Solar conundrum (updated with shopping list)

My setup. 34' 5th wheel toy hauler - finished the install 1 month ago.

4 - 100W Mono
Renogy mounts - they look sturdier than z mounts
Stainless hardware to mount the panels
Gobs of lap cement (About 1 tube)
Home made combiner box - about $35.00
10awg from each panel to a combiner box - each run from panel to combiner is over 20'. Used 10awg UV and underground rated cable. Two 10awg THHN copper stranded inside a UV rated sheath. Put my own MC4 connectors on them. Cable was about $100.00 Parallel not serial as I'm concerned about partial shade on some panels.
#4 from the combiner box to the PWM Tristar 45. About 25' long. A 60A breaker next to the tristar on + side of the solar panel.
#4 from the tristar to 60A breaker. About 1' then #1 from the 60A breaker to 60A fuse next to the batteries about 3' (I used #1 here instead of #4 because it was tighter in the set screws on the breaker and fuse holder, should have used lug style for the breaker and fuse holder).
#1 from the fuse to positive bus in battery compartment
#4 neg from the tristar to negative battery bus in battery compartment
All welding cable between combiner box/tristar/batteries was put inside 1" split flexible plastic conduit (Fry's)
Temp sensor - about 6'
Sense cable - about 6'
Victron battery monitor - comes with a shunt. Shunt is mounted between the negative battery and negative bus (where the rest of the negative connections are in the battery compartment).

I bought the toy hauler used.
Room for two 6V on right side of generator in front compartment
Room for another two 6V on left side of generator in front compartment
They had a mishmash of 6awg/8awg/10awg connecting the batteries.
I put 4 Costco GC2 6V batteries
4 new GC2 battery boxes
Watering system for the batteries so I don't have to remove covers and crawl through that tight space to check water.
Rewired all batteries using 1awg. Equal length crossovers and equal length between the 2 sets of batteries.

While I was in there doing all that. I replaced the 8awg 45' long positive cable between the batteries and the converter and replaced it with 20' of 4awg cable.

Total was around $1500.00 for everything. (the trailer had a single 100W panel when I purchased it - I replaced everything after the panel).

#4 and #1 above is welding cable. If using welding cable, be careful with the connections. Using crimp lugs is best. The wire is so fine that using a set screw type connection (like a bus bar) might break the wires or fan them out so you don't get a good connection. NEC is not fond of that type of connection.

Once complete and working. The outdoor speakers was picking up major RF noise generated by the PWM controller (when in Absorption or float). Solar controllers are very noisy and somehow FCC is very lax on the noise they legally generate. Turns out RF noise generated by the solar controller exposed a ground loop issue in my sound system between an amplifier and equalizer - I fixed by installed a $14 ground loop isolator between those two pieces.

I have a similar solar setup on my 17' travel trailer - but half the size (same morningstar controller). 2 panels, 2 batteries. Been using it for 4+ years.

Again, if you want to see my setup, I live around the corner from you. My 17' is in the driveway; I'll have the toy hauler home this weekend in preparation for an Easter trip.

I would use 2-0 for the batteries, not 2 gage.

Also. Are you wiring your panels for series or parallel?
I wired mine for parallel. I ran #2 from the combiner box to the MMPT 60 amp controller as per voltage drop chart.

Lillyputz

Have you looked into the feasibility of using MC4 "Y" cables and 8awg cable as opposed to the 4awg and the combiner box? I don't know what the distance limitations would be. 4 gauge cable is pretty big.

Your on the right track , your the one that has to be happy with the purchase
I went through the same process , trying to keep it cheap
This is the fifth rv of mine I put solar on
As all the bits and pieces added up I wanted all the bang for my buck and decided to do MPPT
As long as you tell yourself its a 380 watt system and not a 450 watt system and because pv panels are cheap you are happy with a PWM all is good 15.? volts in absorb x 8.33 amps = 375 watts
When you start cutting holes and wiring your new 5th a few dollars more might not seem so un realistic
For the Bogart system with temp wire and shunt aren't you over 300.00
For the Tistar 45 amp rated for 600 watts of PV and the remote panel / with temp included , that has terminals up to 2 ga wire that does everything the bogart does that I can tell is 530.00
Minus the extra money for larger wire and combiner box
I do have a Morningsar PWM on my Lance camper
But that's just how I got to that decision for myself on my 5th
Good luck with the install

I was originally looking at MPPT, but planned on the Bogart Engineering battery monitor from the start. Then someone suggested the Bogart charger as well. Reading up on the charger it seems to fit what I am looking for and at a great price. The charger and monitor talk to each other for more efficiency and I would only have to have one display to install in the RV. I know Blue Sky has a monitor that does both the charger and battery, but it is a lot more money. According to the install manual for the Bogart charger an adapter is needed for 2-ga, not 4-ga. It also states it can accommodate up to four 135-watt panels (540 watts total) and 30-amps max. The three panels I am looking at add up to 450 watts and just under 27 amps max. I originally was thinking a 300-watt system (2-panels), but the extra panel was only $165 and nominal increases in install parts. I do not think I will need any more than 450-watts of solar, but might upgrade to 4 batteries if needed. I know the 450-watts is more than needed for the 2 batteries, but if I am running all the wire and doing everything, might as well get all the solar I would want/need. Also, I am only using 2-ga cable for the batteries, the 4-ga will run from the roof through the controller and breakers and into the battery.

I am looking into the two breakers and dropping the switch. There is no rush at this point as I just found out the panels are backordered until April 20th, but it would be nice to have everything installed and just waiting for the panels to throw up onto the roof.

Right now I am trying to figure out what charger I want and all of the install parts.

What do you guys think? Am I on the right track?

I've not used them but here's a 4awg to 8awg reducer.

http://www.amazon.com/Stinger-SPT522-Gauge-Reducer-Input/dp/B001H4Y5O0

Yes you could , but your creating a voltage drop problem depending on the distance between disconnect and controller , and controller and batts , also a potential problem with the breaker size you need to use being to large for the short piece smaller wire
I went through all this when I did the system on my 5th , a lot of pwm`s have smaller terminal, you can use a short piece of wire and somthing like this or I opted to get a controller that would accept the wire size I was using
I`m not familiar with Knukoncepts wire , I looked at it on their site , just make sure its rated for 600v , I would use this
I use panels that have j- boxes not mc`s and use this wire , you can see the cost savings if you run this to the controller

Good point, the terminal block on the SC-2030 takes up to 6 awg. You could use 6 between a disconnect and the panel.

Sounds like a nice system but before you jump , you might want to price out what you would need to go mppt , delite the combier box the expensive #4 wire , compare #10 wire to MPPT direct from last panel in series ,
you will see that the price difference is not that much
Also check the PWM terminals for solar and battery sides I don't think that unit will take #4 on the solar side and #2 on the battery side , you will need a way to reduce the wire at the controller
Also a 30 amp controller may not be large enough for three 150 watt panels , or at least not to add more to later
Do you have a breaker on the panel side and the bat side of the controller , I only see one, have you considered using a baby box and two breakers in it ?babyboxbreakers
babybox

clotus wrote:
Thanks for the replies. My thought was get a bigger solar system and add the batteries of needed. That way I am on the roof installing all at once. I will look into building my own combiner box and the strain reliefs for going into the fridge vent. I want to stick with the 4ga that way I can handle whatever I need to throw at it later on down the road. Man there is so much to consider!!

I'm pretty sure you live around the corner from me. I recognize your 5th wheel and the houses in the picture. I'll have my toy hauler home from the RV lot this weekend, preparing for an Easter trip. If you want to stop by this weekend and look at what I've done on the toy hauler and on my small trailer, give me a PM and we can arrange it.

Mike