Portable solar generator project

CorbinKaleCorbinKale Registered Users Posts: 21
I have a collection of AA/AAA devices- GPSR, radios, lights, NODS, Eotech, etc. that I use on a continual basis. To feed them long-term, with no grid or resupply of alkaline cells, I need a reliable solar solution. The only other thing I intend to, occasionally, run off this system will be an old laptop, used as a reader for .pdf manuals on mechanics, gardening, medical...

Since I need a quick turn around on the AA/AAA NiMH cells, I use the 15 minute chargers. I have used those for a couple of years and they work great for my purposes.

I understand that I will need to get a good reading on my power requirements, thanks to the extensive information already posted here, but I want to make sure I am not being unrealistic, or missing something that would be obvious to an expert.

With that in mind, here is my project idea. I have a very rugged gurney, with locking wheelchair wheels on one end, that is the PERFECT size to attach a 135w (59" x 26") panel on the top.

Max Rated Power (Pmax) 135 Watts
Voltage at Max Power (Vmpp) 17.7
Current at Max Power (Impp) 7.63 Amps

I will attach it with hinges on one side of the gurney and have the ability to tilt the panel perpendicular to the sun, using adjustable supports on the other side. I will install a shelf under the panel to support the battery(s). My intent is to mount a Xantrex C-12 12v/12amp charge controller to take care of the charging and DC load monitoring, and run 12v outlets from it for the AA/AAA chargers and laptop. I don't intend to use an inverter.

This will allow me to move the unit outside during sunny days, yet be easy to wheel back into the shop at night, during storms, etc. The idea is to have a backup system to keep my devices running without having a permanent panel installation, or having to move panels and cables when using the solar rig. It will be a self-contained unit.

I THINK I have a generally good handle on this project, but I don't want to go any further without bouncing it off you guys, first.

This is not going to be a project that will grow over time. There is only room for the one panel, so I will never need more CC than the 12amp Xantrex.

Where I am a bit iffy is the size of battery to get. I don't want more battery than the panel will reliably recharge. Please, suggest some specs for my first battery.

Thanks for any advice.
«1

Comments

  • PhotowhitPhotowhit Solar Expert Posts: 5,108 ✭✭✭✭
    Re: Portable solar generator project

    I'll go lowtech/no tech next time I do a trip. NiMH batteries will take a 1/8th capacity charge with minimal damage. I'd just have a couple 6 volt(nom) 3-5watt panels with 4 NiMH battery sets attached.

    With the money you save buy a Kindle to do your PDF reading, you'll need to setup at least one of the battery sets to have USB conectivity... With the Kindle you'll also have Email in most of the US.

    If you look through my old posts you'll find links to battery sites stating this.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • mike95490mike95490 Solar Expert Posts: 8,614 ✭✭✭✭✭
    Re: Portable solar generator project

    Your 135W panel should be able to keep a group 24 (case size) 12V deep cycle battery charged - you should be able to pull 500Wh daily from it, on sunny days, when panel is well aimed.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    Great info, thanks, guys!
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    Finances, finally, allowed me to place my order for the 135w panel for my project. This is the last piece to the puzzle. Once it is all together, I will post some pics. Thanks, again for the help.

    BTW, I was pleasantly surprised to find that NAWS is having a sale! $50 bucks off normal price for my panel! Good thing I am poor and had to wait so long. lol
  • cfcwcfcw Solar Expert Posts: 25
    Re: Portable solar generator project

    Looking forward to the pics!

    BTW, I've been told fast charging isn't good for AA batteries. I'w swapped to Sanyo eneloops. They have a very low self discharge rate and can sit on the shelf for months if needed without losing too much energy. You might want to have a look
  • BB.BB. Super Moderators, Administrators Posts: 30,053 admin
    Re: Portable solar generator project

    Charging AA batteries--Just as confusing as charging Lead Acid Batteries. ;)

    Generally a good charger will monitor cell temperature and voltage for proper charging. I guess that 1-2 hours is "fast charging".

    There is faster charging cells/chargers (less than 1-2 hours), but the cells are designed to support fast charging.

    And, slow charging (such as 10 hours) is not good either for NiCAD and NiMH--That can cause the "grains" inside the cell to become larger (they grow like a few large crystals instead of many small crystals). The reduced surface area of the large crystals limits the peak current from the cell (causes voltage depression).

    And yes, the Sanyo Eneloops are very good rechargeable cells.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    I have been using the Energizer 15 minute charger for two and a half years now. Using 2 sets of four AAA cells in small FRS radios, keeping one on, at all times, I get about a day and a half run time from each charge. If there has been any damage to the cells, I can't tell it. They seem to be as good as they ever were.

    I have looked at the eneloops, and agree that they are better. I would get them, but I already invested in the energizer NiMHs.

    A 7500 watt inverter just became part of the project. One thing I did today was to get a beefy battery shut off switch for the inverter cables. I decided to get some 4 gague cables with ring terminals made. That way I can secure them to the battery/inverter, prevent arcing and reverse hookups, while still being able to shut off that tiny inverter draw, even when it is turned off. The alternator shop down the road makes custom cables for a very reasonable price.

    I'm not sure if I should put the shut off switch on the positive, or negative cable, though. Does it make a difference? I'd appreciate input on that.
  • BB.BB. Super Moderators, Administrators Posts: 30,053 admin
    Re: Portable solar generator project

    A 7.5 kWatt inverter is pretty large... What is the battery bank voltage you plan to power it from and what is the maximum intended load (maximum and surge power/current).

    Generally, equipment assumes a Negative ground. So all return wires go directly to the negative battery bus.

    All positive wires leave the battery go through a fuse/breaker and a switch. If the fuse/switch opens, then the circuit is "safe".

    If you put a switch/fuse in the negative lead, then if the switch/fuse opens, then the wires / circuits are still "hot" with respect to the Negative Ground. That is why we don't fuse/switch the "return leads" with respect to ground.

    Of course, there are exceptions. Telecommunications systems are frequently positive grounded, and old (and some older foreign cars) have positive ground too... In those cases, the "negative" circuits would be switched/fused.

    Same thing with AC systems... You switch/fuse the hot leads and the Neutrals (which are ground referenced) are never switched.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    Thanks, Bill. I will put the switch on the positive lead with confidence, now. I am only using one 12v 120 RC(reserve capacity?) AGM battery. I figured that was about the most I could reliably recharge with a single 135w panel. Which brings up another question. Is 'reserve capacity' the same thing as amp hours?

    The only loads the inverter will be powering, are relatively minor. I have a very small 2 gallon compressor that I have already used with the rig, successfully. It has a fist sized motor and it reaches peak pressure of 100 lb psi in 5 minutes. The Kill-a-watt meter says it pulls 1.7 amps and 177 watts.

    The other items I intend to run are an electric chainsaw blade sharpener and maybe a dremel tool on occasion, that each pull about a tenth of what the compressor does. I need to put a large warning sign on this rig - NO HAIR DRYERS OR COFFEE POTS!!

    The reason I am using the 7500w inverter is because it was free. One of the cables was frayed a bit, and my brother got better one as a gift. He passed his old one on to me. Is it bad to use one larger than needed? I have nothing against getting a smaller one, if the 7500 might cause a problem.
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    WHOA! Big edit- the inverter is a 750 watt, NOT a 7500 watt. The sticker on the front was worn a bit and it looked like 7500.
  • BB.BB. Super Moderators, Administrators Posts: 30,053 admin
    Re: Portable solar generator project

    I would avoid the 7,500 watt inverter... It might draw 60-100 watts just to run its internal electronics before you plugged in your first load.

    If you stay with 12 volts and less than 300 watts of continuous loads---I would highly recommend that you pry out $270 from your wallet and get this guy. Even at its worst--it only wastes 6 watts with no loads connected:

    wind-sun_2119_16063131Morningstar SureSine, 300 Watt Sine Wave Inverter 115VAC

    It has to be hardwired to the battery and a 120 VAC outlet--but it will be a very nice addition to your system. It has a DC inhibit (nice for a remote on/off switch. And it has "search mode"--you can leave it on drawing only a couple watts of power until you attach a >6 watt AC load--then it "turns on".)

    You can get any small MSW inverter for $20 or so--However, if you have lots of small AC powered items (battery chargers, TV, things with wall transformers, etc.)--I would highly push the TSW (true sine wave) inverter. The chances that small (and cheap) electronics power supplies will be damaged by a MSW inverter is pretty high.

    A couple Inverter FAQ's if you are interested:

    All About Inverters
    Choosing an inverter for water pumping

    For Reserve Capacity:
    What is reserve capacity?
    Reserve Capacity, (RC) is a battery industry rating, defining a battery's ability to power a vehicle with an inoperative alternator or fan belt. The rating is the number of minutes a battery at 80 degrees F can be discharged at 25 amps and maintain a voltage of 10.5 volts for a 12 volt battery. The higher the reserve rating, the longer your vehicle can operate should your alternator or fan belt fail.

    Or, this means that the 2 Hour Rate in Amp*Hours is:
    • 25 amps * 2 hours = 50 AH capacity at 2 hour rage (120 minutes)
    25 amps * 12 volts = 300 watts average load

    So, a 50 AH 2 hour rate AGM battery is probably around a 60 AH battery at the 20 Hour Rate we typically use around here (using this AGM capacity chart).

    However, I would look up the battery on the Internet--Reserve Capacity as defined for a car does not make a lot of sense for an AGM battery (they are not usually sold into the automotive market). They may have another definition that I am not aware of for their applications.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 30,053 admin
    Re: Portable solar generator project

    Gee--Now after I write my 20,000 word post about your 7.5kW inverter--it is 1/10th that size... Thanks a lot. :roll:;):p

    Regarding the maximum battery charging for a 135 watt panel... Assuming it has Imp = 7.26 amps or so and we recommend a minimum of 5% rate of charge (based on 20 Hour Rating):
    • 7.26 amps / 0.05 charge rate = 145 amps
    That is the maximum sized battery I would recommend.

    So, at this point, you actually have a nice hefty sized solar panel for the battery you currently have connected (assuming it is ~60 AH rated). That means you will be able to recharge quickly on nice sunny days. Nothing wrong with that.

    We try to size the batteries based on the loads--So, you should plan on your loads using a maximum of 50% of the battery's capacity on a "daily basis" (25% of capacity would be better for daily loads--but for portable operations where space and weight is at a premium, you take what you can get). You can use upwards of 80% of the battery's capacity--but that gets into "dangerous" territory of killing the battery from over discharge (one or more cells go flat and actually begin to reverse charge--pretty much ending the life of your battery at that point).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    Your words were not wasted, Bill! It is all good info, and I am soaking it up. Since all of my stuff already has DC plugs, I won't be using the inverter for anything other than appliances with small motors, ie. no tvs, computers, etc. Having one of those 300w TSW rigs will be worth having, just in case, though. I appreciate the recommendation, and have put it on my 'wish list'.

    With the new information about my battery, I seems like I might do well to get a second identical battery to boost me up to 120 AH. The rule of thumb I gleaned from your post is that a battery rating in RC = 1/2 AH (120 RC = 60 AH). Two of those in parallel with a 135w panel? This system can only be so big before it outgrows the gurney platform, but I would like to get as much potential built into it as possible. This platform will be moved and turned throughout the day to avoid shadowing, even tilting the panel to remain perpendicular to the sun. Is 120 AH of battery bank too much for that one panel?

    Again, this system is just to keep small AA/AAA powered devices recharged and an occasional small motorized AC device for a few minutes. I would like to maximize my AH capacity for cloudy days, but I don't want to get more battery than I can charge up on an average sunny day.

    UPS tracking has my panel arriving on the 8th. Now I have to figure out how to mount it on the plywood base. I looked at the various mounting hardware, but didn't see anything designed to secure a panel directly to a wooden base. I cut the base to be a large rectangle '8'. That will allow for ventilation under the panel, access to the wiring, and of course, cuts down on weight. The plywood is treated, 1-1/8 flooring plywood. VERY sturdy. I cut it to allow an inch of wood to extend outside the PV panel on all sides. I am hoping that I can find some suitable 'Z' mounts, so I can screw the bottom flange of the 'Z' into the wood, with the top flange securing the PV panel. Most of them will go on the hinged side to support the weight of the panel from sliding off the base when tilted vertically, with a few more on the remaing three sides to keep it from being blown off the base in a strong wind. What do you think?

    Thank you, so much, Bill.
  • BB.BB. Super Moderators, Administrators Posts: 30,053 admin
    Re: Portable solar generator project
    CorbinKale wrote: »
    Your words were not wasted, ... I appreciate the recommendation, and have put it on my 'wish list'.
    Not a problem--just a little teasing! It may not look like it--but we do have a sense of humor too (although, that creates its own problems on the Innertubes :roll:).
    With the new information about my battery, I seems like I might do well to get a second identical battery to boost me up to 120 AH. The rule of thumb I gleaned from your post is that a battery rating in RC = 1/2 AH (120 RC = 60 AH).

    Actually no--It is more completed that that... Basically, you get an AH rating from this equation:
    • Time (in Hours) * Amp Load = Capacity (in Amp*Hours)
    • 120 min ( 1hr/60min) * 25 amps = 50 AH
    Next, the batteries typically have a list (can be a mathematical equation based on Peukert's law) where you have 1 HR, 2 HR, 4 HR, 8 HR, 20 HR, 100 HR capacity ratings in Amp*Hours

    In this case the 25 hour load lasted 120 minutes, so this is pretty much the 2 Hour Rating from the battery... If the 25 amp discharge lasted 1,200 minutes, then that would be equivalent the 20 Hour Rating.

    All in all--Basically, the larger the value of current you pull from the battery, the less efficient they are. So, if you have 120 min, that is a C/2 discharge rate. If your batteries lasts for 1,200 minutes with XX load--then that is a C/20 discharge rate.

    And again the capacity is Time(Hours)*Amps=Amp*Hour capacity at that rate.

    Also, as a class, AGM batteries are very efficient over a wide range of current levels (their capacity is not that much different between C/2 and C/20 discharge rates).
    Two of those in parallel with a 135w panel? This system can only be so big before it outgrows the gurney platform, but I would like to get as much potential built into it as possible. This platform will be moved and turned throughout the day to avoid shadowing, even tilting the panel to remain perpendicular to the sun. Is 120 AH of battery bank too much for that one panel?

    You have to define what is important to you... If most of your power needs are when the sun is up--then all the battery needs to supply is some surge current and when a cloud or bird flies overhead. So a minimal battery is all that is required (keeps costs and weight down).

    If, however, you need the power day/night/sunny/cloudy weather/etc... Then sizing your system for the battery bank is very important. Again--Normally your daily loads should be ~20-50% of the battery capacity before it is recharged again. And never draw more than 80% of the battery capacity to reduce the chances of deep discharging damaging the battery.

    In general, the deeper you cycle the battery, the less overall charging cycles the battery will last. However, having more batteries costs a lot of money too... So, if a 2x larger battery bank lasts 2.2x longer--The ongoing battery replacement costs are not much different--it just means you only have to replace twice as many batteries batteries every 4 years instead of every two.
    Again, this system is just to keep small AA/AAA powered devices recharged and an occasional small motorized AC device for a few minutes. I would like to maximize my AH capacity for cloudy days, but I don't want to get more battery than I can charge up on an average sunny day.

    This gets back to your needs... Figure out the Amp*Hour load per day (here are a couple nifty DC Amp*Hour / Watt*Hour meters designed to log DC loads) and size the battery bank to that...

    Once you know your battery bank size--Then you need to size the solar array to supply the bank and the load... Typical rules of thumb are 5% to 13% of bank capacity for charging current which we went through in a previous post.

    But, you also have to know how much sun per day you can collect... 2-3 hours in the winter and 4-6 hours of "noontime equivalent sun" in the summer are typical values... So, the panels also have to be large enough to recharge your daily loads too.

    I.e., you may have enough panels to "properly charge" a battery bank, but not enough panels to recharge your daily loads because your system is on the coast line and is subject to marine layer overcast during the entire summer (like parts of the SF Bay Area).
    UPS tracking has my panel arriving on the 8th. Now I have to figure out how to mount it on the plywood base. I looked at the various mounting hardware, but didn't see anything designed to secure a panel directly to a wooden base. I cut the base to be a large rectangle '8'. That will allow for ventilation under the panel, access to the wiring, and of course, cuts down on weight. The plywood is treated, 1-1/8 flooring plywood. VERY sturdy. I cut it to allow an inch of wood to extend outside the PV panel on all sides. I am hoping that I can find some suitable 'Z' mounts, so I can screw the bottom flange of the 'Z' into the wood, with the top flange securing the PV panel. Most of them will go on the hinged side to support the weight of the panel from sliding off the base when tilted vertically, with a few more on the remaing three sides to keep it from being blown off the base in a strong wind. What do you think?

    Basically, you are mounting a piece of single weight window glass. So--the frame cannot allow bending or twisting forces to be imparted to the glass.

    For example, you tilt the panel at 45 degrees and place a mounting stick in the upper right corner... Big gust of wind comes and the unsupported corner is pressed back causing the glass to shatter. (not saying you will do that--just an example of twisting forces).

    Most likely, your system will not be out in a full on hurricane--So, it does not need a licensed structural engineer to design/approve the mounting...

    However, the overall rig needs to be stable enough that when freestanding a large gust of wind does not topple the whole rig (again shattering the glass).

    Also, when transporting, you want to make sure that the panel is protected against knocks and such... Placing plywood on the back (with some vent holes/heavy screening) such that when folded the rear of the panel is protected by plywood and the face is facing the gurney--an example of how the mounting also becomes transportation protection.

    1" Ply may or may not be overkill--It is all a trade-off between ruggedness and weight (for transportation). The aluminum frames are pretty strong and only need to be supported in a couple locations (typically two mounting bars roughly 1/4 the way in from the edges)--And as long as the mounts do not cause flexing/twisting/bending in the solar panel--you should be OK.

    And, I cannot emphasize enough protection for transportation... These are thin (tempered) window glass--and one heavy scratch, knock, or twist--and you have modern art instead of a $500 power source.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    With this portable system, I had to approach it backwards. First, I had to figure out what the biggest, most efficient panel was. In this case it was the 135w Kyocera. It fits PERFECTLY. I fooled around with a folding design that would incorporate two of these panels, or a couple of smaller panels in various configurations, but it was not practical. A single panel mounted on a rigid tilting base is the optimum answer for this project.

    Since the PV panel component is my absolute limiting factor, then I go with the best case scenario for battery capacity. I could reasonably fit six 12v batteries on the bottom shelf, but that is WAY too much. I am thinking that one more of what I have will be just right and still give me some grace for winter and cloudy days. LASTLY, I consider my loads. The system will be what it is. I will tailor my loads to the system, and those will be very light.

    If it turns out that the second battery keeps me from getting a full charge, I will disconnect it, and alternate batterries every few weeks. I think the AGMs will be forgiving of this technique.

    The base is overkill, on purpose. The last thing I want is to break my panel. One whole side is clamped on a pipe that rotates in ring mounts. The unhinged side is supported in the middle by a board with spring clamps. I have grabbed the corners and tried to twist and warp it. There is no flex. Clamping a PV panel frame onto it, will only make it stronger. My plan is to take the original gurney cushion ( 2 inches of vivyl covered foam with 1/2 inch plywood backing) and bungie cord that cushion on top of the panel when not in use, plywood facing out.

    I really need to post some pictures of this thing. Explaining it feels inadequate.
  • BB.BB. Super Moderators, Administrators Posts: 30,053 admin
    Re: Portable solar generator project

    Sounds good... Any battery will be killed if discharged "flat". And AGM's are very sensitive to over charging. A good charge controller (with float stage if this is going to sit for weeks at a time under charge) and a remote battery temperature sensor is almost mandatory.

    Also, I really like Battery Monitors--As close as you are going to get to the equivalent of a "gas gauge" for your car (ever driven around with broken gas gauge--a real pain). Of course, expensive overkill for your system--but still can justify if you need to know how much power is left in your battery bank (under charging/deficit charging is also a major battery killer).

    And--it may sound silly--But I would also look at a Honda eu1000i genset (and AC battery charger) too... Not much larger than your battery. A siphon and a car gas tank could be very useful in an emergency/under heavy use.

    When I started working with solar--I was amazed how much electricity you can get from a 1/2 gallon of fuel (upwards 1-2.5 kWH or so---Or the equivalent of 4-10+ days of full sun on your 135 watt solar panel system).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    This might give a better idea of what I am working with.

    aut0629.th.jpg

    aut0628.th.jpg

    aut0627.th.jpg

    aut0626.th.jpg

    I completely agree about the generator and AC charger. Our group has several generators including a Honda 1000 and 3000. A 3500, a 4500 and even two 10k generators for welding. Between us, I know we have at least five AC chargers. Anytime we fire up a generator for pumping water, welding, or whatever, we will be charging batteries, too.

    This project is a backup plan to the backup plan. It will only see everyday use if the grid is down and there is no fuel for the generators. Just a last ditch solution to keep commo, optics, etc. in operation.

    If we get most of our preps in place before some event occurs, we will start working on home solar installations.
  • mike95490mike95490 Solar Expert Posts: 8,614 ✭✭✭✭✭
    Re: Portable solar generator project

    Here's a good shot of my "Monolith" that I cart around, I just pull the 2 deep cycle batteries out of it, and wheel it on a dolly to my truck.

    http://ae-zone.org/wp-content/gallery/bm2002/2002%20Burningman%20-%20205.jpg

    2002%20Burningman%20-%20205.jpg

    Now linked to my facebook page, which is open access to this album:
    http://www.facebook.com/album.php?aid=2074858&id=1196643274&l=7e66e96c3c

    I built a wood frame around the outside of the panel, to mount with.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project
    mike90045 wrote: »
    Here's a good shot of my "Monolith" that I cart around, I just pull the 2 deep cycle batteries out of it, and wheel it on a dolly to my truck.

    I built a wood frame around the outside of the panel, to mount with.

    I love that thing! It is like a verticle version of what I'm trying to work out. Seeing a working model is very encouraging. Neat design! Do you use guy-lines to stabilize it if the wind is up? I am thinking about using a 'just in case' tether to keep mine from flipping over in a sudden gust. Those can strike with little warning where I am.
  • mike95490mike95490 Solar Expert Posts: 8,614 ✭✭✭✭✭
    Re: Portable solar generator project

    The weight of the 2, Group 27 batteries in the base, is pretty substantial. Tipping is not really going to happen unless it's really windy. If high winds are forcast overnight, I pull the batteries, lay face down, and then park the batteries on the top (was backside) as anchors. that should hold it till hteh whole place gets blown away. As-Is, handles up to 25mph gusts just fine.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    The panel arrived tonight! NAWS packed it well, and it looks like it is in fine shape. Tomorrow, I go to locate some stainless steel bolts, washers, etc to secure this thing to the base platform. I know it seems like a small thing, but I have been thinking about this for years. To be so close to completion is very exciting.
  • BB.BB. Super Moderators, Administrators Posts: 30,053 admin
    Re: Portable solar generator project

    Minor point... If you use stainless hardware, get some "anti-seize compound" from the local auto parts store to put on the threads... Stainless can "gall" and become almost impossible to unbolt at a later date (you may have to drill/cut the hardware).

    Or use Bronze (aka brass) boat hardware--Those threads will be fine over time.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    Thanks for the tip. I'll hit it with PB Blaster, occasionally. I got it mounted and tested it in the sunshine. Everything looks like it works great! Another battery and a battery monitor should be the last items, but I am functional, at this point. Once I get those items installed, I will figure out my cable management.

    One more thing to be added will be a skirt that will hang from the bottom edge of the panel platform. That will block the sun from shining on the batteries and wiring, and will flipped across the panel when the unit is stored flat, to protect the panel.

    This forum is the best source for newbies like me. Thanks again, for all the help!

    aut0661.jpg

    aut0660.jpg

    aut0662.jpg
  • BB.BB. Super Moderators, Administrators Posts: 30,053 admin
    Re: Portable solar generator project

    CorbinKale,

    When you get it completed and functioning the way you want--Feel free to do a writeup and post it here in this thread. I am sure people will find your project very interesting too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    Will do. It might be a few months before I am able to purchase that battery meter, but when I get it all finished, I will list the components in detail and describe the process I went through.
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Portable solar generator project

    Okay, that thing is very cool! Nice workmanship as well. And also a neat way to recycle a wheelchair.
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    Thanks! It is lots of fun to work on, too. The chassis is, actually, an old gurney used in home patient care. I like the wheelchair wheels on one end, though. They smooth out the bumps when easing it down the front porch steps, plus they serve as a guard for the charger / inverter board.
  • CorbinKaleCorbinKale Registered Users Posts: 21
    Re: Portable solar generator project

    Here is an update to the project. I added another battery in parallel, giving me about 120 AH total (60 useable). Also, added larger cables for the inverter, including a beefy cutoff switch for safety and to eliminate the phantom draw.

    Even in the winter sun, this thing is charging VERY well. I think adding any more batteries would be more than the panel could recharge efficiently, not to mention making the rig too heavy to move. :)

    aut0761.jpg

    aut0760.jpg

    aut0762.jpg

    aut0763.jpg

    I was considering attaching a skirt to shade the chassis, but with Murphy's Law in mind, I decided to just use a loose cover to drape, as necessary. I'll fold it up and place it between the batteries when not in use.

    I'd still like to add a better inverter and a battery meter. The parts I am looking at will run another $800, though. Since that is low priority, and the rig is very servicable right now, that might take another year.
  • cfcwcfcw Solar Expert Posts: 25
    Re: Portable solar generator project

    Thanks for the update!
  • survivorsurvivor Registered Users Posts: 2
    Re: Portable solar generator project

    Tell me something: I like the idea of building this solar powered battery charger thing; Not being an electrician but being open to suggestions, tell me if my idea is workable:
    I see where this solar panel will run a battery charger! I have a battery charger for my golf cart. I know the solar panel will not run the golf cart, but if i could mount the solar panel on the roof of the cart and use it to run the battery charger would this not work to have a solar powered golf cart? Input please!
Sign In or Register to comment.