Solar Crossroads

[Keystoned]

Hi all, been reading many of the solar related threads here and want to get some ideas on our situation.
Our old TT has this 200W kit along with 2 12v AGM Grp24 batteries; https://www.amazon.com/gp/product/B00BCRG22A/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
The batts are 1 year old and the system is going on 4. I had to use those batts because that is all that would fit on the A frame due to the shape of the trailer nose.

Our 'new' 5W has one dead Grp27 battery :(

Has enough tech improvement happened in the last 4 years such that it would be better to leave the system on the TT, which is for sale now, and get new stuff for the 5W?

I was thinking about leaving the wiring on the TT and transferring everything else over. Running the wires was the hardest part honestly. I'm not sure many prospective buyers even see the solar as the great thing it is.

It served us well for how we use it. We pretty much just use what 12v stuff that is in a normal trailer. We might want to watch OTA TV for news and weather, so either a 12v TV or inverter might be added. We prefer not being hooked up in a rv park if we can avoid it...

I've also read about the power the auto-leveling uses and I plan on doing the work myself, again.

Thanks in advance!

[roadglide]

Hi all, been reading many of the solar related threads here and want to get some ideas on our situation.
Our old TT has this 200W kit along with 2 12v AGM Grp24 batteries; https://www.amazon.com/gp/product/B00BCRG22A/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
The batts are 1 year old and the system is going on 4. I had to use those batts because that is all that would fit on the A frame due to the shape of the trailer nose.

Our 'new' 5W has one dead Grp27 battery :(

Has enough tech improvement happened in the last 4 years such that it would be better to leave the system on the TT, which is for sale now, and get new stuff for the 5W?

I was thinking about leaving the wiring on the TT and transferring everything else over. Running the wires was the hardest part honestly. I'm not sure many prospective buyers even see the solar as the great thing it is.

It served us well for how we use it. We pretty much just use what 12v stuff that is in a normal trailer. We might want to watch OTA TV for news and weather, so either a 12v TV or inverter might be added. We prefer not being hooked up in a rv park if we can avoid it...

I've also read about the power the auto-leveling uses and I plan on doing the work myself, again.

Thanks in advance! T he questions are what ? Since I drank a half fifth of Jd here in the desert passed out with my friend and woke up to raw t bone stakes 1045 and probably get wack by the weight policy .

[chuckster57]

I’m not a solar expert by any means, but I will say it seems to be a very popular feature among newer customers. I would be inclined to leave it and use it as a selling point.

It seems like panels are getting more powerful for their size so technology probably has improved.

[Keystoned]

T he questions are what ? Since I drank a half fifth of Jd here in the desert passed out with my friend and woke up to raw t bone stakes 1045 and probably get wack by the weight policy .

Has enough tech improvement happened in the last 4 years such that it would be better to leave the system on the TT, which is for sale now, and get new stuff for the 5W?

[flybouy]

Has enough tech improvement happened in the last 4 years such that it would be better to leave the system on the TT, which is for sale now, and get new stuff for the 5W?

That's a question only you can answer. You need to figure out if leaving it on increases the value and by how much, what the replacement cost would be and if the increase in performance (if any) is worth the money that you would have to lay out for the "new and improved" system. Only you can place the "value" of that number.

[Keystoned]

Sounds like not much has changed in the last 4 years...

[Customer1]

Nothing has changed, move the system

[coop341]

T he questions are what ? Since I drank a half fifth of Jd here in the desert passed out with my friend and woke up to raw t bone stakes 1045 and probably get wack by the weight policy .

Ha! Been there! :lol::lol::lol

[Keystoned]

Nothing has changed, move the system
I'm tending towards that but probably will put the panels at the rear this time to balance out the load of more batteries up front. I'll probably need larger cables anyway due to the much longer run, so I'll leave the old cables on the old TT.

[Keystoned]

Okay 5th Wh solar folks...I'm scratching my head on how to route the wires here. It was cut and dry for the old TT.
My fridge is in the slide out, so it's vent is not on the roof, there goes that idea.
The batteries are in the front storage area and I don't see a nice drop down route there.
Not an easy path thru the wardrobe on the side of the bed back to the batteries.
Probably should not route wires down the outside, right?
Any ideas or good examples out there?

[JRTJH]

There are "midship galley cabinets" over the sink. You might be able to route the wires through a "roof passthrough device" (available at most RV stores) down to the cabinets, then either along the corner of the trailer (in an electrical run) or from the cabinet, into the wall separating the bath from the main cabin and down into the space behind the passthrough storage. I'm just looking at the floorplan in the 2015 brochure, so not sure whether the cabinets reach the ceiling or if you'd have some "cosmetic issues" with that type of entry.

[chuckster57]

We use a wall that will take the controller. Open the wall and drill UP through the rafters and out onto the roof. There are different styles of roof plates, and it may shorten the cable run. Often times we use the wall that has the breaker panel because there will be plenty of room from all the wiring to get the cables into the underbelly.

[Keystoned]

There are "midship galley cabinets" over the sink. You might be able to route the wires through a "roof passthrough device" (available at most RV stores) down to the cabinets, then either along the corner of the trailer (in an electrical run) or from the cabinet, into the wall separating the bath from the main cabin and down into the space behind the passthrough storage. I'm just looking at the floorplan in the 2015 brochure, so not sure whether the cabinets reach the ceiling or if you'd have some "cosmetic issues" with that type of entry.

Good ideas. The cabinets do not reach the ceiling but maybe some corner trim can cover the cables. I'll trace this route and measure the length, etc.

[Keystoned]

We use a wall that will take the controller. Open the wall and drill UP through the rafters and out onto the roof. There are different styles of roof plates, and it may shorten the cable run. Often times we use the wall that has the breaker panel because there will be plenty of room from all the wiring to get the cables into the underbelly.

Another good idea but I've not removed an interior wall before and don't want to mess it up. I'll look for some you tubes I guess.
Unfortunately, the breaker panel is at the exact opposite and farthest diagonal corner from the batteries...

[JRTJH]

...
Unfortunately, the breaker panel is at the exact opposite and farthest diagonal corner from the batteries...

That "shouldn't be a significant issue" when you think about it, Keystone has already run the "battery charge wiring" from the circuit breaker/charger panel to the batteries for you. All you need to do is connect your solar charging system to the existing "battery wiring" (assuming it's large enough for your new system). No need to "run all new wiring" when the existing wiring will work...…

[Keystoned]

That may be a brilliant idea!
Can I piggy back onto it or do have to switch between solar and the converter to prevent charging issues?

[chuckster57]

We usually run separate wires to the battery. I’m not sure you would want to tie the charging systems together.

Taking a wall apart is easy. Just take the trim off the edge, and then gently pull the 24g staples out. We use 18g brads to plug it back together and putty the holes.

[Keystoned]

Yeah, I'm not sure either. But from a circuit point of view, and I'm not great at that, the two charging systems meet at the battery when separate wires are run. Are they not tied together anyway?
I would hate to ruin one or both systems...

On the TT, we rarely used the converter to charge the batts anyway, since the solar does a great job. We plug in to run the fridge before departing or run electric heaters or watch the TV or worst case, AC. We are usually dry camping if we can help it.

[chuckster57]

Both systems are charging the battery(s), but I’m not an electrician or electrical engineer so I don’t know the science. Maybe the controller has some protection to prevent any hack feeding.

[Keystoned]

If it saves me from running 40 feet of wire, I have no problem with an A B switch near the converter and co-located solar controller...assuming that would work.

[JRTJH]

From an "electrical circuit vantage" there is no difference in connecting a circuit at either end of a wire. There is a "consideration" about whether that wire has the capacity to carry the load, so if it's a "undersized wire" then connecting to the end that doesn't require it to carry the amperage would be important.

That said, if a wire is sized to carry 50 amps for 25', then it can carry 50 amps in either direction. So, there's no "requirement" from an electrical current perspective, to connect to one end as opposed to connecting at the other end.

There is voltage drop on any DC circuit and amperage load capacity requires "heavier wire for larger/longer loads" but if a wire is carrying 50 amps for 25' "FROM" the battery to the converter/fuse panel, that same wire is capable of carrying 50 amps for the entire 25' "back to the battery from the converter/fuse panel. It just can't be expected to "carry both at the same time".....

[chuckster57]

I was just wondering about back feeding the panels if he hooked up the solar wires at the converter.

[JRTJH]

Most "large inverters have a transfer switch in them to prevent backfeeding. And, he mentioned installing an "A/B" switch to connect the solar when not on shore power and the converter when "plugged in".

As for the wire "from the battery to the converter" if it's heavy enough to carry 45-50 amps from the charger to the battery, it can surely carry 45-50 amps from the solar array to the battery. The key is making sure that only one system, converter or solar array is connected to the battery at any time. Either an automatic transfer switch or better yet, an A/B manual switch. I've seen lots of "automatic stuff" that got slowed down, stuck or just wore out" and has been the cause for damaged or burned out components. You won't have that issue with a manual A/B switch.

[Keystoned]

I'll have source a 'S/C' switch, lol. Or something appropriate and unmistakable because you know, humans. Actually, as long one or the other is selected, the system is protected...
I can mount it and the solar controller near the converter somewhere and be able to mount the panels at the rear of the 5th wheel.
I call that a win/win

Sort of like the Chiefs just now!

[flybouy]

I'll have source a 'S/C' switch, lol. Or something appropriate and unmistakable because you know, humans. Actually, as long one or the other is selected, the system is protected...
I can mount it and the solar controller near the converter somewhere and be able to mount the panels at the rear of the 5th wheel.
I call that a win/win

Sort of like the Chiefs just now!

Actually all you need is an on/off switch in the wire from the solar panel.

[Keystoned]

Not too sure about that, it leaves a possible AND condition subject to human error, I think. Worst case is both chargers on at once.

The A/B is always an OR condition with no chance of error. Worst case is lack of charging by solar.

Any logics folks here to weigh in?

[chuckster57]

Like I stated before, we have always ran the solar wires to the controller and then directly to the batteries with zero issues. Tiffen motorhomes that are “prewired” have it set up this way, I was only questioning running the solar leads from the controller to the converter/inverter.

[flybouy]

Like I stated before, we have always ran the solar wires to the controller and then directly to the batteries with zero issues. Tiffen motorhomes that are “prewired” have it set up this way, I was only questioning running the solar leads from the controller to the converter/inverter.

I'm no solar expert but here's my take. Connecting both charging sources to the same battery cable (anywhere in that cable) will have no need for any switch.

Think about it this way, the positive cable always has battery voltage present when connected, the converter's charger and the solar panel only serve to increase that voltage to replenish the battery "charge". Having both connected simultaneously in my thinking would possibly result in the solar panel (if sufficient size and sun exposure) may cause the converter to "satisfy" and shut off if the solar panel is producing a higher voltage.With clouds/darkness resulted in a lower voltage from the solar panel than the converter will supply the charge.

Last thought on this. Do you disconnect the camper from the battery while towing? Same principle, your TV is charging the batter via the 7 way umbilical. Electrically no different.

If my thinking is flawed someone step in and correct it.

[JRTJH]

Marshall,

The only "flaw" I see in your analysis is that the converter "charging circuit" is voltage dependent. It will ONLY produce a charge if the voltage sensed from the battery (the red + cable) is below a specific voltage threshold. If the solar system is "concurrently connected" to that same red cable (without an A/B switch) then as long as the sun is shining, the solar array on the roof will provide 12+ VDC, exceeding the "threshold voltage" sensed by the converter charger and keep that device "turned off".

It's the same with connecting a secondary battery charger to the battery while connected to shore power. The secondary battery charger will "inhibit charging" because the "line voltage on the red + cable" is always above the threshold, triggering the converter/charger to "believe the battery standing voltage is able the level that requires charging....

So, connecting BOTH may not cause damage to the converter/charger, but: I'm not sure about back flow DC to the converter and whether it will cause damage to the sensing circuit. I do know that if the solar panels send more than the threshold voltage to that "converter/charger/solar panel" connection site, the converter/charger will be "turned off as long as the solar panel voltage is greater than the threshold"...

[Keystoned]

While it 'may' be okay to just tie everything together, I'm still tending towards an A/B switch. One position for when plugged in and the other for when not. Just need to find one to match the system.

[JRTJH]

While it 'may' be okay to just tie everything together, I'm still tending towards an A/B switch. One position for when plugged in and the other for when not. Just need to find one to match the system.

I agree, a manually operated A/B switch is the "foolproof way" to make sure that only one system (converter OR solar) is connected to the battery at any specific time. If I were doing the add to my trailer, I'd install an A/B switch to make sure the systems are isolated.

[Keystoned]

This one might work;

https://www.amazon.com/1-2-Both-Off-Disconnect-Waterproof-Isolator-1250Amps/dp/B07HT44MP5/ref=sr_1_2?crid=206MSQ8WZGC12&keywords=12v+selector+switch&qid=1580833151&sprefix=12v+selector+switch%2Caps%2C255&sr=8-2

Open to suggestions...

[flybouy]

Marshall,

The only "flaw" I see in your analysis is that the converter "charging circuit" is voltage dependent. It will ONLY produce a charge if the voltage sensed from the battery (the red + cable) is below a specific voltage threshold. If the solar system is "concurrently connected" to that same red cable (without an A/B switch) then as long as the sun is shining, the solar array on the roof will provide 12+ VDC, exceeding the "threshold voltage" sensed by the converter charger and keep that device "turned off".

It's the same with connecting a secondary battery charger to the battery while connected to shore power. The secondary battery charger will "inhibit charging" because the "line voltage on the red + cable" is always above the threshold, triggering the converter/charger to "believe the battery standing voltage is able the level that requires charging....

So, connecting BOTH may not cause damage to the converter/charger, but: I'm not sure about back flow DC to the converter and whether it will cause damage to the sensing circuit. I do know that if the solar panels send more than the threshold voltage to that "converter/charger/solar panel" connection site, the converter/charger will be "turned off as long as the solar panel voltage is greater than the threshold"...

I believe this is essentially what I said. I would not think that backflow to the converter would be an issue as I would think the converter, let's say a 55 amp one, would have a diode capable of the voltage & amperage designed for the converters 12 vdc capability. I would be more concerned with the charge controller in a low end say 100 watt solar charger. The solar charger should have a diode to prevent voltage backfeeding from heating up the solar cells but is it sufficient enough to handle the potential 55 amps? That's what I don't know as I'm no expert on solar chargers or arrays.

The only thing I do not like about a manual switch is the failure is wholly dependent on human thought and error. Failure of a quality electrical component is typically in a "non working" mode. That failure rate could be in the thousands or tens of thousands of cycles. The human failure rate, the possibility of someone (or child) wanting to find out "what this switch does" or thinking "this must be the speaker selector switch", or just getting distracted and forgetting to properly set the switch is a risk greater than a device failure in my mind. YMMV

[JRTJH]

I agree, manual switches do require "human thought AND action" where automatic systems require "no human interaction". We did that with photo-electric cells (so humans don't need to turn on a light) and now with "active cruise control" (so humans don't need to pay attention to the following distance or closing rate). Both are OK, but both can be controlled with a manual switch or "foot on the brake" as they've been done in the past. Either system will work, the worst scenario that I can think of with a manual switch would be a dead battery or a charging circuit that doesn't charge (until the switch is manually changed).

The "key to success" with either an automatic or a manually controlled system is assuring that the battery is connected to the fuse panel "24/7" while the charging system (converter or solar) is switched. It takes a bit of thought "beyond 1 wire/1 switch/2 inputs" as the output must always remain connected. Easy to do, but much easier to "skip over" as well....

[Customer1]

Both systems are charging the battery(s), but I’m not an electrician or electrical engineer so I don’t know the science. Maybe the controller has some protection to prevent any hack feeding.

It isn't an issue. The RV charging system won't back feed to the panels anymore than the battery will back feed to the panels.

Think about it, whether the panel feed is connected at the batteries or elsewhere, the circuit is actually the same except one way uses more wire and the other way uses less.

[Keystoned]

https://roadslesstraveled.us/charging-rv-marine-batteries-solar-power-shore-power/

This is the best explanation I have found on this topic. In a nutshell, not a personal safety issue or equipment damage risk, just that neither system is optimal due to possible voltage reading issues. The two charging systems kind of fight each other and nobody wins...

[bbells]

Nothing has changed in 4 years, and your panels should be producing almost as much as new. But, it is hard to sell a used RV these days unless you drop the price dramatically. The solar would most likely be the reason someone would buy your trailer over someone else's. Plus filling in the holes or removing the glue marks are too big of a job to save $200.

[Keystoned]

If it sells with the trailer with added value then no problem, I'll get new stuff.
If they buyer does not value it and wants to pay too little, I will remove the panels, controller and batteries, leave the wires, replace the hold down screws with flatheads and cover them with self leveling goop. A new large battery will replace the AGMs and it will be 'solar ready'.
The value of the panels, controller and batteries is closer to $800 in parts, at least. I'm not hard up for money but I won't give stuff away either, just on principle.

[bbells]

If it sells with the trailer with added value then no problem, I'll get new stuff.
If they buyer does not value it and wants to pay too little, I will remove the panels, controller and batteries, leave the wires, replace the hold down screws with flatheads and cover them with self leveling goop. A new large battery will replace the AGMs and it will be 'solar ready'.
The value of the panels, controller and batteries is closer to $800 in parts, at least. I'm not hard up for money but I won't give stuff away either, just on principle.


$800? Never buy panels from that dealer again. I sold 200w panels before the tariffs for $130 each. After the tariffs I see them for between $150 and $200. If you get 12v panels you only need a pwm controller, which is about $10 on ebay. If you decide to go mppt because you got a 24v panel, you can get an adequate one for about $90. Sorry. You got taken for a ride. Plus, you now have the option to go with semi flex panels. They simply tape on with permabond roof tape. No holes to drill. Remember, with a 200w panel you are only sending a max of about 17 amps to your battery (and very rarely that high). You do not need extra heavy duty wire to do that.

[Keystoned]

It's always good to get new viewpoints, but here is where I got my numbers from.
AGM batteries are about 200 each, so there's 400.
The system on the TT looks like it has gone down a bit in 4 years, but I paid close to 350;
https://www.amazon.com/gp/product/B00YJIB7WE/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Misc stuff was like another 50, that makes 800.

If you can provide me links to create a new system for less, I'd appreciate it. I like the idea of flexible panels, assuming they last as long as rigid ones.

[Keystoned]

As for hooking up a controller near the converter, I have a 75 amp WFCO WF-9875 with big fat wires to the battery, hehe...
Not sure what gage they are, anybody might know?

[Keystoned]

So I've been afraid to check the gage of the wires because after removing some fluffy insulation around the area I realized it was rodent midden. Yes, some kind of rodents have been living there as the PO kept the unit plugged in since the battery was dead and created a nice warm area for them.
I'm in the process of cleaning out the area and disinfecting before proceeding. Looks like I'll probably remove the panel/shelf above it so I can really clean up the area.

[JRTJH]

So I've been afraid to check the gage of the wires because after removing some fluffy insulation around the area I realized it was rodent midden. Yes, some kind of rodents have been living there as the PO kept the unit plugged in since the battery was dead and created a nice warm area for them.
I'm in the process of cleaning out the area and disinfecting before proceeding. Looks like I'll probably remove the panel/shelf above it so I can really clean up the area.

When you start digging into it, check the insulation on the wiring very carefully. Much of the "Chinese wire" is covered with a "soy based plastic insulation" and to those "critters in the belly" soy is "food"....

[Keystoned]

Will do when I get better access.

[Keystoned]

The wiring is all good and rodent waste is all cleaned up. I had to remove the side table completely to get at it.
I have 6 ga wire for the 12v converter system, btw.
Now what to do to seal the hole where all the wires come up through to prevent this from happening again?

[JRTJH]

Aluminum wool or brass wool (not steel wool, it rusts) stuffed in the holes, then covered with a sheet of 1/16 - 1/8" plastic (think frisbee or butter tub lids). The plastic is easy to cut, easy to staple or screw in place and easy to seal with DICOR (left over from the roof seal job)…..

[Keystoned]

Thanks, I picked up some aluminum screen door mesh as I could not find the 1/8" stuff...

[Keystoned]

Planned the path from the roof to near the converter so I can tie into the two 6 gage wires to get to the batteries.
Would wire nutting the cut 6 gage wires to the 10 gage wire be sufficient or should I use some kind of junction part?

[flybouy]

Planned the path from the roof to near the converter so I can tie into the two 6 gage wires to get to the batteries.
Would wire nutting the cut 6 gage wires to the 10 gage wire be sufficient or should I use some kind of junction part?

There are better methods than wire nuts (the worst method). The method I'd use would be ring terminals with a waterproof box that has a stud for the connection.

Why the two different sizes?

[Keystoned]

The trailer run 6g to the batts from the converter. The solar system uses 10g throughout. The junction will occur inside the trailer near the converter so I'm not sure it needs to be waterproof?
Certainly don't want the positive flailing around, lol

[flybouy]

The trailer run 6g to the batts from the converter. The solar system uses 10g throughout. The junction will occur inside the trailer near the converter so I'm not sure it needs to be waterproof?
Certainly don't want the positive flailing around, lol

For inside something like this. https://www.amazon.com/Fastronix-Stainless-Single-Ground-Junction/dp/B01LLYS5FK/ref=sr_1_29_sspa?keywords=single+stud+power+post+w ith+cover&qid=1584208922&s=automotive&sr=1-29-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFLNEVMUVI5OFVVNzkmZ W5jcnlwdGVkSWQ9QTA0MjE3MzAzRUFMWkZRSDRJOE1EJmVuY3J 5cHRlZEFkSWQ9QTA1MjQ3NjIySlFCNTBWQlFNNVZZJndpZGdld E5hbWU9c3BfYnRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm9 0TG9nQ2xpY2s9dHJ1ZQ==
And order terminal boot to cover the positive

[Keystoned]

Thanks, I'll try to source parts locally first.

[flybouy]

A lot of auto parts stores and custom car audio install shops would have it.

[Keystoned]

Any chance that 6 ga terminals can be crimped on? My crimper only goes to 10 ga and there is not much room to work behind the electrical panel where the converter is. I've soldered large terminals on before with a torch, but not in close quarters...

[flybouy]

They can but not with a "standard" wire crimper from HF. What brand/model inverter are you looking at?

[Keystoned]

It's a WFCO 75A model and it's tucked in real good. Here is a pic before I cleaned up the rodent mess. Would be nice if I could just shove the 10g wires in the same holes as the 6g wires are, or other convenient location. Here is another pic with the end table removed (it was a PITA).
Looks like the ground bar might work for the negative cable...

[Keystoned]

Looks like a 6 and 10 will fit in the converter and hold them very tight, so I have an easy solution...now for the rest of it.

[Keystoned]

Got the solar controller hooked up to the converter and removed the rest of the system from the old TT. Waiting for decent weather to finish the install on the 5W...

[Keystoned]

Question about the battery temp sensor...using one is better than using none, right?
The sensor wire is about 30' too short to reach the batteries, so I'm thinking of routing it to somewhere shady and mostly dry to at least get outside temps fed into the controller. Last time I asked Renogy's tech dept a question it seemed like 'they' didn't even read the question...previous guy was sharp as a tack.
Any thoughts on this?

[Keystoned]

Just to close this out, got it installed and works great so far. Just need to cover 2 wires with matching trim in one corner and maybe add the temp sensor later.