DIY Solar/Trimetric/6 Volts on a 2015 Grandby

I may have overstated it a bit about the battery limiting the current, although it does decline and the battery approaches 100%, and it will help to add more solar power. This is way overkill but it is an interesting subject to me so here goes. Here in Plano TX the cities website shows the solar power W/sqm for each day. About now it's peaking around 680 W/sqm at solar noon, 12:40 pm. For today sun rise and sun set are 5.37 hrs before and after solar noon. Using a power curve y=680 x abs(Kt)^p curve, I found K and p to approximate the solar power for a sunny day here. I then did the same to approximate the solar elevation angle for today, here in Plano it reaches 41.2 deg at solar noon. I projected this solar energy onto a horizontal (flat roof mount) solar panel and multiplied that by the effective solar panel area for 2 100 W panels to get solar panel watts.

The camper load is different at different times of the day so the second section finds the camper load each hour for one day. The difference (solar panel watts- camper load) is the available battery current. Starting with a 100% battery charge at sunset, limited the battery current to 0.5 amps if the battery is more than 80% charged and found the % charge for the battery. Day after day the ending % charge is copied to the new day % start. The first screen shot is for 200 W panels (Solar panel watts multiplier =2) and 200 Amp hr Battery. The second shot is for 300 W panels and 200 Amp hr.


In Portland Oregon the solar elevation angle is 12 deg less, the solar intensity is about half, 341 w/sqm, and the solar day is slightly longer 5.82 hr.

It appears that I overestimated the Load. I have it at 72 amp hr so things should look a lot better at 50 amp hr.
 

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Carl,

OK...I now have a headache trying to pull the charts apart so that I could understand them. You did one hell of a lot of work!

Are there Cliff Notes?

"-12" is 2400 hrs?

The amount of amps used by the various on-board systems was particularly helpful to me...thanks.

Phil
 
The simple answer is that solar recharging of your batteries is based on many factors including angle of the sun, solar day light hours, tilting the panels, type of charge controller, amount of consumption during the day, size of your batteries, etc...

Campers collecting sun in Texas have a totally difference experience than say Washington because of sunlight, clouds, trees, etc...

The newer system for FWC is 150 watt panel and like around 150 amps of battery power. This is propably adequate for most people. But I wanted something more because I don't have the same solar hours where I live. So I need to collect more power on a daily basis than someone who lives further south.

There is a limitation on all things including battery power. It turns out 2 6 volt AGMs fit perfect in the battery compartment in my front dinette model. A larger battery was not possible unless I wanted to remodel the cabinet or use the space the front dinette, which I didn't.

Everyone's setup is slightly different so you can adjust it however you want to fit your needs. Mine works great and I've been very happy with it.

My favorite test is the ice cream test. If my ice cream is still cold in my freezer at the end of the day I'm a happy guy.
 
Dr J,

Got the concept of the variables impinging on the solar panel power production. What is a TBA for us is with the FWC 160 W mounted and 80W portable and their two battery set-up will we be able to keep up with our demand under differing environmental conditions and of course so many factors play into that.

As a corollary; am I correct in believing that the Tundra alternator will charge the truck battery AND the two Hawk batteries?

There was some discussion that a FWC owner is not seeing his camper batteries being charged via the truck alternator.

Carl's charts clearly point to the power consumers and gives us the means to slow down the power draw by shutting down or lessening specific high power uses.

Thanks for all the input; it really helps us.

Phil
 
Sorry, I told you I went overboard. A second look reduces the load by 30% and it looks good. Also if you add your portable solar on cloudy days it helps a lot especially if they are directed and out of the shade during sunlight hours.. With 200 Amp Hr your good for two or three days. Your initial assumptions look good. Just don't go to Alaska and leave the fridge going.
 
"There was some discussion that a FWC owner is not seeing his camper batteries being charged via the truck alternator."

I am at least one of those owners. I have a 2006 Tundra with a Fleet and 2 camper batteries. I get zero amps of charging and was told by FWC to not expect any significant charging from the truck, yet I read here of people getting 15 amps/hr.

My truck/camper has been checked by FWC, multiple times to my local dealer, and a local battery/alternator shop. I'm at a loss of where to go next. Even with my solar system, one/two days of cloudy weather and my batteries are dead given no charging from the truck.
 
Don,

I am sorry about your issues with your system. That must be very frustrating. One of the biggest problems is that so few services are available for RV people who want to learn solar and off grid power mangement. There is no one within hundreds of miles from where I live to do that. I had to learn much of it myself from studying on line. I'm still learning more all the time.

I am not sure why your system does not work.

When I wired my toy hauler with a solar system and an inverter, I hired an electrician to help me do some of the AC wiring. Maybe you need an electrician to look at your system? Sounds like you've tried everything else reasonable to this point.

When it is connected correctly, I can definitely verify that there is power coming from the truck alternator to my camper batteries. I have certainly had 10-15 amps on a regular basis before.
 
Dr J - will a regular electrician understand all these 12V components? I always figured it would take a 12V/RV or perhaps an auto tech person to understand the battery wiring, battery separator, alternator interactions, etc. Maybe there is still something wired incorrectly, but like I said, it was shipped to FWC once, and the local distributor has had it 3 times in an attempt to diagnose my on-going electrical issues.

I finally got the solar right with the help of this forum, including your support, so that's good. Turns out some of that was simply bad Renogy flexible panels which it seems most people have moved away from now. But no matter how much solar you have you can't store any more energy than your battery capacity, so a few cloudy days are trouble, and charging from the truck is important.
 
My question still is:

Does FWC installation with solar or without provide for charging of camper batteries from the truck alternator? Factory not after purchase.

Not can it be wired to provide this, but does FWC wire the camper and truck connection to provide the charging of the batteries via the truck alternator?

Thanks,

Phil
 
Wallowa said:
My question still is:

Does FWC installation with solar or without provide for charging of camper batteries from the truck alternator? Factory not after purchase.

Not can it be wired to provide this, but does FWC wire the camper and truck connection to provide the charging of the batteries via the truck alternator?

Thanks,

Phil
Click to expand...
Yes, supposedly, but I was told directly by FWC (someone who is no longer there) that it is not enough to make a real difference and not something you can count on... I tried to dig into this but it seemed I was given "gut feeling" info, rather than engineering data which I expect they would have. "if you have xx truck or alternator, expect xx amps".

At the time I purchased my FWC, and they did the install, I was not informed enough to really understand the issue and how important it was. In another thread where someone was asking what to do at the time of purchase /install, I suggested they have FWC show/prove that the batteries are being charged and everything is wired correctly. It is critically important.
 
pvstoy said:
This is a long story but there is good information had here charging batteries with different inputs.

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

And one from the Expo portal
http://www.expeditionportal.com/forum/threads/142118-Charging-battery-bank-via-solar-and-alternator-simultaneously
Click to expand...
Excellent links pvstoy! I have wanted an in depth explanation of how solar and alternator charging affected each other and now I know that and a whole bunch more!
 
Before my ATC camper I had a Palomino pop up camper. The Palomino connected the truck battery to the camper battery in parallel through a 40 amp circuit breaker. The ATC adds a APOC R12140B dual sensitive isolator located in the battery compartment. I had problems with the camper battery discharging, so I bought a cheep cigarette lighter type plug-in voltmeter for the 12V camper socket. You can use it to measure the truck battery voltage with the truck key on so the 12 V plug is connected.

1) Truck off both voltmeters should read the same between 12V and 12.8V.
If not you have a truck to camper connection problem.
a) check wire connections, plugs and fuses.
:cool: if only one of the batteries are low the battery isolator may be switched off
if starting truck doesn't fix you need to trickle charge the low battery
2) Truck on both voltages read between 13 and 14.5 V
a) if truck battery is low you have an alternator regulator problem
:cool: if camper voltage increases but is low there is a connection problem
c) if camper voltage dose not increase its probably the isolator

When I met with Marty at ATC to get my camper he said that if the camper battery voltage drops below (some level 11V?) the battery isolator will not connect to the truck battery and you will have trickle charge the battery. I haven’t had this problem but I have noticed with the 3-way fridge on 12 V and the truck idling, I can hear the isolator switching on and off every second or two.

Otherwise there is a connection problem (check both white wires and black wire connections) or blown fuse probably located next to the truck and/or camper batteries. In my Palomino I found there was an additional inline fuse hidden under the sink that connect to the truck battery but thats another story. If while running the truck the truck battery voltage is 0.5 V or more than the camper battery, there is connection problem between the truck and camper.

Adding solar should not change the connections of the truck and camper batteries, they are still wired in parallel with a fuse or two and the battery isolator. The only difference depends on the solar controller. For some controllers the camper load distribution for the lights, fridge, heater ... is connected directly to the camper battery or for some it is connected to a load connection on the controller. Either way the connection described above should work the same.

There are some exceptions the D250S Dual solar controller isolates the truck camper batteries. I got this feedback from the manufacturer.

"The D250S DUAL will take power where it is easiest to find. If the engine is running it is from the alternator, even if the solar panels are producing a bit.
When the engine is turned off the power will come from the solar panels. If the voltage is below 13,1V the D250S DUAL will not start.

If you have a D250S DUAL connected between the starter battery and the service battery, there will be at the most 20A flowing between the batteries, if the batteries or the charger for some reason should be short cutted there is a built in barrier that will prevent a too big energy flow.

As an extra insurance you could mount a fuse near the positive pole on the batteries."



I am in the process of changing out the fuses with circuit breakers that are in line with batteries. The circuit breakers automatically reset, so if for some odd reason something inadvertently shorts one of the battery connections it will reset and you won't wake up some morning with a battery problem.
 
Read the Expo posts listed in the thread site given above...very informative but with this limiter; not knowing exactly what FWC has installed in the camper as delivered, nothing definitive can be ascertained. Something that resonated with me in one of the posts was that FWC is "terrible" at disseminating information and specifics about what is installed in the current camper models.

I am "In a penny, in a pound" and do not question my decision to buy a Hawk; even sight unseen yet. But all along I have tried to glean the details of what components are going into the Hawk as delivered to us on 2-25. No luck. I understand running changes, but the FWC website should be updated and more detailed in my estimation. A buyer should know exactly what components are in the product they are laying the bucks down for.

I love discovery learning and will ferret out how it all comes together in our Hawk. But the less time dicking around and the more time using the camper would be a plus... :D.

Yet again, can't thank all the folks on this forum enough for their excellent McGyver ideas and details on the FWC campers.

Thanks!

Phil
 
My Hawk batteries are definitely charged by my Tundra. That said, careful management of all charging sources and battery state of charge is a learning opportunity. On my first extended campout in my new Hawk, my camping space was in the trees and there was enough shade that my single 100 watt solar panel was rarely in full sun. Before I realized it, my battery voltage was below that required to enable charging by the truck through the isolator.

It wasn't until I left the campground and was in full sun at noon, that the solar panel charged the battery enough to allow the truck to begin charging the camper batteries. By the time I got home, the solar and truck had significantly recharged the camper. To finish restoring the batteries, I plugged into AC and let the Iota take the state of charge to full and enter float stage.

I'm sure that I reduced battery life in that one trip. Now, I monitor the voltage on the Zamp controller and run the truck for a while to boost battery charge if it drops too low. I also bought a 100 watt panel that can be tilted & placed in full sun early & late to take advantage of available sun. Live and learn.

Paul
 
"Before I realized it, my battery voltage was below that required to enable charging by the truck through the isolator"

"..run the truck for a while to boost battery charge if it drops too low".

What exactly are these voltage threshold amounts referenced above?

Year of truck and camper?

Thanks,

Paul
 
When we lower the top to go sight seeing I've noticed a significant increase of amps on my Zamp after driving. We had several days of rain in the Smoky mountains and drove see the sights and got some charging done. jd

Sent from my SM-G900V using Wander The West mobile app
 
Wallowa said:
"Before I realized it, my battery voltage was below that required to enable charging by the truck through the isolator"

"..run the truck for a while to boost battery charge if it drops too low".

What exactly are these voltage threshold amounts referenced above?

Year of truck and camper?
Click to expand...
Sure Power battery separator data sheet

2010 Tundra, 2014 Hawk with factory two battery auxiliary system and factory Zamp solar 100 watt solar and 15 amp controller.
Portable Renogy 100 watt bendable panel (yes, mine is still working)
Note the recommended battery cable sizes in the data sheet. FWC uses 10 gauge that runs approximately 20 feet counting the down to the frame and up to the camper and jogs. This results in a larger voltage drop than ideal depending on current flow.

Unless I am misunderstanding the data sheet, if the camper battery drops below 12.4 volts, the separator will not connect the camper battery to the truck charging system. You will need to use solar, connect to AC mains, or use a separate battery charger to get the camper batteries above 12.4 volts for the truck charging system to charge your batteries. The truck charging system must provide at least 13.2v at the battery separator to connect the truck charging system to the camper batteries.

When my camper battery was too discharged, I could hear the separator click on after starting the truck then click off after a delay of a few seconds as I was trouble shooting the issue. I did not have many tools and did not have the data sheet with me at the time.

Paul
 
I spent a trip or two riding in the camper while my wife drove. All in name of science of course.
Besides mentioning that it can be pretty cold and noisy back there I did learn a few things. I did this with the solar system unplugged so that only the truck charging could be evaluated.

1 - it took several minutes of running the truck before I got any power at all as seen on the trimetric. The truck voltage would have to get up to at least 14+ volts before I noticed anything. I could see inside the cab and the trucks volt meter while we drove.

2- there is certainly voltage loss in the stock system. I have a Chevy 3500 Duramax and the voltage was less than I could see in the truck. When I've measured it before with my volt meter not while driving I've noticed a 0.1-0.3 voltage drop between camper and truck.

3- if your camper voltage is 12.4 or below you may not get any charging from the truck at all. The isolator won't make the connection between camper and truck batteries.

4- if your voltage is high enough in the camper and if your truck alternator is putting out enough voltage you can get decent battery charging. It would take a very long drive to full charge a system from 50% to full.
Most people wouldn't routinely drive 8 hrs or more to make it charge completely. It would be like putting out a solar panel and expecting it to completely charge your system in 2-3 hours. Just isn't going to happen.

5- the truck charging is best if you are in the "bulk" charging state. It makes up the most difference then. You'd have to drive forever to get to 100% once you are in the float stage of charging.

I suspect that most of these issues are due to differences in truck alternators, isolator issues or how FWC wired the campers.

Personally they have wired 2 different trucks for me and both worked great.
 
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