Solar The Solar Panel Thread

[pcutt]

Hi,
I'm new to this forum having just bought a 2015 17.56-1 expanda tourer, which hasn't had any batteries or solar panel fitted. Since we're going to be doing plenty of off grid camping I'm going to install a 300W panel and 2x 100Ah batteries with a Victron SMPPT charger. I'm comfortable with the electrical side of things as I do install12v solar systems at work and the solar supplier I use has given me a solution I like for panel adhesion to the roof.

The thing I'm a bit nervous about is getting the solar cables into the interior through the roof. There is a very small junction box on the roof that has been well sealed up that is close to where the cables from the ceiling come down into the cupboards so I assume there is already a penetration in the roof there. It is however too small for me to put a double gland in to bring the cables inside. My idea is to replace the small existing junction box with one of those streamlined boxes with the two horizontal glands pointing to the rear of the roof. The other idea I had was to remove TV antenna as I will never use it, and put the panel on the same place and use an existing penetration for the solar cables.

Anyone tried either of these ways of getting the cables in?

 

[Drover]

I would just make the hole bigger in the current box, sounds like it was done in anticipation of adding panels.......... they just normally use a square junction box with the cables using a silastic gasket thru the roof...... make sure you give those panels on roof plenty of air flow though and layout to allow additions, good to see someone comfortable with wiring as that saves a lot of questions, in fact we may be able to throw some at you as well.................

You may want to up your batteries to 120a or so, on paper should be more than enough but you may find after awhile you want a little bit more on the roof and a bit more storage as the paper equation doesn't always equate.

If your tourer hasn't had the axles rolled to give a bit more lift you may want to look into that as well so you don't drag its bum..... Start your own thread about your rig.....

 

[pcutt]

Thanks Drover. Yes I did open the box up and there was a twin core cable approx 4mm2 inside. I was able to trace this back to one of the two cables in the battery box under the seat. Only issue is that the junction box is so small I can’t fit a cable gland in it, probably not the way that caravans usually seal cable entries but they only cost a few cents and give more peace of mind. I’ll adhere a slightly bigger junction box over the top of the existing one and solder on solar cables and seal the entry with a gland.

 

[Drover]

You are lucky its pre wired that makes life easier for sure, I would fit a couple of MC4 plugs on the end of the lead outside gives you better flexibility for later on... I assume your van is using a Setek ST35 system so keep the solar seperate from it and go direct to battery via the reg, you can fit your Reg in the battery compartment but set it up so you can expand by just adding another battery box without having to redo the layout.
In my box of tricks I have a MC4 wall mount which would be ideal to use instead of a gland, nearly used it when I upgraded my roof panels but when I looked at the junction box I wondered if the hole was bigger than the wall mount so decided to leave well enough alone, "aint broke leave it" ..... my 2nd rule after "The KiSS Principle".

 

[pcutt]

You are lucky its pre wired that makes life easier for sure, I would fit a couple of MC4 plugs on the end of the lead outside gives you better flexibility for later on... I assume your van is using a Setek ST35 system so keep the solar seperate from it and go direct to battery via the reg, you can fit your Reg in the battery compartment but set it up so you can expand by just adding another battery box without having to redo the layout.
In my box of tricks I have a MC4 wall mount which would be ideal to use instead of a gland, nearly used it when I upgraded my roof panels but when I looked at the junction box I wondered if the hole was bigger than the wall mount so decided to leave well enough alone, "aint broke leave it" ..... my 2nd rule after "The KiSS Principle".

Thanks Drover, yes I will solder the MC4 extension cables onto the existing cable, there’s not a whole lot of cable to work with though. I like the sound of the wall mount MC4s but I am going to have to put my panel too far away to utilise the pre-fitted MC4 leads in the panel. So hence the MC4 extension leads. The SETEK manual said you could add up to 2x100Ah batteries so that’s really what’s influenced my decision there. I went with the Victron supercycle ones which should give me the best capacity.

 

[Drover]

If you set up your solar for off grid, the Setek charging isn't really in the equation so you set up storage to suit your solar as it will be doing all the work and the Setek will just be the distribution box ........... My rig even though it has 240 charging capability its very rarely used and your MPPT reg will charge the batteries better than the Setek no matter what model it is, just solar direct to battery....
I just made up extension leads for my panels, try to keep them off the roof a bit so they don't cause pools of water to collect along with dirt etc, I don't know how they handle the sun but Ive kept mine out of the direct sun anyway.

 

[pcutt]

Thanks Drover, now I’ve got a solar charger, an inverter and the 2x100ah in the box under the seat there’s not much space left for more batteries anyway.
On a related note, I’ve been through all the connections from the setec to test what is powering what and labelled it all. There’s one heavy gauge twin core cable connected to the aux terminal but following some testing this doesn’t appear to be wired to the trailer plug, which the manual suggested it should be. Anyone got any suggestions as to what this could be? Also can’t seem to get the fridge to work on DC. Anyone know if the tourers have the 12vdc input connected? I’m a bit nervous about damaging a gas connection if I pull the fridge out to have a look. I didn’t get a power connection through my car to the trailer socket as I figured I have solar and batteries so no need. Could the fridge be directly wired to the trailer plug?

 

[pcutt]

UPDATE: removed the lower fridge vent on the exterior of the caravan and found the 12v terminals on the fridge. Seems they wired these directly to the trailer plug. Still no idea what the Aux cable in the SETEC is from yet.

 

[jazzeddie1234]

According to the most common jayco wiring (which always needs to be verified) the aux of the setec should be connected to pin 2 of the 7 or 12 pin plug via a 20amp fuse and pin 2 on the tug side should be 12v (they say from the starter battery which is most common)

In my case the aux wire on the setec travels forward to a hole in the floor. On the outside this connects to a rats nest coil of wire which is the end of the trailer loom - usually easily traced where it exits the A frame. Sometimes the joiner is there or just above the hole in the floor (in my case behind a section of skirting).

For the fridge (and assuming there is a 12v manual selection option on the fridge front panel) I would look behind the lower outside vent for a red and black very heavy gauge wire. These also run to that hole in the floor, then a joiner to the rats nest as above - usually changing colour to pink and white. 12v must be present across those 2 when the tug engine is running (it might be 11.5V but anything lower will probably stop the fridge cool properly).

 

[Drover]

Fridge on 12v only runs off vehicle never off van batteries ............... In original set up the 12v supply from tug will be just one run from 7/12 pin, this will split in a mess of wires usually under the van behind a metal panel near the end of draw bar, often called the birds nest, this 12v supply will split into two runs, one going to the Setek unit and one to the fridge, the fridge does not have any connection to the Setek at all and the Setek circuit has a diode which stops power being drawn back along this line .................... A very common mod is to disconnect the fridge circuit and run a dedicated line from tug via an anderson plug or by using the 12 pin so van supply and fridge supply are seperate, a very wise idea as it allows more suitable gauge of wire for fridge..........

12 PIN Wiring - Brake Controller - 12 Volt Fridge Hotwire - 12 Volt Hotwire DIY

_______________ Disclaimer: If you have no experience in this type of job it may be best to seek professional assistance. Any auto electrician should be able to do this work for you and as a caution you need to know what your doing when performing this work. I accept no liability from damage...

expandasdownunder.com

 

[pcutt]

Thanks all. I was looking at the setec manual for the trailer plug wiring, which didn’t help! I really want a backup power supply for the fridge if I run out of gas so will wire the fridge into the setec so I can power it while driving (via caravan solar and batteries) and as a backup for no gas. Seems like I also have the trickle charge from the car into the setec while driving so should be ok for keeping the batteries topped up alongside the solar panel.

 

[jazzeddie1234]

The normal way is to run the fridge directly from the alternator due to the high current draw (mine is 17amps) of the fridge. If you do need it from the van battery then it would be important to calculate what the van plus fridge needs and how this will be provided.

Personally I would disconnect the setec aux wire (this input is not current protected/limited and not nearly grunty enough) and connect this to a dc dc charger (min 20 amps) which is then directly connected to the van battery. That way you have a backup from the tug supply on a cloudy day. I would also have some auto system to switch the fridge to gas when you stop - trusting your memory will only work sometimes and not when you really need it!

I did consider variations on this idea and try a few things but ended back with the normal setup of a direct connection to the fridge.

 

[Drover]

Thanks all. I was looking at the setec manual for the trailer plug wiring, which didn’t help! I really want a backup power supply for the fridge if I run out of gas so will wire the fridge into the setec so I can power it while driving (via caravan solar and batteries) and as a backup for no gas. Seems like I also have the trickle charge from the car into the setec while driving so should be ok for keeping the batteries topped up alongside the solar panel.

I think we all have looked at this idea but when you look at the draw of a 3 way fridge , 12v from the car battery when engine is running is the only way, these 3 ways fridges will draw from 175 to 275watts roughly depending on model, so thats 15 to 23 amps so to try and cover that draw down and other van draw with solar isn't practical if at all possible.

I think @Boots in Action did a good thread on 12v fridges..........

Look at the tag on your fridge it will show the gas rate in mj/hr, varies from 1.2 to 1.7 mj/hr again fridge size determines consumption, a 9kg bottle holds approx 441 mj, (I work on 400) so a simple bit of division will give the hours your bottle will last ..... roughly a small fridge (90lt) will run for 16 days continuous while one like mine (186lt) around 10 days, I work on 8 days to be safe, the backup is a Honda genny but in all this time have never run out, if I'm going to be off grid for longer and too far out I will bring an empty along and refill it at he last stop, that will give me just over 3 weeks, far longer than I want to stay in one place anyway....

A dedicated run from tug to fridge, with nothing to do with Setek or van battery, will ensure you have a good supply whilst driving and not kill your tug battery and fitting of a fridge switch will ensure you can start the engine when you stop for smoko..... It is not wise to leave the fridge running on a solo battery.

 

[BaldEd]

jazzeddie1234 and Drover +1

What I did was split out the frig +ve and -ve (thickish Pink and White wires connected to pins 9 & 10) from Jayco's 12 pin plug loom at the point where the loom exited from the drawbar. Re-sheathed those wires in an old bicycle inner tube for protection and connected a 50A Anderson plug. The tug supplies the power from the alternator through a VSR and 6AWG cable to the tug's matching Anderson plug.

To provide some peace of mind that the frig is being supplied with power by the alternator I wired a small digital voltmeter across the frig element wires, and positioned it just above the frig doors where it is visible from outside the van. This displays the voltage being supplied by the alternator - usually around 13.8 - 13.9v. I always peer in through the window to check the frig voltage as I walk around doing my pre-drive off check of the lights, indicators and stop lights.

 

[mikerezny]

jazzeddie1234 and Drover +1

What I did was split out the frig +ve and -ve (thickish Pink and White wires connected to pins 9 & 10) from Jayco's 12 pin plug loom at the point where the loom exited from the drawbar. Re-sheathed those wires in an old bicycle inner tube for protection and connected a 50A Anderson plug. The tug supplies the power from the alternator through a VSR and 6AWG cable to the tug's matching Anderson plug.

To provide some peace of mind that the frig is being supplied with power by the alternator I wired a small digital voltmeter across the frig element wires, and positioned it just above the frig doors where it is visible from outside the van. This displays the voltage being supplied by the alternator - usually around 13.8 - 13.9v. I always peer in through the window to check the frig voltage as I walk around doing my pre-drive off check of the lights, indicators and stop lights.

Hi,
yep, I did the same to measure the voltage at the fridge terminals.
I can easily measure the alternator voltage inside the car from the diagnostic readout on my brake controller.

If all is well, there is a 0.8v drop from the alternator voltage to the fridge terminals.
If I have a dodgy connection on the 12-pin plug, the voltage difference will be 1v or so. It has happened a few times in 5 years. Usually connection terminals on the 12-pin plug or socket.
If the voltage at the alternator is the same as at the fridge, it means there is no current draw. That has also happened a few times. All caused by me forgetting to turn the fridge over to 12V before we set off! It could also indicate an blown 12V heating element.

take care
Mike

 

[Boots in Action]

jazzeddie1234 and Drover +1

What I did was split out the frig +ve and -ve (thickish Pink and White wires connected to pins 9 & 10) from Jayco's 12 pin plug loom at the point where the loom exited from the drawbar. Re-sheathed those wires in an old bicycle inner tube for protection and connected a 50A Anderson plug. The tug supplies the power from the alternator through a VSR and 6AWG cable to the tug's matching Anderson plug.

To provide some peace of mind that the frig is being supplied with power by the alternator I wired a small digital voltmeter across the frig element wires, and positioned it just above the frig doors where it is visible from outside the van. This displays the voltage being supplied by the alternator - usually around 13.8 - 13.9v. I always peer in through the window to check the frig voltage as I walk around doing my pre-drive off check of the lights, indicators and stop lights.

@BaldEd , Further to what @mikerezny explained about voltage at the fridge terminals, I too have a volt meter connected across the input fridge terminals at back of fridge. When connected to the tug with engine running, it is normally around 13.8 or 13.9 volts with NO load - ie fridge not switched into circuit. However, under same conditions and fridge switched IN to circuit, voltage drops to approx. 12.3 volts because of the 14 amp load on the line from alternator. As my 2011 Colorado has standard type alternator, I consider this to be satisfactory. Later model tugs with "smart" alternators do not have as high voltage output from the alternator although current output would be plenty to run fridge. These "smart" alternators are not suitable for charging auxiliary batteries including your van battery. You need a DC to DC setup to overcome the charging problem as @jazzeddie1234 advised. See attached for more info.

 

[Drover]

jazzeddie1234 and Drover +1

What I did was split out the frig +ve and -ve (thickish Pink and White wires connected to pins 9 & 10) from Jayco's 12 pin plug loom at the point where the loom exited from the drawbar. Re-sheathed those wires in an old bicycle inner tube for protection and connected a 50A Anderson plug. The tug supplies the power from the alternator through a VSR and 6AWG cable to the tug's matching Anderson plug.

To provide some peace of mind that the frig is being supplied with power by the alternator I wired a small digital voltmeter across the frig element wires, and positioned it just above the frig doors where it is visible from outside the van. This displays the voltage being supplied by the alternator - usually around 13.8 - 13.9v. I always peer in through the window to check the frig voltage as I walk around doing my pre-drive off check of the lights, indicators and stop lights.

Yeppers, I just disconnected the original fridge cable and ran a whole new line via anderson to fridge, anderson at fridge mainly used as a step down connection from 6 or 8 B&S to fridge wiring but it also serves as a quick disconnect, minimal voltage loss and so I know I have power to fridge it also run my rear view camera.

 

[BaldEd]

Hi mikerezny & Boots,
I have 2016 Colorado7 which has an 'old-style' alternator. I do have a voltmeter permanently plugged into one of the cig. sockets in the dash. It always reads over 14. something volts. Before driving off with the caravan in tow I have always just checked that the frig is on with the 12v indicator lit and volts dare being displayed on the frig's voltmeter. But the thing that you both raised, that I hadn't thought of, was that there maybe no load being drawn from the alternator viz. the heater element may have failed. Will specifically check for that the next time I am on the road. Thanks.

 

[BaldEd]

Hi mikerezny, Boots and everybody,.
This morning I went and did a test with engine running.
With frig OFF
Dash voltmeter read 14.8v whilst Frig voltmeter read 13.8 to 13.9v
With frig ON
Dash voltmeter read 14.4 to 14.5v whilst Frig volmeter read 13.4 to 13.5v
Clamp meter over the frig element +ve read 18.69A. (Thetford N3185, 3 way)

Now I know to look for an approx 1v drop between the 2 voltmeters to verify that the 12v element is good and working.
Cheers, Eddie