Solar Install Complete

[cmysstailights]

Originally Posted by Duckogram

I was getting ready to install solar on my Class A so I stopped at Bend, OR and talked to the engineers at Zamp. The plug on the side of the new MH’s is a convenience if you are going to use a portable panel, which is what Zamp recommended for my situation. Roof mounted panels are fine and easy to use
but if you park under trees like I do, they are not very efficient. Hence the portables (and a locking cable :-). The better portables have a built in controller
so they are literally “plug n play”. Be advised that the Zamp plug only works for Zamp panels. You can use your plug on other brands but you will need an adapter to reverse the wires.

Then there is the Monocrystaline vs Polycrystaline conversation...

OP: Nice installation.

You are also limited on how many panels or amps threw it. Think its 10 or 12gage wire which is good for about 400 watts

[Duckogram]

Originally Posted by cmysstailights

You are also limited on how many panels or amps threw it. Think its 10 or 12gage wire which is good for about 400 watts

I think the controller is a limiting factor. 12ga can handle 1920 watts.
i.e. 20 amps x 120 volts = 2400 - 20% = 1920w
for 10 gauge:
30 amps x 120 volts = 3600 - 20% = 2880w

And as usual, I reserve the right to be wrong.

[Rich.M]

No wire is limiting . Panels if in parallel will send 16 to 21 volts to controller. 20 amp*18volts=400 watt and that's at the wire limit with highest resistance, loss and may heat the wire.

[babock]

Originally Posted by Rich.M

No wire is limiting . Panels if in parallel will send 16 to 21 volts to controller. 20 amp*18volts=400 watt and that's at the wire limit with highest resistance, loss and may heat the wire.

How is wire not limiting wehn you have 20A flowing?

Best thing to do is to use a voltage drop calculator and based on the wire size and current, try to keep the voltage drop between 1% and 2%.

For example, if you used 10 gauge wire and you had 25 feet of wire(adding both positive and negative). Assuming 20A you would have 1V of voltage drop. That is over 5%.

4 gauge would drop that to 0.25V and 1.39% which would be much better.

My panels will be 700W total with 4 175W panels. They will be in a parallel series config. The panels in series will go to a combiner box with 8 gauge on the roof and from there use 4 gauge to the controller.

[Rich.M]

Sorry missed punctuation and struggle with fat fingers. Meant No, wire is limiting.

[cmysstailights]

From the rv solar site i am on

[babock]

Originally Posted by Rich.M

Sorry missed punctuation and struggle with fat fingers. Meant No, wire is limiting.

LOL....silly comma changes everything!

[pd2436]

So I also have the. ZAMP plug on the side of my camper for solar. Does this mean a solar panel will only charge the single battery on my camper? I had thought about getting a panel but it doesn't seem like a viable solution if it only charges my single battery.

[cmysstailights]

Originally Posted by pd2436

So I also have the. ZAMP plug on the side of my camper for solar. Does this mean a solar panel will only charge the single battery on my camper? I had thought about getting a panel but it doesn't seem like a viable solution if it only charges my single battery.

Yes it will only charge battery.

[Duckogram]

Originally Posted by cmysstailights

From the rv solar site i am onAttachment 162091

Thanks for the chart. Anything about wattage there?

[cmysstailights]

Originally Posted by Duckogram

Thanks for the chart. Anything about wattage there?

Not sure, panels have different amperage 12v vs 24v vs 36v. Wattage isnt the problems amps is. There are more people better suited to answer. Im just getting my feet wet in the whole rv solar thing. A lot of info and research before you buy anything.

[aeblank]

Originally Posted by cmysstailights

From the rv solar site i am onAttachment 162091

So is 3% the voltage drop goal? I find all sorts of wire sizing charts or calculators, and the give me a voltage drop....but I never know what's ok. I'm a mechanical engineer....our limits are much more defined....

I'll be putting in a 2k inverter probably 15 or 20 cable feet away. I'm in the 2/0 or 3/0 range, methinks. Need accurate lengths and what voltage drop is ok.

Also, do I count the length of the positive lead, or do I have to add the positive and return negative lengths??? Big difference for me!

[aeblank]

Originally Posted by Duckogram

Thanks for the chart. Anything about wattage there?

It says at 32A.
You can convert amps to watts, if you want. Tons of online calculators.

[cmysstailights]

Originally Posted by aeblank

So is 3% the voltage drop goal? I find all sorts of wire sizing charts or calculators, and the give me a voltage drop....but I never know what's ok. I'm a mechanical engineer....our limits are much more defined....

I'll be putting in a 2k inverter probably 15 or 20 cable feet away. I'm in the 2/0 or 3/0 range, methinks. Need accurate lengths and what voltage drop is ok.

Also, do I count the length of the positive lead, or do I have to add the positive and return negative lengths??? Big difference for me!

Inverter should be closest to battery. For the panels to distribution or combiner block #8 wire. From that to the solar (battery type same thing) disconnect switch bigger better depending on amps. Battery to battery 4/0 as well to inverter.

[Duckogram]

Originally Posted by aeblank

It says at 32A.
You can convert amps to watts, if you want. Tons of online calculators.

Yes I can. But that does not factor in percentage of loss which I why I asked the specific question. Additionally, the voltage is a variable as well depending on the panel used. I was hopeful that a manufacturer published an easy to read table.

[babock]

Originally Posted by aeblank

So is 3% the voltage drop goal? I find all sorts of wire sizing charts or calculators, and the give me a voltage drop....but I never know what's ok. I'm a mechanical engineer....our limits are much more defined....

I'll be putting in a 2k inverter probably 15 or 20 cable feet away. I'm in the 2/0 or 3/0 range, methinks. Need accurate lengths and what voltage drop is ok.

Also, do I count the length of the positive lead, or do I have to add the positive and return negative lengths??? Big difference for me!

You count both lengths summed up to calculate the voltage drop. Personally, I go for between 1% and 2% but 3% is a number many strive for...just not me. I am an EE.

Put that inverter as close to the battery as possible. 15 to 20 feet away is going to have a huge voltage drop even if you use 4/0 cable. I am going to be putting in a similar sized inverter and it will be a couple feet away and I will be using 4/0.

With the distance you are looking at, you could easily trigger the low voltage cutoff of the inverter.

[aeblank]

Originally Posted by babock

You count both lengths summed up to calculate the voltage drop. Personally, I go for between 1% and 2% but 3% is a number many strive for...just not me. I am an EE.

Put that inverter as close to the battery as possible. 15 to 20 feet away is going to have a huge voltage drop even if you use 4/0 cable. I am going to be putting in a similar sized inverter and it will be a couple feet away and I will be using 4/0.

With the distance you are looking at, you could easily trigger the low voltage cutoff of the inverter.

I know, I know. The (otherwise) perfect location is a ways away though. Using both lengths definitely messes with my (preliminary) calcs. I doubt I'll be anywhere near max capacity on the inverter. At most, a hair dryer, which I know can be up there. Getting it as much for the charger and transfer switch, as it's full output.

I need to bust out a garden hose and measure the distance... And maybe source some 4/0. Crikey.