Newbie question - converting a van to camper, need advice on the solar system

[velio]

Hello everyone,
I'm new to the forum, although I've read quite a few topics in it over the past 2 weeks or so.
I found the site by a youtube video where Will was discussing pros and cons to the 12v and 24v systems.
So as the thread title suggests, I recently bought a van with the intention to convert it to camper (yeah, I know everyone seems to be doing that lately...). Unfortunately for me, the electrical system is the thing I'm the least comfortable with during this build. I'll start by stating what my intended use for this van is going to be.
I will mostly travel with it for 3 or 4 days, wild camping with my wife and 1 child. As we're both working remotly, having 220v AC to charge the laptops is mandatory, so an inverter is inevitable. Other power consummators will be the phones, which can charge off 12V, lighting in the van and a 12v small top loading compressor fridge (by the specs, consuming 60W, but I reckon it won't be working full time).
The battery is going to be a 12V one, between 150-200A. With these in mind, I have a few questions:
1/ First question is - would I be able to use a 24V panel(s) through the controller to charge the 12V battery - I actually know it's possible, the question is whether there are any pros and cons to that. So far I've read opinions on both ends - that it's actually good because the controller will charge the battery faster, others have said that it's a bad idea as the system won't be efficient.
2/ My second question is regarding how I arrange the panels. I'm aiming to have panels in the range of 300-400 Watts. Should I strap 2 175-200W ones on the roof, or is it a better idea to maybe have something like a 200W single panel on the roof with maybe another 100-150W mobile which I can move around the van for better positioning and use a second controller for this to charge the battery?
I think these are the things I'm mostly interested in currently so that I have an idea how to plan.
I can buy a reasonably priced 200W 24V panel and I lean towards the idea of having 1 of these on the roof with another mobile 100-150 panel to move around.
Thanks to anyone that cared to read these rumblings

 

[time2roll]

1) Yes an MPPT controller will extract the higher voltage and convert down to charge the 12v battery just fine. Post the equipment to check compatibility before you click and buy.

2) I would get 400+ watts on the roof and try to skip the portables. Portables can be added later if you find it will help for your camping style.

3) Consider a direct 12v DC adapter to power the laptop.

 

[Rocketman]

For the roof - put as much solar on the roof as you can. But use all the same panels.

Because the roof is flat, you never get the full watts of the panel. It is much better to be over paneled on your solar charge controller. A good one to start looking at is Victron mppt 100/30. (Your final one may be smaller - but that one is in the right range). A mppt will use any voltage of panels efficiently (even 40v ones) and convert it to the 12v.

A few other items to look at are Victron Smartshunt (so you know the exact status of your battery).

I would go completely Victron (I did), because the items can “talk” to each other. The Cerbo & touch (or roll your own with a Pi) gives all the info on the electrical system in one place.

A Multiplus for the inverter:charger and a Dc-Dc charger to charge while driving will complete the system.

Good luck (I added the additional possible equipment so you can start researching).

 

[velio]

@time2roll @Rocketman
Thanks a lot to both of you for the replies! I'll try to catch up to both in this post.
As far as the equipment goes, the controller I'm looking to get will be a Victron, either a SmartSolar MPPT 100/30 or a 100/50.
For the panels, I can find a discounted 24v panel with the following specs (the brand is Hanwha SolarOne (Qidong)):
- Monocrystal
- 200W
- max voltage 36.2v
- max amperage 5.52A
- open circuit max voltage 45.2v
- open circuit max amperage 5.93A
I was considering either 1 or 2 of these on the roof
Alternatively I can buy (for a bit more money) a Victron energy 175W with the following specs:
- Monocrystal
- 175W
- max voltage 19.38v
- max amperage at max power 9.89A
Again, I was thinking to put 2 of these on the roof.

Regarding the 12v DC adapter to power the laptop, I am not sure I have any idea how to do that or what I may need. The laptop is a macbook pro with the M1 chip and it charges through a usb-c port. Truth be told, I can power the laptop when I use my external monitor, but I've no idea what voltage that monitor is pumping back to the laptop.
Regarding going all-in on Victron, I'd love to but the price of some of the components I just can't justify. I'm certainly getting a Victron controller and inverter (if required), maybe Victron panels, but the batteries seems a bit out of reach. For example - looking at Victron's Super Cycle AGM VRLA 230Ah - I can get that locally for around 850 euros. On the other hand, for 1030 euros, I can get a 200Ah LIFEPO4 battery (the brand is ULTIMATRON FRANCE). I might be wrong, but I think that latter is a better deal?
As for the DC-DC charger to charge while driving, I think I need to research whether the van's alternator is capable of doing that?
Again, thanks a lot for the replies, seems like going all-in on the roof is the way to go initially.

 

[mikefitz]

With a MPPT solar controller it converts the panel power, watts, into a voltage suitable for the batteries. This means you can use any panels that are available at reasonable cost and will fit on the roof. Plan your roof layout so you get maximum space for the panels and are still able to fit rooflights and fans. The concept of 12 volt and 24 volt panels is dated from the early days when simple or no controllers were used. Actual panel volts operating volts will be 18 or 36 volts for panels in your power range. Forget portable panels for the moment, storing when not deployed and the risk of theft is a problem. Put at least 400 watts of panels on the roof, only consider rigid framed panels, flexible types fail within a year or two. Solar controllers from the Victron range are recommended, example Victron Smart Solar 100/30.

Although its possible to obtain laptop chargers that connect to a 12v supply, many of these on Amazon and eBay have questionable performance, only consider types offered by the laptop manufacturer. Its probable you will need a small inverter, consider the Victron Phoenix range.

You will need alternative charging from the engine when the sun does not shine, using a battery to battery charger is a easy option, recommend Victron Orion tri smart, non isolated 12/12/30.

You posted as I was typing, Victron batteries are overpriced.

What van are you converting?

Mike

 

[time2roll]

12V to USB-C adapter:

https://www.amazon.com/Converter-Charging-Voltage-Regulator-Adapter/dp/B0B212GFM9

Shop around

No issues on the alternator to power it. Very light on power.

 

[velio]

@mikefitz Thanks for the suggestion for Victron Orion trismart - I'll look it up and research about it. Initially I will likely try to get away with just the solar and see how it goes, although I'll consider the potential upgrades to other charging solutions for the batter when building the van.
I'm based in Bulgaria and if I was to import anything from the UK I need to pay import duty as well so everything from there is quite expensive nowadays.
The van I bought is a 2016 Nissan NV400 L2H2 - essentially a Renault Master with a different look.
@time2roll thanks for the link for the adapter. If possible, I'd like to get away without adding an inverter so that looks like a really good option.

 

[ianganderton]

There are 3 calculations you need to do before looking at system components. You need to get the foundations right for anything to work as needed/expected

1 - Power use
2 - power generation
3 - power storage

1 - Have you done a power audit yet?

2 - irradiance tables

I use

Solar Irradiance Calculator

www.solarelectricityhandbook.com

Here is the data for sofia. Multiply your solar pv watts by the solar hours to get an indicated average of daily power generation



You need to generate more per day than you use

Lastly calculate your battery size based on days cover you want. This depends on the weather where you will be using the van. 2 or 3 days is a good place to start.

Remember a lead acid battery only has 50% of its capacity available to use. Lifepo4 has 80%

This is my calculation spreadsheet. It might help under stand your needs. It helped me

Van CALCS

Power Audit Van Conversion -- Electrical loads Estimate Calculations based on 24 hr period. 1 - Electrical Loads: Inverter Item,Usage,Time (min),Wattage,Energy (W),Peak Amps,% of use,Ah,Notes Laptop,240V,1,275,45,206,4,15%,17 Toaster,240V,8,1000,0,83,0%,0,12 minutes is about 6 slices of toast so...

docs.google.com

 

[velio]

@ianganderton
Thanks a lot for your post and the link to your spreadsheet. This is the result from my calculations with it:

		The battery will power the van for	3	days without sun or other charge
		The solar panels would charge the battery from flat to full in	1	days in summer with no load
		The solar panels would charge the battery from flat to full in	4	days in winter with no load
		The solar panels would charge the battery from flat to full in	2	days in summer with calculated load
		The solar panels would charge the battery from flat to full in	-8	days in winter with calculated load

I think this is quite decent and I think I bumped my power usage a bit more than what I would actually need. If I go out with the van for Thursday through Sunday, I would need to work with the laptop only for 2 days, not all 4 so I won't be charging the laptops every day.

For the winter I will obviously need an alternative power source (engine running most likely) but for now winter is no concern

 

[ianganderton]

@ianganderton
Thanks a lot for your post and the link to your spreadsheet. This is the result from my calculations with it:

		The battery will power the van for	3	days without sun or other charge
		The solar panels would charge the battery from flat to full in	1	days in summer with no load
		The solar panels would charge the battery from flat to full in	4	days in winter with no load
		The solar panels would charge the battery from flat to full in	2	days in summer with calculated load
		The solar panels would charge the battery from flat to full in	-8	days in winter with calculated load

I think this is quite decent and I think I bumped my power usage a bit more than what I would actually need. If I go out with the van for Thursday through Sunday, I would need to work with the laptop only for 2 days, not all 4 so I won't be charging the laptops every day.

Cool. With good information you can make good decisions.

 

[littleharbor2]

One factor that hasn't been mentioned yet is fitment of the panels on the van's roof. The panels already mentioned sound like smaller size than the typical 60 cell format . 60 cell panels are usually about 39" x 65" Not sure if this size would work in your application but you might consider them. The price of these panels is usually the best per watt you are going to find. Something to consider.

 

[velio]

One factor that hasn't been mentioned yet is fitment of the panels on the van's roof. The panels already mentioned sound like smaller size than the typical 60 cell format . 60 cell panels are usually about 39" x 65" Not sure if this size would work in your application but you might consider them. The price of these panels is usually the best per watt you are going to find. Something to consider.

The panels I'm keen to get has dimensions of 808x1580x35mm - so, a bit smaller than the mentioned 39"x65". Unfortunately they don't specify how many cells they are so I reckon less than 60. Price wise, currently they are discounted and I can get them for 145 euros (or pretty much the same in usd) each (regular price of 210 euros). I just got the measurements on the roof of the van and I can just fit them on the top perpendicular to the van without them sticking out.

 

[ianganderton]

The best value will be to fit as much wattage as will fit neatly.

Mine are 4 x120W.