How would you do a Split System like this?

[PsycoGeek]

The Task:
I am about to pull a small Travel Trailer, for long time, but not "full" time RV traveling, just almost full time, with the intention of it being self powered.
I am thinking/calculting the way I will assemble and operate a solar system that at least the solar part is split, because it wont all fit on a small trailer without issues.

The Vehicles:
Van with ~2-300watts of solar on top of it, small Travel Trailer with ~2-300watts on it, eventually adding portable setup solar with the ~200Watts extra/backup.
~200-300amps of 12v battery. ( it is not a 5th wheel or motorhome, but highly seperated items)

The Voltage:
12V which sucks because a system like this should probably be 24v, but too many items are already designed for 12V, and availability for 12V at any auto parts store is easy, finding 24v things is more truck stop type of items, which is plentifull also, but not as plentifull. So it is 12volts and that sucks but that is how it is going to start out.
The solar itself assuming the right charge controller (I assume) could be higher voltages, but , that is not ideal (imo) either because shade blocking parts of any pannel or series of pannels means no power from the series set. Seperated 12V (and 12x2) panels any one of them or half of them could be shade blocked cloud blocked or outright broken cell items in there and I still get some power. Conversion from 24 to 12 , yes it is know how that can be done, but for the purpose of this question 12V is a given.

The arrangement?
So sticking (at least for now) with 12V being generated in one towing vehicle, with or without 12V storage batteries , and trailer items with 12V solar being generated and with or without storage batteries there also.

Take 2 Thier Small:
These combined solar generating, and either combined or seperated battery storage systems, then the power itself is used in only 1 place, the trailer. There will be no high use of the generated and stored power in the towing vehicle.
The towing vehicle would make trips without the trailer, that can last ~1/5th of the total sun time, which might be enough concideration to have battery storage in the Van , and the trailer too.

The Storage:
The batteries, are likely to be li-fe-po4 type. I actually intended to use only 100A units then 2 of them to start out.

Now let's waste it all:
The use of the power would be to run a full gaming desktop computer , instead of a laptop. Gaming computer will utalise new technology (14nm and large disks and ssd) to keep it under ~400watts max. AC based now. Air-conditioner, likely a AC air conditioner of a lesser wattage type.

Options:
Well there is microcontrollers that could motivate the power at higher voltages, then I become my own PG&E with "high voltage" transmission lines but this is the question, so what are the possible options for a situation like this? Be it dual storage or single, it is dual and longer wire seperated solar generation. Efficency and loss are a concideration, because much of my other projects have very little wastes, and very little heat comming out due to wastes.

The other question:
Where is the gas generator that is designed for quiet and has a 12V charging capability that is of the 100Amp type for charging the storage system quickly during couds and all, Because generators are a Bane to peace, so i would prefer that it be used as minimally (in time) as possible.

Multiple different opinions are welcome, debate is also welcome, name calling and personal herassment is not welcome at all. Thanks.

[Mike90250]

A small, quiet inverter generator like a honda EU1000 or EU2000 could power a mains battery charger to recharge the battery. There are few 12V generators, unless you build one yourself from an old lawnmower engine and automotive alternator.

[PsycoGeek]

Ahh building it myself again, why does it always come to that
3.5-5Hp horizontal shaft engine, super muffler, ratio on the belt drive for the right rpm. Premium build alternator, wonder if there are any with real ball or roller bearings now? Disconnect the (power from) the alternator for starting? or centrifugal clutch? Probability of me making the prototype correct the first time zero, probability of things flying apart before 10 hours run

The conversion losses for a AC to DC charge might not be terrible but the added chunky converter/charger would add lots of un-nessisary weight, , unless it also served the purpose of feeding the power from one vehicle to the other also somehow. Once a real plug-in grid is reached (when at a RV park) speed charging is not nessisary.

If a speedy AC-->DC charger for the batteries is needed, one of the ideas that reels in my head, to have the Van (tow vehicle) to be a portable grid of its own, to be plugging into the van as the "grid" then have sine sync (complication) where needed.

[Mike90250]

here's a decent conversion guide

http://www.ki4u.com/webpal/b_recovery/3_alternate_energy/electricity/lawnmower/generator/generator.htm

and Balmar makes some really beefy alternators http://www.balmar.net/ but a decent alternator from a full size pickup generally has 100 - 150A alternator

[emartin00]

Both the Ryobi and new Generac inverter generators have 12V outlets.
As for the solar, you can only fit 300W on the camper? Is this a small camper?
I think what I would do is make a small folding rack for more modules. You could easily store it in the trailer, then pull it out and position it in the ideal location and direction when you stop. You could keep some permanent ones on the roof as well for travel times.

[PsycoGeek]

Yes all the portable generators have some minor 12volt output, I assume they are generating high voltages first, then tossing in a simple power conversion for the 12&5 volt just like you would do from an AC plug? If my purpose for the generator is to recover an 80% charge on the batteries instead, it seems to me like it would be more efficient to generate at the lower voltage , do a simple AC-DC convert (the diode bridge on the alternators) and have less conversion losses? I do not know for sure, but much of my experience/experiments/testing has showed that the losses from these conversions are always more than the specs say, and Up-To doesn't mean a lot.


Ok now I am rambling . . .
We also get a lot of convert then convert again, take the example of charging the modern tech device batteries with solar, which does not even work well direct usually because of the sporadic solar output. Assume a small 12V solar system used for charging a cell phone or GPS unit.
18V (max) solar convert to 5V at a loss, then into the phone charge circuit to a battery that maxes out at 4.2v . Not bad right, 2 simple converts with claims of high efficiency. I took one panel out of a system like that 6V, traded the lossy diode for a hexfet and photo diode for fet switching, added in overvoltage protection which is mosfet, bypassed the 2 conversions. Results 2Amp charging from 1/3rd the system, yea that bad, because it was designed for only Me and only 1 Purpose, for only 1 device. Now a 1 foot square of great solar was enough power for non stop operation. In that project I tossed 2 middle men, and slammed the solar direct to the battery.

What is the real efficiency:
Because I do not have a 2000-3000 watt inverter, or 80amp charge controller yet , I have not yet tried to analyze their efficiency and losses. But if heat is pouring off of something, and they say it is 97% efficient, and it has heat sinks the size of a bus, and it is hot to touch, how many watts waste do you figure that is?
sooo many things I do not know, but 2amps draw for zero actual conversion (an inverter just on) in 2 days is the end of the stored energy.

not saying I am an expert, in fact I am just Don Quixote https://en.wikipedia.org/wiki/Don_Quixote taking a run at off-grid. I am claiming there are losses everywhere that some can be avoided. I am hoping to not pay the $3000 first to find them, the people on this board knows much of that information already. The total solar, the azimuth, the one size fits all controllers, the inversions and conversions, what to do, what to do.

[PsycoGeek]

Yes my choice is a trailer that is smaller than 19' like 16' for the box, a one human type, something easy to navigate around places. I had lived before in a very small like teardrop sized trailer before and the internal size did not bother me, because there is the whole outside too. I have not done measurements on the possible choices, but they often have the AC clunk on top, something that makes no sence to me either, as the ac unit is in the sun, and the fan is closest to your head. Ohh we gonna try and do something about that craziness too

On folding solar panels, and the weight problem. It is not efficient to haul 300lbs of solar & wind resistance (and azimuth tilt). I was looking into the full efficiency type "bendable" or low frame type mono solar panels, weighing more like 5lbs for 100watts instead of 14lbs. One person framed them with heavy PVC, that was interesting for sure. making lightweight foldables, that get put away if a storm comes.

From much reading and reviews, these lightweight but still glass cell type of panels are micro-fracturing breaking and even breaking to a hard short. Can a person have their lightweight cake and eat power pie at the same time, by redesigning the solar panel one more time?
Ideas on creating a foldable full power but lite panel set, that has no weather resistance (for hot and calm), and be able to easily store/stack without breaking while bumping down the road. The gluing of a panel that is prone to failure to an expensive surface like the trailer or the truck, seems stupid , the labor to remove the mounting or foam tape or whatever would seal it down to a surface, is more craziness.

[ewarnerusa]

OP,
It seems you're thinking outside the box which is of course commendable and you could come up with something really cool. But I'll offer the following because it seems to me you're reinventing the wheel.

It seems to me you're buying/using a manufactured camper. Any modern camper REQUIRES a 12V battery system to operate, and for towing to energize the emergency braking system in a situation where the trailer becomes separated from the tow vehicle. Of course how you make 12V (1x12V, 2x6V, 6x2V, etc.) is up to you, but the appliances and lighting operate off of 12V. So it doesn't make sense to describe a camper system that doesn't have battery storage system. The camper will also have a converter on board that acts as the battery charger when plugged into shore power. These are often WFCO brand and are notorious for not actually performing as the 3-stage battery charger that they're marketed as. They don't go into 14.4V "boost" mode at all, they just cruise along at 13.6V which doesn't do a good job of recharging batteries in a short amount of time. bestconverter.com offers several different replacement models that do a good job at actually achieving the absorption charging voltages you need to get recharged in a hurry. I recommend a nice inverter generator and upgrading the onboard converter for a quick charging system, not building your own 12V generator. A common practice is to use the generator and converter to get your batteries up to 90% SOC by early morning, then let solar work on them the rest of the day to complete the charge. Of course this is for lead acid batteries since they're still the norm. I don't know how lithium batteries change the charging parameters, but I've always heard that bestconverter.com offers terrific support so I'd talk with them about what converter would work best.

As for solar on the tow vehicle...you say you'll be pulling the trailer a long time. So just use the 12V already being generated by the vehicle alternator and maximize that charging path. I don't think adding solar to the tow vehicle would be worth it when the alternator makes so many amps already.

Throw 300-600 watts of higher voltage panels on the roof of the camper, get a nice MPPT controller, and you'll have your 200 Ah batteries well maintained.

[PsycoGeek]

Manufacture supplied junk:
Yes, It would figure that the built in stuff would be enough to do a normal job, but not enough for what I would hope to accomplish. Some people keep both systems, or have other redundancies, like extra heaters , added controllers and converters and chargers, and this and that. Then maintaining any usable warranty that comes with a new one, means you can not up and change things without companies and dealers and repair using those changes as an excuse to not fix the original failures in manufacturing.
It wouldn't be the first time for me to toss the warranty 2 days after testing something, which means I might be better off with a cheaper trailer there is no warranty left on it., For me I do not see it being practical to have loads of extra stuff if I can avoid it, or transistion stuff, more research into single correct things, then getting by without some stuff some times.

So what controller and inverters would you recommend?

Lite load ahead:
My intended tow vehicle which has free miles available (old in time young in miles) limits the tow weight , then I will be shifting from a whole life with all tools and gadgets and every part and piece to be able to build something, to mobile. The li-fe type system would dump some of the weight, while I up the amperage. so at a huge cost in some lightweight stuff, I save big money in not buying a better tow vehicle, and getting worse gas mileage with it.

Generating power - costs, wherever it occurs:
My problem with running the vehicles engine to generate power is , compared to the solar at least, pouring gas into power does not beat the "grid" .As humans driving we perceive that the engine is running, and the generation of power off that engine is therefore free, the work done moving the vehicle is far more power than the drain from the alternator.
Instead I had experience with a car (metro) with a 50HP engine, and the alternator and the air conditioner , which we take for granted on larger vehicles demonstrated there a huge drain on the engine and the MPG. While nothing is free, generating loads of power with the vehicle has big cost. With the metro I could turn off the AC to make it up the hills, I converted all of its (minor) lighting to led to reduce the loads. Same thing here, until I destroy and finish off the used tow vehicle and replace it with a beast that 50amps draw is a mosquito , the vehicle engine is a bad choice for additionally being the power generation.

But I see what your saying, get enough solar and some good controller stuff and I would be set. I would, then I am going to try the neer impossible trying to keep an AC unit going (California Arizona Nevada), off the solar, with as efficiently insulated and sun shielded trailer as possible. That part is a consideration now, but due to the problem it is , it will be a later thing to solve.

Li-Fe variations:
13.6v is an ok stopping voltage for li-fe, according to my experiments. a bit more complexity if it is to be balanced, but that is an ok range for it, and it stopping at 10.5v on (the worst) discharge would be ok for the low end as long as there is not a huge imbalance of cells.

Either the chemistry selection for li-fe was purposeful to match well the voltages of your usual lead acid stuff, or if it was adopted quickly to that use because it does match so well. 4 li-fe cells to the 6 ~2volt cells in the lead. So that is kinda cool. (3.6v li-ion did not match as well)

A big difference in the li-fe is the resistance can be lower , especially on a new or well maintained pack, so an accidental short would go from a few sparks and a hot wire, to a melting contact and a red hot wire. And some other considerations which some manual observations and corrections would handle.
What would be handy in the manual adjustments , and controllers and all IS being able to select some minor voltage variations, even if that is an added cut-out relay.

Given fancy charge controllers , which of them allows for at least some variation in at least the max voltage charge levels?

[ewarnerusa]

Morningstar Tristar allows for fully programmable charging parameters, including max charge levels. This is offered in both the MPPT and PWM version of this controller. I'm running the PWM one. I'm sure that other brands offer programmability, but I only have personal experience with the Morningstar Tristar PWM.

[ewarnerusa]

I never replaced my WFCO converter because solar has done the job for us. If I was a full timer, I would spend the $200 for an upgraded converter so I could use our generator to get some useful bulk charging done in a hurry (few hours) if needed. But since low and slow solar has kept up with our battery use while we're out weekend warrior camping, I've never bothered to to this. I don't even bring the generator anymore, it isn't strong enough to reliably run the rooftop AC which is the only 120V AC appliance we would want to use that the battery and inverter can't already handle. Our generator is a Yamaha EF2400iS, which is a really nice quiet inverter generator. It offers the 12V charging you mentioned, but Mike90250 is right that it is low amperage and generally useless. Even the OEM WFCO converter does a better job of battery charging than the generator's 12V feature. Honda and Yamaha own the market on nice quiet inverter generators, but Champion is also mentioned as a lower cost alternative. 2000 watt models are adequate for most typical battery chargers/converters. They are relatively lightweight and easy to use. But unfortunately not strong enough to reliably run a standard RV 13.5kBtu air conditioner. Most of the inverter gens can be paralleled with a second so you can get the power needed to start the air con compressor and that is a common route. But then you're dealing with 2 generators to operate and maintain, although you only need one for most power needs until you decide you want to turn the air con on. The other option is moving up to a 3000 watt or higher inverter gen which are larger and heavier and more inconvenient to move around.
Since I've never upgraded our converter, I don't have any first had experience to base recommendations on. But I know that Progressive Dynamics with the Charge Wizard is spoken well of, as well as Iota brand converters. I don't know of converters that offer programmable voltage set points.

[ewarnerusa]

http://www.bestconverter.com/9200-148-Volt-Deck-Mount_c_227.html

Looks like PD converters are now offering models that bulk charge to 14.8V instead of 14.4V. 14.8V is the recommended voltage from Trojan who make the much touted 6V golf cart batteries that campers like to wire in series for high capacity deep cycle 12V use. Again, I don't know if this relates to lithium batteries at all. But it is another promising option for getting a quick charge from a generator/shore power.

[Mike90250]

The trailer brake battery is supposed to be isolated from the rest of the trailer electrical system.

The 12v outlets on generators is quite limited, generally 3-5 amps is all, just for recharging a small battery, not any good for charging a household battery bank

[ewarnerusa]

Same battery as far as I'm aware of. Brake power is wired to the resettable circuit breaker located close to it. Main power feed to the rest of the trailer's 12V system is also wired to this breaker. So same battery, but the breaker is where the systems are isolated from each other. Hitching up the trailer includes attaching a cable to the vehicle that is attached to a key system on the trailer tongue. If the trailer were to separate, the cable would pull the key out and the trailer brakes would engage. A cargo trailer must include it's own small emergency battery for this. But both campers I've owned, as well as others I've been around, shares the same battery.

[PsycoGeek]

ewarnerusa thanks, that makes sense. Another factor I am going to have to be careful of, if changing the battery is going to change the load there due to the slight change in how the li-fe battery would provide power to that load.

[ewarnerusa]

I'm not quite sure I understand the concern. I believe the full amp draw on electric trailer brakes is in the neighborhood of 15A, it doesn't matter what 12V source is providing it. When the trailer is hooked to the vehicle, it is basically getting this power from the vehicle alternator and only full amperage during full braking. In the event that the break away key is pulled out and the electric connection between the trailer and vehicle is interrupted (like pulled out due to trailer on the loose!), then the power for engaging the trailer brakes is coming from the house battery on the camper. 15A shouldn't be a problem for any camper house battery setup.

[PsycoGeek]

to ewarnerusa The li-Fe battery has way less resistance. so while a regular lead acid would droop a bit in voltage, in either direction (load or charge) the li-fe doesn't as much at all. Of course this also depends on the wiring and resistance through the whole system. Take an example of tossing my car type battery charger on it, the 10Amp charger hits 15amps and isn't about to cool out from that, whereas on a LA it might peak at 12 and drift down.

Because of this people up and swapping out a LA for a Li-Fe into the place of a regular car battery, they have methods to add slight resistance so the alternator doesn't get driven too hard. you could toast an alternator by changing the battery and not taking into consideration how the battery acts.

sooo, I have to wonder if sending power to a braking system that is expecting a weaker power source, and instead the battery does it with gusto how that would effect the braking system, and calibrations for the brake controller and the other 20 possible things I have to account for before just tossing it in. Most of them easily mitigated by 10+ feet of low grade lossy wiring that might not even be copper anymore.