Solar Power!!

[Defjr333]

"back east".......dat be me. LOL

Not a crack on your system. It is much nicer than mine. Thats why we all here tho, WE get to choose how to make our lives easier and work for how WE want. Not everyone use a device the same way.....I mean just because your system COULD power an ac unit for x number of hours does not mean YOUR priorities are the same. No ac on batts means everything else runs MUCH longer on a charge. To each their own

Doug

[JDOnTheGo]

Originally Posted by Defjr333

Not a crack on your system.

Oh no.. I didn't read it that way.

Originally Posted by Defjr333

Thats why we all here tho, WE get to choose how to make our lives easier and work for how WE want.

YES - exactly right!!

[Defjr333]

I know u took it the way intended JD...we discussed this one b4.lol That was for everyone else.

Still nice set up tho. I admire the work u put in there. Def not a half azz job

Doug

[JDOnTheGo]

Originally Posted by Defjr333

Still nice set up tho. I admire the work u put in there. Def not a half azz job

Thank you!! I always appreciate compliments! As with all things, there are always ways to improve on it and, of course, our nature is to "more, more, more" but it is serving me quite well.

[Defjr333]

I have ended the more more more mentality for myself. I have downsized from a 3bedroom house by myself to renting a one room and bath till I get this project built. Now its about self reliance. If i have days with little/ no sun, I will use the CubicMini instead of furnace to save LP, and genny to save solar, etc. I have multiple back ups planned for most systems. I blame the Navy for this mindset.
Doug

[Brewerbob]

Originally Posted by JDOnTheGo

No to both Doug. I use altitude during the warm months so it is pretty rare to even need A/C when parked. The times it seems to nail me is when traveling and I get caught for a day or two in the low-lands.

Back east is me as well. I really want AC on solar. Would your system, with two extra panels slapped up there handle the load well enough? I have a 40 ft roof with only two hatches. That should leave room for 8 panels if need be. Your blog said 4 panels at $1720. 6 panels would still be "only" $2500.

At this point, I'm not planning on laundry especially when disconnected from shore power. I really don't want to take up the real estate (with a washer/dryer anyway).

Originally Posted by Blog

That is four, 435 watt SunPower E20 panels. These are 128 cell panels so are very large measuring 41″ x 81″ and produce approximately 6 amps at 72 volts.

I'm not seeing the panels you called out.

Originally Posted by Data Sheet

SPR-E20-327
Nominal Power (Pnom)11 327 W
Rated Voltage (Vmpp) 54.7 V
Rated Current (Impp) 5.98 A
Open-Circuit Voltage (Voc) 64.9 V

[/quote]The X Series are 345W but I'm not seeing anything in the 400 range on SunPower's site. No idea id I'm looking in the right place tho.

[Defjr333]

I think he said in a different thread they were model # SPR-E20-435-COM.

https://us.sunpower.com/sites/sunpow...lar-panels.pdf

Those are pretty large. But a full size bus does have lots of roof area compared to a shuttle. If somebody wants to spend the $ im sure its possible to go 100% solar. I just dont see why you would do that. The cost is too preventative. $800 EXTRA in panels. Adding an additional MPPT $200-600. Adding additional batteries $200-$1000.....Thats a LOT of fuel for a generator. Plus even with additional panels you WILL have days on end with poor conditions and not produce much power. The generator for me is used when i need AirCon or using microwave. I can run my window AC for 5 hours on batt if emergency or indef while bus running (alternator) but i like to save my batteries for everything else. I can go more than 5 days no sun with lights, TV, Furnace, Water Heater, Water Pump, Fridge/ Freezer, Laptop, etc working. Now if batteries are 100% and is still early in day, sure...use that power. But I try to get as close to 100% each evening as possible.

BUT, again, that is why we are all here.....to do it OUR way. It is possible, but for me not practical.
Doug

[JDOnTheGo]

Originally Posted by Brewerbob

Back east is me as well. I really want AC on solar.

Would your system, with two extra panels slapped up there handle the load well enough?

I'm afraid I am one of those darn facts guys. The short answer, I don't know. The numbers answer: A typical 15,000 BTU A/C unit draws something around 15 amps at 120VAC (or 1800 watts). The problem is that it's duty cycle varies depending on the space to be cooled, the outside temperature/humidty, and how much it has to run to maintain the desired temperature. If you were to assume worst case, 100% duty cycle, then it would be about 1800 watts continuous. A clear day in an area with good solar insolation will yield something around 80% of rated panel output (maybe more, maybe less, depends how they are mounted/aimed/etc.). You'll need to include conversion losses into the mix and whatever the actual insolation is but, in theory, 2300-2400 watts of solar panels is enough to power the A/C unit. That said; one 15,000 but A/C is not enough for my coach on a sunny, hot day. I'm not sure exactly how much I need but I know 15k is not sufficient - two 15k units probably is but that is a guess.

I never think of my solar panels directly powering anything. I think of the battery bank as a "fuel tank" - some things draw from that tank, other things fill that tank. That view is not entirely accurate but it helps many people keep things straight.

The big PV panels can generally be found in the $1/watt range if you shop creatively.

Originally Posted by Brewerbob

I'm not seeing the panels you called out.

https://us.sunpower.com/solar-resour...ix-compatible/

My opinion is that it is possible to generate enough solar power to operate A/C but I don't think it very plausible/cost effective in most situations. For example; do you need the A/C unit(s) to run ONLY when the sun is brightly shining (typically not - in many (humid) cases it is needed all night). If needed all night, you are talking about harvesting a huge amount of power during the day and having a huge storage system to draw from at night. How often do you need all this solar power (for A/C)? Of course, one could help themselves by cooling only a small portion of your coach (well insulated and all that). Again, all sorts of specific situations where it works/doesn't work.

If A/C is required when boondocking, I am of the opinion that running a generator is probably the best solution.

[Brewerbob]

Originally Posted by Defjr333

I think he said in a different thread they were model # SPR-E20-435-COM.

https://us.sunpower.com/sites/sunpow...lar-panels.pdf

Can't say I'm a fan of their website. Thx. Finally figured out where to look to get at it myself.

$800 EXTRA in panels. Adding an additional MPPT $200-600. Adding additional batteries $200-$1000.....

This is the part that I need to research way moar betterer.

I'm ok with an extra $800 in cells. Hell, make it $3500 in cells. More batteries as a result makes sense too tho I've not looked at their costs.

I understand Ohm's Law and even square wave vs sine but the controllers, inverters/converters seem overly complicated. I'm not used to time in formulas either. Charging times, batteries %, etc. I just plug **** in the wall. If I trip a breaker, I run a larger wire and a bigger breaker.

Thats a LOT of fuel for a generator.

The sun and wind are free once you've bought the equipment. Even at a penny per gallon of fuel, the genny is going to cost more eventually. Sure you'll need to replace batteries oneday someday but same with the genny. You'll need fuel filters.

Hmm, wonder what it would take to convert my genny to a push button start. The only reason I have to use it is it's raining sideways. Not the time I want to go out and yank on a cord.

BUT, again, that is why we are all here.....to do it OUR way. It is possible, but for me not practical.
Doug

I think mine is fairly noisy, not terribly great on fuel, etc. Those (noise anyway) don't really fit in the practical bucket but certainly sway what you're willing to live with. And as you mentioned, everyone's pain in the a$s point is different.

[Defjr333]

I hear you on all those points. To me the replacement/ maint of equipment was far cheaper the route i chose. Panels generally good for 20 years, batteries not so much. On the low end of batteries are the Duracell GC2s they are 6V 215ah, so 2 make 12v 215ah, 8 equals 860h. At around $100 per battery (mine on sale for $78 ) That is a chunk of change that will only last 5-10 years. Inverters, chargers, charge controllers, they all go bad too. Just not as much of a certain window of time. The way I decided on mine was if any one or possibly 2 major components fail, I have one I can fall back on until I have the time or $ to fix/ replace. Just my mindset. If I had $ to blow, I could see 100% solar possible.
Doug

[Brewerbob]

Originally Posted by JDOnTheGo

I'm afraid I am one of those darn facts guys. The short answer, I don't know. The numbers answer: A typical 15,000 BTU A/C unit draws something around 15 amps at 120VAC (or 1800 watts). The problem is that it's duty cycle varies depending on the space to be cooled, the outside temperature/humidty, and how much it has to run to maintain the desired temperature. If you were to assume worst case, 100% duty cycle, then it would be about 1800 watts continuous. A clear day in an area with good solar insolation will yield something around 80% of rated panel output (maybe more, maybe less, depends how they are mounted/aimed/etc.). You'll need to include conversion losses into the mix and whatever the actual insolation is but, in theory, 2300-2400 watts of solar panels is enough to power the A/C unit. That said; one 15,000 but A/C is not enough for my coach on a sunny, hot day. I'm not sure exactly how much I need but I know 15k is not sufficient - two 15k units probably is but that is a guess.

Where's that Chris kid (Cadi-Kid); he's a sharp cookie with this HVAC crap.

Numbers: so 6 panels to run nothing but the AC. Ouch. 1) that isn't going to happen since even if it's daylight, there's the fridge and computer/tv to run. Fridge is another what 7 or 8 amps running plus (ignoring the compressor kick).

I never think of my solar panels directly powering anything. I think of the battery bank as a "fuel tank" - some things draw from that tank, other things fill that tank. That view is not entirely accurate but it helps many people keep things straight.

I get that part. I really have no idea why I make the solar stuff so difficult on myself. I should just sit down one day and read up on it. It's all electronics and ohm's law anyway.

The big PV panels can generally be found in the $1/watt range if you shop creatively.

Define creatively. Looking thru the internet for the best price I can handle. If you're talking about trading the used motorcycle and some labor with the guy that has a scrapped RV, I don't know that guy, I don't have a motorcycle, and my labor time is already eaten with the bus.

My opinion is that it is possible to generate enough solar power to operate A/C but I don't think it very plausible/cost effective in most situations. For example; do you need the A/C unit(s) to run ONLY when the sun is brightly shining (typically not - in many (humid) cases it is needed all night). If needed all night, you are talking about harvesting a huge amount of power during the day and having a huge storage system to draw from at night. How often do you need all this solar power (for A/C)? Of course, one could help themselves by cooling only a small portion of your coach (well insulated and all that). Again, all sorts of specific situations where it works/doesn't work.

So let me know when you have the AC, cooking, and laundry all sorted on solar and I'll just copy your system.

At this point and probably any time in the future as well, it's more academic than anything else. Having grown up in and lived in the SE heat and humidity, you'd think I could tolerate it more. I can NOT stand it. As the bus has wheels and I have nothing tying me here, I don't foresee myself wanting to spend Aug in the Everglades. Feb, maybe. Summer, not very damn likely.

If A/C is required when boondocking, I am of the opinion that running a generator is probably the best solution.

You, someone else, somewhere else (don't remember) said it; noise.

The answer is probably somewhere in the middle like Doug said. Run the AC in the worst of it for 3~5 hrs, wall off a separate section, etc. Even a bedroom with just a door would make a huge difference.


By the by, I don't recall but how well did you insulate your bus? Rigid or spray? How thick? You've got an extra 5' of length on me but likely more insulation than I will have so if 15k BTUs doesn't work for you, it won't likely work for me either.

[Defjr333]

Originally Posted by Brewerbob

Hmm, wonder what it would take to convert my genny to a push button start. The only reason I have to use it is it's raining sideways. Not the time I want to go out and yank on a cord.

I think mine is fairly noisy, not terribly great on fuel, etc. Those (noise anyway) don't really fit in the practical bucket but certainly sway what you're willing to live with. And as you mentioned, everyone's pain in the a$s point is different.

I bought this as a Christmas present to myself ( hey im single) LOVE IT!
Quiet, fuel efficient, and fairly inexpensive:
Doug

[Brewerbob]

Originally Posted by Defjr333

I hear you on all those points. To me the replacement/ maint of equipment was far cheaper the route i chose. Panels generally good for 20 years, batteries not so much. On the low end of batteries are the Duracell GC2s they are 6V 215ah, so 2 make 12v 215ah, 8 equals 860h. At around $100 per battery (mine on sale for $78 ) That is a chunk of change that will only last 5-10 years. Inverters, chargers, charge controllers, they all go bad too. Just not as much of a certain window of time. The way I decided on mine was if any one or possibly 2 major components fail, I have one I can fall back on until I have the time or $ to fix/ replace. Just my mindset. If I had $ to blow, I could see 100% solar possible.
Doug

Replacement/Maint may very well bite me in the as$. I tend to ignore those since you got 10 yrs out of your batteries and I only got 3. Sucks for me but doesn't get my batteries replaced. Point being $hit dies without looking at a calendar or checking to see if you're ok with it or not. Hence the redundancy.

I would need a fuel cell for the gasoline genny I have. I think it ran all night once on a single 5 gal tank. I can't remember if that was with 2 fridges or just one. In either case, I had my fish tank plugged into it as well. A 20 gallon fuel cell would get me thru a long weekend. Not exactly what I'm looking for. With money being no object, I'd like both systems to be 100%. Will I ever need 100% of either, probably not.

[Brewerbob]

Originally Posted by Defjr333

I bought this as a Christmas present to myself ( hey im single) LOVE IT!
Quiet, fuel efficient, and fairly inexpensive:
Doug

Yeah, I saw that. My 5500W is free tho. If I have to buy a genny, I'll get a diesel and be back to single fuel source. That's a HUGE plus in my book. I think $700 would get me a decent diesel genny used.

[Defjr333]

If you have other propane items, this is the company i went with for tri-fuel kit for my generator. Seems they are fairly universal.
https://centuryfuelproducts.com/gene...onversion-kits

LP appliances are cheap compared to diesel. Now I need to source a nice size tank(currently have 2 grill 20lbs tanks).
Doug

[Brewerbob]

Originally Posted by Defjr333

If you have other propane items,

Trying to avoid that but as you say it may just be so much cheaper than the headache is worth.

this is the company i went with for tri-fuel kit for my generator. Seems they are fairly universal.
https://centuryfuelproducts.com/gene...onversion-kits

Nice. I need the diesel, kerosene, gasoline option. Where's that? Space heaters work on kerosene.

LP appliances are cheap compared to diesel.

Tell me about it!! Same with the gennies; gasoline is so much cheaper than diesel.

Now I need to source a nice size tank(currently have 2 grill 20lbs tanks).
Doug

If I did propane, I might make the space big enough for a 40 lb horizontal (if there's such a thing) that I could get refilled. But most likely easier to travel with two, three, or even four of the 20 lb tanks. You can always stop at a Walmart for a bottle swap but can't always find a refill station. It's only going to run out when the forecast is for -10° and it's already Sunday at 7pm.

[Defjr333]

Originally Posted by Brewerbob

But most likely easier to travel with two, three, or even four of the 20 lb tanks. You can always stop at a Walmart for a bottle swap but can't always find a refill station. It's only going to run out when the forecast is for -10° and it's already Sunday at 7pm.

Cant argue that. I would retain the 20# for emergencies, just would like a larger "main" tank i should say.
Doug

[Robin97396]

The point is to have backups for your backups if you expect to remain comfortable.

Thank you guys for bringing up these points. This reminds me of the reasons for buying an easily repairable and common mechanical bus. The same would apply to generators. Gas genys are much less expensive and easily replaceable. I've also been leaning toward a diesel generator over the past several years, but a quiet gas generator would have a lower overall cost. It's pretty inconvenient to buy gas while I'm getting diesel, but I'll learn to live with it. Those diesel genys can cost as much as a bus.

[Brewerbob]

Originally Posted by Defjr333

Cant argue that. I would retain the 20# for emergencies, just would like a larger "main" tank i should say.
Doug

How big are you looking at? I've no idea what sizes they come in, whether you can get one custom made (but still cheap), etc. Ideally you'd want something like a 100 lb tank squished into a D shape with the valve on the end.

Originally Posted by Robin97396

I've also been leaning toward a diesel generator over the past several years, but a quiet gas generator would have a lower overall cost. It's pretty inconvenient to buy gas while I'm getting diesel, but I'll learn to live with it. Those diesel gennys can cost as much as a bus.

My gas one isn't all that quiet. I didn't buy it with quiet in mind and it was the only one available at the time. That said, are the gas models quieter? I've never been around a diesel one that I know of. I think the diesels are supposed to be more fuel efficient. They are pricey even used. I'm not sure I've seen one for less than $600~$700.

[Brewerbob]

Well looky there. There are horizontal tanks for RVs.


The price difference between a 30 lb and a 40 lb is one hell of a jump. On two random sites the 30 lb is $170 and the 40 lb is $400. I guess with a store bought RV you get whatever they give you whereas we can customize more. But for those prices, give me two 30 lbs, I'll have more gas for less and a backup to my back up (2x 30 + 5 grill).

But speaking of custom, if you were to build an outside closet, you could do a vertical tank and not worry about horizontal.