Please help check my camper solar power setup

[baker329]

I'm completely new to solar so any help or suggestions on my setup would be great! Here's a schematic of how I am wanting to set everything up on my 24V system...

 

[Rocketman]

Looks good overall…

A couple of items you may/may not want to consider:

Are you planning on adding a Cerbo and touch (or rolling your own GX)? That would be very handy seeing everything all in one place.

Another change may be to use the Victron Distributor instead of the power-in. Or add the fuses to the power-in. It may/may not make sense to have fuses in the power-in or distributor instead of the mid nite baby breaker boxes.

The Smartshunt will have a small positive wire. You probably want to attach it after the kill switch - so the Smartshunt doesn’t drain the battery when the camper is not in use.

Good luck!

 

[corn18]

You need a circuit breaker on the AC input to the inverter.

You need a type T fuse between the battery and the power in.

You need a fuse between the power in and the inverter.

You need a fuse between the power in and the DC-DC converter.

I agree, you should get a distributor vs a power in to handle some of these fuses.

 

[baker329]

Would I need all these fuses if I have everything going to the breaker box instead? I was trying to go without fuses if possible? Also it was nice to have the breaker box so I can shut off different things separately if I need to.

 

[Rocketman]

One other item… make sure the batteries are warmer than outside. It is easy for the batteries to get too cold to charge. The smart solar mppt’s have low temperature non- charging. The Multiplus can be more difficult.

 

[baker329]

Looks good overall…

A couple of items you may/may not want to consider:

Are you planning on adding a Cerbo and touch (or rolling your own GX)? That would be very handy seeing everything all in one place.

Another change may be to use the Victron Distributor instead of the power-in. Or add the fuses to the power-in. It may/may not make sense to have fuses in the power-in or distributor instead of the mid nite baby breaker boxes.

The Smartshunt will have a small positive wire. You probably want to attach it after the kill switch - so the Smartshunt doesn’t drain the battery when the camper is not in use.

Good luck!

I am planning on getting a Cerbo. Do you know where at in my setup, I should put that at?

 

[Rocketman]

The Cerbo will just have small power wires - but you will have data wires going to almost all the other Victron items.

 

[HRTKD]

It looks like the power from the array #1 is going into the battery port of the Victron 100/50. Ticky tacky detail.

In real life, the PV ports are on the left side and the battery ports are on the right. Not that it matters for a diagram like this.

The 1360 watts of array #1 has the potential to produce more than the solar charge controller can pass on to the battery, but not by much. It's about 6 amps, in theory, so not much to worry about since you're unlikely to see 100% output from the panels.

You'll want an MK3-USB device for connecting a laptop to the Multiplus for configuration. It's possible that the Bluetooth dongle connected to a phone with Victron Connect could do most of what you need, but I've been told that the laptop application can do more than the phone can.

VE.Direct for each MPPT and one for the Smart Shunt to the Cerbo. I'm not sure on the Smart Shunt. I have the BMV-712 and it does have a port for the VE.Direct. The Multiplus will use a VE.Bus cable to the Cerbo. I don't know about the Orion.

I'm starting my install of a Multiplus in a 12v system that looks similar to yours with two MPPT and a BMV-712.

 

[Rocketman]

You need a circuit breaker on the AC input to the inverter.

You need a type T fuse between the battery and the power in.

You need a fuse between the power in and the inverter.

You need a fuse between the power in and the DC-DC converter.

I agree, you should get a distributor vs a power in to handle some of these fuses.

Remember fuses/breaker are wire and device protectors. If you modify the power- in to add the Mega fuses that will cover the fuse to the Multiplus and DC-Dc converter. (You could also eliminate the breakers for the mppt’s).

And yes add a class T fuse just after the batteries.

 

[MichaelK]

I'm not trusting the numbers you are posting for your solar arrays? For array #1 you state 20A at 48V, with a max of 1360W? First off, 20A X 48V = 960W. How are you wiring panels to get 20A and 48V? Where are these numbers coming from? What are your panel specifications?

Likewise for array #2. 12A X 48V = 576W, not 815W?

 

[WYtreasure]

Would I need all these fuses if I have everything going to the breaker box instead? I was trying to go without fuses if possible? Also it was nice to have the breaker box so I can shut off different things separately if I need to.

Here is a "Class T fuse" discussion for your reading enjoyment. I suggest reading the thread until you are convinced.

Class T vs ANL fuse

I'm about to start my upgrade to our RV electrical system. It will be a Victron MultiPlus 3000 with 4 Battleborn Batteries and 700 watts of solar. I went and go everything from BattleBorn but noticed that they supplied me with a 400 Amp ANL fuse to place between the battery and the inverter (it...

diysolarforum.com

 

[baker329]

I'm not trusting the numbers you are posting for your solar arrays? For array #1 you state 20A at 48V, with a max of 1360W? First off, 20A X 48V = 960W. How are you wiring panels to get 20A and 48V? Where are these numbers coming from? What are your panel specifications?

Likewise for array #2. 12A X 48V = 576W, not 815W?

Sorry those numbers I was using the max power voltage of the panels which is 34v. I have one array of 335w panels and then another array of 200w panels.

 

[MichaelK]

Sorry those numbers I was using the max power voltage of the panels which is 34v. I have one array of 335w panels and then another array of 200w panels.

Here's where the details become very, very important. Is 34V Vmp or Voc? Depending on what the answers are, the panels as configured may not be able to fully charge a 24V battery if MPPT functional minimums are not met. Can you provide the full panels specs for both. That's Vmp, Voc, Isc, and Imp.

Also, how many panels each, and whether they are in parallel or series?

 

[baker329]

Here's where the details become very, very important. Is 34V Vmp or Voc? Depending on what the answers are, the panels as configured may not be able to fully charge a 24V battery if MPPT functional minimums are not met. Can you provide the full panels specs for both. That's Vmp, Voc, Isc, and Imp.

Also, how many panels each, and whether they are in parallel or series?

I have 4 335w 24v panels in 2s and 2p and 4 200w 24v panels in 2s and 2p.

• Maximum Power(Pmax): 335W
• Maximum Power Voltage(Vmp): 34.1V
• Maximum Power Current(Imp): 9.85A
• Open Circuit Voltage(Voc): 41.6V
• Short Circuit Current(Isc): 10.4A
• Maximum System Voltage(Vmax): 1000VDC
• Temperature Range: -40°F ~ 194°F
• Max Series Fuse Rating: 20A

• Maximum Power(Pmax): 200W
• Maximum Power Voltage(Vmp): 37.6V
• Maximum Power Current(Imp): 5.36A
• Open Circuit Voltage(Voc): 45.4V
• Short Circuit Current(Isc): 5.83A
• Maximum System Voltage(Vmax): 1000VDC
• Temperature Range: -40°C ~ 90°C
• Max Series Fuse Rating: 15A

 

[MichaelK]

OK, I plugged your values into Midnight's string calculator. Here is what I got for your larger panels. It looks like they would not reach a Voc of 100V till the winter low is less then -30F. How cold does your area get?


Here is what I got for your smaller panels. These are more of a concern. Because they have a higher Voc, they will surpass 100V at 20F, far warmer than the other set. Here is where you really need to pay attention to your winter lows.

 

[WYtreasure]

MidNite Solar - Classic Sizing Tool.

MidNite Solar is the industry leader and manufacture of quality Renewable Energy System electrical components and E-Panels.

www.midnitesolar.com

Assuming you are in the US of A:
The National Weather Service can give you the all time recorded low temp for your area. I suggest using a temp about 10 degrees below that temp, as insurance against frying your equipment due to over-voltage.

 

[baker329]

OK, I plugged your values into Midnight's string calculator. Here is what I got for your larger panels. It looks like they would not reach a Voc of 100V till the winter low is less then -30F. How cold does your area get?
View attachment 79438

Here is what I got for your smaller panels. These are more of a concern. Because they have a higher Voc, they will surpass 100V at 20F, far warmer than the other set. Here is where you really need to pay attention to your winter lows.
View attachment 79439

So I live in KY which definitely gets below 20F at night and every once and awhile below 20F in the day. I didn't know I needed to pay attention to the temperatures with the panels. Good to know!

So for the 200w array, even though I have them parallel at 48v and 12a... that 48v could get to 100v below 20F?

 

[rmaddy]

Since I suggested, in your other thread, that you post this diagram I thought I should add some feedback.

For the 4 200W panels in 2S2P you need the 150/35, not the 100/30. The Voc of those 200W panels is too high to use with a 100V charge controller. You will see my math for that in the other thread.

 

[baker329]

Since I suggested, in your other thread, that you post this diagram I thought I should add some feedback.

For the 4 200W panels in 2S2P you need the 150/35, not the 100/30. The Voc of those 200W panels is too high to use with a 100V charge controller. You will see my math for that in the other thread.

Thanks for checking the diagram out for me. Ok I can change the 200w panels to go through the 150/35.

Should I be doing the 335w panels through 150/45 then?

 

[rmaddy]

Thanks for checking the diagram out for me. Ok I can change the 200w panels to go through the 150/35.

Should I be doing the 335w panels through 150/50 then?

No, as shown in the other thread the 4 335W panels in 2S2P work with the 100/50.