800W Solar Powered Sprinter Conversion. (pics)

bee · Feb 22, 2013

There is a guy who is building a 1000 watt solar system on his tavel trailer.  He uses a different kind of efficient house ac unit that doesnt mount to the roof making more room for panels. It has a split condensor and evaperator system, it was pretty cool.  I don't remember exactly how it mounts but if I can find the link I will post it up.  He would have first hand experience on how much supplemental charging he needs in addition to solar.  This is his second build so he has real world experience. Assuming you will be running the engine for a reasonable amount of time each day I would really consider the high amp charging ability of agms to be your friend. AGM batteries can have thick plates they come in all shapes and sizes.  Their bulk charge rate is through the roof fast.  Quality agms are basically limited on their bulk charge by the charger not the battery. The more I think about it I would look into a 2nd high output alternator 200-300 amps and have it only feed the bank. So the original alternator charges the start batteries and the 2nd alternator feeds the house batteries.  This way you can use a smart multi stage regulator on the 2nd alternator to maximize charge efficiency.  For example a smart regulator will allow you to compensate for voltage drop in addition to having different voltage levels for bulk and float.  Unfortunately this would not be a cheap option. Another very expensive option would be something like an onan diesel generator the new ones are supposedly pretty quiet.  You could have it set up to auto cycle on and off based on house battery voltage.  Probably could have it setup to cycle the engine instead removing the price of the generator. I guess it all comes down to how much you plan to run the A/C unit.  If you plan on running it a lot I would not expect the solar to keep up. Were you going to insulate to keep the cold air in?  That will reduce head room.

rokguy · Feb 22, 2013

ickkii, Looks like you might have to stretch this Sprinter. <IMG class="emoticon bbc_img" src="/images/boards/smilies/smile.gif"><IMG class="emoticon bbc_img" src="/images/boards/smilies/smile.gif">

ickkii · Feb 23, 2013

rokguy A guy who gave me some advice earlier on over at vandwellersteve.blogspot.com has an alternator setup very similar to the one you just described in the electrical section. He seems to be a bit more enthusiastic about it than you are though. So from what I understand there are a few ways to do the alternator setup. 1.) A battery isolator like you mentioned 2.) An alternator regulator - http://baymarinesupply.com/store/sterling-proreg-b-alternator-regulator.html 3.) A battery to battery charger - http://baymarinesupply.com/store/sterling-b2b-original-121250.html The last one I don't think I'll be using, it was in my original power plan I posted but now I see it's not going to be good for my starter battery. So that leaves me with the other two methods. I started this project initially with an e-350 in mind and decided to go with a sprinter because I'm seeing more and more of them popping up in town for small businesses. Even the standard roof is still a big step up over the ~50 inch roof in an econoline, and I've talked with some guys who've modded their sprinters (in AU like you mentioned) and it seems like their only regrets are that they can't convince their wives to stick with it longer haha. You have me interested in those low heat panels, heat is energy loss, so I'm going to check into these for sure. If it seems like I'm planning a lot it's because I am. I want to make this a smooth transition and make sure the money is used to it's highest potential. I've got about 7 more months of saving to do, 5 of which are behind me - and it's something I want to think about before blowing a years worth of savings. I'm sure you understand. I appreciate you mentioning the consequences of overplanning, but I assure you - I don't have it in me to work paycheck to paycheck to afford an apartment. This is going to happen regardless. Also for stretching the sprinter, as much as I'd love more space, I drive a tiny honda civic, so it could be too much of a shock to drive a miniature bus around on the 170" WB sprinters. All it takes is one accident, and it could be costly in more ways than I can put a price on. A standard size unit should be sufficient, and stealthier. bee A kilowatt! This is what I wanted to do initially but had to drop it down to 800w to fit a fantastic fan vent and some wireless cameras. As for the house ac, most of them are going to get some kind of inverter loss assuming you mean a window unit. Even a low watt 500w will cost additional watts over ac with a modest 9% inverter loss. 550w is just not manageable 8 hours a day, even if I could manage to cut even with power loss - it would cycle the battery bank too much, and that doesn't include the surge for it to kick on and off. I'd be curious to see if he did anything differently - have a link or something? The other idea, the split ac air conditioner would be perfect. 12v and under 35 amps at max cooling, it's small in size, and built just for my purpose. The problem is that they run over $3,000 and while it's perfect, the cost is really steep considering the rest of the initial investment on the project. Perfect may be a bit of a stretch with a split AC system, because with a roof covered in solar panels - it would have to go on the back door - making the hoses more vulnerable, and the expensive unit at eye level with cops or potential thieves. While the AC I linked in the first post isn't much cheaper at $2000, it consumes less energy, and I can rest assured it is made SPECIFICALLY to cool a sprinter. That, in addition to being mountable to the undercarriage, makes it the best candidate so far. The peltier cooler/heater I mentioned in the original post still kind of intrigues me. At 300w a unit, 12v dc, and a 250-500 cost, it could be a gamble that pays off. I've seen them make ice cubes in 30 seconds - but cooling a larger area could be a completely different story. I have experienced passive and compressor based cooling systems, I can't say the same for thermoelectric air conditioning. AGM vs Lead-Acid is more of a battle between fast charging vs longevity for me. What one gets in one area, the other one loses. Since I have planned a few different power sources, I think longevity will be more important. AGM is safer, LA is more Ah for the dollar. I want to try to avoid too much of a debate about AGM vs Lead acid because it's an ongoing argument even to this day, I think what matters comes down to looking at the strengths and weaknesses of each technology - and determining which suits personal usage best. I am curious about a second alternator now that you mention it. I think that's what I'll mostly be researching into tomorrow. I'm more of a computer guy than a car guy, so this is a vastly unexplored area of electricity for me.  I have been building more of an appreciation for vehicles the more I understand what goes into them. The generator sounds pretty neat too, I'll put that on the list of things to check out. The AC will be ran 8-16 hours at most, only when fans can't cool the van. I can get out of the van for at least 8 hours for most days. I have quite a few insulation ideas, cork floor, some of the heat/sound isolating materials I've found to line the van around the internet, specialized paint, among others.

ickkii · Feb 23, 2013

on the topic of lead-acid batteries, further research has showed me that there have been external catalysts that can be added to battery vents to create water from the hydrogen fumes. This is an independent water recycling system. Thomas Edison patented this technology some 100 years ago. http://www.battcon.com/PapersFinal2008/ODonnellPaper2008PROOF_6.pdf here is an example! http://www.hoppecke.com/products/accessories/aquagen_r_premium_top now I just need to find out where to buy them, no ventilation for the banks will be necessary as these have a 99% recombination of hydrogen into water to give back to the batteries. It is marketed as maintenance free for the lifetime of the battery. Checking the electrolyte may still be necessary just to be on the safe side. Quite the find huh? no excess power, water, or holes in the van necessary.

rokguy · Feb 24, 2013

ickki,  As a said, if you do alot of driving (every day) there is nothing wrong with any alternator / isolator setup. If you do a lot of driving.!!  I'm probably negative towards these cause I don't. Good luck with your project. Geoff

wrcsixeight · Feb 24, 2013

I also considered the second alternator idea for a while.  My ac compressor is basically just a Big heavy pulley and will never be returned to service. My issue is my Dodge's voltage regulator is in the engine computer and much too early it drops the voltage to 13.7 while the batteries were still happily drinking in higher amperage at a higher voltage. This internal engine computer voltage regulator is also the reason I gave up on the idea.  I was not sure how a separately regulated alternator sharing the same grounds would effect the engine computer.  Perhaps no big deal, perhaps a big expensive  deal/mistake. It wasn't worth the risk, and I find often that I try to make improvements to things that are not ideal, but not a huge problem either.  Getting a second alternator properly aligned and regulated and not fighting my engine computer was too many possibilities to end up in an expensive, embarrassing, tool throwing curse fest, to which I have been prone to in the past and usually when only seeking a small improvement in something not really important in the long run anyway.  And when it comes down to it, it was easier to add more solar, and further upgrade the existing alternator charging circuit with a direct feed to the battery switch and thicker ground cables to my shunt, and from shunt to batteries. The premature falling to 13.7 is just something I will deal with. The water miser cell caps available for years have many people that speak ill of them, saying they worked great for a year, and then looked again in 4 months and the batteries were half dry and ruined.  The catalyst used previously, perhaps currently, does not last forever and those claims of lifetime sound too good to be true.  Also those AquaGen caps appear to 4 to 6 inches tall.   I also think the AGM's higher rate charging profile might also be overstated by those who spent the considerable extra for AGM and wish to justify the added expense.  My flooded batteries can't be called healthy at their age, but they can still ask for everything my alternator can make when they are thirsty.   They were pulling 50 amps each the other morning.   I think the true benefit with AGM is the low self discharge rates and the no maintenance and higher CCA ratings, if used to start an engine, or power huge loads.  They weigh more for the same rated capacity, cost twice as much, and many claim they do not last as long as a good deep cycle flooded battery that was not  chronically undercharged, or let to run low on water. Look into mounting batteries under the van.  It greatly opens up interior storage space, adds to safety through both lower center of gravity, and not having batteries in the passenger compartment. Have a look under a sprinter and see how much height you have to work with, and decide how much ground clearance you are willing to lose. My flooded group 27 12 volt batteries are 9 1/4" high to the top of the terminals. Golf cart batteries are a few inches taller. The bottom of my battery box sticks below my body 1.5 inches or so,

and the hatch cover comes within a half inch of the battery terminals.  While I lost some ground clearance on the side of my Van, the transmission pan and exhaust still hang lower, so it would take some serious trail riding for ground clearance to be a factor for me. But I have gotten my Van into some tricky places where momentum, ground clearance and knowledge of where my tires were got me in and out safely, with only slightly soiled underwear. Many different ways to get the alternator to contribute to the house batteries.  No one best way,  but adequate cabling is the hallmark of all effective systems, and Diode based isolators are in very few effective systems.  Look into Blue Seas ACR latching voltage sensing relays.  One of these models and a Fat cable from ALT(+)  fused properly there, running to the engine battery, and fat cabling from engine battery to The Blue seas relay and then to the house batteries is about as good as you can hope to do. http://bluesea.com/products/7620 Though I prefer single sensing.  I don't want solar amps bothering with a fully charged engine battery, though it likely makes little difference with a lot of solar available

ickkii · Feb 24, 2013

The video on this products page suggest this alternator regulator may help with engine computer issue, but it also has a disclaimer for some modern power management systems. http://baymarinesupply.com/store/sterling-proreg-d-alternator-regulator.html I have actually considered a sunken battery bank, but I need to get a better idea of what the undercarriage of the van will allow for. I need to keep some room open to mount the ac to the bottom of the van as well. I keep meaning to get around to car lots to get some better ideas for planning something like this out, but I've been caught up with higher priority research. I'm not buying the van for a couple of months because I'm still saving to cover the initial cost of the power system. My bigger problems with sinking the bank is that of gas mileage and driving over puddles. It would also be ideal for me to put as few holes in the van as possible for the sake of potential resale value down the road. It's something that has me torn. As for the recombination plugs, I have found pricing - roughly $340 for the bank. Considering no fumes will escape and it will lower watering cycles, saving me power from ventilation and money on distilled water over the course of the battery lifetime - it's a hard bargain. Ultimately I think I'll go with it because trojan t-105s have a 'hydrolink' watering system with indicators for when the electrolyte is low, so I'd get a better feel for when replenishment is necessary. I'm not the type to let a product description give me a complete sense of comfort with such a large investment at risk, I'll still be doing routine checks on the battery regardless. At the end of the day it should greatly reduce maintenance whether it be months or years, and address the safety concerns, so it's something worth utilizing I think. http://www.nwcomp-solar.de/epages/N...ctPath=/Shops/NwCompSolar/Products/S-10-00014

bee · Feb 24, 2013

I couldn't find the page with the trailer with 1000watts of solar.  I will post it up if I come across it again.  I did find the air conditioner setup he used.  This might even be the same model  http://www.totalhomesupply.com/Ductless-Mini-Split-Air-Conditioner-Inverter-p/friedrich-m09ch.htm I have no idea how you would compare efficiency to the a/c you found.  Let me know if you find a way.

ickkii · Feb 24, 2013

I'm seeing 'inverter technology' which has proven to be a no-go from similar air conditioning units I've found in the past. Basically these coolers tend to have their own dc-ac inverters for the compressors which results in inverter loss. It's kind of against the point to use an inverter for something meant to run on dc, because you could just look for ac powered cooling and achieve the same results. With a 1000w system it can run, but probably not as efficiently as a 100% dc unit. The DC unit I found is efficient, but expensive. You'd think ACs with lower cooling capacity would be cheaper lol. I did check out your solar link you posted earlier on. May I ask where you found it? The problem with that spreadsheet is that it doesn't cover any panels 30 inches wide and under, so I'd have to put 3 rows of 60 inch long (200w) panels, leaving 2 big gaps on the sides of the fan vents. If there's something like this for smaller panels it would be pretty useful. If you see the way I had 3 rows laid out  with one panel missing from the center of the 3rd row for the fan vent, you end up getting more power off the smaller 100w units because you can fit more of them. Today I'm trying to figure out chademo quick dc charging to see if it's possible to use charging stations to replenish battery banks. My buddy suggested renting a cheap storage unit for a personal wall outlet and homebase, but if I can figure this out that won't be necessary. Documentation for this type of thing doesn't seem to be widely available for uses outside of hybrid vehicles. After this I'll be jumping back into the capacitor banks.

wrcsixeight · Feb 24, 2013

Perhaps some research into fuel cells and their current capabilities is warranted, since many other emerging technologies have been explored in this thread  

bee · Feb 24, 2013

What you have to understand about that A/C unit I linked to is that it is designed to run on 120v.  A/C motors however do not like to run at variable speeds.  So The way I read it is they are converting 120v A/C current to D/C current with an inverter.  This allows them to finely vary the dc voltage which in turn varies the RPM of the compressor.  By varying the compressor speed instead of cycling it on and off like a standard A/C unit they increase efficiency substantially.  This can be seen when comparing SEER numbers between it and a standard A/C unit. So their is no question this is an extremely efficient setup for a house, but now you have to have a large inverter to convert your battery bank to 120v.  At high loads even the best inverters will be around 80%-85% efficient.  I have not tried to figure out wether that negates the efficiency increase or not. I would probably look into what those seer numbers actually mean and do a comparison between this high efficiency unit and a standard wall mount.  A standard wall mount uses the same technology as a 12v dc system.   So you could put a % figure on the efficiency increase.  Then subtract inverter efficiency and see if you end up ahead or behind.  Of course the only real way to know is to actually compare to working units.  Don't know if that made sense. Ideally you would want a variable compressor speed unit designed for 12volts, I do not know if that exists. All the information I have on solar panel dimensions is from this post.  I am rexx on that forum btw. http://www.wind-sun.com/ForumVB/showthread.php?18398-Search-solar-panels-by-dimensions

ickkii · Feb 25, 2013

I have read about fuel cells when I was looking up LFP batteries, there was a site breaking down the competing power storage technologies and LA / Fuel Cells were among them. They did make lead-acid out to be a bit more inefficient than it actually is (they attacked fumes but left out cost efficiency), probably for the sake of marketing, but what was said about fuel cells resonated with me. They are more difficult to refuel than typical batteries as they're more of their own source of power and dealing with liquid hydrogen can make maintaining them more of a hassle. It's also a bit more dangerous to be transporting these chemicals around for an extended period of time. Bee This ac unit is truly odd, it's marketed to be highly compatible with solar - but the power specs seem to go back and forth against that lol. The pdf I just looked at has all of their products instead of just the ac, and it looks to be a house ac because most of these diagrams are showing that they specialize in grid connected solar systems. No doubt, a 600w ac is SUPER efficient for a house, an array over a kW in size can definitely eat a chuck of that. But 600w x 8 hours = 4.8kWh. Seeing as my solar output is limited to about 4kW on the sunniest of days, it would take a grid connection or help from the alternator, just to power the ac. Don't forget the TE refrigerator & cameras, 62w x 24 hours = 1.488kWh,  (absolute minimum consumed when the van is empty) leaving me the rest of that power to go for computers, fans/vents, lights. The AC is always going to eat a ton of power no matter which I get, but I need to try to keep it around 300w max per hour to get 12 hours a day of usage, so basically under 12v 30a. This over-accounts for what is actually needed so the power system is a little more excess of what is required. So these 12v 30a ambulance units can give at least 8 hours of day use on really hot days. Enough to go to work, hang out somewhere after my shift, then come back to the van to sleep comfortably at night. It's only really hot days that this is necessary, most of the time running the fan / roof vent will be enough, perhaps even on hot days if my power situation permits it I could still even chill (no pun intended) in the van after work. On hot days there's going to be more sunlight, and this is really only considering the solar panels as a power source. The alternator will be giving a helping hand here and there, so I should always be over my consumption levels. It's also good this way because 4kw cycles on a 10kwh bank doesn't go under 60%, which gives slack for cloudy days so cycling under 40% battery doesn't happen frequently in this situation. The ambulance units are where it's at I think. I've never been in a hot ambulance and the power consumption is built for it.

ccbreder · Feb 25, 2013

"This internal engine computer voltage regulator is also the reason I gave up on the idea.  I was not sure how a separately regulated alternator sharing the same grounds would effect the engine computer.  Perhaps no big deal, perhaps a big expensive  deal/mistake." The alternator failed on my dodge because of the computer. An after market regulator was easily connected and all was fine.

peacetara · Feb 25, 2013

I'll just mention 2 things, overall, around cabling and fusing.  You want to size cable for each individual run.  You then use a calculator, and it will tell you how much you need.  The online calculators will have a % loss, 1% is ideal, 3% is about as much as you want to go.  Use the calculators, and save yourself possibly overloading your cabling.  Secondly, for fuses, you always size fuses TO the cable.  I.E. an example: Say you sized your cable for 25amps, and you installed it, then your fuse should be a 25AMP fuse, because if you are maxing out your cable, then you want the fuse to blow, so your cable doesn't melt, or catch fire.  that's the whole point. The other thing I wanted to mention, I'm guessing with all of your 'needs' like AC, you will be looking at a bunch of money, you might think about just buying a ready-made solution, like the Airsteam Eco model.  Airstream now makes a 100% electric Sprinter van.  (the go go part is still diesel).  They include solar panels, etc, fuel cell system optional, and have a heater and air conditioner built in.  No propane.  I've never seen one in person, but I'd love to see one.  I'm sure the price is downright scary tho.   I have no experience with sprinter vans personally, but I'm told the maintenance costs on sprinter vans are horrendous. Regardless, I wish you lots and lots of successes! With Love, Tara

rokguy · Feb 25, 2013

Yes, Tara, thats the only problem with these vehicles is the maintenance. I've heard this several times now. being a Mercedes Benz you pay a premium for parts and service. Geoff

bee · Feb 25, 2013

So I was looking over that A/C link you posted on the first page.  I am pretty sure those add a compressor to the engine.  They do not work unless the engine is running. Yes the split A/C units are for houses.  From what I have read as long as you mount them so the fan isn't turned by the wind while driving down the road they work fine in mobile applications.  There is (no joke) a 52 page thread on them over at wind-sun.com

ickkii · Feb 25, 2013

Thank you for the cabling refresher Tara. I suppose I could cut some of the money by using smaller cabling where necessary. Someone recommended vauxhall to me instead of Mercedes recently, they say the parts are cheaper. I was never really intending to get a Mercedes, more like a Dodge or Freightliner, whichever was the better deal. The Airstream sprinters look pretty expensive with a quick search result showing 100k msrp, a lot of the pre-made conversions like this I see being marketed in the $100,000 area can be done to a used sprinter for less than $30,000 total. I recently found a website to not only do fast charging for the battery bank, but they specialize in 100% electric conversions. More importantly - THEY OPEN SOURCE. So basically they will sell the parts and you can use their schematics to build it yourself to fit your needs, but they make their personal charging adapters somewhat affordable. http://www.emotorwerks.com/cgi-bin/index.pl I emailed him about the battery bank use and he quickly responded a few hours later with a reassurance it will work, and even linked me something to a cheaper alternative. Now that's service.

<div>Good work on the solar energy storage!</div><div> </div><div>This unit can be easily used to charge 12V Lead Acid - there is a LA profile already programmed into the charger and just needs to be activated. However, the output current will be limited to 100A max. Which is fine for LA (as far as I remember, you can't charge them faster than 0.1C anyway) but obviously does not use the full power capability of the charger (12kW). To get 100A 12V output from AC lines, you could also just use 2-3 12V power supplies such as <a href="http://www.ebay.com/itm/600W-12V-50...pt=LH_DefaultDomain_0&hash=item20ced02377" rel="nofollow" target="_blank">http://www.ebay.com/itm/600W-12V-50...pt=LH_DefaultDomain_0&hash=item20ced02377</a> connected in  parallel. </div><div> </div><div>Hope this helps - thanks!</div>

I'll have to weigh the options. One of their units may be better because it has some redundancy built into for multiple types of batteries, so if any changes are made in battery technology down the line - that unit is prepared for it. But at $65 a piece, the other option doesn't look bad either. Speaking of batteries. Trojan also emailed me back concerning the recombination catalysts and basically told me they void warranty due to 'contaminants'. This surprises me because the sealed lead acid batteries they sell should be using recombination based off of the dozens of documents I've come across while reading into these. It's not really complex to see how a catalyst can convert hydrogen and oxygen fumes back into water.  I asked for more information on this, I may end up ditching the t-105s if he doesn't give me a decent enough explanation or sources. I've found a polish company that specializes in industrial battery banks, and they're made to use recombination plugs that the company manufactures specifically for use with them. http://www.bater.pl/langs/bater.pl/...n-batteries/batteries-and-traction-cells.html or once I finish reading through this website I may switch battery technology all together. http://batteryuniversity.com/learn/ bee you're scaring me, just when I thought the ac thing was figured out <img rel="lightbox" src="/images/boards/smilies/frown.gif" class="bbc_img"> I'll have to call their service line and check.  30amps of power is 30 amps of power is it not? I don't know if it would matter where it comes from. I guess it would depend on if it uses a belt, since the compressor can be mounted to the bottom/top of the van I would assume it would be no where close to the engine.

ccbreder · Feb 26, 2013

Danfoss makes 12 volt compressors for refrigeration, advertized as solar, why not 12 volt air conditioning. They would use amps all the time they ran, but would not face loss from power conversion.

ickkii · Feb 26, 2013

The dometic refridgerator is 12v, 45w The ac is 12v 30a. I emailed the ac people to make sure it doesn't require any engine connections last night, waiting for a reply. Right now I'm trying to think of a new switch to use. 4 position switches rated for 100A don't come cheap. I found one that looks 3-4x as old as I am on ebay for $100, but a new one runs almost $350. If I don't find something I guess I could opt for the WW2 era switch lol. Need this to switch between solar, alternator, and ev charger. Instead of using a changeover switch I might just go with 3 rockers. The problem is finding an on off rocker switch that can handle 100A from the alternator or quick charger. dc switches that go that high aren't turning up many search results.

wrcsixeight · Feb 26, 2013

Most switches for DC current only goto 15 amps. After that the switch is used to power a relay which can handle huge currents. look into a continuous duty solenoid rated for at least 100 amps. Soon I will be using my headlamp switch to activate relays for high and low beams. Currently, pun intended, all the current runs through the headlight switch, and dimmer switch, and bulkhead connectors over 14awg or thinner and the result is at 12.8 battery volts, my headlamps are seeing under 11.

800W Solar Powered Sprinter Conversion. (pics)

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