Unusual electrical set up on camper advice please?

thankyou for your quick replies. Yes John and Val- I've read up a lot but it gets daunting!

I can take on the second battery and the weight it brings and still be well under the GVM.

Ok, I need a second battery set up along with my Redarc isolator, the latter that I already have. Being auto trans in the trike I might as well get a aux battery that could start the trike if the main battery went flat. I understand there is a small connection wire on the isolator that I can momentarily switch on to achieve this.

Considering this what size aux battery (deep cycle/starter) would you recommend?

You can get thin, lightweight semi-flexible solar panels made to custom sizes at very reasonable prices from here. I have recently had 50W panels, 1150 x 350 made for $180ea. They are about 2mm thick, and that size weighs 1.7kg. Delivery takes 2-3 weeks.

Alternatively you could think about fully flexible, amorphous panels. Lower output for a given size, but better in poor light, even lighter and would better suit installation on a soft roof. An example here. You'd have to do your own search for custom-sized amorphous panels if that's what you want.

Usual disclaimer re the businesses linked to above - no benefit to me, just a satisfied customer of both.

Cheers

The Redarc isolator will switch off very soon after stopping the motor as the battery voltage will rapidly fall below the set point with the fridge running, so best to forget that idea.
For weight saving and less size for available capacity consider the advantages of a LFP battery.
Frank's suggestion for the lightweight panels deserves serious consideration. I would keep away from the amorphous type as the have a much lower performance than the mono or poly ones.

Hi Eaglefree,

Battery sizing is related to charging opportunities, so first my thoughts on that -

Like Frank, I wondered if solar panel/s might be a good option for you, especially the ones Frank has referred to. There is a catch 22 compromise here though - at first sight, fitting panels to the top of your rig sounds good - but - that will require that you park in the sun, which will add to the fridge's load. Being horizontal is suboptimal too. I think your panels would be best if removable, so the trailer can be in the shade with the panels in the sun and correctly oriented. If that's possible, then adding some light weight panels sounds very good.

How big should the battery be ? Without solar you probably need about 40Ah to give 2 days use. Ideally this shouldn't run your battery down more than 2/3, so you'd need at least a 60Ah battery. (Let's assume that you can fully recharge it from the alternator on the next travel day. Recharging is a whole new area of concern, so easier to make that assumption, while not forgetting that it can come back to bite!)

With solar, assuming 7 hours good sun per day, (assumptions make it much easier!) to meet your daily needs you need to generate about 20-25 Ah, ie a charge rate of about 3.5 amps, which would call for a 60W panel with a PWM controller, or 50W with an MPPT controller. With this idealised system you really only need enough battery capacity to deal with the other 17 hours, so a 25 Ah battery should be adequate. Being reasonably conservative, lets say a 50W panel and a 40 Ah battery should be good. (Sorry about all the vague numbers and simplistic analysis, but there are many unknowns and it's probably best to be conservative and aware of the underlying assumptions.) These considerations rely on the solar panels to provide all charging. In fact the alternator will probably also be a major contributor.

Being able to use the auxiliary battery as a starter sounds a very good idea. It also suggests thinking about using a marine style battery, rather than an AGM deep cycle type. These are suitable for both cranking and deep cycle applications. Rather than the household chores, the ability to crank the vehicle will probably decide the minimum size of the battery.

HTH

Cheers

John

Thankyou all. I have my answer among this thread now and will study it all after print off. Great stuff.

For those interested like Tony H15 the trike is a Panther made in Gosford NSW and customised over 5 years by myself. It has won awards all over the world.

It now has a Subaru brumby engine with single point fuel injection.

Recent retirement from work means camping planned. We had a small Guppy caravan but it was too heavy for the trike. At 460 kgms tare and 600 kgms GVM the caravan still towed ok with enough down force on the front wheel of the trike. But was illegal hence sale.

The trike ball weight allowed is 30 kgms. The Detour camper has been ordered with the longer drawbar. The builder is to move the axle forward to compensate for the added weight and a small water tank will be mounted under the rear of the trailer to help offset the fridge on the drawbar. So have that in hand.

What is important is brakes on the trailer. Not only does it allow you to go from towing weight of 250 to 300 kgms but considering you only have an inch or two of rubber steering the rig its a concern. I towed a larger camper trailer (outback) around Tassy and once went downhill on tar and had rubble in the middle of the road. When braking the front wheel lost traction and the terrifying fishtail began. Lucky to save it as the "T" intersection was at the bottom. Swore then that brakes would be mandatory.

The detour was selected after many days of web surfing. It has brakes, 3 drawbar tubes, rear tailgate that we'll mount our 2 burner stove and dish bucket on, lift up bad and most important about 2-3 minute set up.

http://www.youtube.com/watch?v=itCnN9KGyT8&feature=player_embedded

thanks again

John wrote
"There is a catch 22 compromise here though - at first sight, fitting panels to the top of your rig sounds good - but - that will require that you park in the sun, which will add to the fridge's load. Being horizontal is suboptimal too. I think your panels would be best if removable, so the trailer can be in the shade with the panels in the sun and correctly oriented. If that's possible, then adding some light weight panels sounds very good."

I have an idea ...

What if you were to get the lightweight custom-sized panels. Then on the camper mount some low-profile aluminium channels so that the panels could slide into them, retained with a simple locking device. The panels I linked to will bend lengthwise over the curvature of your camper, so you could make them as long as you can practically handle.

Rig it electrically so they contribute to charging while driving. When camped, park in the shade, remove the panels, deploy in the sun, hook up with some cable and voila ...

Just a thought.

Good ideas. Ok, so have decided on a second Aux battery charged by the trike battery with the isolation redarc unit. As we will have only the fridge and some LED lights to run (not even a electric water pump) we think 40AH deep cycle battery will do at around 10 kgms.

If we take one step at a time, we install this battery, insulate the fridge in the poly chest type toolbox recently purchased and see how the rig goes on its first trip.

With the few stops longer than one day relaxing we just might not ever need a solar panel. If we do we can indeed instal a panel say 60W on the chest lid detachable to- as you say, place it in the sun.

For calculation a 40AH deep cycle battery should last 2-3 days I think running our trailer if drained 50%. Especially if the fridge is disconnected at night?

Boy batteries are expensive. A marine battery would be nice but I just cant justify this expense at the moment. Will seek a AGM 40AH battery and see how I go.

We plan to head north in the late Autumn and will report our findings with our set up.

Eaglefree,

Thanks for sharing the images etc. A great bit of kit. Now I've seen the pics, I think Frank's panel idea looks increasingly good.

re "insulate the fridge in the poly chest type toolbox". I assume (again!) that you aware that you can't expect a fridge to work if it's shut inside an insulated box. Adding insulation is good, but the heat sucked out of the interior has to be disposed of somewhere.

"We plan to head north in the late Autumn and will report our findings with our set up". Please do!! And have a great trip.

Cheers

John

Eaglefree,

Sorry, my follow-up above is not really relevant, is it? I though you were using the van, hence sliding the panels into curved tracks on the roof.

But you're not. Oh well, sit seemed like a good idea at the time.

Cheers

thats ok Frank P. no, I've sold the van. the camper is on order. the chest to go on the drawbar is 900x500mm. so large enough for a future solar panel. Yes, am planning vents for the fridge -in vents and out vents.

The chest will also house the porta potti. We have one of those folding shower tents. a portable shower unit running on 12v or rechargable batteries. half a bucket cold water, add boiling water- works great. I like simple solutions. The more complicated to less pleasure.

Well we purchased a 28AH gel battery. We went camping for two nights. The battery lasted for 28 hours running the fridge and a little lighting. Most lighting came from a small 12V rechargable light.

Remember everything on this motorcycle camper is miniaturised, lighter and smaller than normal to keep the GVM at a low 300 kgms. The tare is 190 kgms (up from 175 due to the longer than standard drawbar). Means we have only 110 kgms for load. Fridge 16kgms, trunk 12 kgms, porta potti, battery, clothes, kitchen items bedding etc.

I'm very impressed with the Detour camper. It does what the larger ones do but lighter. We towed it with our Hyundai i30 diesel and - no change from normal power. It's well thought out, has 3 tubes for the drawbar, rear tailgate as well as lift up bed and brakes.

As for the electrics I'm satisfied with our set up as we will mostly travel daily. Thankyou again for your replies.

oh, by the way, the trailer is now wired for a solar panel. Will get a removable 60W panel in time mounted on top of the trunk.