87 Starcraft expedition pop up build

[ColoDisco]

Soooo.. I had a chance to try out my solar setup in moab for a week of boondocking. Here goes. I have the following setup in my 1987 starcraft astrolite.
I will have a price breakdown at the bottom of the post.

[ame="http://www.amazon.com/gp/product/B002OSAB2I"]Amazon.com: HQRP KIT (85W Monocrystalline Solar Panel 85 Watt Power 12V DC, Solar 10A Charge Power Controller / Regulator 12V / 24V 10 Amp) + HQRP Coaster: Patio, Lawn & Garden[/ame]

[ame="http://www.amazon.com/gp/product/B003R7LQDI"]Amazon.com: Whistler Pro-2500W 2,500 Watt Power Inverter: Patio, Lawn & Garden[/ame]

I have a bit of a elaborate connection through my Popup. I will start with the power from the Discovery. I have power and ground going from the Disco to the Popup through a 7 pin connector. It runs through the charge controller to the battery through 8 gauge red and black wire bought at Lowe's. I used screw in stereo gold plugs to connect the 8 gauge to the controller. Seen here:

I installed a battery and battery box purchased through walmart. Group 27 deep cycle/marine 120ah maxx battery.

With sound advice from a solar guru I know at work I ran a 5 foot run of 2/0 cable from the inverter to the battery from Storm Copper. I covered all wires with corrugated wire sheathing bought at Lowe's for external protection. I used only insulated clamps with self tapping stainless screws to attach the cables to the frame. I used a small run of 8 guage negative cable to ground the inverter to the chassis. I also filled all the drilled holes with clear 2x flexible silicone sealant to keep weather and bugs out. Cheapest best cable you will find with free shipping.

http://store.electrical-insulators-and-copper-ground-bars.com/

As seen here:

As you can see I have room for 2 batteries. I plan on turning it into a 24v setup down the road. I had some custom fab work done to accommodate 2 batteries, storage bin for jacks etc and a full size propane tank. I thought I had a picture of this up close in action but I do not. I will have to take one. Here is the before and after the fab work:
Before:

After:

I did a direct connect with the same 8 gauge wire to the panel connecting it with a female 7 pin trailer socket on a 10 foot run of wire. What this allowed me was the option to just plug the Disco into the Popup and charge the battery while driving, then simply unplug the truck when setting up and plugging in the panel directly to the solar charge controller giving me easy plug and play operation. The 10 foot run of cable gives me flexibility to park the Popup under a tree in any direction and just setting my panel where I want it. Pic of that later. As for panel storage during travel I found a sweet spot below the queen bed and on top of the collapsed kitchen counter seen here:

And some campsite pics:

Final cost breakdown for my solar setup keep in mind I have prime membership at amazon so I did not pay shipping on everything:
Panel with charge controller w/shipping: $321.86
Inverter: $179.99
2/0 cables from Storm Copper: $60.00
Battery and Batt box from walmart: $85.00
60' of 8 gauge cable from Lowe's: $30.00
7 wire tow connections from Home Depot: $60.00
Misc hardware from Lowe's: $50.00

Total cost for my solar set up as it stands: $786.85

Future expense to add another battery and box with tie in cables from Storm copper: $105

I was asked by a good friend with a PU if this was cost efficient. Of course it is as it is renewable energy.

As for the performance. I do not have any onboard lighting so did not have alot of nights of draining. I also do not have a furnace onboard. We used a mr. buddy heater connected to the big propane tank and this worked perfectly.
We did use a Dolce Gusto coffee maker every day but it did not work everyday. Not because of power but because we were new to the machine and did not understand how to use it. 1 night we charged a laptop, camera battery and ran the coffee maker in the morning and it only went down to 11.1v and recharged by 10am completely. Really impressed with the setup I already have and intend to use some more power hungry items like a real refrigerator in place of the icebox which did not work very well. Kept food at 50 degrees with a iceblock or 40 degrees with just a bag of ice on the shelf. Neither temperature made me feel good about eating the food.

We do not intend to get a generator yet but still have all the shore power plug in with the converter installed in case we want to plug in. I keep her plugged in while at home anyway.

I also intend to add a lift with sliders to the underside giving me way more flexibility for offroad trails. I picked the bottom of the line camper to keep weight down but see that a onboard fresh and grey water tank will be in order down the line including a sink. Aquatainers are convenient except they are not stable enough when offroading.

 

[yarro]

If you are going to run a refer with that set up you best have at least a small backup generator to charge the batteries. An 85 watt panel will only give around 68w/hrs AC for every hour it is in optimal sun after efficiencies in charging then inverter efficiencies are taken into account. AZ or SoCal will give you 5.5-6 hours in the summer average for a stationary panel and it deceases as you go North and to wetter areas. You might get an extra hour or two by repositioning the panels periodically. Surprisingly little cloud or the shadow of a branch really hurts output on a single panel setup. You can play the game of drawing down your batteries on the trip, but that really decreases the life of the batteries. Drawing more than 80-90% capacity and the lifespan drops off in a non-linear manner. Also, Deep cycle/Marine batteries are actually in between a deep cycle and a starting battery and don't tend to last as long as a true deep cycle, but will provide a higher peak current without damage.

The small 120V refers unless you specifically buy one of the very expensive ones are horribly inefficient. My Kill-a-watt told me that my full size fridge 26cu ft used almost the same amount of power as the 8.5 cu ft one in my office so I got rid of it. (2.4kw/hrs per day versus 2.1 @ 73F ambient) They make ones that have solidstate peltier coolers, but they don't do any better than a cooler with ice as far as the internal temp goes.

-yarro

 

[pods8]

Do you have a product link on those propane tank hold downs?

I have a bit of a elaborate connection through my Popup. I will start with the power from the Discovery. I have power and ground going from the Disco to the Popup through a 7 pin connector. It runs through the charge controller to the battery through 8 gauge red and black wire bought at Lowe's.

Maybe you're explaining wrong here because below you were talking about feeding the disco from the charge controller. But above are you saying you've wired the power FROM the disco TO the camper battery through the solar charge controller such that when the disco is driving you're sending voltage to the charge controller input? If so you may want to rethink that setup since solar charge controllers aren't meant to take alternator output as their input.

 

[ColoDisco]

Very valuable information. I have not done the calculations on kw/h on a small fridge as of yet. I have looked into the cost of a 3 way but they tend to be exhorbitant. Have been searching for a used one but my specs are pretty small. 18" tall by 21" wide is the box size. I am planning on removing the icebox this weekend and seeing how much depth I have to work with.

I am adding a 2nd battery to the set up and have thought about the 2000w honeywell generator as backup. Right now my truck being plugged in is the back up but it is not enough charge amps to sustain a refer and all the other usage I am planning. Currently heat is supplied with a mr. heater and a standard propane tank mounted externally (this worked very well in moab with lows in the mid 30's). I have entertained a furnace but that adds electrical draw to the equation.

 

[ColoDisco]

Do you have a product link on those propane tank hold downs?



Maybe you're explaining wrong here because below you were talking about feeding the disco from the charge controller. But above are you saying you've wired the power FROM the disco TO the camper battery through the solar charge controller such that when the disco is driving you're sending voltage to the charge controller input? If so you may want to rethink that setup since solar charge controllers aren't meant to take alternator output as their input.

Propane tie downs were made by my fab guy. I will ask him for you.

As for the solar charge controller I was told this would work fine. Admittedly I did not ground my battery to the chassis and I am not sure I was actually getting a charge off the alternator on the truck. Correct me if I am wrong but the solar panel is charging via a 12v 600w through 8 guage copper. The truck is also sending a 12 v charge. Controller is only seeing the 12v charge and should work. It's primary purpose it to keep the battery from overcharging.

 

[pods8]

Correct me if I am wrong but the solar panel is charging via a 12v 600w through 8 guage copper. The truck is also sending a 12 v charge. Controller is only seeing the 12v charge and should work. It's primary purpose it to keep the battery from overcharging.

All I know is I called one of the solar controller companies when I was wondering about adapting a one to be a DC-to-DC smart charger between the alternator and the aux. battery. I was told no by their engineers, I don't know enough about their circuits to argue back... However I was talking about MPPT controllers with them at the time. A PWM controller might be okay now that I think about it at face value however do your own research to confirm one way or another. I was just pointing out a potential issue for you to check into. You'll likely want the line fused to max amp rating on the controller though.

 

[dwh]

Have been searching for a used one but my specs are pretty small. 18" tall by 21" wide is the box size. I am planning on removing the icebox this weekend and seeing how much depth I have to work with.

My camper has the smallest Norcold, the 323 and the problem is the depth. I think the cabinet it's in is around 2 feet deep.

I am adding a 2nd battery to the set up and have thought about the 2000w honeywell generator as backup.

I wouldn't. If you look at the Honeywell 2000 on Amazon, look at the reviews (the all reviews page), the newest review, by "umv" is mine. I suggest you read it. Bottom line is Northshore, the company that bought the gens from the Chinese factory and glued the Honeywell name on, got taken over by Generac on March 7th. If you look at the Honeywell site now, what you see is a different generator - same one as the Generac ix2000 but in a white case with the Honeywell name glued on. That one is made by a different Chinese factory then the red Honeywell I have.

I was lucky enough to get a refund from Generac (a year and a half after I bought it from Amazon) and immediately ordered up a sweet little Champion 42431 from buychampionpowerequipment.com. According to FedEx, it'll be delivered tomorrow.

I bought the 2000 because I was planning to put a/c in the camper, but then I decided it didn't need it. For just battery charging, the little 1200w Champion is perfect.

Also, the math works out to better fuel economy than the Honda inverter gens.

Little Champion claims 10 hours at 50% load on a 1.2g tank.
10h x 600w = 6000wh / 1.2g = 5000wh/g
Honda eu2000i claims 9.6 hours at 25% load on a 1.1g tank
9.6h x 400w = 3840wh / 1.1g = 3490wh/g
The Honda eu1000i works out even worse.

One reviewer on Amazon says his little Champion goes 14 hours on a tank running only his laptop.

Personally, I'll never order another gas powered anything from Amazon - once you put gas and/or oil in it, they consider it "hazardous" and won't let you ship it back.

Right now my truck being plugged in is the back up but it is not enough charge amps to sustain a refer and all the other usage I am planning.

Actually, the truck alternator is likely 60 amps or more. Of course, by running it through that charge controller, you'll never get more than 10a into your batteries from it...

The bigger problem is the voltage drop. From the alternator back to the charge controller (I know you said #8, but is that the entire run from the front of the truck, or just from the trailer plug to the charge controller?)...your alternator may be putting out as much as 14.8v, but by the time it gets to your battery, it's likely down below 13v so it will never get your battery fully charged - even if you weren't choking it down so much with that charge controller.

 

[dwh]

As for the solar charge controller I was told this would work fine. Admittedly I did not ground my battery to the chassis and I am not sure I was actually getting a charge off the alternator on the truck. Correct me if I am wrong but the solar panel is charging via a 12v 600w through 8 guage copper. The truck is also sending a 12 v charge. Controller is only seeing the 12v charge and should work. It's primary purpose it to keep the battery from overcharging.

Not exactly. A few points to ponder...


The panel likely puts out more like 15v under load (Vmp - Voltage Max Power). A "12v" solar panel has to put out at least 15v Vmp or it can't push the battery all the way up to full (over 14v).

Using #8 is good for reducing the voltage drop. If you are using it from the solar panel to the charge controller, then to the battery - that's excellent. If you are using #8 from the charge controller to the battery, but using some skinny wire from the solar panel to the charge controller - then the #8 is pretty much pointless since the main voltage drop will be in the wire from solar panel to the charge controller anyway.

I bet you aren't using #8 from the truck battery in the front all the way back to the trailer battery. You should. Or even bigger to tell the truth. If you aren't, then the wire from the alternator/battery in the front, to the trailer plug on your bumper is dropping the voltage a LOT.

Batteries aren't fully charged with 12v. To be fully charged, they need to get pumped up to over 14v. If you only see 12v at the battery from the truck's alternator, then you've got so much voltage drop in the wire that the battery will never be fully charged no matter how much you drive. The battery will never get to 14v if the wire is dropping the voltage to 12v.

The charge controller needs OVER 14v on the input side in order to be able to "cut off" when the battery is full. If it never gets a high enough voltage from the alternator (and if you don't have big fat wire running all the way from the front to the back, it doesn't), then it will never cut off - because it will never see the battery get up over 14v and so it will think the battery is not fully charged (which is correct - it isn't). So if it never turns off anyway - because the input voltage is too bloody low from all the voltage drop to be able to fully charge the battery - why have it in the circuit to begin with?

PLUS! - you don't need the charge controller to protect the battery from over charging from the alternator in the first place - that's what the truck's voltage regulator does. (You only need the charge controller to keep the *solar panel* from overcharging the battery. Without the charge controller, the panel could push the battery voltage up to whatever the solar panel's Vmp is (15v or more usually.)) So even if you weren't gonna toast that charge controller with the massive current (amps) the alternator is capable of producing - you shouldn't have it between the alternator and the battery anyway. All you are doing is restricting the 60a (or more probably) that the alternator -could- be feeding to the battery, down to 10a. Ouch.

Grounding to the frame is cheezy. It's one of those, "it'll do if there's nothing better" things. For a big inverter tapped of a battery, you should definitely be using a dedicated ground straight to the battery. Same size as the positive wire of course. (And you need a big fuse in the positive wire where it meets the battery.)

If your battery is sitting at a resting voltage of 12v - then it's bloody near halfway drained. If it's below 12v and you charge it up to 12v, then it's bloody near halfway full. A fully charged "12v" battery will be one that is pumped up to between 14.4v - 14.8v (except Gels, they need 14.1v or 14.2v) and after being charged drops to a resting voltage (couple of hours of no charge and no drain) of between 12.8v - 13.6v (depending on who made it).


Hope this helps clear it up some...

 

[ColoDisco]

Well being new to solar these are all great points. My trade is as a Audi technician so what I am going to do is begin testing my electrical with a DVOM and see what I am actually getting for a charge rate.

You are correct that I am using the Land Rover supplied aux charge circuit at the tail of the truck, the 8 guage is in the trailer wiring harness. Has 14 guage wires for taillights into a 6 pin connector which I eliminated and bypassed to a direct connect 7 pin circuit. The whole point of the setup is ease of use. Plug and Play. Not ideal I know but the last thing I really want is to have multiple holes in the camper just to plug in my solar setup. I already have 3 holes in the bottom. 1 each for the 2/0 positive and negative cable to the battery including the charge controller 8 guage wire to the battery. I have a 3rd for ground from the inverter to the chassis and wires from the 7 pin to the controller. No doubt this leads to voltage drop. If my results show what you are saying I will entertain a direct connection to the battery for the truck rather than running it through the controller. This will however force me to lose the plug and play feature.

If I buy a generator I will do some more research, honeywell is at Costco and I get 2% back, that is the attraction for me. Plus if it needs to be returned it is just down the street. I put the solar setup in primarily to elimate the annoying sound of a generator so money spent to improve that will be better spent.

I really appretiate all the input and will follow up with my test results this weekend.

 

[dwh]

One thing to keep in mind when testing, is that there are several variables which affect voltage drop.

Wire size.
Wire length.
Temperature.
Load.

That last one, load, throws a lot of people off. You might test a charging circuit with a meter, and see a voltage number that looks close enough - say 13.8v, but that's with no load. Once you add 10a or 20a of load, all of a sudden the *real* drop shows up and the battery might only be seeing 12.8v.


If the wire is just "way too skinny", then it might have something like a half volt drop even with a very small load, like 1a or 2a. In that case, the battery is always going to be (at least) a half volt below full charge voltage because at any useful amp load (charging current) the voltage drop shows up.



Testing can be a little tricky. The best way, is to measure the resistance of the wiring, and then you can use electrical math to figure out what the voltage drop will be at any given load.

A quick and dirty test would be to disconnect the battery and hook up a known load, like say a car headlight (usually 50w-60w...that's about a 5a load), and then measure the voltage to see how much drop that particular load causes. If it drops a significant amount with just a headlight for a load, it'll be worse when trying to charge a battery.

 

[ColoDisco]

Not sure why I forgot to check this sooner. All great information! I am running 8ga wire straight from the panel to the controller and straight to the battery itself. I believe this charge circuit is good. I was showing 13.6v in the wires coming out of the truck. I am running the same 8ga wiring from the truck to the controller.

I geuss that the real question is what is the best way to route the wiring? Have seperate connections from the truck to the battery and then keep the solar on its own circuit?
This is very doable but will take some rewiring to make it happen. I may try and do a crude wiring diagram so people know what I end up doing for the best power usage.

I have also been thinking of adding a 12v circuit and running some of my lighting (looking at 12v LED lights as I have no lights at the moment) direct from the battery. Thoughts?