I’ve bought a Hobby caravan for leisure use, along with a Li Time 12V 320Ah battery.
I’d now like the battery to charge when the caravan is hitched to the car, and also when shore power is connected. Ideally, I’d also like to add solar power on the roof at a later stage.
I’d also like the battery to supply the caravan with 12V and 220V when neither the towing vehicle nor shore power is connected.
What components do I need to make this work?
Perhaps someone here has already set this up and could help me accordingly.
As a minimum, you would need an Orion XS, a MultiPlus and an MPP PV controller.
Since the battery does not allow bus connectivity, you would also need an SBS (Smart Battery Sense or shunt) for the internal smart networking.
For external control of the PowerAssist function, you would also need a control panel in the WOWA interior.
Discuss this with your installer or electrician, as it is not necessarily straightforward for non-specialists (installation). You may need the Mk.3 programming adapter for the configuration.
First, you need to find out what the maximum current from the trailer socket is. You’ll have to ask a garage about that. Then choose a charger booster: the Victron Orion 12-12 is available in different capacities. However, it’s unrealistic to fully charge a 320Ah battery while driving. Assume that the charging current will only be 10A. That means you’d have to drive for more than 30 hours. So I wouldn’t design the system around that in the first place. As an inverter, there’s the Victron Multiplus 12/xx-xx. These can also charge the battery, and they can combine mains charging current with battery current in such a way that the shore power connection isn’t overloaded when you use a kettle or hotplate. Suitable charge controllers for PV include the Victron SmartSolar 100/20, 100/30 and 100/50. However, that depends on the solar panels. A Victron SmartShunt can act as a “fuel gauge” for the battery.
Charging from the car is the last thing to worry about.
I have a small system 130w solar panel connected through a smart solar MPPT 75/10 controller, this keeps the battery almost fully charged most of the time.
230v is supplied by a 1100 watt non Victron inverter, if I was doing it again I would use a Victron 1600/12 inverter. A Smart Shunt monitors the current in and out of the battery.
This all talks through a Raspberry Pi running Venus OS over WiFi to my VRM account so I can monitor it when I’m away.
As for charging from the car it all depends on the charge voltage from the car, if it’s 14.4v or lower with my LifePo4 battery there is no need to fit anything in line as the car/caravan wiring will regulate charge current to about 5 amps. I have just fitted a B2B charger as the charging voltage on the new car is 14.7v and have had to reduce the charge current to 10amps as low as it will go and set the charge voltage to 13.7v this is in order to minimise voltage drop in the cars wiring.. A way round this would be for me to run cables directly from the car battery to the B2B but that would involve major disruption to the cars inside.
Solar is the way forward I may well double mine over winter not because I really need to but because I can.
A year ago I converted our caravan to fully electric off-grid vehicle. No gas, everything runs of battery/ mains/ solar or V2L (I have EV).
There are many things you need to consider but starting point would be to calculate max expected load (Amps) of all your DC and AC devices (separately).
This will define how powerful inverter you need to run AC devices - you can play with this number and assume that when using electric kettle you are not going to switch microwave for example. This will drive your inverter choice.
Batteries will have charge and discharge rating so you will need to match that your expected load.
Furthermore, you need know what how long you want to be able to run on battery only. Combine that with your expected power consumption (kWh) and that will gave you answer to how big battery you need (Ah).
Having that you can plan your solar setup, how much space you have on the roof. Do you want to go for “regular” panels - more powerful but heavier or flexible - light but less powerful and almost flat.
Once you know how many panels you can put you will know maximum voltage and current output - this will define what solar controller you need. You can play with numbers by connecting panels in different configuration, series or parallel or mixed.
On top of that I would consider smart shunt for battery monitoring - unless your battery can communicate with victron directly. Combine it with Cerbo and display for easier management and extra smarts- completely optional.
I can’t help you on charging from towing vehicle front as I haven’t done it.
I had great fun designing and building my system but if this is not your cup of tea there are companies who will work with you on design and will sell you all necessary gear with fitting instructions.
One of them is Nohma - I’m not associated with them in any way.
If charging from the towing vehicle while driving is the preferred option, there is another possibility: when supplied with 230 V, the Multiplus in the trailer can charge the battery at high power. While driving, a Multiplus installed in the towing vehicle can provide 230 V at high power. This requires an alternator that is capable of—and permitted to—deliver the necessary power. However, a 230 V connection to the trailer would then be required. Otherwise, the current through the 12 V wiring of the trailer socket would be limited to an unacceptable level. Even with heavier-gauge wiring, the charge booster would be the bottleneck.