Big voltage drop at controller connection

[CurtisM]

Good Day all.

I've got an interesting problem. I recently warranteed a charger controller through Silentwind but the new one is wonky too. I've got right around 20 volts and 15 amps going to the controller. The second I connect the wires the voltage drops into the low 12 volts and the readout on the Silentwind app says only 11.0v but the 15amps. I don't seem to get any charging into my batteries at all from this (the wind has been dead lately) and during the day all we have running is refrigeration at 7 amps or so but the batteries end up lower at the end of the day.

Am I right in assuming the controller is shorted inside?

[smac999]

How are you getting 15a with the wires disconected?

And with dead wind...

[CurtisM]

Originally Posted by smac999

How are you getting 15a with the wires disconected?

And with dead wind...

Solar. It's a wind and solar controller (hybrid) as in it does both. The wind part of the controller works fine when the wind blows. I tested the panels disconnected and they put out 19 to 20 volts and 15 amps like they should. Then I connect it to the controller and the voltage drops to 11 to 12

[noelex 77]

Originally Posted by CurtisM

Solar. It's a wind and solar controller (hybrid) as in it does both. The wind part of the controller works fine when the wind blows. I tested the panels disconnected and they put out 19 to 20 volts and 15 amps like they should. Then I connect it to the controller and the voltage drops to 11 to 12

I think all the hybrid controllers are PWM (not MPPT) types. With this type of controller, ignoring small voltage drops, the input and output voltages are the same.

The 19-20v is the open circuit voltage of the panels, but when connected to the battery via a PWM controller this will drop to the battery voltage, in this case 11-12v.

Rather than a defective controller the results suggest flat/defective batteries or a high resistance connection on the battery side.

[CurtisM]

Originally Posted by noelex 77

I think all the hybrid controllers are PWM (not MPPT) types. With this type of controller, ignoring small voltage drops, the input and output voltages are the same.

The 19-20v is the open circuit voltage of the panels, but when connected to the battery via a PWM controller this will drop to the battery voltage, in this case 11-12v.

Rather than a defective controller the results suggest flat/defective batteries or a high resistance connection on the battery side.

Interesting.

This is one of their newer controllers that is supposed to be either PWM or MPPT. I chose MPPT at setup and we have brand new (about 6 weeks old) AGM batteries. The actual voltage readout from the batteries is at 12.2 while the readout from the solar voltage on the controller is 11.0 volts right now. (I had to run the generator to get the batteries charged this morning) But, again, if i disconnect the panels and check them, they read right now at 20.21v.

I also have good new 6 guage wire running from the controller to the batteries. Each wire is only about 3 feet long clear of any shorts.

On a side note: This whole thing with Silentwind products has been frustrating. My wind gen rotted inside after 18 months due to incorrect bearing and improper seal installation and the first controller failed at bluetooth (which is the only way to connect and get or change info on it). I loved my BlueSky controller but it got damaged in Irma a few years back. They said they will warrantee it still but mail from Grenada to California and back is a PITA right now with COVID. Eventually though...

[noelex 77]

Originally Posted by CurtisM

This is one of their newer controllers that is supposed to be either PWM or MPPT.

Nice to know they are finally producing something a little more sophisticated. Is it MPPT just for wind, just for solar, or both solar and wind?

Originally Posted by CurtisM

The actual voltage readout from the batteries is at 12.2 while the readout from the solar voltage on the controller is 11.0 volts right now.

Are they reading these different voltages at the same time? If there is a positive current from the wind/solar, any voltage drop or bad connection would result in a voltage difference the other way. I would first check the voltage reading at various points with a multimeter. This will show which reading is correct and if there is any point of significant voltage drop. A clamp-on multimeter would also be useful to measure the current.

Originally Posted by CurtisM

But, again, if i disconnect the panels and check them, they read right now at 20.21v.

This is quite normal. It is just measuring the OC voltage of the solar panels. This will be around 20+ volts even in poor light. Once connected to the controller and delivering current this will drop to the Vmp for a MPPT controller or battery voltage for a PWM controller.

[CurtisM]

Originally Posted by noelex 77

Nice to know they are finally producing something a little more sophisticated. Is it MPPT just for wind, just for solar, or both solar and wind?

It's supposed to be MPPT for solar and wind according to Samuel who is their lead tech. This is their latest one. I still wish I had gone a different route on wind energy, but it is what it is now.

Are they reading these different voltages at the same time? If there is a positive current from the wind/solar, any voltage drop or bad connection would result in a voltage difference the other way. I would first check the voltage reading at various points with a multimeter. This will show which reading is correct and if there is any point of significant voltage drop. A clamp-on multimeter would also be useful to measure the current.

Not sure what you mean about "at the same time" here. Can't really check the wind portion right now as the wind hasn't been much of anything the last week or so. It'll blow a bit but by the time I get to check it all the wind dies. But, the few times I've seen, the wind seemed to work really well when it was blowing as it put out a constant 13+v and the amps of course depended on the wind. This is all confirmed with the controller readout and multimeter (clamp-on style)

The solar has always been at around 11v on the controller readout since i got the thing. The end of the solar wires are 20v when disconnected and about 12.5v with a multimeter or so at the connection when connected but the readout is at 11v from the controller.

This is quite normal. It is just measuring the OC voltage of the solar panels. This will be around 20+ volts even in poor light. Once connected to the controller and delivering current this will drop to the Vmp for a MPPT controller or battery voltage for a PWM controller.

The strange thing is though I am using about 0 to 7 amps all day depending on cycling of refrigeration with 10 to 17 amp going in through the charger (supposedly) but end up with my batteries losing up to 0.5v during the course of the day. The batteries never charge. I've checked all my wires so many times for shorts beyond quadruple checked. Everything is good. This only began with this controller and the weird low voltage readout.

[caffel]

I'm with noelex77.
Check the batteries carefully.
And be mindful of the charging rate (amps) measuring at the battery itself.
One practical check (in any port) is to measure the specific gravity of each cell. Easy to measure and a good way to track the aging of each battery. Esp as you will be checking the level monthly in the tropics anyway.
One weak cell in a parallel connected bank can give all of the symptoms that you mention.
A second test (one that we use in robotics for sealed batteries) is to get the bank up to full and then apply a modest but constant load. Then record the voltage about every 15-30 minutes. You should see a nice smooth decline in voltage. Both weak cells and dirty connections will usually exhibit a sharp drop at some point in the first half of the discharge cycle.
Rules of thumb: (that you may know already) charging voltage S/B about 14.5 v measured at the battery. Over 15v initially for a flat battery. A fully charged battery will read 13 - 13.25 v (after a few minutes of cooling off).