Victron Solar Charge Controller

[Fred L]

I know this should be in the solar forum, but have a bit more comort here...
Getting ready to buy my 2108 TB and "collecting" things I will need. Bought the Victron 100/50 and intend to put 2x200 watt panels on the roof. My understanding (although possibly misguided) was that i could put 3 x 200watt panels on the controller. My math was 3 x 200 =600 / 12 so 50 amp ?
I will probably go with 2 controllers long term as understand the 2025 comes with a 180? watt panel. (Can i pair a 200 watt and a 180 watt?.... and how do they get a 180 when everything for sale is 100, or 200, etc...)

[Marine359]

Winnebago purchasing dept no doubt got a good deal on the 180w panels in a close out. So, they charge you for a 200 and give you a 180. No surprise there. You can use a 180 in series with a 200 because voltage is additive. If you try it in parallel, the 200 will behave like it’s a 180; the array will adopt the voltage of the lowest panel. In parallel, Probably less important if both panels are the same voltage. The number of 200w panels you put on a controller is mostly limited by the total voltage of the array. This number must not exceed the controller’s maximum input voltage. Penalty is death to the controller. You can however “overpanel”, meaning the total amperage may exceed the max amp rating of the controller. The excess amperage will simply not be used. Finally, you should not exceed the maximum wattage rating of the controller. That number is 700w @12v. For Victron 100/50. So you should be good to go with 3x200w panels as long as you do not exceed 100v. Likely only an issue if you’re using BougeRV CIGS panels which have a very high Voc.

[Fred L]

Appreciated Jim. I have backed off the cigs for this trailer and most likely using standard glass mono panels on strut channel, per Brian on Tito.
Assuming the 1 x 180 has its own mimimalist charge controller, so will leave that one alone and put the 2 x 200 in parallel on the 100/50 victron for now. Unless of course there is an issue in getting 2 more wires down from the roof?

[Marine359]

Originally Posted by Fred L

Appreciated Jim. I have backed off the cigs for this trailer and most likely using standard glass mono panels on strut channel, per Brian on Tito.
Assuming the 1 x 180 has its own mimimalist charge controller, so will leave that one alone and put the 2 x 200 in parallel on the 100/50 victron for now. Unless of course there is an issue in getting 2 more wires down from the roof?

The wire gauge from roof is 10awg. It can carry 30 amps dc. I would use the old controller for a portable sidewall port. SAE port cost $15 with inside 10awg 3ft wires. I’ve always carried a 100w portable panel in addition to my roof panels. I used a Victron 75/15 for that chore, and Victron 100/30 for roof. While you’re installing your new Victron, put in a 30 amp manual reset breaker where the wires enter the pass through. Gives you safety, and ability to disconnect the array if you need to, like when working on your system. Arrays are always hot.

[Sparky19053]

Originally Posted by Marine359

You can use a 180 in series with a 200 because voltage is additive. If you try it in parallel, the 200 will behave like it’s a 180; the array will adopt the voltage of the lowest panel. In parallel, Probably less important if both panels are the same voltage. The number of 200w panels you put on a controller is mostly limited by the total voltage of the array. This number must not exceed the controller’s maximum input voltage. Penalty is death to the controller..

Learning as we go here. Just installed a Victron MPPT100/30 my panels are 1x 200, 1 x180 and 1 x 100. There are wired in parallel. With the statement above does this mean the larger wattage panels are limited to the 100 watt panel?

Confused but looking to learn.
Thanks, Mike

[Marine359]

Originally Posted by Sparky19053

Learning as we go here. Just installed a Victron MPPT100/30 my panels are 1x 200, 1 x180 and 1 x 100. There are wired in parallel. With the statement above does this mean the larger wattage panels are limited to the 100 watt panel?

Confused but looking to learn.
Thanks, Mike

Rather than boring you with the details, watch this video. This guy is really good at explaining things, and you can download his diagrams. You should be an expert after watching it.

https://youtu.be/jejro4zkl8I?si=rW7sKV18mZvkBq7_

[Sparky19053]

Thank you so much. I book marked this video so I can re-watch,,, several times.

[Sparky19053]

OK, I see where I went wrong with solar array and will make corrections based on the very helpful information provided here. Many thanks again Marine359 for providing the video link.
So I'm going to add 100 watt panel and rework the wiring so my panels are 1 x 180 and the 1 x200 wired in series and with the addition of a second 100 watt panel connect the 2 x 100 panels will also be wired in series. My question with the panels now providing 40 volts are there any changes required at the controller or will this regulate the output voltage down to 14.2 for the Life-pro battery. The panel voltages are all 20 open volts

[Marine359]

Originally Posted by Sparky19053

OK, I see where I went wrong with solar array and will make corrections based on the very helpful information provided here. Many thanks again Marine359 for providing the video link.
So I'm going to add 100 watt panel and rework the wiring so my panels are 1 x 180 and the 1 x200 wired in series and with the addition of a second 100 watt panel connect the 2 x 100 panels will also be wired in series. My question with the panels now providing 40 volts are there any changes required at the controller or will this regulate the output voltage down to 14.2 for the Life-pro battery. The panel voltages are all 20 open volts

You needn’t be concerned about the output side of the controller. Its job is to deliver as much amperage to the battery as the incoming maximum power point will provide, up to its maximum output rating. As long as you program the controller for the correct battery type, you’re good to go. Just remember voltage is additive in series. Amperage is additive in parallel. Many people will wire series/parallel, which is the best thing to do if your array is approaching either the max voltage for the controller, or the max amperage of the cable. I think that’s covered in the video. If not, he has other videos on his channel.

[Sparky19053]

I figured so much but want to ask someone with more knowledge. Thank you again.

[No1Hunter]

Originally Posted by Marine359

Rather than boring you with the details, watch this video. This guy is really good at explaining things, and you can download his diagrams. You should be an expert after watching it.

https://youtu.be/jejro4zkl8I?si=rW7sKV18mZvkBq7_

Just be careful using his diagrams, as I found a couple errors in them, as well as some other information. I pointed them out in the form of a question, and he replied with a snarky comment, but then changed his info to fix the errors. That and he likes to try to sell you stuff you don't need.

[powercat_ras]

Solar cells are current generators. It is important to use solar panels of about the same size when connecting them in series. 180 and 200 watt would be OK.

When connecting solar panels in parallel it is important that they all have about the same voltage specs. You will want their Optimum Operating Voltage, sometimes listed as Vmppt, about the same.

A typical RV panel, Renogy 200 watt, will have 72 solar cells, have an Optimum current rating of 10.4 amp, and have an Optimum voltage rating of 19.2 volt.

Just be aware that there are other panels made for larger arrays of solar panels that have different voltage and current. Generally they will have sizes of 300 watts each or more. For example on my RV, I have used Mission Solar PERC-60 320 watt panels that have Vmppt of 34V and Imppt of 9.4A.