/30 version). So far, no problems. Love it!

I too would check things with a good multimeter right at the battery posts, then all along the runs. Something ain’t right...

[zstine]

PO here. Yes, The 11.8 volts was checked with a multi meter and is correct. The controller thinks the batteries have a higher voltage, so I don't see how corroded wires would cause higher voltage, but the wires show no sign of corrosion that I can see.

Main Sail - The system has 6 gauge wire from the batteries to the controller via a 50Amp breaker and the run is less than 3 ft. 10awg to the panel, 20ft run. Controller is stand alone, so that's it.

zboss - Just after the photo I manually put the controller in Equalize mode and I was getting over 300W and 25Amps of charge. So, the controller was limiting the panels to 41 watts, it was not the panel max output.

Contact their Tech support!? I can only find phone numbers for sales on their web page.... I guess I can try that and hope they have a number for Tech Support.

Why would the controller think the battery voltage is HIGHER than the actual true voltage? Corroded wires doesn't make sense.

[Maine Sail]

Originally Posted by zstine

PO here. Yes, The 11.8 volts was checked with a multi meter and is correct. The controller thinks the batteries have a higher voltage, so I don't see how corroded wires would cause higher voltage, but the wires show no sign of corrosion that I can see.

Main Sail - The system has 6 gauge wire from the batteries to the controller via a 50Amp breaker and the run is less than 3 ft. 10awg to the panel, 20ft run. Controller is stand alone, so that's it.

zboss - Just after the photo I manually put the controller in Equalize mode and I was getting over 300W and 25Amps of charge. So, the controller was limiting the panels to 41 watts, it was not the panel max output.

Contact their Tech support!? I can only find phone numbers for sales on their web page.... I guess I can try that and hope they have a number for Tech Support.

Why would the controller think the battery voltage is HIGHER than the actual true voltage? Corroded wires doesn't make sense.

Is it wired to a contiguously wired parallel or series/parallel house bank? Same bank the BMV is monitoring? What are the exact settings for the controller?

[zstine]

The panels are wires in series, two 265W Kyrocera panels. I have 3 Lead Acid batteries in the house bank, the controller connected to directly to the first battery. The monitor shunt is obviously in the Negative Bus, but there is a small ~18awg fused power wire to the monitor, which I guess must also be how it senses voltage(?). That is connected to the 2nd battery in the house bank (Same bank) and there is heavy 0awg wire connecting the 3 house batteries in parallel. The voltage difference should be minimal, certainly not over 2V different.

[john61ct]

Originally Posted by fallingeggs

The solar controller has a set absorption voltage of 14.4, which it thinks has been reached, switching itself to absorption mode from bulk.

side note, no controller "switches itself" from CC to CV, that is transition is inherent in the batt chemistry's resistance, even with a simple power supply

[fallingeggs]

Originally Posted by zstine

The panels are wires in series, two 265W Kyrocera panels. I have 3 Lead Acid batteries in the house bank, the controller connected to directly to the first battery. The monitor shunt is obviously in the Negative Bus, but there is a small ~18awg fused power wire to the monitor, which I guess must also be how it senses voltage(?). That is connected to the 2nd battery in the house bank (Same bank) and there is heavy 0awg wire connecting the 3 house batteries in parallel. The voltage difference should be minimal, certainly not over 2V different.

Where the solar controller is connected might be the problem. Best practice is to connect the positive to battery 1 and the negative to battery 3. Connecting both leads to battery 1 could cause uneven charging.

The monitor, however, is reading the entire bank.

Maybe on an old bank battery 1 could reach 14.4 while the whole bank is lower? Perhaps with already old batteries.

Curious what the Mainesail has to say.