Looking to design a solar system (input wanted)

[T.he I.nvisible M.an]

Hello forum,

I have to admit that I read the CRVL forums daily ... (old posts, new posts) all are VERY informative. Bob has done a wonderful job here and the forum seems fairly active with "experts" every where you turn.

So here goes ...

This is what I am interested in doing.

The top of my step van has a "skylight" down the center of the cargo area. For obvious reasons I do not want to cover this up. There are two strips on each side of the skylight that are available (working area 2ft x 14ft on the left and 2ft x 14 ft on the right). In the front over the cab there is a working area that is 4ft x 7ft. If the panels are slightly wider than 2ft this would be ok but not overly wide as to cover the skylight. The entire roof structure is fiberglass over aluminum ribs. The non skylight areas have a 2nd ceiling below and is insulated between the roof and ceiling.

I would like to develop a phased approach with the idea to build up to the ultimate maximum design potential.

A full design is needed so that the components add up to the end design.

And then the full design needs to be broken down into affordable phases that make sense.

I currently have two batteries in parallel for starting that are Exide Select Performance 31XHD 925 CCA 1050 CA 180 RC @ 25 amp. I am not sure how the specifications translate into AH as these are starter batteries.

Obviously some "house" batteries would be a nice start along with some monitoring and auto switching.

I have a heavy duty alternator already installed 240 amps at 1700 rpm and 140 amp rating at idle. I had to go with a new factory Cummins serpentine belt as an aftermarket belt I bought was squealing on startup and sometimes when the engine revved up.

So there you have it my forum friends and experts ...

I await your input on a most excellent design ...

(money is no object here however if comparables are close I don't mind saving a few bux here and there) 


T.I.M.

Also a few pointers on the best way to test the amp output of the alternator would be great (I have a commercial mulitimeter and could look up the procedure but again your input is desired)

Thanks in advance

 

[T.he I.nvisible M.an]

Interesting enough the Cummins Serpentine Belt had this "fuzzy" side facing the pulley and the aftermarket belt was notched rubbery with no fuzzy material what so ever.

The squealing stopped upon installing the Cummins belt and has not returned since.

T.I.M.

 

[Optimistic Paranoid]

Kyocera makes 140 watt panels that are 60"x26".  Two on each side and two across the front for a total of 6 panels, wired in parallel - 840 watts, 48 amps.  Your skylight is still mostly unblocked.

A Morningstar Tristar 60 amp controller will handle the whole system just fine.

Kyocera and Morningstar are both top shelf products.

Regards
John

 

[T.he I.nvisible M.an]

Kyocera makes 140 watt panels that are 60"x26".  Two on each side and two across the front for a total of 6 panels, wired in parallel - 840 watts, 48 amps.  Your skylight is still mostly unblocked.

A Morningstar Tristar 60 amp controller will handle the whole system just fine.

Kyocera and Morningstar are both top shelf products.

Regards
John

What about a great battery design? (possibly one that can also be charged by the alternator and the starter batteries charged by the solar ... if they are low)

 

[T.he I.nvisible M.an]

Kyocera makes 140 watt panels that are 60"x26".  Two on each side and two across the front for a total of 6 panels, wired in parallel - 840 watts, 48 amps.  Your skylight is still mostly unblocked.

A Morningstar Tristar 60 amp controller will handle the whole system just fine.

Kyocera and Morningstar are both top shelf products.

Regards
John

Also I see for the Kyocera there is a junction box option and an MC4 connection option. which is better? ... (I'm a noob at solar don't you know lol)

 

[Optimistic Paranoid]

What about a great battery design? (possibly one that can also be charged by the alternator and the starter batteries charged by the solar ... if they are low)

Lot of variables.  How many amp hours do you expect to use in a day?  How many days reserve do you want to have in case bad weather prevents solar recharging?  Do you want flooded batteries or AGM?  Do you plan to have an inverter, and if so, how big?

Arguably, Trojan makes the best flooded batteries and Lifeline makes the best AGMs.

As you probably know, you are not supposed to deplete house batteries more than 50%.  That means if you have a battery bank with 800 amp hours in it, only 400 amp hours are actually usable.

The rule of thumb - with flooded batteries - is to have one amp hour of battery capacity for each watt of solar panel.  Thus, with 840 watts of solar panels, you could support a battery bank with 800 amp hours in it.

On the other hand, Sternwake has convincingly demonstrated that the Lifeline AGMs do not do well at low rates of charge, and need a minimum of 20% of their amp hour capacity.  So for every 100 amp hours of capacity you have, you would need 20 amps of input.  Since the panels previously discussed put out 48 amps, those panels can only support a battery bank with 200 amp hours in it.  If you want maximum longevity of those expensive batteries.

Inverters only work well when you have a BIG battery bank.  The more power the inverter draws, the bigger the bank needs to be.  If you want to run an inverter in the 1,000 - 1,500 - 2,000 watt range, you will almost certainly need 600 to 800 amp hours.

I would, btw, only go for the pure sine wave inverter.  I personally like Samlex.  Morningstar makes a good one, but it is only 300 watts.

All in all, I would go with the Trojans.

Keep in mind that you should never add new batteries to a bank of old batteries, but a couple of months isn't critical.  You could buy a third of your batteries now, add another third a month from now, and add the final third in two months, if that's the way your finances work.

Charging from the alternator?  Sure.  Lots of people here will tell you that you only need a fat wire and a continuous duty solenoid to make that work.

If you want to examine some high tech alternatives, look at:

http://www.hellroaring.com/

and

http://www.sterling-power-usa.com/ , particularly their battery to battery chargers

Finally, you've covered Solar and Alternator charging.  Do you want to be able to charge from the grid or a generator?

Check out the marine battery chargers at the Sterling site.  Go with http://www.park-power.com/en  for shore cables and hook ups.

Finally, for miscellaneous electrical stuff, try https://www.bluesea.com/

Regards
John

 

[Optimistic Paranoid]

Also I see for the Kyocera there is a junction box option and an MC4 connection option. which is better? ... (I'm a noob at solar don't you know lol)

The junction box option lets you run your own wire from the panel all the way to the controller.  The MC4 option means there are shot pigtails with MC4 connectors coming from the panels, and you have to buy MC4 extension wires.

Personally, I went with the junction box option and bought 100 foot of good wire.  I'm comfortable cutting, stripping, and terminating wire myself.

Regards
John

 

[jimindenver]

Ok so what do you want out of the system. How much power do you use or would you like to use? 800w is a nice system but only if you need it and have the ability to take advantage of it. Otherwise you are just spending money for nothing.

Having the ability to take advantage of it means either having the battery capacity to hold what the solar can produce or like me, use it as a solar generator. I prefer the first as the second can leave you in a lurch in bad weather and the system will still act like the generator when the bank is full.

So how much battery then. That can be decided with how much you need for 3 or 4 days of crappy weather or a balance between the solar and bank. Personally I would think 3 of the Lifeline AGM 8-Ds I use would be a beautiful match at 750 Ah but be warned, three will set you back a few grand.

I'll second the Morningstar TS-MPPT-60 for the wattage. A bit out dated but still the best choice at that level. The competition has fans and that was a killer for me.

Branch connectors are limited to 30a so you will likely have to use bus bars to combine the current coming down from the roof. For wiring I am using 1/0 welding wire.

So you have a start and some things to consider. Your system can be larger than mine and we run a air conditioner, cook on a hot plate, and use a auto drip, a bathroom heater and more.

 

[T.he I.nvisible M.an]

My goal is to be able to operate completely off grid. I currently have a pretty good selection of 20v cordless tools and can charge the batteries with a 400 watt inverter (800 watt surge) no problem. I run a laptop off the inverter that draws 210 watts when charging the battery and running the cpu's/gpu's at full speed. If the laptop is not plugged in and even if the battery is at 100%, because of the cpu/gpu power consumption the laptop can drop back to as much as 50% of it's full potential. This is done in order to protect the components from under voltage as the battery is not enough to run full on.

I am also planning a convertible sleeper in 25% of my current setup that will double as a mobile office/design studio. I have a crazy desktop, and with that said, I need to check it's total power consumption, as well as a pair of 2560 x 1600 high res monitors All of this runs through an APC UPS that provides battery backup for 45 minutes with everything running. I am fairly sure I can hookup the UPS directly to the 12v system with it's main lug disconnects. I will dig up all the specs, post the info as well as pictures. The UPS has a series of batteries inside (all look like golf cart batteries) and a crap load of 110v receptacles both front and back. Under normal configuration it takes in 110 volts and charges the battery system on the fly. The batteries then convert back to full sine wave 110 volts. With this type of unit the computer and peripheral units (mouse, monitors, speakers, etc) never run directly off the incoming 110 volts so that in the event of a power outage it acts more like a laptop than a desktop that will reboot it's self on black or brown out.

I am fairly sure the computer setup will use the most power.

If I don't configure for the desktop system I will be stuck with the laptop only and I really need the desktop up and running to do actual "work" on it. Mind you both the desktop and laptop are both very high end. I put 28k into the pair about a year ago. So they are both "power hungry".

With my current 4g connection I will be truly free to roam around and use my mobile tool/work shop handyman/contractor as a back up or as a launching pad to finance going back to "full time" computer work. This time I will now be doing my own projects instead of working for others. I also won't need to seek out out any "angel" investors (more like demons with 2 hands in each of your pockets lol) as I plan to self fund as I go.

So I want the strongest solar + batteries I can get and then back that up with an ultra quite generator. I like the shore power option but I would rather be setup to stealth park anywhere than "need" to be plugged in in order to work.

Thanks for your help in advance,


T.I.M.

 

[T.he I.nvisible M.an]

Reading the posts so far gives me more to study as to differences in product and design.

Thanks again,

T.I.M.

 

[MikeRuth]

A couple tools you will want in addition to your Multi Meter, A DC amp probe and a Kill A watt

The DC amp probe is going to come in handy when you start checking amp draw on the vehicle, like seeing how much that alternator is really putting out, how much your inverter is really sucking down etc.
DC amp probe... http://www.amazon.com/MASTECH-MS210...d=1444071477&sr=8-3&keywords=dc+current+clamp

The kill a watt like this http://www.homedepot.com/p/Unbranded-Kill-A-Watt-Electricity-Monitor-P4400/202196386
Would let you see how much that monster desktop and screens are pulling down on 120, actually on the exact voltage as measured. Also for anything else you may be curious about that is currently running on 120 VAC

Mike R

 

[T.he I.nvisible M.an]

A couple tools you will want in addition to your Multi Meter, A DC amp probe and a Kill A watt

The DC amp probe is going to come in handy when you start checking amp draw on the vehicle, like seeing how much that alternator is really putting out, how much your inverter is really sucking down etc.
DC amp probe... http://www.amazon.com/MASTECH-MS210...d=1444071477&sr=8-3&keywords=dc+current+clamp

The kill a watt like this http://www.homedepot.com/p/Unbranded-Kill-A-Watt-Electricity-Monitor-P4400/202196386
Would let you see how much that monster desktop and screens are pulling down on 120, actually on the exact voltage as measured. Also for anything else you may be curious about that is currently running on 120 VAC

Mike R

As it turns out ... I already own two probes. I use these probes mostly on 240v or 360v electric calculations if I am working to determine actual load on a building (usually commercial) for design purposes. If the panel looks to be undersized it still might be approved with engineering calculations along with an as built electrical survey and 1 month monitoring as provided by the power utility.

I mostly use the Ideal 61-746 and have never used my Klein tool CL3100 as shown below...


Moving my "stuff" into my new diggs lol (a pair of 10x20 mini storage units) As I slowly downsize over and over ...


AND ... the Klein tool battery is dead but it looks like it does DC as well. The ideal tool (of course) has fresh batteries and I see an unnoticed DC setting on it.
The Kill-A-Watt is now on my short list of up coming purchases (as I might be in the H. Depot at the very least 1x per week and frequently 2 or 3 times a day lol)

I use the Ideal test kit to do trouble shooting both residential and commercial. The sender injects a digital signal that can be "heard" up to 15 feet away, through walls and underground and runs up to 4 miles down a wire if the wire is live. (its a great tool as I have come behind many a master electrician to fix or find their screw ups ... works great for lightning strikes as well)

 

[akrvbob]

I would like to develop a phased approach with the idea to build up to the ultimate maximum design potential.

A full design is needed so that the components add up to the end design.

And then the full design needs to be broken down into affordable phases that make sense.

From what you say here you want lots of solar but want to buy it slowly, as you can afford it. I understand and I did exactly that myself. I started with a 55 watt Kyocera panel in 2009, added a 135 watt Kyocera, then a 140 watt and finally a 240 watt for a total of 580 watts.

In a step van, unless you have a very specific need for lots of power, 500 watts is a huge abundance, that's what I would shoot for if I were you.

Here's your biggest problem with your plan. Your battery bank has to be sized to your solar. So you can't start with 500 ah of batteries for 100 watts of panels. You start 100 watts of panels with 100 ah of battery. Then a year later you buy another 100 watt panel but now you can NOT add another battery to that bank THEY HAVE TO BE NEARLY THE SAME AGE!! If you do, you'll reduce both of their capacities. Bad idea! I speak from lots of experience at wrecking batteries.

My recommendation is to start with a 250 watt panel like the Kyocera and a controller that can handle it like the Blue Sky 3000i going to Trojan T105s. That will probably meet your needs. 

A year later, if it doesn't, then add a complete 100 or 200 watt Renogy kit and new batteries to go with it. Yes, you will have two complete systems and two controllers. The controllers are so cheap, who cares!? Plus, you  have redundancy. If one system fails, you still have power. I have three controllers and three complete systems because I bought them over a period of 6 years. I have no regrets about that at all!! 

Just some thoughts.
Bob

 

[T.he I.nvisible M.an]

From what you say here you want lots of solar but want to buy it slowly, as you can afford it. I understand and I did exactly that myself. I started with a 55 watt Kyocera panel in 2009, added a 135 watt Kyocera, then a 140 watt and finally a 240 watt for a total of 580 watts.

In a step van, unless you have a very specific need for lots of power, 500 watts is a huge abundance, that's what I would shoot for if I were you.

Here's your biggest problem with your plan. Your battery bank has to be sized to your solar. So you can't start with 500 ah of batteries for 100 watts of panels. You start 100 watts of panels with 100 ah of battery. Then a year later you buy another 100 watt panel but now you can NOT add another battery to that bank THEY HAVE TO BE NEARLY THE SAME AGE!! If you do, you'll reduce both of their capacities. Bad idea! I speak from lots of experience at wrecking batteries.

My recommendation is to start with a 250 watt panel like the Kyocera and a controller that can handle it like the Blue Sky 3000i going to Trojan T105s. That will probably meet your needs. 

A year later, if it doesn't, then add a complete 100 or 200 watt Renogy kit and new batteries to go with it. Yes, you will have two complete systems and two controllers. The controllers are so cheap, who cares!? Plus, you  have redundancy. If one system fails, you still have power. I have three controllers and three complete systems because I bought them over a period of 6 years. I have no regrets about that at all!! 

Just some thoughts.
Bob

Interesting idea,

Thanks

T.I.M.

 

[jimindenver]

Yeah, I have to admit that were I to go out and buy my system all at once at retail, it would be a bank breaker.

I've done multiple systems before, up to three. It has it's advantages in that you can handle multiple banks at once or combine them when you really want to smack a bank around.

The area in front of the cab is big enough to handle a BIG panel like a 435w poly. Those are 40x 77 i think. You would need a 30 a MPPT controller for it, there are both high end and acceptable low end units depending on features needed. I used 490w for a season, it's nothing to sneeze at.

T.I.M., what area are you in? There are some sweet deals here and in N.M. on solar and batteries right now. I could replace my lifelines with 600 Ah of new AGM's for $500. The 435w's are in ABQ for 65 cents a watt. I find it all on craigslist or ebay. My first 230w system cost under $200 my 490w system ( two 245w systems) under $400 and selling those for $500 each paid for a good chunk of the 750w system that I have under $2000 into including the inverter, TS-MPPT-60 controller and Lifeline batteries. Everything but the batteries is new and warrantied, the three lifeline 8-Ds for $675 were a steal that I drove hours to pick up.

So until you start buying, keep your options open, keep your eyes open. There is more than one way to do this.

One thing to consider is if you did get the batteries first, you could use a generator or the truck to keep them up until you had enough solar. Some do the bulk charging early on and then let a smaller solar system handle the rest when the acceptance rates are lower anyways. Then you could slowly add solar until you had enough to cover your needs.

A large solar system on a smaller bank can be used like mine is, a solar generator but only if the solar is sufficient to cover your needs without the batteries when the sun is up. Like I said this can be limiting in bad weather and at night.

Don't mind me, I spend hours building systems in my head and running the numbers. I lead a boring life. lol

As for batteries, there are no best batteries. Only what's best for you. My Llifelines are cool and can suck up juice like no others. I could put a 350a alternator in my truck and it would make them snicker. They can handle 10 times that rate. They can cost a lot but nothing like cutting edge LiPo's. You don't sound like you have any high amp loads so a good set of heavy duty deep cycles might be in order. You have the advantage of payload so you can go multiple smaller batteries or fewer BIG batteries. A pair of Surettes is a perfect match to that big 435w panel.

I wouldn't worry about the two monitors much, and you have a handle on the lap top. The desk top could be interesting if you run it a lot. One of mine has a 450w power supply and that's the equivalent of running my little A/C or the cook top. I can do it straight off the solar from 10 am to 3 pm if it's sunny but with out the solar it would take my bank down in 10 hours or less.

What about other loads like lighting, (LED I hope) heat, pump, refrigeration, etc?

 

[T.he I.nvisible M.an]

Yeah, I have to admit that were I to go out and buy my system all at once at retail, it would be a bank breaker.

I've done multiple systems before, up to three. It has it's advantages in that you can handle multiple banks at once or combine them when you really want to smack a bank around.

The area in front of the cab is big enough to handle a BIG panel like a 435w poly. Those are 40x 77 i think. You would need a 30 a MPPT controller for it, there are both high end and acceptable low end units depending on features needed. I used 490w for a season, it's nothing to sneeze at.

T.I.M., what area are you in? There are some sweet deals here and in N.M. on solar and batteries right now. I could replace my lifelines with 600 Ah of new AGM's for $500. The 435w's are in ABQ for 65 cents a watt. I find it all on craigslist or ebay. My first 230w system cost under $200 my 490w system ( two 245w systems)  under $400 and selling those for $500 each paid for a good chunk of the 750w system that I have under $2000 into including the inverter, TS-MPPT-60 controller and Lifeline batteries. Everything but the batteries is new and warrantied, the three lifeline 8-Ds for $675 were a steal that I drove hours to pick up.

So until you start buying, keep your options open, keep your eyes open. There is more than one way to do this.

One thing to consider is if you did get the batteries first, you could use a generator or the truck to keep them up until you had enough solar. Some do the bulk charging early on and then let a smaller solar system handle the rest when the acceptance rates are lower anyways. Then you could slowly add solar until you had enough to cover your needs.

A large solar system on a smaller bank can be used like mine is, a solar generator but only if the solar is sufficient to cover your needs without the batteries when the sun is up.  Like I said this can be limiting in bad weather and at night.

Don't mind me, I spend hours building systems in my head and running the numbers. I lead a boring life. lol

As for batteries, there are no best batteries. Only what's best for you. My Llifelines are cool and can suck up juice like no others. I could put a 350a alternator in my truck and it would make them snicker. They can handle 10 times that rate. They can cost a lot but nothing like cutting edge LiPo's.  You don't sound like you have any high amp loads so a good set of heavy duty deep cycles might be in order. You have the advantage of payload so you can go multiple smaller batteries or fewer BIG batteries. A pair of Surettes is a perfect match to that big 435w panel.

I wouldn't worry about the two monitors much, and you have a handle on the lap top. The desk top could be interesting if you run it a lot. One of mine has a 450w power supply and that's the equivalent of running my little A/C or the cook top. I can do it straight off the solar from 10 am to 3 pm if it's sunny but with out the solar it would take my bank down in 10 hours or less.

What about other loads like lighting, (LED I hope) heat, pump, refrigeration, etc?

I have done a lot of electrical design and engineering work in the past (mostly AC not DC) but I am sure once I get up to speed and figure out what is what I will put a full design together. Do all the load calcs, size the wiring and breakers as well as placement. I have been a CAD jockey since 1983 so drawing it all up would be no problem. I have done electrical Design up to 1500 amps (AC not DC) and probably put together 50 to 60 whole house standby generator systems including all the switching and such. I also have done a lot of HVAC design and Engineering using a program called Wrightsoft. Main thing is to get my head around this ... look at all the options such as fastener systems for the panels and such. Spec it out and draw it up ... (with my laptop of course as no place to plug the monster system in yet) lol

btw this "beast" of a desktop has 128 gb of ECC ram and a pair of Nvidia Video Cards with 32,000 "cuda" processors It has a pair of 8 core CPUs that show up on the task manger as 32 processors running. Needless to say the video is lightning fast. Most of the newer video games will run with all the options turned all the way up. When you see this on 2560 x 1600 32 inch monitors it looks quite amazing (and I am usually hard to impress).

I plan to "develop" a design based on the idea that the 4th left and right bays nearest to the cab are convertible into a sleeper and office/design studio. If need be (like the removable shelving) the Sleeper/office/design studio will break down and stow away as if it wasn't ever there. In this way I am not permanently committing space and have "flex" space working for me.

I will probably model the Van in Sketchup or Revit then export the Model to Lumion and do some Video clips of the proposal. I already have the Van in 3d and only need to do the interior at this point.

Cheers,

T.I.M.

 

[akrvbob]

btw this "beast" of a desktop has 128 gb of ECC ram and a pair of Nvidia Video Cards with 32,000 "cuda" processors It has a pair of 8 core CPUs that show up on the task manger as 32 processors running. Needless to say the video is lightning fast. Most of the newer video games will run with all the options turned all the way up. When you see this on 2560 x 1600 32 inch monitors it looks quite amazing (and I am usually hard to impress).

Okay, you are an extreme power user, then I agree with Jimindenver, get the biggest panel you can find to fit the one big space you have.
Bob

 

[Optimistic Paranoid]

BTW, if you haven't already discovered this site:   https://handybobsolar.wordpress.com/  I highly recommend that you go there and read through all of Handy Bob's angry rants.  There are a lot of us here who think this guy really knows what he is talking about when it comes to designing GOOD solar systems.

In particular, I recommend you read his rant on inverters.  He considers most inverters to be unsuitable for use on solar systems (he refers to them as "trucker's inverters") because the high voltage cut-out is only 15 volts.  A few inverters have high voltage cutouts of 16.5 volts, and those are the only ones he considers suitable for use on solar systems.  Well, read his post and you'll understand why.

Regards
John

 

[jimindenver]

Bob has some interesting thoughts, that's for sure. 15v is a cut off for many RV systems like refrigerator control boards too. Above that I disconnect the battery I am conditioning or equalizing for the safety of the whole system.

As far as reading I'll toss in Jack Mayer who you can find on RV dreams and the 12v side of life. Get done with those and more await. None are absolute, just different perspectives as mine is. A lot has changed since some of it was written such as gear available and prices.

I would like to suggest the solar forums but I found most were using grid tied, fewer off grid and many look at RV systems as toys. There is info their if you are willing to wade through the rest of it.

That's why my favorite places are here and the other RV forums where you will find people that actually use solar the way we do. The variety is huge as no two RV's, user needs, gear choices and conditions are the same. You will find everything from tiny portables to systems that make mine look small.

Even my advice is just to be added to the pile. My system is unique being designed as a generator which I was told was not possible. Batteries run things and solar recharges them was all I got when I came up with the concept three years ago. We also deal with a lot of overcast weather here which is what generators are for I was told. We don't take one so I worked it out so that the system can do as much as 25a in cloudy weather.

 

[SoulRaven]

With all that computer equipment and that truck painted black in full sun there will be no need to install an oven.