Camper trailer wiring question

[John_D4]

I have a jayco Swan outback that I'm doing some electrical work to & need some advice.

1) I'm running 3b&s dual wire from the 65ah dual battery in the discovery via large capacity Anderson plugs on the tow bar. There's a 130ah AGM Gel in the Swan that it's getting terminated on. What sized fuses on either side of the wire? 80amp?

2) on the tow bar where the lg Anderson plug gets terminated, I was thinking of splicing in a regular Anderson plug so I can plug in my folding solar panel & charge the dual battery. Would adding the extra plug effect charge to the camper? Is 3b&s more than sufficient to compensate for the small loss created by adding the 2nd Anderson?

3) I'm aware of DC/DC chargers & I'll add one if necessary, but I'm adding 2 solar panels. I've got a Victron MPPT 100/30 and Bluetooth dongle to add, plus 2x130w solar panels. By memory the panels are rated to about 7amps (or so, I'd need to check to make sure). I was going to run 2 x 15amp wires from the panels to the controller. What is the best way to wire up multiple panels in this situation?

4) upgrading the power wire between the battery and the dometic 3 way camper fridge, and adding a movement sensor. How thick a wire is recommended?

Thanks for the help in advance, I've asked similar questions on a caravan forum but never got answers to some of the detailed questions.

[John_D4]

Really, no suggestions?? Maybe there's no one out there. Am I all alone? Oh no a zombie apocalypse, all the computers are out. Help!

[loanrangie]

All I can suggest is forget running a 3 way off 12v, will draw too much as they are very inefficient .

[John_D4]

All I can suggest is forget running a 3 way off 12v, will draw too much as they are very inefficient .

Agreed. The 3 way only draws 12v during travel & will have an inertia switch to cut the power when the vehicle stops for a certain length of time.

They are brilliant on gas tho

[weeds]

1) rarely see 3B&S used for charging trailer batteries. 6B&S is all I’ve ever used....fuses protect the cable, I think I have either 80 or 100amp

2) use 6B&S and no need to splice and 50amp Anderson plug. If you stick with splicing than it won’t affect your charging

3) shouldn’t need a DC-DC, nice choice for your regulator and the dongle is a handy gadget. I fit Anderson plugs to my solar panels, made a Anderson double adaptor and have a 10m 6B&S extension which I plug into the Anderson plug on My Victron which is mounted at the battery.

4) given I use 6B&S every where I would also use it on the three way and a movement sensor is a good add

For me.....6B&S everywhere using 50amp Anderson plugs. I have converted everything 12v to Anderson plugs.....portable water pump, portable shower, portable compressor, fridge, LED light strips etc

[drivesafe]

Hi John, and you can easily charge a bank of batteries in your trailer using 6B&S ( 13.5mm2 ) so your 3B&S ( 25mm2 ) cabling will make a breeze of charging your battery, or batteries.


If you have run 3B&S cabling from your cranking battery to your house battery, the an 80 amp fuse is fine.


Even with the heavier cable running to your house battery, a 3 way fridge can still drain your house battery while you are driving.


You will need to do some testing and if the 3 way is a small one, you may getaway with it being powered from your house battery, but it is still not the ideal setup.


Best practice is to run a separate power supply from your cranking battery to your fridge, via an ignition controlled relay. or as suggested above, fit a fridge switch.

Last but not least, DC/DC devices are not needed in an Land Rover DBS, because the Land Rover alternator can charge faster than a DC/DC device can.

[John_D4]

Hi John, and you can easily charge a bank of batteries in your trailer using 6B&S ( 13.5mm2 ) so your 3B&S ( 25mm2 ) cabling will make a breeze of charging your battery, or batteries.


If you have run 3B&S cabling from your cranking battery to your house battery, the an 80 amp fuse is fine.


Even with the heavier cable running to your house battery, a 3 way fridge can still drain your house battery while you are driving.


You will need to do some testing and if the 3 way is a small one, you may getaway with it being powered from your house battery, but it is still not the ideal setup.


Best practice is to run a separate power supply from your cranking battery to your fridge, via an ignition controlled relay. or as suggested above, fit a fridge switch.

Ok. Thinking...if I splice in a 6b&s with a 2nd Anderson on the tow bar (remember it's feeding from my dual battery) and run a length of 6b&s as a 2nd feed direct to the fridge switch then onto the fridge? Would I need to do anything to stop it back feeding/draining from the house battery? Not an issue in the day time as I'll have 260w of solar assisting, but might be an issue at night.

[drivesafe]

Ok. Thinking...if I splice in a 6b&s with a 2nd Anderson on the tow bar (remember it's feeding from my dual battery) and run a length of 6b&s as a 2nd feed direct to the fridge switch then onto the fridge? Would I need to do anything to stop it back feeding/draining from the house battery? Not an issue in the day time as I'll have 260w of solar assisting, but might be an issue at night.
That should be fine an the ridge switch will stop the fridge drawing from your has battery when the motor is off.

[John_D4]

1) rarely see 3B&S used for charging trailer batteries. 6B&S is all I’ve ever used....fuses protect the cable, I think I have either 80 or 100amp

2) use 6B&S and no need to splice and 50amp Anderson plug. If you stick with splicing than it won’t affect your charging

3) shouldn’t need a DC-DC, nice choice for your regulator and the dongle is a handy gadget. I fit Anderson plugs to my solar panels, made a Anderson double adaptor and have a 10m 6B&S extension which I plug into the Anderson plug on My Victron which is mounted at the battery.

4) given I use 6B&S every where I would also use it on the three way and a movement sensor is a good add

For me.....6B&S everywhere using 50amp Anderson plugs. I have converted everything 12v to Anderson plugs.....portable water pump, portable shower, portable compressor, fridge, LED light strips etc

That's a good idea (keeping everything the same). I'll keep it in mind.

I've already bought 3b&s & lg andersons specifically to run the feed to the camper. I only bought 1 plug & socket as I'm not expecting to use it anywhere else. My folding solar uses 50amp Anderson hence why I considered fitting a 2nd Anderson on the tow bar.

[weeds]

Ok. Thinking...if I splice in a 6b&s with a 2nd Anderson on the tow bar (remember it's feeding from my dual battery) and run a length of 6b&s as a 2nd feed direct to the fridge switch then onto the fridge? Would I need to do anything to stop it back feeding/draining from the house battery? Not an issue in the day time as I'll have 260w of solar assisting, but might be an issue at night.

It would work but will be drawing off the system car and van battery.

but for me keep it simple.....rarely see two Anderson plugs on draw bars....way back when I had a van with a 3 way fridge it was just wired to the battery in the van like all the other 12v items. I didn’t bother with a motion switch or relay, just switched to gas when we pulled up at camp.

[Pedro_The_Swift]

The infamous 3-way dometic is a cluster****,,

it draws 15A running down the hiway,,
and you cant run it on it best fuel, LPG, untill you stop driving.

of course its sold to caravan owners that stop at van parks,, just plug it in [thumbsupbig].

[John_D4]

A solar panel wiring question. I’m wiring 2 identical panels: 130w, 18v max, 7.5amp

Wiring them parallel is the go isn’t it? I was thinking of running 6b&s from the controller to the roof & putting a weather proof junction box under a panel & connecting up all the positives to the positive feed and the negatives to the negative feed.

So...assuming this is right...if I ever buy 3rd 12v panel with different amp & watts would I just connect up the red & black wires?

[weeds]

18v max?? Is that open circuit voltage, sound a little low.

Parallel is fine

I run 6B&S to mine and yes just connect the + and -‘s

I regularly at additional solar panel that are not the same spec....seems to just work.

[bee utey]

18v max?? Is that open circuit voltage, sound a little low.

Parallel is fine

I run 6B&S to mine and yes just connect the + and -‘s

I regularly at additional solar panel that are not the same spec....seems to just work.

Parallel is fine for simple solar controllers. If you purchase a MPPT controller you can wire them in series, but adding other panels is then difficult.

Example MPPT controller (https://www.ebay.com.au/itm/Victron-SmartSolar-MPPT-Charge-Controller-100-20-12-24V-BUILT-IN-BLUETOOTH/263279734835?epid=2235721556&hash=item3d4cb1f033:g:-AEAAOSwjZJZ8CU-)

[DiscoMick]

Your solar panels should have controllers on them and they should state a maximum output, so that helps with sizing fuses.
Another option is just to run the power from the vehicle to the trailer to a DC-DC there to overcome voltage drop and boost the charge to the battery. That way you don't need Anderson plugs or a DC-DC in the vehicle.
I think it's better to pick up the power from the vehicle in a way which cuts when the engine stops, so your van can't flatten the vehicle, so I wouldn't power the van from the second battery in the vehicle.

[John_D4]

I’ve got a Victron 100/30 controller with Bluetooth dongle.

Here’s a pic of the faded sticker on the back of the panel

https://www.aulro.com/afvb/images/imported/2017/12/346.jpg

[John_D4]

I think I’m having problems with my Victron 100/30. Here’s a screen shot:

https://www.aulro.com/afvb/images/imported/2017/12/460.jpg

I’ve got the 2 x 130w panels on the camper roof. They each have an Anderson plug and each is running via 6mm (4mm2) twin to the 100/30. I’ve wired them parallel. Some forums have indicated that series is a better way of wiring.

As you can see from the screenshot the system isn’t producing watts or amps and the battery isn’t charging. Could it be that the 20v is too low & if I wire in series it will fix the problem?

Incidentally, I ran 3b&s from the D2 2nd battery to a 120amp (plus a 50amp next to it) Anderson plug on the towbar, then onto the camper battery via an 80 amp fuse (at the dual battery also). There is no voltage drop between the dual battery and the camper battery (over 13v - can’t remember exact figure). No BCDC charger necessary - nice. Gotta love the large disco alternator.

Just need to work out why the panels aren’t charging...