Help confirming some assumptions from my solar build please WIP!

[Nillerk]

Hi all,

First off, I am super excited to have found this group. I just bought my first new trailer. It is a 27' Vintage Cruiser 23QBS and I am going to take a crack at the electrical system. I have been researching for a couple of weeks now and think I have landed on the parts I want to use. I am an EE so do have a good understanding of electricity but I don't use it a lot as I moved into computer programing after school (20 years ago but I do still tinker with Electronic projects). I would love some advice to help me confirm my setup and assumptions.

Requirements:

• 300-500Ah/day usage
• Budget $7000
• Able to run AC with a Micro-Air EasyStart 364 only running for short periods (before bed on a super hot day)
• Able to stay long periods off Grid
• No generator unless massive cost savings
• Ability to charge batteries with Vehicle in an emergency (multiple rainy days)
• Needs to be as light as possible due to towing with SUV
• Will be safe

Assumptions:

• 60% panel efficiency average (360Ah/Day
• Can sustain rainy days by limiting consumption
• Inverter 90% efficient
• Can mount that many panels on the roof. (Do not have possession yet)
• NMD90 12/2 wire from the inverter/charger to AC breaker box and shore power to inverter/charger
• 4g wire from the power system to the DC fuse block
• 2g wire for the line from the alternator to DC-DC (~20')
• 2/0g wire for wire up systems

Gear:

• VICTRON ORIONTR SMART 12/12/30 30AMP(360W) NON ISOLATED DC-DC - $339 Amazon Canada
• Victron Energy SmartSolar MPPT 100/50 - $392.28 Amazon Canada
• Victron Energy MultiPlus Compact 12/2000/80-50 120V VE.Bus - $1524.80 Volts.ca
• Victron Energy GX Touch 50 - $291.72 Volts.ca
• 700W - 4 - 175 WATT 12 VOLT FLEXIBLE MONOCRYSTALLINE SOLAR PANEL - $1279.96 Renogy
• Renogy 200 Watt 12 Volt Monocrystalline Solar Suitcase with Voyager $379.99
• 900W total solar
• DIY 2 - 12V 280Ah Xuba LifePO4 Batteries with Overkill Solar BMS - $1770.80 Various
• Various Cables, Fuses, Monitors - $1000

Total: $6978.55+tax
Alternative: Replace Victron with Renogy. Save about $1000

Questions:

• What monitoring equipment do I need to work with the Victron ecosystem of the components and display screen? Renogy ecosystem is very easy for this.
• How should I configure the wiring from the panels?
• Is 700W roof plus 200W suitcase enough Wattage?
• Am I missing anything?

 

[MichaelK]

Your numbers are way out of line with reality. You plan on 300-500Ah of useage per day? It appears you're expecting this to happen at 12V? That would be about 3600W- 6000W of power per day. How are you going to produce 500Ah of power per day with a controller rated at 50A?

Assuming 5 sunhours per day in summer, that might make half of what you are proposing? And, 875W of panels on the roof is never going to get close to producing that much power. This is way too much power for a 12V system. And you want to spend 1279$ for 875W of panels? I recently payed 220$ for 980W of panels.

If you panels are laying flat on the roof, don't expect to get more than maybe 60% of rated production. That means 875W of panels might actually be making 525W. You ain't gonna make 6000Wh of power from panels putting out max about 525W.

 

[Nillerk]

Your numbers are way out of line with reality. You plan on 300-500Ah of useage per day? It appears you're expecting this to happen at 12V? That would be about 3600W- 6000W of power per day. How are you going to produce 500Ah of power per day with a controller rated at 50A?

Assuming 5 sunhours per day in summer, that might make half of what you are proposing? And, 875W of panels on the roof is never going to get close to producing that much power. This is way too much power for a 12V system. And you want to spend 1279$ for 875W of panels? I recently payed 220$ for 980W of panels.

If you panels are laying flat on the roof, don't expect to get more than maybe 60% of rated production. That means 875W of panels might actually be making 525W. You ain't gonna make 6000Wh of power from panels putting out max about 525W.

Hi Michael, thanks for the input, this is why I ask. Some questions, clarifications:

1. In summer our daylight hours in Canada are 5am-10pm July-Aug. My estimation was 8 hours at 60% efficiency would give me 350Ah/day. Is this wrong? I could maybe go with 6 - 175W panels which would give me 1250W with the solar suitcase.
2. Would the Victron energy SmartSolar MPPT 150/85-MC4 work better? Full efficiency at 1050W would give 88A
3. As mentioned I have a weight restriction and a sloped, all fiberglass roof so I will likely use flexible panels. If you can tell me where I can get 980W of panels for $220, or even less expensive flexible panels that would be great!

 

[Hedges]

In summer our daylight hours in Canada are 5am-10pm July-Aug. My estimation was 8 hours at 60% efficiency would give me 350Ah/day. Is this wrong?

Find an "insolation" calculator where you can input your location. Some include weather history, some just calculate angles of sun. Check their results against what you got by "60% efficiency"
Calculator will let you put in PV panel angle. Yours on roof may be far from optimum, depending on how steeply sloped.

As mentioned I have a weight restriction and a sloped, all fiberglass roof so I will likely use flexible panels. If you can tell me where I can get 980W of panels for $220, or even less expensive flexible panels that would be great!

$0.25/watt and even less is rigid panels. Usually 250W to 500W.
Flexible usually puts out less power per unit area, costs more, wears out sooner.

Maybe use rigid panels (some weigh more, some less). Come up with a mount you can tilt and rotate to get more hours effective sun.
Perhaps tilt is unclipping and lifting one side off roof, and rotation is moving the RV.

 

[Nillerk]

Find an "insolation" calculator where you can input your location. Some include weather history, some just calculate angles of sun. Check their results against what you got by "60% efficiency"
Calculator will let you put in PV panel angle. Yours on roof may be far from optimum, depending on how steeply sloped.



$0.25/watt and even less is rigid panels. Usually 250W to 500W.
Flexible usually puts out less power per unit area, costs more, wears out sooner.

Maybe use rigid panels (some weigh more, some less). Come up with a mount you can tilt and rotate to get more hours effective sun.
Perhaps tilt is unclipping and lifting one side off roof, and rotation is moving the RV.

Ok so I did some reading on that and my Summer angle here would be 21.5 from horizontal. Adding tilting will add weight and space so I am not sure where the line is on making it worth it for that small of an angle.
Spring and Fall are 47.5 so more of a benefit here.
I am in southern Alberta which has the best solar rating in Canada at an average of 125 kwh/kw/month.

Another thing to keep in mind is when I did my ah/day calculation, I went really high. IE: 20min/day toaster, coffee maker, microwave so realistically I am on the lower side of 300-500ah/day.

250-500W panels will be too big for my roof. (250w might work) so what is a good supplier that I can get closer to the $0.25/W rate?
The closest thing I looked at was a 380W panel at $0.3/W USD without shipping and I don't think 2 would fit on my roof. I have space but I need smaller panels to navigate all the vents, AC that are there.

 

[Hedges]

The calculator starts out showing production of flat orientation, so December 0.88 hours effective sun.
Click on the tilt pictures below to see their performance.

Here's a vendor of used (and some new) where a lot of us have bought. e.g $50 for 250W used.
Catch is shipping cost for a pallet, very cost effective for 20 or 100 pieces but not 2.

Solar Panels | SanTan Solar

store.santansolar.com

Check eBay (sort by distance) and Craigslist for local deals.

Note that panels vary in efficiency (power per unit area) so with limited space you're better off buying what fills the area and delivers most watts.
There are panels that would span width of roof. I envision mounting then with a hinge at one end, and latch down vs. tilt up on other end. (add corner gussets to hole frame together if you try this.)

 

[Nillerk]

Thanks Hedges, I clicked the tilts and the difference between flat and optimal summer seems neglagable for may-jul but does start making a bigger difference aug-oct.
Thanks for the link, I will check it out.

Any thoughts on the rest of the components or suggested alternatives?
Also are my wire calculations adequate?

 

[Hedges]

And even Summer tilt doubles December production.

While I haven't used either, I think people would say if Victron is in your budget, buy that rather than Renogy.

2kW at 12V is 160A plus extra for inefficiency. 2/0 is good wire, keep as short as possible.
Class-T fuse (able to interrupt 20kA) is good for lithium battery (0.17 milliohm per cell suggests 20kA short circuit current.) Ideally, fuse per 12V battery string.

2 awg is 0.16 milliohm/foot x 40 foot round trip, 6.4 milli ohm x 30A is 180 mV or 1.5% of 12V, that's good. More than enough, considering DC-DC boosts and regulates voltage.
You have a trailer and tow vehicle - is it really just 20'? Will need suitable connector for 30A to join them.

4 awg to fuse block - probably OK, depends on current draw and distance.


Do your two different types of PV panels have similar Vmp? That would be necessary to share same SCC. Otherwise, two SCC.

What is tow vehicle? Could some PV panels go there, park it in the sun while trailer is in the shade, have tilt or fold-out panels?
Long wire runs would be easier with higher voltage into SCC. Looks like your Victron is 100V. Others are 150V, 250V, even 600V.

 

[Whinny]

You will have a hard time finding new panels up here for less than .75/watt. Flex panels are more and they are less efficient. I would think you could get 4 200w glass panels up there.
Make your own solar suitcase with two 100w panels, some hinges and a PWM controller for $230
To use the transfer switch in the inverter you will need 2 runs of #10 nmd to your existing electric panel if you use an external transfer you need 1 run of #14, your inverter is 1600w. WFCO makes a transfer switch that works with your converter.
I wouldn't buy a Renogy inverter-don't seem to have a good track record. (wouldn't buy a Victron either-but thats just me...)

I thought it didn't rain in Alberta............(I'm in BC)

Hedges......looks like it's 26'

 

[Rocketman]

About your Victron Equipment List: (I used Victron on my MotorHome and really like it).

One item needed - SmartShunt or BMV712 Battery Monitor. (if going with the GX monitoring save money and get the SmartShunt).

The SmartSolar 100/50 is has an output of 50amps (700 watts / 14.4v = 50amps) - which is 700watts at Standard Conditions. You can overpanel it - (I did with 800 watts). That way you get a bit more energy, when sun conditions are not "ideal".

When using a portable solar panels it is usually better to run them into their own solar controller. A Victron SmartSolar 15amp will handle 220w of solar (75/15 or 100/15 - or 100/20) - Can you get a portable kit without the Charge Controller? Or build one?

The GX Touch50 is an accessory for the GX Cerbo. Victron's GX system is great! Gives at a glance info on your whole system. You will have a communication wires (VE.Direct cable) going from the ShartShunt/BMV712 and from the MPPT to the Cerbo. So you want them located close. The Cerbo in the bay with the other stuff and using the Touch50 in your rig is a very nice way to control and see it.

Items to check:
On the Onion DC-DC charger - I think (but I am not sure), that when using it with a trailer, the isolated model is better.

Solar Panels - The rigid solar panels usually work better (longer lasting & smaller/more efficient) than the flexible panels (and I think are cheaper too).

Will the Multiplus Compact 2000 drive the air conditioner? How many watts is your air conditioner? The Multiplus2000 at 100% is rated for 1600 watts - once is gets to 40C/104F (inside) it derates to 1450 watts (it does have a surge to get the A/C started). This may be a marginal case (it is close enough case to see if you can find a Kill-a-watt and find out what the A/C uses to run). When you want to run the A/C it will be after a HOT day - so the Multiplus will be close to derating. Also, the BMS's selected will be maxed out as well. If you go this route think about the ventilation and heat from this area.

If the A/C energy needs are too much for that Multiplus, I can think of 2 choices, First going with a Multiplus 3000 - unfortunately the BMS's become a problem (and you have to decide before you buy), or Second, if you get a small Honda (type) generator 1800 watts or so - that with the power assist of the Multiplus will run the A/C. (so you could do that if running the A/C becomes a problem). If you have a generator - you may decide not to install the DC-DC charger (apply that money to the generator).

One installation Note:
Is the shore power of your trailer 30A or 50A? I am assuming 30A because 30' trailer. You will want to have the shore power cable run through the Multiplus. then from the Multiplus to the fuse box. That's probably not where that cable runs from the factory. That way the voltage assist from the Multiplus will work for the entire rig, plus all your 120v outlets and stuff will run all the time. - You will have to manage the stuff that is on - so you don't overload when on battery.

Good Luck!

 

[Nillerk]

You have a trailer and tow vehicle - is it really just 20'? Will need suitable connector for 30A to join them.

It is about 10' from the battery in the vehicle to the back and another 10' from the front of the trailer to the foot of the bed where everything is going. I will measure for sure once I get possession.

Do your two different types of PV panels have similar Vmp? That would be necessary to share same SCC. Otherwise, two SCC.

The solar suitcase I was looking at has its own SCC so I was just going to put in a plug and run a line to the battery. Any problems with this?

What is tow vehicle? Could some PV panels go there, park it in the sun while trailer is in the shade, have tilt or fold-out panels?

It is a 2020 Ford Explorer ST. That is a super interesting idea. My backup plan if all the panels don't fit on the roof was to make more 200W Solar Suitcases.

You will have a hard time finding new panels up here for less than .75/watt. Flex panels are more and they are less efficient. I would think you could get 4 200w glass panels up there.

I am not super worried about cost here vs weight. But $50 is $50 if you know what I mean. I am mostly worried about tongue weight so putting panels farther back would help. I found some not bad panels at cdnsolar.ca

Canadian Solar Wholesale - Solar Panels and Solar Equipment

Buy Solar panels in Canada! We offer a wide variety of solar, battery and generator equipment tailored for

www.cdnsolar.ca

Make your own solar suitcase with two 100w panels, some hinges and a PWM controller for $230

This is a good idea. Thanks!

To use the transfer switch in the inverter you will need 2 runs of #10 nmd to your existing electric panel

My brother is an electrician and he also said use #10 or even #8

I thought it didn't rain in Alberta............(I'm in BC)

Well it if you compare us to BC you are correct ;P

 

[Nillerk]

When using a portable solar panels it is usually better to run them into their own solar controller. A Victron SmartSolar 15amp will handle 220w of solar (75/15 or 100/15 - or 100/20) - Can you get a portable kit without the Charge Controller? Or build one?

Yes, I am going to explore building one. Can I run multiple portable units into 1 SCC as long as I size it correctly?

The GX Touch50 is an accessory for the GX Cerbo. Victron's GX system is great! Gives at a glance info on your whole system

Yes, I want to go this way. I was unsure what I needed but you have cleared that up. Thank you!

If you have a generator - you may decide not to install the DC-DC charger (apply that money to the generator).

I may go the generator way anyway or even not have any DC-DC charging besides SCC.

One installation Note:
Is the shore power of your trailer 30A or 50A? I am assuming 30A because 30' trailer. You will want to have the shore power cable run through the Multiplus. then from the Multiplus to the fuse box. That's probably not where that cable runs from the factory. That way the voltage assist from the Multiplus will work for the entire rig, plus all your 120v outlets and stuff will run all the time. - You will have to manage the stuff that is on - so you don't overload when on battery.

30A.
I was going to run 2 lines from all the new electrical to the existing panels and connect shore power to 1 and panel to the other 1 back to Multiplus.

 

[Nillerk]

Items to check:
On the Onion DC-DC charger - I think (but I am not sure), that when using it with a trailer, the isolated model is better.

Generally speaking, one only needs to isolate the negatives when the installation does not share a common negative return path, such as may be the case on many fiberglass boats that don't have a chassis and may not have a common grounding bus to which all their battery banks connect.
Source:

Non-Isolated vs Isolated Orion-Tr - Victron Community

community.victronenergy.com

 

[Whinny]

Portable panels-I use separate controllers, I put a Zamp type plug towards the back of the trailer and made an adapter to plug into the truck connector. lots of shade in lots of our campsites so I get to chose best location. Got a broken photo tripod off craigslist-made 3 effective adjustable legs for the panels. For 200w just use PWM unless its a higher voltage panel. Will's tip is to use landscape lighting wire.

For the roof panels-make your own z brackets from 2 pieces of angle aluminium and 1 bolt/nut. Allows for easier assembly/disassembly for roof maintenance, also allows for your sloped roof. You can make them as long as needed for 3 or 4 screws to attach. The fridge vent is always an easy way to get solar wires into the trailer-just remember to seal openings due to co leaking in and run wires on the cool (non flame) side.

Someone in Edmonton was looking for panels.............

Where to source panels in Canada

Hi there, Looking for panels for an RV application. I’ve spent hours researching all of the various components with the exception of panels, I just assumed I’d be going with Renogy. Now I’m not so sure. At $240 per 200W panel I wonder if there’s a like quality bit cheaper alternative...

diysolarforum.com

First snow of the season last night! Just turned off my outside water 3 days ago.......

 

[Nillerk]

@Rocketman is this the product I need to monitor my DIY batteries?

Victron Smart Battery Sense – Solacity

Victron Smart Battery Sense, wireless battery temperature & Voltage sensor (up to 10m), SBS050150200 #SBS050150200 #SmartBatterySense #Victron

www.solacity.com

 

[Hedges]

@Rocketman is this the product I need to monitor my DIY batteries?

Victron Smart Battery Sense – Solacity

Victron Smart Battery Sense, wireless battery temperature & Voltage sensor (up to 10m), SBS050150200 #SBS050150200 #SmartBatterySense #Victron

www.solacity.com

"Wireless" Bluetooth?

KISS

 

[Nillerk]

"Wireless" Bluetooth?

The connection between Smart Battery Sense and one or more Solar Charger(s) is wireless: It uses VE.Smart Network – a wireless technology based on Bluetooth Smart.

 

[Rocketman]

Nope.

SmartShunt - Victron Energy

The SmartShunt is an all in one battery monitor, only without a display. Your phone acts as the display. The SmartShunt connects via Bluetooth to the...

www.victronenergy.com

The Smart shunt is probably better for you install.

Here is the BMV712

BMV-712 Smart - Victron Energy

Communicate wirelessly between products and simplify system installation and enhance performance using the BMV-712 Smart. Find a dealer now.

www.victronenergy.com

This difference - SmartShunt is newer, but does the same job. The biggest difference is the VE.Direct cable attaches to the Smart shunt - while it attaches to the monitor on the BMV712. You will probably have everything close to your batteries, so the Smartshunt would probably be better.

Let us know if you have any other questions.

 

[Rocketman]

Also, Both the SmartShunt and the BMV712 will transmit the voltage & temp data that the Smart Battery Sense (the item you linked above) does, so you will not need that at all.