Solar Newbie's First Build

[Beef]

Greetings solar friends,

I am getting my first camper van in the following weeks and with getting that purchase squared away comes the real fun part in building out my vans solar buildout.

I have been utilizing a lot of Explorist.life diagrams, videos and as many things as I can find to try and make this all make sense in my head as anything electrical is quite scary to me since I am not the most handy.

I wanted to include my most recent diagram for my build and vet it with the community and see if I am on the right track as well as see if I am making any glaring mistakes that might result in me blowing up my van.

I appreciate any and all advice here since electrical set ups are very new to me.



Best,
Beef

 

[Bobert]

Greetings solar friends,

I am getting my first camper van in the following weeks and with getting that purchase squared away comes the real fun part in building out my vans solar buildout.

I have been utilizing a lot of Explorist.life diagrams, videos and as many things as I can find to try and make this all make sense in my head as anything electrical is quite scary to me since I am not the most handy.

I wanted to include my most recent diagram for my build and vet it with the community and see if I am on the right track as well as see if I am making any glaring mistakes that might result in me blowing up my van.

I appreciate any and all advice here since electrical set ups are very new to me.



Best,
Beef

I would suggest putting the solar panels in series. The voltage is a bit low for a 24v system. I am also wondering why you have chosen to go 24v with your system? 12v has a lot of advantages in a smaller installation.

 

[Beef]

I would suggest putting the solar panels in series. The voltage is a bit low for a 24v system. I am also wondering why you have chosen to go 24v with your system? 12v has a lot of advantages in a smaller installation.

Some of the content I had reviewed when I started building this out suggested it was better to go in parallel vs a series. Not being too well versed in all things electric, if I string the panels in a series, do I have to redo my battery set up as well? What other changes will I have to make on my system to change that?

 

[Bobert]

Some of the content I had reviewed when I started building this out suggested it was better to go in parallel vs a series. Not being too well versed in all things electric, if I string the panels in a series, do I have to redo my battery set up as well? What other changes will I have to make on my system to change that?

As long as the charge controller is capable of double the voltage of 2 panels all you do is pug the positive mc4 connector into the negative mc4 connector on the other panel this creates a single array with double the voltage and the same amperage. The 2 remaining wires go to your switch. It’s the same principle you used to make you 12 volt batteries into 24volt. You don’t need or want fuses between this type of array as they accomplish nothing in this scenario they are only needed when paralleling more than 2 panels or arrays. You do need a double pole disconnect though most people use a breaker as they are cheap and easy to use and readily available dc rated.

 

[Beef]

As long as the charge controller is capable of double the voltage of 2 panels all you do is pug the positive mc4 connector into the negative mc4 connector on the other panel this creates a single array with double the voltage and the same amperage. The 2 remaining wires go to your switch. It’s the same principle you used to make you 12 volt batteries into 24volt. You don’t need or want fuses between this type of array as they accomplish nothing in this scenario they are only needed when paralleling more than 2 panels or arrays. You do need a double pole disconnect though most people use a breaker as they are cheap and easy to use and readily available dc rated.

Here's the info on my MPPT controller:


So as far as my understanding goes, if we string them in a series, amperage stays the same vs additive but the voltage will be combined (Open Circuit Voltage 27V each panel *2 = 54V). According to the MPPT specs on Renogy's site, I believe I should be good as the Max input Voltage is 100V correct?

Is the double pole disconnect covered by the Solar Isolator Disconnect in my diagram from the panels to the controller or do I need the same style disconnect I have on the battery?

 

[Bobert]

Some of the content I had reviewed when I started building this out suggested it was better to go in parallel vs a series.

This is not bad information but the solar panels must produce more voltage than the battery needs. Under load the voltage will likely be lower than that and you may not get any amperage unless sun conditions are very good. It’s my experience that some of the most needed and valuable solar energy is desired in marginal sunlight.

 

[Bobert]

Here's the info on my MPPT controller:
View attachment 100482

So as far as my understanding goes, if we string them in a series, amperage stays the same vs additive but the voltage will be combined (Open Circuit Voltage 27V each panel *2 = 54V). According to the MPPT specs on Renogy's site, I believe I should be good as the Max input Voltage is 100V correct?

Is the double pole disconnect covered by the Solar Isolator Disconnect in my diagram from the panels to the controller or do I need the same style disconnect I have on the battery?

2 in series will be no problem for your controller the solar isolater will work fine

 

[73powerstroke]

The advantage of 24v would be the charge controller can handle more panels. It's more for big stuff not mobile. The mppt will take high voltage low amps and convert it to higher amps lower voltage. Also in series since amps are less you can. Get away with cheaper wire because you won't have so many amps.

 

[73powerstroke]

Parallel is more popular with pwm charge controllers. Because they don't like usually rate more than 50v and won't convert higher voltages into more amps than are coming in like a mppt
So for example I have 40 amp mppt. I have 10amps at 60v coming in. The controller converts that to 14.4v at 25amps to my battery. Im not sure exactly what mine does but that's a example. I usually get close to 40 amps under load but I also have several panels hooked.

 

[Beef]

Parallel is more popular with pwm charge controllers. Because they don't like usually rate more than 50v and won't convert higher voltages into more amps than are coming in like a mppt
So for example I have 40 amp mppt. I have 10amps at 60v coming in. The controller converts that to 14.4v at 25amps to my battery. Im not sure exactly what mine does but that's a example. I usually get close to 40 amps under load but I also have several panels hooked.

Thanks for the insights.

I redid my diagram and also realized I should probably rearrange the battery set up as well. Can ya'll take a look below at V2 and let me know if this is looking more spot on.

 

[Beef]

As a side follow up, I see some diagrams utilizing the below on left and some on the right, what's the real differences in these style of switches, is there a benefit of one over the other?

 

[Bobert]

Thanks for the insights.

I redid my diagram and also realized I should probably rearrange the battery set up as well. Can ya'll take a look below at V2 and let me know if this is looking more spot on.

View attachment 100569

The disadvantage of using 12v is that the amperage of everything related to the battery system will double. This is very doable with a 2000 watt inverter but you do need to increase the capacity of everything except the PV wiring to double the amperage compared to the 24v system. Most of the essential devices in a standard rv are controlled by 12 v so if your solar setup is 12v based you eliminate converting to 12v and the losses involved with that process. If you are successful at enabling everything that you use regularly to operate off 12 volt you can accomplish more with a smaller system if you don’t need to use the inverter all the time you will save the idle consumption power also. If you intend to expand your system beyond this initial design 24v begins to have cost saving advantages. For instance if space allows you could add 2 more solar panels to a 24 volt system by simply plugging them into your existing controller nothing else would be needed. If you want to expand later figure out what that system would look like now it will save you money in the long run.

 

[Beef]

The disadvantage of using 12v is that the amperage of everything related to the battery system will double. This is very doable with a 2000 watt inverter but you do need to increase the capacity of everything except the PV wiring to double the amperage compared to the 24v system. Most of the essential devices in a standard rv are controlled by 12 v so if your solar setup is 12v based you eliminate converting to 12v and the losses involved with that process. If you are successful at enabling everything that you use regularly to operate off 12 volt you can accomplish more with a smaller system if you don’t need to use the inverter all the time you will save the idle consumption power also. If you intend to expand your system beyond this initial design 24v begins to have cost saving advantages. For instance if space allows you could add 2 more solar panels to a 24 volt system by simply plugging them into your existing controller nothing else would be needed. If you want to expand later figure out what that system would look like now it will save you money in the long run.

At this point the primary plans for the inverter is going to be having several outlets powered in the van for laptop power, etc as well as planning to power my refrigerator. The rest of the devices (2 maxx fans, puck lights, etc) will be powered through the fuse block side.

 

[73powerstroke]

Thanks for the insights.

I redid my diagram and also realized I should probably rearrange the battery set up as well. Can ya'll take a look below at V2 and let me know if this is looking more spot on.

View attachment 100569

Looks ok. You can always re do it later