Victron 150/45 stops charging at 150+ open voltage

[lynhnn]

4 of 24V panels in serial feeds to this Victron controller and it stops working when the open voltage is just above 150V. This is such an expensive controller and why can't it be tolerant a few open volts? Usually, the load takes the voltage down around 130V. However, it keeps stop working now and then with over voltage error.
I need help how to fix this?
Thanks,

 

[Dzl]

Unfortunately not only should you not be at or above the maximum input voltage of the controller, but you should also leave some safety margin to account for higher VOC at low temperature.

 

[Dzl]

Your best option may be to rewire your panels in a "2S2P configuration"

 

[Supervstech]

You are lucky.
Some lower cost controllers would burn up and need replacement if voltage spikes over the rated value.
ALWAYS arrange the PV input so VOC never approaches maximum voltage for the controller.
Looks like 3S is the max your controller can accept.
Either get 2 more panels, and wire them 3S2p, or as mentioned, use the panels you have in 2s2p.
Or get a 200v controller.

 

[lynhnn]

I love to do 4S and wish that Victron can handle 160V max and the problem is solved. It's not easy to do 3S mid-flight. Thanks guys!

 

[JoeHam]

I love to do 4S and wish that Victron can handle 160V max and the problem is solved. It's not easy to do 3S mid-flight. Thanks guys!

They do have 250v models

 

[RickP]

This is why I bought a 250/100 to begin with... room to roam. I read too many horror stories with lesser brands. As noted, at least the Victron cuts off and doesn’t start smoking, as many lesser items will. Not at all intending to be snarky, but stating the obvious... it says 150 volts. Hence my move up: buy once, cry once.

 

[lynhnn]

The price is steep for 250V. Now, the question is for traveling 50ft of 10awg, do I lose any significant energy going 75v PV vs 150v PV carrying the same wattage and stepping down at the controller conversion to 24V battery bank?

 

[Forbisher]

The price is steep for 250V. Now, the question is for traveling 50ft of 10awg, do I lose any significant energy going 75v PV vs 150v PV carrying the same wattage and stepping down at the controller conversion to 24V battery bank?

Use Vmp for the voltage not Voc
10AWG is good for
60Vmp
50 feet
14A
I guessed the Vmp and amps so change the inputs to what your actual specs are in this calculator.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

 

[lynhnn]

It drops 1.2v (on 67v) vs 0.6 (on 134v). So at the end, they both drop about the same 80w/h? Am I missing something?

 

[snoobler]

You are lucky.
Some lower cost controllers would burn up and need replacement if voltage spikes over the rated value.
ALWAYS arrange the PV input so VOC never approaches maximum voltage for the controller.
Looks like 3S is the max your controller can accept.
Either get 2 more panels, and wire them 3S2p, or as mentioned, use the panels you have in 2s2p.
Or get a 200v controller.

Victron is pretty explicit about this:

It drops 1.2v (on 67v) vs 0.6 (on 134v). So at the end, they both drop about the same 80w/h? Am I missing something?

Yes. You are missing something. 1.2/67 = 1.8% drop. 0.6/134 = 0.4% drop

So, the drop is about 4X larger on the 67V wiring scheme, and this equates directly to power loss. IMHO, it's nothing to worry about.

 

[lynhnn]

I heard someone said that 2x down conversion is more efficient than 3x or 4x on the controller. Is that true?

 

[snoobler]

I've said that. Yes, but it's very small. Optimal is about 50% higher than battery voltage, but that can be offset by worsened voltage drop, so it's basically a wash unless you have a short run between panels and SCC.

This is a fight to gain or lose 1-2% efficiency at best.

 

[pollenface]

Your best option may be to rewire your panels in a "2S2P configuration"

I agree.

My rule of thumb is to stay 20-40% under max voltage of the controller, although it gets to 45c in my part of the world in summer.