Where do you want to go?

charliemagpie

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It's a horses for courses thing

A few months ago, I was pondering the power setup for my RV

I looked at distances between chargers and potential future chargers, googled caravan parks, measured distances. It was fun.

My power setup was reaching mega bucks. I figured at this juncture, a generator was a must. But the penny dropped when I realised I only need to first follow the grid. Other places will catch up soon enough.

I decided this :

I don't need a generator
I don't need a huge battery bank. It was either full hog or minimal.

I need as much solar as I can fit

 

JBee

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It's a horses for courses thing

A few months ago, I was pondering the power setup for my RV

I looked at distances between chargers and potential future chargers, googled caravan parks, measured distances. It was fun.

My power setup was reaching mega bucks. I figured at this juncture, a generator was a must. But the penny dropped when I realised I only need to first follow the grid. Other places will catch up soon enough.

I decided this :

I don't need a generator
I don't need a huge battery bank. It was either full hog or minimal.

I need as much solar as I can fit
If you must drag a caravan around and its 2.4m wide then you can fit 35mm thick solar panels to the sides as well as the roof. You make it so that you can fold up the sides as a awning and preferably so you have a few angled stops along the way to optimise orientation.

That way on a 6m long caravan body you can get about 8kW of solar onboard, you then add a 11kW MPP Solar off-grid charger for around $2.5k, plus another 10kWh (90kg) or more of lifepo4 batteries for around $2.2k from trakkas on ebay. Ideally you'd have 30kWh (thats 270kg tho) or so which would allow a full days worth of RV summer solar to be stored and charge your CT at night.

With that you can max out L2 single phase charging and you'll get around 32kWh per day and around 64km a day depending on how much load your RV has with the shortest cycle times possible. You could add another 3kW PV to the CT with my CT pop top sliding and tracking solar roof, that will give you another 20km. CT range would be more without the trailer, and you'd travel at around 70-80kmh to make the most of energy, so expect to be overtaken by roadtrains.

The good thing is that the side and roof mounted solar will continue to charge whilst you drive as well, not at full capacity but probably around 40% which is something at least to offset the RV drag too.

The ideal driving/solar charging profile for travelling would be drive early morning and evening and stop to solar charge between 7am and 5pm. If you are operating out of base camp the same profile would be ideal to minimise loses, but you could also charge in 3-4 hours from the 30kWh battery in the trailer at night and drive around 90-100km a day just with the CT from the RV charge alone.

Depending on how far you have to go in one hit to get somewhere, at 80km total solar range a day your travel budget will only be for around 1 hour travel per day. You'd then also need to budget some for excursions and shopping. Overall you could make it work. In a pinch you could just charge the CT over a few days, drive slow and leave the RV somewhere to get help in the form of a generator.

For more normal trekking through towns and RV parks you could then do a switcheroo, by adding a 3.6kW RV charger on a RV hookup you could then charge your CT using the inverter at L2, and recharge the RV battery from the mains all day as well as from the solar. You'd have to swing by with the CT twice a day during the day (say brunch and afternoon tea) and stay connected all night to discharge the RV battery, but you'd get another 150km a day that way, so around 230km. Technically you could also park the CT at another powered site and grab another 120km or so too for 350km total. It would take 9 hours to charge the RV battery just from the RV hookup and 4 hours from full solar so you'd have to switch it around in a optimum way.

Then of course there's the whole RV hub motor option, which adds more weight and cost, where the RV would help push itself along instead of having to be stationary and transfer power to the CT which has losses. It would probably help off road too though. It would be perfect if you could charge whilst driving as this would cut you 4hour RV charge time out of the equation. Maybe we'll get a PV input on the CT or V2X.

But of all of the options I think a custom built caravan is the way to go, that also pops down to half the size and snuggles up to the CT with a telescoping hitch. That should halve the RV drag without adding any weight or materials. All these things are on my drawing board atm getting design iterations done so we can do a product release next year sometime when the CT comes out.
 
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charliemagpie

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Pop rop not for me, but a lot of fun ahead reviewing your post. Maybe I'll swing around for tea lol

trakkas ?
 
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JBee

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Pop rop not for me, but a lot of fun ahead reviewing your post. Maybe I'll swing around for tea lol

trakkas ?
Yeah sure PM me when you swing by.

Something like these:
https://www.ebay.com.au/itm/3342954...cbEWOQ7RS6&var=&widget_ver=artemis&media=COPY

Just need to watch C rating for discharge.

Pop top would be solid insulated sidewalls for both CT and caravan. So no floppy canvas.

The reasoning for solid wall pop top is that every caravan predominantly transports air in volume, which in turn creates more air resistance which is bad for consumption. So why take air from Syndey to Alice, if you can just open the door and let fresh Alice air in once you get there and pop the top? 😁
 

charliemagpie

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JBee

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I hear most time is spent out of the caravan anyway. Still 2 years to ponder.

I was looking at one of these
https://itechworld.com.au/collectio...y-lifepo4-deep-cycle-recycle-camping-rv-solar


Standard discharge current:250A
About 25% better rated discharge, but nearly 3x the price per kWh of capacity?
There's obviously different models, and higher charge/discharge rates are better, but overall you're always better off buying more capacity and running them at lower charge/discharge C rates. But in two or so years there will be better ones, I was just demonstrating where the prices are already to make the above scenario work.

 

 
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