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gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA

1 edit

[Electrical] Small solar system

Click for full size
I have been studying about solar for a while now and I am building a small system for my mobile workshop a 2005 Chevy Express 2 1/2 ton box van. Automotive forum is not really the right place because of the complexity of the system.

I have spent a lot of money on electricity over the years to the power company PG&E.
I would really like to give them the finger, and the pushy salesmen at the grocery store, home depot, orchard supply, and a few other places pushing solar contracts where they own the system and get the benefits like the tax deductions and then sell the contract to who knows what venture capital.

It's a small but expandable system for the future.

I decided on this »www.amazon.com/gp/product/B00E0YBL0K kit to work from.
I read up more on systems at »forum.solar-electric.com/forumdi···allation
I cant afford a huge system right now or the really fancy stuff they are hawking at that site. High voltage inverters are very expensive ...

Anyways I drew up my current plan and have most items except the 2 huge battery's and one Gladiator cabinet I will put the inverter in and vent to outside with the controller mounted on the outside of it.

The battery's are going into a Buyers 36x18x18 14 gauge steel powder coated underbody truck box with 2 Dura vents to the outside.

I drew up this diagram and it's still a work in progress, if anyone can help with good ideas it would be welcome. I'm thinking to put some more grounds from the solar array and maybe the middle battery. The reason I am using the smaller battery is that it's one I already have and use for the fan and lights.
I will be able to use a 50ft extension cord from the system no problem.
I think I am up to around $2400 now with some high end high amperage audio grade components and the furniture.
--
Let them eat FIBER!


ampsmore

@50.138.50.x
just general ideas:

for times when the sun not shining, it'd be helpful to be able to charge from the truck alternator or from the home ac.
many folks put in a 2nd alternator to only run the non-starting batteries.

=
powder coating eventually comes apart. you might look at stainless box instead.

-
you don't mention the amperes you will be pulling from the inverter when the whole mobile shop is running. let's just say e.g. 20 amps. the rule of thumb is 1:10, if you need 20 ac amps, you will be pulling 200 amps dc from the batteries. (rule not exact, but close enough, since you are converting 12 volts to 120 volts) choose your wires, connectors, and breakers accordingly.

-
batteries conventionally rated at their 10 hour rate, for consistency. a 100 amp/hr rated battery thus means that it can deliver 10 amps for 10 hours, less when actually run at 100 amps.

car starters typically pull 50-100 amps, so the wire to the starter is a good indication of the size wires you'd need for e.g. 100 amps, with wire diameter ~1.4 times that for 200 amps.

-
quick disconnect switches are a good idea at the batteries, in case there's a problems and the battery wires start getting hot or melting.


nunya
LXI 483
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
reply to gaforces
The first thing I would do is skip the solar all together. A 3500 Express should already have a H.O. alternator. Charge the auxiliary battery off of the vehicle charging system.

I use these inverters: »dimensions.sensata.com/product-i···inverter
I use these batteries: »www.optimabatteries.com/en-us/pr···/bluetop

Rarely do I even need to start the truck for a charge in an 8 hour day. If I drive to lunch, they get topped off.
I only have Ford Super Duty trucks, and they come with electronic PTO control wiring. I built PTO High Idle boxes for about $25 at Radio Shack. I can idle the engines at anywhere from 900 to 2400 RPM. I'm not sure if GM heavy duty vehicles have the same thing.

It's just like a diesel-electric submarine. Every once in a while you "come up for air" and charge the batteries. As I mentioned, I rarely have to even use the PTO option. TBQFH, I use it more in the summer time for running the AC while I'm eating lunch in the truck.
--
If someone refers to herself / himself as a "guru", they probably aren't.

bronco85

join:2003-09-09
Grover, NC
reply to gaforces
I also would skip solar also. Ladders on my roof would block the panels. I use 2 deep cycle battered in parallel connected to my truck using an isolator relay from my starting batteries. I bony run the truck wile during high current tools like large hammer drills pvc heating box. Drill chargers are left on with truck off. With no issues.


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA
reply to ampsmore
said by ampsmore :

for times when the sun not shining, it'd be helpful to be able to charge from the truck alternator or from the home ac.
I'm thinking Honda eu2000 generator.
many folks put in a 2nd alternator to only run the non-starting batteries.
Uses a lot of gas, expensive. Wear on my motor.

=
powder coating eventually comes apart. you might look at stainless box instead.
Yah that's nice, the price was right on the powder coat box, and it arrived yesterday.

-
you don't mention the amperes you will be pulling from the inverter when the whole mobile shop is running. let's just say e.g. 20 amps. the rule of thumb is 1:10, if you need 20 ac amps, you will be pulling 200 amps dc from the batteries. (rule not exact, but close enough, since you are converting 12 volts to 120 volts) choose your wires, connectors, and breakers accordingly.
Around 20 amps with occasional 15 amp power tools + chargers and a laptop, fan, led lights. 8 gauge for the solar array 0 gauge for the battery bank with 8 gauge grounds, not positive about the 200 amp fuse for the battery bank yet.

-
batteries conventionally rated at their 10 hour rate, for consistency. a 100 amp/hr rated battery thus means that it can deliver 10 amps for 10 hours, less when actually run at 100 amps.

car starters typically pull 50-100 amps, so the wire to the starter is a good indication of the size wires you'd need for e.g. 100 amps, with wire diameter ~1.4 times that for 200 amps.

Thanks
-
quick disconnect switches are a good idea at the batteries, in case there's a problems and the battery wires start getting hot or melting.
Thanks I am considering that, and the placement of them.

--
Let them eat FIBER!


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA

1 edit
reply to nunya
The original owner didn't order it with the HO alternator, It has I think a 35 amp alternator. The HO alt are close to $400, I would like one but the regular one works to keep starting battery charged.
This thing sits more than it's driven and running the engine uses a lot of gasoline and wear on my motor.
I think my heart skipped when I saw the price on that sensata pure sine wave inverter.

Heh I have sat at lunch with the AC on before with the engine running when I had to work over the hill in Palo Alto or Woodside burning stinking smoggy heat.
Much better here by the ocean, and you don't need AC here.

I don't think they have the pto option from the factory, GM has a dual battery HO alternator option that this vehicle did not come with, I'm pretty happy it has AC though
--
Let them eat FIBER!


nunya
LXI 483
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
It looks like the stock alternator is 105 Amps if your engine is gasoline. There's a 145 Amp drop in for less than $150.

I used to use a small Honda EU1000i, but switched over to the inverter system. I don't have to lug a gas can around or listen to the generator run all day. Although the Honda is quieter than most, it can still get annoying.
Idling the engine actually uses less fuel than you think. Plus with all the emission control systems on modern vehicles, it's less polluty than any generator.
The problem you are going to run into with solar is that the kit you listed is expensive, and still wont have the balls to do much. If you are going to drop $900 just on the panels alone, you may as well get an EU2000i.
You don't have enough square footage on the roof of your truck really do much with solar. I assume that with a box truck / inverter setup you intend to use it for some commercial purpose such as construction. Anything more than a small load, and your solar system really will not be able to keep up or recover.
--
If someone refers to herself / himself as a "guru", they probably aren't.

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1
reply to gaforces
said by gaforces:

This thing sits more than it's driven and running the engine uses a lot of gasoline and wear on my motor.

You will burn extra gas when moving because of the heavy lead-acid batteries and weight of the panels.

You can make a much lighter system using a single 24V "Lithium Iron Phosphate" battery pack and a single (SunPower) 435W solar panel on the roof.


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA
reply to nunya
I'm pretty sure it will run my highest amp air compressor just with the 4 panels if it's in the sun. That's all the balls it needs.
The panels are 150 each, so 600 for 4. I can fit 6 more of these panels if I need to. You can put 2 of these controllers together if you wanted, and more battery's.
After that expansion is to 24v with an expensive inverter.
--
Let them eat FIBER!


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA

1 edit
reply to lutful
I'll look into that system you write of and the pricing. Sounds awesome. Thanks
I'm already $400 over budget.
--
Let them eat FIBER!

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1
If your roof is curved, semi-flexible SunPower panels provide better aerodynamics. But they cost more. This plug-in hybrid has 3 such panels on the roof providing 330W for main battery.


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA
Yah I did see the flexible panels at Amazon, they have different sizes long and skinny ones that roll up, and they are very light.
It's a flat roof till the front and the huge plastic air dam might be able to hold some of the flexi panels.

The flat panels I have weigh 18 pounds each, not too bad.

This is my first system therefore it's a test and a learning experience and I'm doing it with limited budget to see if it would be worth going further in the future.

They are on around 3rd gen controllers 4th - 5th gen panels, I know it's close to being worth doing.
--
Let them eat FIBER!


notworthit

@69.118.94.x
I don't understand what you are trying to run here... why go though all this effort, btw those panel ratings are in *direct* sun. So *if* you ever get direct it would be for like 15min. After that everything is less than rated.

Put in a battery bank with a battery isolater. Run the truck when needed

I mean if you paid so much money to the poco...

You have 600 watts of panels it looks like you said...

say 12H day you use the FULL output (not possible but whatever) that's 7.2kw/day

Your in cali not sure of your rates I'll give ya a pretty high one... .20cent/kw

1.44$/day

Your system cost here say $2500.

1736 days or 4.7 years to pay off...

By that time you will need new batteries...

Not worth it. Easier to use the poco and like I said I gave you a full 600 watts for 12 hours. EVERY DAY of the year... your never going to get 600 watts for more than 1 hour unless you mount the panels so they can follow the sun.

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1

1 recommendation

said by notworthit :

You have 600 watts of panels it looks like you said... your never going to get 600 watts for more than 1 hour unless you mount the panels so they can follow the sun.

You are pointing out a very important FACT which I hope the OP will seriously consider and do some calculations to avoid spending too much money.

I have helped some people who really wanted to have solar power on their vehicles or vessels. They wanted to be "green" and also wanted power for emergencies on the road like dead batteries.

Anyway, that 435W SunPower panel I suggested is about 7ft x 4ft in size. They are the most efficient panel available at this time but still could not generate more than 2000Wh on a very sunny day when mounted horizontally on the roof of a vehicle.

So OP really needs just two off-the-shelf 100AH AGM auto batteries to store that energy.

1 435W panel + MPPT charge controller = $500
2 100AH AGM batteries = 2x$100=$200

Total cost: $700

Spending more on panels or batteries won't be wise for this project.


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA
reply to notworthit
I will measure output and post the stats. Your numbers don't make sense. It's 400 watts at 32v.
1.44$ a DAY? Are you joking? I pay $9.17/day
--
Let them eat FIBER!


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA

3 edits
reply to lutful
said by lutful:

1 435W panel + MPPT charge controller = $500
2 100AH AGM batteries = 2x$100=$200

The cheapest I can see that panel is for $415 at ebay rebadged without the sunpower warranty. I'm pretty sure it takes an expensive controller, and I don't care about that panel it wont fit on my application.
1 100AH agm battery cost around $200.00 with tax.

Are you people getting these numbers from duke energy?

I read a lot of reviews of these 100w panels and others, one of the most interesting was »www.amazon.com/review/R30DTXH9O09N54/
and »www.amazon.com/gp/product/B003FFVI8A/ are the battery's I ordered 2 of.


maybecrazy

@69.118.94.x
reply to gaforces
Okay I'll admit I did those numbers at like 3am lol that was way to early to even be thinking BUT

I saw 600 watts... and 400 so I gave you the higher number. (high number = greater savings)

Your drawing shows 3 batteries wired up for 12 volts to the inverter...

You said "The panels are 150 each, so 600 for 4" so I used 600 watts of power. (again just looking for the biggest number that was thrown out)

The drawing does say 18v (wired up as 32volts) I used 12v don't ask why, idk. lol

I did not factor in 12volt to 120volt conversion lose, or any other lose. I gave you a straight 600 watts at 120volts...

I aint no power guru like some on here so they might come along and be like, this guy is crazy lol... don't listen to anything he says

But last I thought I knew watts were watts (watts = volts X amps) so, 600 watts at 18volts was 600 watts at 120 volts... amperage would change that is all. (and yes power conversion lose we are leaving all that out)

So when I gave you 600 watts, at 120volts, and ran those numbers (note my cost of power was a pure guess at 20cents/kw you would need to change that to reflect your true cost, my average cost for example is like 11cents) I gave you your MAXIMUM not real never gona happen it will be lower savings with a 600 watt system installed. If you were paying 20cents/kw and using the system 12 hours a day @ full output.

The point was to show your maximum saving and pay off time for the system.

Hopefully I've not lost my mind? lol Not that I would count on that.

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1

1 edit
reply to gaforces
said by gaforces:

Are you people getting these numbers from duke energy? ...
I read a lot of reviews of these 100w panels and others, one of the most interesting was »www.amazon.com/review/R30DTXH9O09N54/

Please don't insult people trying to help you ... because we could legitimately wonder if YOU are affiliated with Renogy after mentioning it TWICE with Amazon store link.

Compare these options:
a) 4 generic 100W panels: 400W for $600 ; mounted area almost 4x(4'x2')=32 sq ft
b) 1 best-in-world SunPower panel: 435W for $420 ; mounted area less than 7'x4'=28 sq ft

Option b can actually use a compact 10A MPPT controller which can handle 80V open circuit. You may need more expensive controller for option a because voltage or current goes up based on series or parallel connection.

said by gaforces:

... »www.amazon.com/gp/product/B003FFVI8A/ are the battery's I ordered 2 of.

Seriously, you ordered 2 batteries already before proper cost-benefit analysis?

Exide brand and that particular model is very good, but you could have bought any reputable AGM battery, any model, from any automotive distributors, and and saved at least $50 on each battery!


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA

1 edit
Not trying to insult anyone, and I don't know much about renogy, and I don't work for them. I edited out the amazon ref on the links. I am answering your and others criticism here with real info, and I haven't seen that from anyone here yet.
YOU keep pointing to these 435w panels that are not applicable to my system, giving numbers but from who knows where you get those prices, cause I cannot find them. I cannot use those cause I have a fan in the way and plan to put another.
I'd be happy to look at those others if you can point a direction?

At this point the only thing changing is the diagram for safety, cause I have already purchased the 4 panels, 40 amp controller, 2500w inverter. The battery's are ordered, I could cancel those if anyone can see a better deal?
--
Let them eat FIBER!


cowboyro
Premium
join:2000-10-11
Shelton, CT
reply to gaforces
400W ideal x 8h/day (it won't happen)=3200Wh. Count on 2500Wh at best - $0.37 worth of electricity/day at average prices or $135/year.
$400 in batteries that last 5 years - $80/year expense.
You have $55/year that must cover some $1000 worth of panels, wiring, mounting brackets etc etc. - some 18 years to breaking even assuming you can use 100% of the energy produced.
However your batteries can be used for storing 50Ah*12V = 600Wh each (fully discharging them will kill them fast), so only $65/year worth of electricity. Anything produced during the day that is not being used is lost.
Bottom line - it will never pay back.

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1

1 edit
reply to gaforces
said by gaforces:

YOU keep pointing to these 435w panels that are not applicable to my system, giving numbers but from who knows where

Are you suggesting that hooking up 4 separate 100W panels together, which cost at least $200 more all together, and takes up 4 square feet more area, is actually better for your system?

If the answer is no, please Google "SunPower 435W" and you will find $419.99 "Buy Now" price on eBay. You can bid lower.

[ removed ebay link found in google. contact an authorized dealer/installer ]


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA
reply to cowboyro
said by cowboyro:

Anything produced during the day that is not being used is lost.

That, I believe, is the only true statement of your post.
I'm sorry but you should read about how MPPT solar controllers work.
--
Let them eat FIBER!


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA
reply to lutful
Heh I already posted those panels are rebadged, they physically removed the sunpower branding, they are not covered by sunpower warranty. It looks like just some guy selling on ebay with a unknown company branding and warranty.
They are too big, the fan is in middle of the roof. I want to be able to walk up there, put another fan, and possibly an antenna mast for 5/8 wave base station.
--
Let them eat FIBER!

PrntRhd
Premium
join:2004-11-03
Fairfield, CA
reply to gaforces
I would look at a small genset since it works dependably regardless of the weather.
A small Yanmar diesel is a good choice for professional use.

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1
reply to gaforces
said by gaforces:

said by cowboyro:

Anything produced during the day that is not being used is lost.

That, I believe, is the only true statement of your post.
I'm sorry but you should read about how MPPT solar controllers work.

Once again, you are insulting someone who can actually design a better MPPT controller for your system. Read the rest of his post carefully because they are all true.

a) MPPT method does not magically increase how much energy falls on your panels. The numbers he calculated are optimistic for 400W horizontal panels during winter months.
b) You can't store more than 60% of the rated capacity of your batteries if you want long life.


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA
You still haven't backed up what you've been posting, instead you make luticris accusations of insult which are not helpful (or yet true). Hope you liked the pun.

If he can design a better system for a lower price, or you can, PLEASE post specifications and links.
--
Let them eat FIBER!


imlost

@69.118.94.x
I'm a little lost here what is not backed up? You are going to lose money on this deal. It will be cheaper to pay the poco than use your system... unless your power rates are like 3$/kwh.


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA
reply to nunya
I was thinking about using the alternator as you suggested. It is a good idea for backup when weather is bad. Use the 105 amps till that one croaks and upgrade to a ho alt.
I searched and there are a few company's making them, up to 600 amps for $800. There is a 300 amp for $330 looks to be reasonable.
I will need a switch to swap over from the solar controller, run a 20 ft. line from the alternator. Eventually a 3 way switch to add a small generator. I'll have to move the 12v accessory's to the battery bank.
--
Let them eat FIBER!

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1

1 edit
reply to gaforces
said by gaforces:

You still haven't backed up what you've been posting, instead you make luticris accusations of insult.

That is ludicrous, or foolish, unreasonable, or out of place as to be amusing, ... and I highlighted a perfect example above.

I have posted lots of useful information about solar panel and battery sizing, charging, MPPT controllers, inverters, etc. in the past 10 years. I have also seen lots of useful posts from cowboyro See Profile in home improvement and electronics forum.

Search result using only "solar" keyword after you click my username: »/nsearch?q=sol···t6369309

Many of those threads deal with "small solar system" design. If you really came for suggestions, please have a look at such threads.

But if you came to push panels from Renogy Amazon store, I have to let others know that they are CERTAINLY NOT "re-badged" SunPower. Genuine SunPower panels use Maxeon back-contact cells which have no electrical connections on the top face.

*** Have a look at the diagram for Meanwell TN-1500 in »Re: question on how I would be able to wire up an UPS

FYI that single module replaces both charge controller and inverter ... plus you can also hook it up to a generator. There is also a 3000W model.

I will suggest connecting 4 batteries in series for 48V input to increase system efficiency at heavy current usage.

You can mount as many as 6 SunPower 115W semi-flexible panels around the obstruction in the middle of the van's roof. They are really light and thin, and can be applied directly to cleaned roof surface.

Check prices on your own.


gaforces
United We Stand, Divided We Fall

join:2002-04-07
Santa Cruz, CA
reply to imlost
If the system can put out 20 amp in the sun then it is worth it to be able to use my tools at remote jobs or anywhere there is no power and without having to start my motor. Do you know how long it takes to build a house using hand tools?
I have also run out of gas on the way home from a long 2 1/2 hr. drive in stop n go traffic.

I have lived through 2 earthquakes where power was out for weeks.
Don't think I wont run a line to my bedroom to see if I can do it and utilize the power..
--
Let them eat FIBER!