Wiring schemes for new build

[Shotgun Willie]

I'm currently working with Marty on an Ocelot shell build. I've got it all dialed with exception of the wiring. Handy Bob's blog has been my primary source of info thus far in addition to some of the posts here. It seems the primary concern is voltage loss causes by improper wiring and poor / wrong power control components. Speaking with Marty it seems the largest wire he can install for pre-wire solar on the roof is 10 gauge. Reason being, any thicker and the wire flex is too stiff for the pop up mechanism. My initial power needs are: 1) furnace fan during the cold seasons, 2) lighting at night, and 3) charging my lap top computer. Potential power needs in the future: refer, and charging deep cell marine batteries for my trolling motor while dry camping on Cascade High lakes. I'd like to avoid generators if possible.

All this said, my Qs follow:

1) Is 10# wire sufficient for solar pre install?
2) Should I wire for more than one panel?
3) Marty recommends keeping the panel weight below 18lbs total. So two small panels or one large?
4) What wire gauge should I use from a ) truck battery to camper separator, b ) separator to aux battery?
5) I've seen a posting here where someone set up a second panel in a pull out drawer under the cab over / on top of the truck's roof. Is this is a viable option if greater than 10 gauge wire is needed? Seems like a trade-off as sun exposure is limited to when parked.
6) HandyBob recommends atleast 2 6v Trojan batts vs one 12v deep cycle. Thoughts?

Many thanks in advance for helpful info and suggestions,

Colby

 

[ski3pin]

Colby, I am not an expert but I have read handy bob and many others. I also am pretty aware of what the camper builders use. From my experience (we do tend to use the camper) 10 gauge is fine for all your solar needs. I installed solar a few months ago and have used it on four or five trips since then. Our power needs are similar to you, except for that trolling motor, but we do have a travel box fridge running. I bought a panel from AM Solar because it was 100 watts and the lightest I found. I have a 105 amp hour diehard platinum battery (waited for the sale). My needs barely dent the battery overnight and each evening I start with a fully charged battery. Prior to solar, and I tried this by accident, my battery went for five days before dropping to 12.2 volts without any charging. I also ran 10 gauge wire from the truck battery back to the camper.

Marty and Jeff at ATC have a vast amount of experience, trust what they have to say also.


Also, welcome to Wander the West.

 

[Hittheroad]

Colby, I am not an expert but I have read handy bob and many others. I also am pretty aware of what the camper builders use. From my experience (we do tend to use the camper) 10 gauge is fine for all your solar needs. I installed solar a few months ago and have used it on four or five trips since then. Our power needs are similar to you, except for that trolling motor, but we do have a travel box fridge running. I bought a panel from AM Solar because it was 100 watts and the lightest I found. I have a 105 amp hour diehard platinum battery (waited for the sale). My needs barely dent the battery overnight and each evening I start with a fully charged battery. Prior to solar, and I tried this by accident, my battery went for five days before dropping to 12.2 volts without any charging. I also ran 10 gauge wire from the truck battery back to the camper.

Marty and Jeff at ATC have a vast amount of experience, trust what they have to say also.


Also, welcome to Wander the West.


I second all this - though we use a good deal more electricity and could not last 5 days. About 100 watts on top should be plenty for most situations (we have 85). I plan to have some extra panels that I can place in the sun should we want to park in the shade. They would connect via the lower body and not need to run through the pop up mechanism. So I think 10 gauge should be all you need up top.

 

[craig333]

I'd go with one panel. Ten gauge should be plenty. You could have them add a second plug for a portable panel should you find you need it but that wouldn't be difficult to add later yourself. As for the two six volts vs. one 12 volt battery, first I'd get out my tape and see what fits. Personally I like having an agm battery, no maintenance and no worries about off gassing but six volt guys make some persuasive arguments also.

 

[MarkBC]

I don't have anything new to add (that isn't just personal preference), I just wanted to say,
"Wow -- another fellow Bendite new to WTW! Welcome, colby!"

OK, I guess I did have one comment, re:
5) I've seen a posting here where someone set up a second panel in a pull out drawer under the cab over / on top of the truck's roof. Is this is a viable option if greater than 10 gauge wire is needed? Seems like a trade-off as sun exposure is limited to when parked.
The downside -- to me -- is that you have to deploy it -- it's not ready to go all the time. But while you're driving your truck is charging the battery, "so lack of sun exposure while driving" doesn't seem like a big deal to me.
The upside of a panel that's not flat-on-the-roof is that you can point it at the sun, or at least, point it south. On New Years Day at our latitude the sun only gets about 25° above the horizon at noon, and at that sun angle a horizontal panel get's less than 50% of the power that you'd get if pointing directly at the sun. My roof panels are horizontal...but I went for capacity overkill, so I don't worry about it. You may not need to worry about it either, especially if you only camp when the sun is up north, but just so you know the potential issue.

...I'd like to avoid generators if possible...
Colby

And thanks for that.

 

[ski3pin]

Yeah, the Bend pop up cult will soon be a force to reckon with.

 

[MarkBC]

Yeah, the Bend pop up cult will soon be a force to reckon with.

Will soon? The sainted founder of WTW lived in Bend...when WTW was his.

(colby: Sorry for the horrible topic hijack, committed by WTW Moderators, no less!)

 

[dsrtrat]

Hi Colby,

You need to do some wattage calculations to find out what your power requirements are. Most of us get by fine with LED lighting, fridge, and furnace on one battery. When you start running a laptop charger you are looking at a large jump in wattage in the 70 to 90 watt range for the time it takes to charge the computer. Those chargers are power hogs, feel the heat they put off.

For a rough estimate, watts divided by voltage will give you amps. This is before any voltage drop or other losses. Remember that the rated amp hours of the battery is only about 50% usable before dropping below a 12 volt limit. I think you can pretty much forget about charging a trolling motor battery off solar. Do the math and you will see what I mean.

The bane of 12 volt systems is voltage drop. Larger is always better for the long runs.

The solar is fine with 10 gauge as you are only looking at 7-8 amps output from a 100 watt panel or so under the best of conditions. Likely much less in the real world.

I am a fan of AGM batteries, those golf cart batteries are pretty heavy and you have an outgassing problem if located in the camper. Still on my original 75 amp Interstate after 5+ years. Hope this helps.

Dsrtrat





I'm currently working with Marty on an Ocelot shell build. I've got it all dialed with exception of the wiring. Handy Bob's blog has been my primary source of info thus far in addition to some of the posts here. It seems the primary concern is voltage loss causes by improper wiring and poor / wrong power control components. Speaking with Marty it seems the largest wire he can install for pre-wire solar on the roof is 10 gauge. Reason being, any thicker and the wire flex is too stiff for the pop up mechanism. My initial power needs are: 1) furnace fan during the cold seasons, 2) lighting at night, and 3) charging my lap top computer. Potential power needs in the future: refer, and charging deep cell marine batteries for my trolling motor while dry camping on Cascade High lakes. I'd like to avoid generators if possible.

All this said, my Qs follow:

1) Is 10# wire sufficient for solar pre install?
2) Should I wire for more than one panel?
3) Marty recommends keeping the panel weight below 18lbs total. So two small panels or one large?
4) What wire gauge should I use from a ) truck battery to camper separator, b ) separator to aux battery?
5) I've seen a posting here where someone set up a second panel in a pull out drawer under the cab over / on top of the truck's roof. Is this is a viable option if greater than 10 gauge wire is needed? Seems like a trade-off as sun exposure is limited to when parked.
6) HandyBob recommends atleast 2 6v Trojan batts vs one 12v deep cycle. Thoughts?

Many thanks in advance for helpful info and suggestions,

Colby

 

[Shotgun Willie]

Colby, I am not an expert but I have read handy bob and many others. I also am pretty aware of what the camper builders use. From my experience (we do tend to use the camper) 10 gauge is fine for all your solar needs. I installed solar a few months ago and have used it on four or five trips since then. Our power needs are similar to you, except for that trolling motor, but we do have a travel box fridge running. I bought a panel from AM Solar because it was 100 watts and the lightest I found. I have a 105 amp hour diehard platinum battery (waited for the sale). My needs barely dent the battery overnight and each evening I start with a fully charged battery. Prior to solar, and I tried this by accident, my battery went for five days before dropping to 12.2 volts without any charging. I also ran 10 gauge wire from the truck battery back to the camper.

Marty and Jeff at ATC have a vast amount of experience, trust what they have to say also.


Also, welcome to Wander the West.


Thanks for the info and the welcome to WTW. This forum has been very helpful. I'll be sure to look into the AM Solar for panels. I've got Marty beefing up the mounting area for the solar controller so I can include a battery monitor too. Looks like Tri Metrics have a good rep. http://www.bogartengineering.com/ And yes, I've found Marty and Jeff to very helpful and patient with my ideas alike.
Cheers

 

[Shotgun Willie]

I second all this - though we use a good deal more electricity and could not last 5 days. About 100 watts on top should be plenty for most situations (we have 85). I plan to have some extra panels that I can place in the sun should we want to park in the shade. They would connect via the lower body and not need to run through the pop up mechanism. So I think 10 gauge should be all you need up top.


Good to know the 10 gauge is looking solid for the roof set up. And I agree, a removable panel for better sun exposure is a great set up. In the dead heat of the summer a shady spot is a must!

 

[Shotgun Willie]

As for the two six volts vs. one 12 volt battery, first I'd get out my tape and see what fits. Personally I like having an agm battery, no maintenance and no worries about off gassing but six volt guys make some persuasive arguments also.


Yup, the more I look at it the more I'm leaning towards AGM.

 

[Shotgun Willie]

I don't have anything new to add (that isn't just personal preference), I just wanted to say,
"Wow -- another fellow Bendite new to WTW! Welcome, colby!"

OK, I guess I did have one comment, re:

The downside -- to me -- is that you have to deploy it -- it's not ready to go all the time. But while you're driving your truck is charging the battery, "so lack of sun exposure while driving" doesn't seem like a big deal to me.
The upside of a panel that's not flat-on-the-roof is that you can point it at the sun, or at least, point it south. On New Years Day at our latitude the sun only gets about 25° above the horizon at noon, and at that sun angle a horizontal panel get's less than 50% of the power that you'd get if pointing directly at the sun. My roof panels are horizontal...but I went for capacity overkill, so I don't worry about it. You may not need to worry about it either, especially if you only camp when the sun is up north, but just so you know the potential issue.


And thanks for that.

Thanks for the warm welcome. We are very happy with our decision to relocate to Central OR. The sun exposure issue, especially in the fall and winter seasons, seems to add to the portable panel argument... Or load up with panels for greater capacity... First thing, is get the camper out there and get a feel for what I need. Cheers,

 

[ntsqd]

My plan, now shot all to heck, was to install the Tri-Metric meter and see what our consumption was before sizing a panel or two. Then the limited time deal on those Grape 100W panels got posted. Seemed like a good deal so I bought two of them. I plan to mount it/them flat on the roof.

10 ga. seems too small to me, I'd rather have 8 ga. or 6 ga. but the NEC has kind of screwed that plan. Their mandated MC4 connectors come on 10 ga. wire. Most panels now have these connectors, but cutting them off usually voids any warranty. Stepping up the gauge right after the MC4 connector is an option, but what is the voltage drop through that connection? May not make enough difference for the trouble.

Not buying the not flexible enough argument. The 10 ga. wire that comes attached to the MC4's that I have is far less flexible than the considerably larger 1/0 welding cable that I used to put the starting battery in the trunk of my daily driver. A finely stranded wire choice will be flexible enough. Perhaps space is limited, I'm running into that with some other wiring that I've run up thru the roof. I'm at the limit of the split loom still fitting into both holes and will have to figure out how to drill larger holes for larger split loom while the wires are still running thru them.

 

[Shotgun Willie]

Hi Colby,

You need to do some wattage calculations to find out what your power requirements are. Most of us get by fine with LED lighting, fridge, and furnace on one battery. When you start running a laptop charger you are looking at a large jump in wattage in the 70 to 90 watt range for the time it takes to charge the computer. Those chargers are power hogs, feel the heat they put off



For a rough estimate, watts divided by voltage will give you amps. This is before any voltage drop or other losses. Remember that the rated amp hours of the battery is only about 50% usable before dropping below a 12 volt limit. I think you can pretty much forget about charging a trolling motor battery off solar. Do the math and you will see what I mean.


The bane of 12 volt systems is voltage drop. Larger is always better for the long runs.

The solar is fine with 10 gauge as you are only looking at 7-8 amps output from a 100 watt panel or so under the best of conditions. Likely much less in the real world.

I am a fan of AGM batteries, those golf cart batteries are pretty heavy and you have an outgassing problem if located in the camper. Still on my original 75 amp Interstate after 5+ years. Hope this helps.


Dsrtrat


Calculations according to my understanding:
(Please correct me if I'm mistaken)

Computer charger comes to approx 3.5 amps and Marty quotes the furnace fan at 4 amps. I wasn't planning on upgrading to LED in this build, as I figure that's a task I can DIY if it seems necessary. Not sure what the wattage is on the lights they install... 30w or so? How many lights? 2? That would be 2.5amps x 2. Thus,
3.5 + 4 + 5 = 12.5amps as the largest draw at any moment (with my current set-up). Of course once the computer is charged its draw decreases as does the furnace when the fan isn't on. So its viable to keep my amperage at any given moment between the 5 and 10 range, and more times than not within the 5amp range.

I don't know that I'll stick with Marty's Interstate AGM 76 AH standard install. Probably upgrade to a group 27 with something closer to 90 AH. Math: 90 / 20 = 4.5amps for 20 hrs. Divide that by 2 and I get 10 hours at 4.5 amps. So at best, drawing power within the 5 amp range, I have 10 hours before I'm pushing the battery's healthy capacity, no?

Clearly, charging the trolling motor batt is out of the question!

 

[dsrtrat]

Hi Colby,

Sounds like you are on the right track.

It all boils down to intended use. How long in one spot without moving and how often you use the equipment. Everyone has a different level of comfort. I tend to be pretty basic.

My real world experience with my simple install, a 65 watt solar panel and basic Morningstar controller with a 75 amp Interstate battery, using 10 gauge wire from the panel, is that it works fine. No inverter. I added shore power but have never used it as I am always in the backcountry.

The panel more than keeps up with the Engel 45 qt fridge. I don't use the lights very much as I am usually outside and when inside read with a headlamp. I have used the rear flood maybe twice in 5 years. Knocked one light off the first year and converted the other to led and still have plenty of light. You can easily convert the existing fixtures to led yourself for a much lower cost than the factory install.

I don't take a computer so don't have that draw.

In my experience the furnace is the biggest power hog. In cold weather my furnace runs maybe 1/2 the night with the temp set at 50 or so. I am seldom inside during the day. I moved the isolator and battery under the hood of the truck to get them out of the storage area and to have a dedicated battery for the fridge, which is in the truck cab. One downside to this setup is the battery is colder and has less output mounted under the hood, but if it is that cold I just go someplace warmer. Three days with heavy furnace use is about my maximum so a larger panel would be better if you intend to stay in one place in the cold for longer than two or three days.

I don't have a fancy monitor just a simple 10 dollar voltmeter on a switch that I use to check the battery voltage level. I did run #2 gauge welding cable between the battery and the camper so have very little voltage drop; overkill but I had the cable. If you go that route 10 gauge is in my opinion too small as your run will be longer than a camper install. The run from the solar panel is pretty short and the load not that high plus the output from the panels to the controller is usually around 14.5 volts or higher 10 gauge is plenty large. Measured voltage drop on my solar system is less than .2 volts at the controller, I can live with that.

I do live in the sunny southwest so don't have much problem with decreased panel output due to clouds.

When I replace the battery I will most likely go with the group 31 AGM just to have a little cushion, for the cost difference it is cheap insurance. I will watch for a sale and buy one before my other battery goes.

Enjoy the camper.

Dsrtrat

Calculations according to my understanding:
(Please correct me if I'm mistaken)

Computer charger comes to approx 3.5 amps and Marty quotes the furnace fan at 4 amps. I wasn't planning on upgrading to LED in this build, as I figure that's a task I can DIY if it seems necessary. Not sure what the wattage is on the lights they install... 30w or so? How many lights? 2? That would be 2.5amps x 2. Thus,
3.5 + 4 + 5 = 12.5amps as the largest draw at any moment (with my current set-up). Of course once the computer is charged its draw decreases as does the furnace when the fan isn't on. So its viable to keep my amperage at any given moment between the 5 and 10 range, and more times than not within the 5amp range.

I don't know that I'll stick with Marty's Interstate AGM 76 AH standard install. Probably upgrade to a group 27 with something closer to 90 AH. Math: 90 / 20 = 4.5amps for 20 hrs. Divide that by 2 and I get 10 hours at 4.5 amps. So at best, drawing power within the 5 amp range, I have 10 hours before I'm pushing the battery's healthy capacity, no?

Clearly, charging the trolling motor batt is out of the question!

 

[Shotgun Willie]

Anyone have experience with Zamp Solar based out of Bend, OR? http://www.zampsolar.com/Welcome.htm?m=1

I spoke with Tim at Battery Systems http://www.batterysystems.net/locations/index.php and he's quoting me with a "RV Special" deal (the RV show is this weekend):

1) fixed roof application 80w panel w/ 30w controller $500

2) 100w panel w/ 30 w controller $600.

3) portable panel 120w $600

The 100w fixed roof panel is 18lbs, so it meets the weight criterion.

Additionally, he'll include a reduced battery price:

a ) Full River Group 27 AGM 105AH for $200
or
b ) two 6v AGM 250AH at $220 each

The Full River batteries http://fullriverdcbattery.com/ come with a 2yr full replacement and additional 3yr pro-rate warranty. Total 5 yr warranty.

The Zamp Solar products come with a 25 yr "power output" warranty.

I like the idea of a local solar provider, and the battery warranty is good. But is the price point solid on both accounts?

Chime in with your opinions on this deal or anecdotes / personal experiences with these companies.

Lastly, any pros and cons for portable vs fixed? Off the cuff, it seems portable allows for greater sun exposure and reduces roof weight. However, you have to set it up and do so in such a way that it won't get damaged or potentially stolen (if one was away from the camper).

Thanks again,
Colby

 

[ntsqd]

The hundred watt panels that I bought were $149 delivered. The controller that I bought was $82 + the ride.

How much of the install can you do yourself? After reading the Handy Bob blog I was gun-shy of any of the RV type places. Seeing your quotes, and discounting for install labor, leaves me still gun-shy of them.

 

[Shotgun Willie]

The hundred watt panels that I bought were $149 delivered. The controller that I bought was $82 + the ride.

How much of the install can you do yourself? After reading the Handy Bob blog I was gun-shy of any of the RV type places. Seeing your quotes, and discounting for install labor, leaves me still gun-shy of them.


Yeah, Bob is no fan of the RV salesman. I've decided unless they offer a good deal on a single panel - no kit, then I'll pass. I'm not interested in their controller and the portable kit has the controller mounted behind the panel - an essential mistake in HandyBob 101: proper wiring teks.

 

[pods8]

1) Is 10# wire sufficient for solar pre install?
2) Should I wire for more than one panel?
3) Marty recommends keeping the panel weight below 18lbs total. So two small panels or one large?
4) What wire gauge should I use from a ) truck battery to camper separator, b ) separator to aux battery?
5) I've seen a posting here where someone set up a second panel in a pull out drawer under the cab over / on top of the truck's roof. Is this is a viable option if greater than 10 gauge wire is needed? Seems like a trade-off as sun exposure is limited to when parked.
6) HandyBob recommends atleast 2 6v Trojan batts vs one 12v deep cycle. Thoughts?


1) I like it, better than what appears to be thinner stuff on other pre-installs. I'll be using 10ga.
2) Up to you.
3) For a given wattage panels are usually similar weight by the same manufacturer so one verse two doesn't really factor in. Some manufacturers are lighter (but that in turn means thinner frames/glass/or embedment material so take your pick there).
4) Bigger is better within reason (as connectors get harder to deal with). 10ga min, anything less is a joke. I'm personally going to use 6ga I think.
5) No comment
6) For the same physical size battery two 6V is going to double your capacity verse one 12V and also double your cost, roughly. Amp hours take space and generally they take the same space for about the same cost (for a given battery construction type) whether it be 6V or 12V. 6V are supposedly more robust plates, 12V have the ability to still work if one dies. Weight out accordingly. I got a good deal on my 6V so that is what I have, I'll reevaluate when they eventually die.

10 ga. seems too small to me, I'd rather have 8 ga. or 6 ga.


For something up to 10amps of solar I can't see 10ga being small (I'm going to use it). Your voltage drop of 20' is about 3%, that seems totally tolerable to me considering most will be using PWM controllers (and waste the extra voltage) and even with MPPT its not a huge loss.

1) fixed roof application 80w panel w/ 30w controller $500

2) 100w panel w/ 30 w controller $600.

3) portable panel 120w $600



All expensive unless the controller is nice (I haven't looked). Check out pricing on solarblvd for a low cost panel reference.

 

[craig333]

How much of the install can you do yourself? All of it if you're the least bit handy. Routing the wiring was the hardest part. Nothing really very technical involved. Many ways to do the mounting. Lots of install threads here on WTW to look at.