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flintsters · 09-07-2018, 03:10 PM

I hope to add a couple of solar panels to the roof of our travel trailer in the near future. While poking around I ran into this

youtube video

. Instead of wiring it from the solar controller to the batteries he wired it from the solar controller to the rv converter (go to 19:00 into the video). This would greatly simplify things if I were to do this but have never heard or seen this before. What are your thoughts?

ASTMedic · 09-07-2018, 03:27 PM

Quote:

Originally Posted by flintsters

I hope to add a couple of solar panels to the roof of our travel trailer in the near future. While poking around I ran into this

youtube video

. Instead of wiring it from the solar controller to the batteries he wired it from the solar controller to the rv converter (go to 19:00 into the video). This would greatly simplify things if I were to do this but have never heard or seen this before. What are your thoughts?

As far as I can tell he's still basically wiring to the batteries directly. He's just taping into the 12v wire that runs from the converter to the batteries so he doesn't have to run another wire all the way to the batteries. I think putting the solar controller closer to the batteries would prevent loss in the longer run of the wire. I'm not a electrician so I could be wrong about the loss.

Searching_Ut · 09-07-2018, 03:38 PM

It's good in theory, should in essence be the same as a direct connection to the battery. If it was much easier I would probably do it unless you had a setup like in my fifth wheel where Heartland ran way to small of wiring for around 20 feet from my PD9280 converter and the batteries.

vsheetz · 09-07-2018, 03:56 PM

Electrically it's the same point. If the wire size is satisfactory not a problem. If on shore/genny power both solar and converter will both be energizing the wire to the batteries.

Also be aware of the battery cutoff switch. Typically you don't want the battery cutoff switch to disconnect the solar.

DavenFla · 09-08-2018, 06:13 AM

I think it's a good idea with one caveat... the fuse. Needs (the fuse) to be accessible without much trouble.

As long as you are on the 12VDC side of any primary battery wire/source you'll be golden. Avoid and secondary side connections due to smaller wire size.

flintsters · 09-09-2018, 05:51 AM

Thanks....I have a few follow up questions.

1) What size wire would you say would be sufficient for between the converter and batteries (I have 2 6v Costco batteries) that could handle the additional solar load?

2) Other than running a set of wires directly to the batteries I don't know how to get around the battery cut off issue. I don't have solar so I'm not totally sure how it all works. Is there an "off" or way to cut power from the solar controller? Could I put an inline fuse spliced into the positive line going from the panels to the controller (thinking in the fridge access panel for ease of access)? I am not sure where the controller will actually be installed. I am guessing in the lower bunk area (will be about 20+ feet away from batteries).

3) Here is a link to the floor plan for our camper (scroll down to the 29L). I was thinking about putting 2 100-watt panels above the bunks and then run the wires down the fridge vent. The converter is under the bottom bunk next to the fridge so in terms of running wires it doesn't get much cleaner or easier.

Sbrownstein · 09-09-2018, 06:03 AM

I have wired a 1000 watt inverter to my converter in much the same way. There is a 20 foot run from the converter to the house bank and in my coach it is #6. Plenty of ampacity for the inverter or for a solar controller. In addtion, my PD9270 has an extra set of connection points already built in, so attaching #6 to them was simple and it was right below my power panel, which is in the rear basement bay.

I have considered two changes to this for the future. First, I don't like to leave my disconnect switch on all the time and I am considering rewiring the converter (and solar if attached) directly to the battery bank. If I do so I would up the run size to #4, not for solar or the inverter, but for the 70 amp converter as the current run costs me nearly a volt when charging the batteries using the generator. I could use this volt to shorten my boondocking generator run times since I have never seen more than 13.9 or so from my converter with 65% SOC batteries. Solar, converter and inverter can all share the same run to the house bank. The inverter is fused at 100 amps.

Soppy · 09-09-2018, 07:03 AM

Solar should be run to the batteries with its own wire and disconnect switch. That way you can disconnect the batteries and they will still be charged via the solar system. With a disconnect in the solar side, you could also disconnect the solar if required.
Wiring the solar to the converter as you described will work just fine as far as charging is concerned.

vsheetz · 09-10-2018, 01:09 AM

There should be a inline circuit breaker/disconnect on both sides of the solar controllers provide for service needs. On the battery side it should be near any existing battery disconnect in the battery bay - where a service person would see it.

DavenFla · 09-10-2018, 05:06 AM

Quote:

Originally Posted by flintsters

Thanks....I have a few follow up questions.

1) What size wire would you say would be sufficient for between the converter and batteries (I have 2 6v Costco batteries) that could handle the additional solar load?

2) Other than running a set of wires directly to the batteries I don't know how to get around the battery cut off issue. I don't have solar so I'm not totally sure how it all works. Is there an "off" or way to cut power from the solar controller? Could I put an inline fuse spliced into the positive line going from the panels to the controller (thinking in the fridge access panel for ease of access)? I am not sure where the controller will actually be installed. I am guessing in the lower bunk area (will be about 20+ feet away from batteries).

3) Here is a link to the floor plan for our camper (scroll down to the 29L). I was thinking about putting 2 100-watt panels above the bunks and then run the wires down the fridge vent. The converter is under the bottom bunk next to the fridge so in terms of running wires it doesn't get much cleaner or easier.

2- 100 W panels regulated @ 12vdc = 10 or 12awg. (10 prefered)

If you ever want to expand the bank then think ahead. Wire minimum size of 5 amps per 100w unregulated

If your solar controller doesn't have an on/off switch then you should/will have to add one. I would add the switch before regulation.... meaning between the solar panels and the controler. You could use a simple wall switch like you have in your home. You do not need a breaker... you just need an on/off switch of some sort, that is near the controller. If it was me I'd get a LED switch toggle switch, similar to what's on a boat, so there is a visual reference for off -on. I prefer red for "on" green for "off".. or as we say
red =closed
green = open.

SSTraveler · 09-10-2018, 08:15 AM

In thinking more about this, I don't think the Inverter cares about where it gets its amperage to convert to 120vac. It's okay to connect the CC to the Inverter terminal positive and negative terminal that then connect directly to the battery positive and negative terminals. However a few things to consider. Isn't the battery disconnect switch between the batteries and the Inverter, thereby meaning in order to charge the batteries with solar the battery connect switch has to remain on all the time? I wouldn't want to leave my switch on all the time, particularly while in storage because a few cloudy days could let the parasidic loads drain the batteries. For sure at night the batteries would get drained some. Additionally if you switch the house battery disconnect off you removed the load/batteries leaving the Solar panel still suppling to the CC. You can easily burn up your CC by not disconnecting the Solar Panels first before you disconnect the batteries from the CC. Also, the Inverter has a high voltage protection set at 15.5vdc and if exceeded the inverter automatically shuts down along with a loads. I believe when the CC is in Bulk mode it can exceed 15.5v. Also, the inverter is a multistage charger as well, so since you have two charging devices connected at the same input point to your batteries one, both and/or aspects of both will be trying to charge the batteries. *This may not matter for lead acid batteries but may cause a problem down the road is you decide to upgrade batteries, particularly to lithium. Did you really pay $$$ for a sophisticated controller with advance charging features to have it defeated or interfered with by another, lesser capable, *multistage charger on the inverter? *Just some quick thoughts on the matter. Wiring the CC directly to the house batteries is the recommended and preferred method for very good reasons!

Sbrownstein · 09-10-2018, 09:02 AM

Quote:

Originally Posted by SSTraveler

In thinking more about this...

Interesting thoughts, but you didn't go far enough. The real question is why do almost all vendors wire the converter to the panel and then to the disconnects and then to the batteries? Sure it lets you power the coach with the batteries turned off...but then so many people might do this and not charge the house bank even though they are connected to shore power and have a functional converter.

The converter should have a "home run" connection to the battery bank. Then a CC piggy backed to the converter would have that also. If you are plugged in...you charge. If the sun is out...you charge. If you have "equilization level" voltages, you coach can be isolated from them.

Solar panels in an RV lot will always keep the batteries topped off with no chance of parasitic discharge.

ALLOY · 09-10-2018, 06:45 PM

If the solar is connected into the converter the combined power (converter+solar) may exceed the capacity of fuses/breakers/wire.

It would be best to investigate or ask the manufacture for a wire diagram before deciding where to make a connection.

Wire nuts are not meant for DC electrical.

The hot (burner) side of an absorption fridge is not a good place to run wire.

flintsters · 09-11-2018, 06:48 AM

It is not my plan to install a hard wired inverter, although down the road that may change. The primary purpose of the solar is to power the water pump, fans for night time sleeping (2-4 of them), charging phones, radio. There are other draws, I know (LED lights, fridge and water heater running on propane). We almost never use the TV and if we need to we can use one of the portable inverters and power the TV that way. Another benefit is to help make sure the batteries are topped off if we are traveling all day and staying in a Walmart.

The only times I actually use the battery cut off switch is when I am doing some sort of electrical repair/mod. Other than that it is plugged in or being used. We keep our camper at our house and plugged in all winter (although I am considering pulling the batteries this year and keeping them in my basement).

It's interesting to hear that it is not recommended to run the wires behind the fridge. It seems like that is generally considered as a good option.