Solar installation on van in combination with alternator

Hello folks.
I am setting up some solar panels on my van, an old Volkswagen T3 born in 1985. The set up itself will work out quite well i suppose, i have some experience with solar installations set ups.
I bought some 4 50watt panels , a charge controller and the rest is already existing in my van: an inverter and a battery. Those 2 last are connected so far on the alternator. Now my question is coming: how to connect the solar together with the alternator, is it unsafe for the installation(s) to just put the alternator and the solar parallel on the battery? Some ideas came up already, putting some diodes in between or a switch in between to choose the source. I am not sure if they are the right ones, maybe there are better plans? Maybe someone has an electric diagram how to connect this or a helpful link…? I would be grateful if someone has some helpful remarks on this , thanks so much :wink:grtz FRas

Hey FRas!

Kaden here at Continuous Resources. In our designs, we use the Orion DC/DC Charger made by Victron Energy. We’ve been really pleased with it’s performance. This reason why we use this is because it is fully programmable. Depending on the size of your battery bank, you can program the Orion to charge your battery bank at the correct current and voltage for it’s required charging phases.

The orion has a 30A current output, but all of our data shows that it runs a bit hot, around 55A. The max surge power is 60A. We break the wire with 80A breakers on both sides as well.

Let me know if you have any other questions!

I’m sorry but i don’t understand what your answer has to do with my question… @kadenatCR

@FRas

You asked, “Now my question is coming: how to connect the solar together with the alternator, is it unsafe for the installation(s) to just put the alternator and the solar parallel on the battery? Some ideas came up already, putting some diodes in between or a switch in between to choose the source. I am not sure if they are the right ones, maybe there are better plans?”

In our installations, we use the above pictured piece of equipment to accomplish what you want to do.

I use a Victron smart DC to DC, powered up and down by ignition with auxiliary cutoff and fused at the alternator and isolation to the battery. I use in parallel with that a 20amp MPPT charge controller from Newpowa … both are isolated by breakers and fuses on each side of the device. They work great - solar is always charging / connected even when the vans parked. Victron turns on when we start the engine-no issues. Obviously having them both work at the same time for me is most beneficial to charge as I’m running the rear AC off the battery bank.

Hello people…

Thanks for the comments…think I’m almost getting there…as i can see i have 3 choices… installing he thing you are talking about,
-or putting diodes, so that my alternator can’t spoil the solar part,
-or a switch in between,so that either the solar charges the battery or the panels.(never both together)
I think diodes will do the work in my case, i have another kind of protection, as you can see in the drawing above here, in fact it separates the 2 batteries as i understand it…

For what it’s worth I have both my solar and my alternator hooked to my batteries and at points they are both charging them at the same time. They all have regulators on them so they shouldn’t push more than the batteries can take.

I have never had any issues and my batteries have been working great for over 3 years now.

The only real reason people use the isolators and dc to dc chargers is to prevent draining you starter battery when you are parked.

You do however want the option to jump your starting battery from your house battery. You should make sure whatever isolator you use has that option. I use the battery doctor which has a button for that.

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Hello Bretly,

I figured out the charge controller has a protection and the connection made as shown on the picture i added,so yes it will work fine. I am doing some tests now if the home battery that was already there before the solar,is still alright. The pannels i have are in total 200 w, the battery i believe 85Ah or 105. (They are both mentioned on the battery, but i don’t know what is what.
So far (full sun) the battery seems to charge very well…i wander if my (old build in) fridge will soak the battery or not… Let’s see :stuck_out_tongue_winking_eye:
The next thing to do is change all the bulbs into led…i guess the best option is on 12v dc,or does it not make a big difference if i connect them on 220 ac? Because i have more in stock of that…

Grtz Fras

12v DC otherwise you will need to convert it to AC with an inverter which mean lost power and less efficiency

Hello everyone. My wife and I are fishing up our skoolie. I did construction for many years and retired about two years ago. I have one big issue and that is that I am completely lost when it comes to the solar power. We will move in next week and will have to be connected to shore power until we figure out a solar set up that can power our bus full time. I have read a ton of blogs, seen a bunch of YouTube videos but can’t find A set up that can be full time off grid. If anyone could direct us to a blog or website where it’s broken down for dummies I would greatly appreciate it.

Hello Dan.

It all depends on what you want. How much luxury you need. How much sun there is. You could start on calculating
( Solar Panel Size Calculator: What Size Panel Do I Need? - Footprint Hero by example but maybe there are better ones… ) how much you probably gonna need. Forget about electric machines with large resistance. by example, cook on gas, not on electricity. Led bulbs use way less electricity than traditional ones. Coffee you could maybe make on the (gas) stove etc… Once you have decided how much you going to use aprox per day, average, don’t forget there’s sometimes no sun, so count for such times some extra… Based on that, you can calculate a solar installation…
Or an alternative way , could figure out how much space you have on your roof, and estimate how many panels that could be,and next figure out how much electricity that can bring you… Of course than the real work begins… But the calculation is important before starting the project…
I hope my explanation can help you on the way a bit. It’s not all that difficult my opinion, but you could face some problems of course. I myself have glued the panels on the (Plexi)roof , to avoid future leakages. Mine are very light,thin panels. Apart from the panels,you need a charge controller and a battery. If you desire 220v appliances, you are going to need a inverter. Wires in general have to be bigger than the ones usually used in houses…for the dc side.
I used 4 mm² from the panels to the charge controller,same for the wires going to the battery.

Cheers,FRas