First time solar, have questions

BrettBrett Registered Users Posts: 19
Hello,

I found this site through search engine, and have been reading up on matching pieces together. I like the idea of electric power at a "Lean-to" we use to store implements for the garden. Often we work till dark, then scramble to put everything back before light is completely gone.

My first question is, Am I safe to match a panel's published numbers to a similar-sized Amp Hour battery?

My second question is, what sort of work light would be best suited for this spot. I mainly want to be able to have illumination for short spurts that extend past sundown, but it would also be nice to charge a portable tool now and then.

My last question is, do mppt charge conrollers recharge a battery faster, that it justifies the additional cost?

Thanks a lot.
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Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: First time solar, have questions

    Welcome to the forum.

    Can we presume it's completely out of the question to run AC line to this lean-to? Because frankly solar power is expensive. A long run of wire in conduit buried in a trench is often cheaper.

    That said, you have to look at system design from a load point of view: how much power you're going to need to supply. Obviously you have quite a bit of leeway here, as the lighting won't be critical loads. One option would be DC lighting, for instance, which would eliminate the extra expense (and idle current) of an inverter. If you do want AC available for charging battery tools, a sine wave inverter is a must as the MSW type are known to have compatibility issues with some battery chargers. However, you won't need a really big inverter for this task. Take a look at these two lines:
    Samlex http://www.solar-electric.com/sasiwain1.html and Exeltech http://www.solar-electric.com/exsiwain.html

    I think you may be a bit confused about sizing an array in respect to a battery. The battery's size is dependent on how many Amp hours you need to supply your power over time. Like this:
    100 Amp hours @ 12 Volts = 1200 Watt hours
    The most you want to draw a battery down is 50%, so for the above example you'd have a 200 Amp hour battery.

    The panel size is based on that. You have to try for a peak charge current of 5%-13% of the Amp hour rating. So the 200 Amp hour battery would need 10 Amps @ 14.2 Volts charging, or 142 Watts usable. Usually the panel/controller combination give you an efficiency rating of about 77% of the panel's "nameplate" rating, thus you'd look for a 185 Watt panel to recharge that system.

    Your situation is full of options, as there probably won't be any use during charge time so you could use minimum charge current and expect all your "harvest" to go to recharging.

    MPPT type controllers are really only justifiable in larger systems, where they can make use of higher Voltage arrays.

    If we can get an estimate on how much light is needed for how long I think we can give you some options that will work.
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    Cariboocoot,

    Thank you. You are right that I am confused, and on more than one thing!
    The distance of our lean-to from electrical outlet is about a football field's length.
    Sometimes when I go out to check for critters at night, it would be nice to have more than a flashlight to see with. I keep some 'perishable' garden supplies in tubs and closed trash cans. By the way, we do have an electric fence in place that comes down from the house, too bad i can't convert that back to AC.

    On the loads, it really is just lighting for short periods of time. I have some tools from Harbor Freight that recharge from DC directly, but I had not heard of DC lighting-at least not like the kind of lights that I use in the house. Where do I buy DC lights?

    Thanks for the advice on the controller. I need somewhere to save money as the prices I saw on this NAWS website, for your example of the 185 watt panel, and a 200 amp hour battery, have given me sticker shock :(

    Now I don't mean that I have compared prices any other place, I just mean that I hadn't looked at the cost for electricity-to-go.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: First time solar, have questions
    The distance of our lean-to from electrical outlet is about a football field's length.

    Je suis Canadien! How many hockey rinks is that? :p

    I did warn you the stuff is expensive.
    Some of the "fancy" DC lighting: http://www.solar-electric.com/thinlites.html (Nice stuff. Even a motion sensor.)
    But automotive type lighting is also viable. If you have some really cheap auto outlets, they sometimes have 12 V LED units too. It all depends on how much light you need and of what kind; general, or spot, or a combination of both.
    You probably would not even need the battery size I picked - I just tend to use 100 Amp hours as a "default" because it makes for easy calculations. 1200 Watt hours is a fair amount of electric. Think of it as a 60 Watt bulb running for 20 hours straight. Obviously you don't need that much.

    Take a look at some of these controllers from Morningstar: http://www.solar-electric.com/mochco.html Some even have Low Voltage Disconnect, which is entirely suitable for shutting down lights before the battery gets too low.

    In the case of the smallest controller, you'd have something like this:
    120 Amp hour battery (about 720 Watt hours)
    6 Amp controller
    110 Watts of panel

    And you could go smaller than that.

    But you need to settle on what your trying to supply first.
    Or buy 500 feet of 12/2 UG wire. :p
  • BB.BB. Super Moderators, Administrators Posts: 31,910 admin
    Re: First time solar, have questions

    Here are a couple links for "simple" off-grid/emergency solar power projects:

    Emergency Power

    Solar Monolith

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: First time solar, have questions

    if this is just 5 minutes or so of lighting then you will not need a large system, but you still need to evaluate the worst case time the loads will be on and how much ah that is so you could have at least a minimum amount of power you'd need to figure the battery for and that will also determine the pvs needed.

    anyway, as some food for thought, you need to figure how it is you'd turn off that light when you are xx feet away from the leanto. the option is to shut it off at the leanto and use a flashlight, but then why would you then need the solar if you must carry a flashlight?
  • BB.BB. Super Moderators, Administrators Posts: 31,910 admin
    Re: First time solar, have questions

    300' of direct burial 12 awg cable will give you ~3 amps at 3% voltage drop (at 120 VAC). Or 6 amps at 240 VAC.

    300' of 12/3 (120/240 VAC) cable will cost you around $190 at a home center...

    Rent/borrow a trencher for 4 hours a bury to at least 18" deep (I believe that is code) for another $100 or so...

    Any appreciably sized solar power system is going to cost you $300 or more. Plus add battery maintenance/replacement every few years...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: First time solar, have questions

    If it's just a bit of light you need you could opt for one of the "solar lantern" type products, like this one: http://www.amazon.com/d-light-S250-Solar-LED-Lantern/dp/B0043VB70O
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    Niel, BB, Cariboocoot,

    Thank you for the alternatives, I hadn't even considered that solar could be more expensive than a ditch witch. BB, your suggestion is appreciated, but I'd bet that by the time I also added in the cost of pvc pipe, couplers, glue, and misc tools to properly prevent the conduit from being ground, a smaller solar kit sounds more attractive.

    I also did not think of a motion sensor, and that would aid a flashlight, or even alert us to varmints determined to eat the stems off of everything.

    BB, in another thread you posted, "Typically for 12 volt systems, Vmp~17.5 volts and Voc~21 volts." I found a panel that advertises 22.7V and 18.3V, so I am guessing that is a good choice?
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions
    stephendv wrote: »
    If it's just a bit of light you need you could opt for one of the "solar lantern" type products, like this one: http://www.amazon.com/d-light-S250-Solar-LED-Lantern/dp/B0043VB70O

    Thank you for the suggestion, but I haven't had much luck with rechargeable solar lights. They are never bright enough, or the clear plastic goes opaque, or the internal battery dies way too early. I tried a solar security light once before that was bright, but then the rest of the contraption failed after only a couple of days. I'd feel more sure that a small kit, built right from the start, can work and last for years. And I wouldn't have to throw the whole thing out and start over if one thing breaks....
  • BB.BB. Super Moderators, Administrators Posts: 31,910 admin
    Re: First time solar, have questions
    Brett wrote: »
    Thank you for the alternatives, I hadn't even considered that solar could be more expensive than a ditch witch. BB, your suggestion is appreciated, but I'd bet that by the time I also added in the cost of pvc pipe, couplers, glue, and misc tools to properly prevent the conduit from being ground, a smaller solar kit sounds more attractive.
    That was direct burial cable--So you would not need the gray plastic conduit except at the ends to drop the cable down the side of the home and back up the out building. But, again, power usage and type is a personal choice.
    I also did not think of a motion sensor, and that would aid a flashlight, or even alert us to varmints determined to eat the stems off of everything.
    In terms of security--a motion sensor is usually much better than a dusk to dawn light--plus it saves a lot of energy.
    BB, in another thread you posted, "Typically for 12 volt systems, Vmp~17.5 volts and Voc~21 volts." I found a panel that advertises 22.7V and 18.3V, so I am guessing that is a good choice?
    Voltage wise, that would be OK for a PWM controller. Of course, the power (watts) / current (amps) of the panel is important too...

    There are a lot of very inexpensive solar panels (Harbor Freight/Northern Tool)--But those (typically amorphous) panels are not usually very good. The rarely output anywhere near their ratings. A good brand of crystalline solar panels is much better in the long term.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    BB,

    Direct burial doesn't work too well in our area. We live near a minor fault, and the ground leaches rocks to the surface. Over time, I've started an assortment of rock piles around the place.
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    My panel will arrive middle of next week, and so now I'm looking at battery size. In searching the threads, BB posted this formula to find the 5-13% rate of charge. So if I plug in the panel's rated output, it should look something like this:

    85 watts * 0.77 derating * 1/14.4 volts charging * 1/0.13 rate of charge = 34.9 Amp Hours (one at end).

    or

    85 watts * 0.77 derating * 1/14.4 volts charging * 1/0.05 rate of charge = 90.9 Amp Hours (at the other end).

    So I am good with any 12V deep-cycle battery in the range from 34 - 90 Amp Hours?

    I also read that I should not go below a 50% discharge, so the working limitations would be 17 - 45 Amp Hours range.

    Looking at the Solsum 12V DC light(Thank You Cariboocoot), the description says it uses about 1 amp per hour?
    So if I get a 90 Amp Hour deep cycle battery, then this light could stay on all night without doing any damage.

    Thanks for the formula, BB. This is the sort of real-life math I wish my school teacher had given me.
  • BB.BB. Super Moderators, Administrators Posts: 31,910 admin
    Re: First time solar, have questions

    Brett,

    You are very welcome... I too hated math and was not very good at it until I had classes/instructors that had real world applications. For me, that was college calculus and physics/engineering classes. Now I enjoy math and not very good at it. :roll:;)

    One correction. It is Amps not Amp per Hour. Amps is already a rate like MPH or Gallons per Hour. Saying Amp per Hour is the same as saying Miles per Hour*Hour.

    Amps*Hours and Watts*Hours is an amount... Likes Miles driving or Gallons pumped.

    And when we talk about power and energy Watts = Amps*Volts ... There are some historical and practical reason why people use Amp*Hours vs Watt*Hours, but for our work we always want to be sure we talk about the system operating voltage. Only talking about Amps is just one piece of the energy puzzle.

    Otherwise your math is correct...
    • 1 amp * 12 volts = 12 watts
    • 1 amp * 12 hours = 12 amp*hours
    • 1 amp * 12 hours * 12 volts = 144 Watt*Hours
    Yes, you can leave the lamp on all night and not do any damage to a 90 AH 12 volt battery (it will still count as a partial discharge cycle, so you are slowly "wearing out the battery" by use--but batteries are not useful if you don't use them):
    • 1 amp * 12 hours = 12 AH
    • 12 AH/90 AH = 0.13 = 13% discharge
    • 45 AH / 12 AH = 3.75 "nights" of use before 50% discharge for long life
    Of course, there is the issue of recharging... You have to have enough solar power (or other energy) to bring make up the energy used and eventually bring the battery back to 90%+ charge (every few days or once a week at least).

    If you leave a lead acid storage battery sit below ~75% state of charge for longer than a day or so, the sulphates begin to harden (actually crystallize) and the lead is "removed" from the available battery chemistry and unavailable for further charging/discharging cycles. Basically costing you battery capacity. Batteries that sit below 75% state of charge for weeks/months will eventually become scrap.

    Also, you don't want to ever discharge a battery below ~20% state of charge. At this point, one or more cells may go "dead" and actually begin to "reverse charge" (battery cell capacity can vary up to ~20% between cells) which is, pretty much, a death sentence for that cell...

    Which brings me back to using your solar power... Yes you can leave the light on all night, but you either must monitor the state of charge of the battery system to ensure you operate it in a manner which will give you long battery life, or include an automatic way of turning off the lights if the battery state of charge goes too low (i.e., cloudy weather, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    BB,

    Amps vs Amp Hours, thast not language I ever hear used in a sentence, but I see there is some order in the numbers you gave. Do you have math for figuring out how long it takes to fully replace what has been discharged? I saw a chart for the number of hours-per-day when panel is in best alignment.

    So my derated system has a 65 watt output, for 5 hours a day(April) that it will get maximum sun. 300+ watts 'harvested' takes how long to replace a 13% discharge(if you don't mind my using your example)? If, by accident, the lamp was left on all night, would the panel be able to replace that in one day? THis is a bit over my head, but I wouldn't want to start a habit of diminishing returns. Thank you.
  • BB.BB. Super Moderators, Administrators Posts: 31,910 admin
    Re: First time solar, have questions

    Very roughly... Recharging a battery from 0 to ~80-90% state of charge is pretty much 1 AH out replaced by 1 AH back in... That last 10-20% charging the battery voltage rises and starts current back on current (tapering) until the current is ~2% of full ~13% rate of charge...

    The last part of the charging is also less efficient. Much of the charging current is turned into Heat and Outgassing (hydrogen/oxygen electrolysis of water).

    A battery tends to be near 100% efficient when replacing Amp*Hours after discharging... However for a flooded cell battery the charging tends to be around 80-90% efficient (new battery is more energy efficient, plus overall efficiency depends on your usage pattern... Shallow discharges and recharges tend to be less energy efficient than deep cycling.

    Watt*Hours... The difference in energy (efficiency) between discharging and charging:
    • 1 amp * 12 hours * 12 volts average battery voltage = 144 watt*hours of energy used
    • 1 amp * 12 hours = 12 Amp*Hours of "current" used
    Replacing the 12 Amp*Hours of current vs the energy required to replace the 12 Amp*Hours:
    • 12 Amp*Hours replacement * 14.5 volts charging = 174 Watt*Hours needed to recharge
    • Where you only need to replace ~12 AH (near ~100% current charging efficiency).
    So the "energy efficiency" of charging (rough numbers):
    • 144 WH used for loads / 174 WH used to recharge = 0.83 = 83% battery cycling efficiency
    The states of charge:
    • Bulk: Battery takes all current available from charger until battery reaches "Absorb Voltage"
    • Absorb: Battery Reaches set point of charger (such as 14.5 VDC) and holds it there for ~2 hours and/or until charging current drops to 2% current.
    • Float: Battery charger voltage to keep battery charged without causing outgasing/water level drop. Long term storage voltage setting for charger.
    • Equalize: Purposely setting charger voltage to ~15-15.5 volts to over charge battery to force current through cells less than 100% charged. Typically only done on flooded cell batteries and not on AGM's.
    So, for a 13% rate of charge on a 90 AH battery:
    • 0.13 * 90 AH = 11.7 amps
    Your load was ~1 amp * 12 hours = 12 Amp*Hours.

    If it was simply recharging at full current (not worry about voltage):
    • 12 AH used / 11.8 Amp rate = 1.03 Hours to Recharge
    In reality, you are ~87% state of charge (100% capacity - 13% energy used). So, your charger should have the battery pretty near 14.5 volts almost as soon as it is turned on.

    And, since we have declining charging current (during absorb stage), typically with a 5-13% rate of charge, it would take 2-4 hours or so to complete the charge...

    Now, the above makes sense with a AC line powered battery charger--But in your case, you want to use the sun... And we know that we only get nearly "full power" from a fixed solar array during the few hours around noontime...

    So, it is really easier to just use the rule of thumb for how much energy you will need to recharge the battery bank... So, assuming 77% solar panel efficiency + charge controller efficiency, 85 watt panel and 4 hours of full equivalent sun per day (reasonable 9 month minimum in a sunny region). Also assume your 1 amp load * 12 volts * 0.80 efficient flooded cell battery (no AC inverter):
    • 1 amp * 12 volts * 12 hours * 1/0.80 Eff = 180 WH to recharge battery bank daily
    • 85 watts * 4 hours of sun * 0.77 panel+charger eff = 262 WH per typical day (or better)
    Since 262 Watt*Hours of estimated solar power > 180 WH of load... You, on average, will recharge the battery 100% every day (strings of bad weather, you may need more lights in winter than summer, etc. will affect your final choices for product/power usage/backup power if needed).

    In general, never assume that a solar panel WH rated for charging = Load WH requirements is a good thing. On average, you would be slowly discharging battery over time (some days you use more power, some days you may have poor sun--all the solar PV planning is based on long term averages of ~20 years--You will have short term variations from average).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    BB,

    I got my solar panel in today, and now need to gather together some hardware to mount it. These bits-n-pieces will probably be my biggest challenge. I wanted to say Thank You for the breakdown on re-charging. Also in-route are a couple of the DC lites which use the standard screw-in socket.

    One thing is curious about this panel. The Sales receipt indicated that the panel is made from Evergreen Cells, even tho it is not an Evergreen-branded Panel. This info is not anywhere on the vendor's site from with I purchased it.

    Did I just buy a grey-market product?
  • BB.BB. Super Moderators, Administrators Posts: 31,910 admin
    Re: First time solar, have questions

    I don't know...

    Evergreen (and other vendors) are known to sell excess inventory and "blemished" panels without their labels--but are just as good.

    On the downside, many vendors will sell solar cell "seconds" that other companies will package into their panels.

    Evergreen is a good vendor (if in financial trouble).

    I am not in the solar business--so on that side, I probably do not know much more (if any) than you.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    If you do want AC available for charging battery tools, a sine wave inverter is a must as the MSW type are known to have compatibility issues with some battery chargers. However, you won't need a really big inverter for this task. Take a look at these two lines:
    Samlex http://www.solar-electric.com/sasiwain1.html and Exeltech http://www.solar-electric.com/exsiwain.html

    In looking at the Samlex inverters, I get concerned about their shut-off voltage (10 V ?)
    From reading other posts, it sounds as if any battery metering 10.5 volts is essentially discharged. If an inverter is pulling the battery below this number, wouldn't that be potentially dangerous? What am I missing?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: First time solar, have questions
    Brett wrote: »
    In looking at the Samlex inverters, I get concerned about their shut-off voltage (10 V ?)
    From reading other posts, it sounds as if any battery metering 10.5 volts is essentially discharged. If an inverter is pulling the battery below this number, wouldn't that be potentially dangerous? What am I missing?

    The part where the solar panels recharge the battery before it gets this low? The low Voltage shut-off point is a safety measure to make sure the batteries are never discharged to the unrecoverable point. Inverters don't draw batteries down this low unless left on with loads and no recharging. In other words, it is unlikely to happen. There's not much difference between 10.5 and 10 Volts for this function, as a battery will usually "bounce back" half a Volt when the load is removed.
  • BB.BB. Super Moderators, Administrators Posts: 31,910 admin
    Re: First time solar, have questions

    Also the 10.5 or 10.0 cutoff voltage is there to protect the inverter and attached AC loads... Below that point, the inverter would draw too much DC input current (overheat the inverter) and probably output too low of AC output voltage (possibly damage the AC appliance).

    Battery protection by AC inverter cutoff is not a feature unless the inverter has something like a 11.5 volt cutoff--Then you may have the inverter turn off during heavy starting loads--It is difficult to win here using LVD (low voltage disconnects) to "save" your battery bank.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: First time solar, have questions

    one piece of advice though.
    don't rely on it to protect your batteries.

    if that device kicks on, most likely (if the batteries are still good) the lifespan has been compromised some already. it also depends on what the load is as heavier loads pull the battery voltage down farther than lighter loads given the same state of charge to start with. that means you can drain a battery to be 100% dod on a lighter load and that "protection" may never have kicked in.
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    What about fuses? Are they needed in my one-horse town? Perhaps I am thinking too much like the fuse panel in a car, but shouldn't their be something in the positive lead somewhere? Thanks.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: First time solar, have questions
    Brett wrote: »
    What about fuses? Are they needed in my one-horse town? Perhaps I am thinking too much like the fuse panel in a car, but shouldn't their be something in the positive lead somewhere? Thanks.

    Yes, fuses (or circuit breakers) are an important safety feature.
    There should be a fuse between the battery and the inverter.
    There should be another between the charge controller and the battery.
    If you have more than two panels (or strings of panels) in parallel than each should have a fuse.

    Fuse rating is generally sized as the max current rating times 1.25 as per NEC spec.
    For panels that's the Isc of the panel * 1.25.
    For the charge controller it should be the max output current (not necessarily the most the controller is capable of, but usually) * 1.25.
    For the inverter it should be the max current draw of the inverter * 1.25 (manuals will usually give a recommended fuse size). That's current at minimum input Voltage and maximum output Wattage, as in:
    1200 Watt "12 Volt" inverter @ 10.5 Volts cut-off = 114 Amps * 1.25 = 142 Amps, rounded up to the nearest available size, i.e. 150 Amp fuse.
    And always be sure the wire can handle more current than the fuse.
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    The rated Isc of this panel is 5.12 A, giving me a fuse requirement of 6.4 amps. I had some solid copper wire I was going to use between the panel's junction box and the charge controller. It's #12 AWG with a vinyl coating.

    Since the controller is going to be a PWM type, would that wire be sufficient from the controller to the battery (rated for 90AH deep cycle)?

    I don't plan on having an inverter right away, since I am going with the Solsum 12V DC light you recommended. If I have enough of the #12 solid copper left, I will use that to run it's power from the battery, I figure no more than 10 feet to get to the screw-in base.
    Should that be fused as well?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: First time solar, have questions

    One panel does not require a fuse. The most current it will ever produce is the Isc rating, and that is into a short circuit (hence "sc" in Isc). Basically it's designed to do that and survive.

    You should fuse the output of the charge controller. The output there won't be more than 6 Amps, so that's a 7.5 Amp fuse.

    It never hurts to put a fuse on a load, even when it's less than 1 Amp. You never know; someone might short the wiring/socket/switch and the battery can push a lot more than 1 Amp of current! You might have difficulty finding those small auto fuses, but they do exist. You could put both fuses in one block, with the "common" connector on the battery (+) and the controller feeding in through a 7.5 Amp and the light running out through a 1 Amp.

    Your 12 AWG wire should have no trouble handling those loads with those short distances. It's practically automotive wiring all the way. :D
  • MadJackMadJack Solar Expert Posts: 37
    Re: First time solar, have questions

    Hear is a security light I have owned for 4 months (through a Maine winter) and have no trouble with! Planning on buying another to put out at the deer feeder so I can watch the deer and shoot the coons robbing it!

    http://www.tractorsupply.com/home-improvement/electrical-equipment-supplies/outlets-lighting-fixtures/lights/solar-motion-light-3400592

    And this one is going in my Genny Shed next week!

    http://www.tractorsupply.com/home-improvement/electrical-equipment-supplies/outlets-lighting-fixtures/lights/solar-shed-light-8500012

    The first one WORKS WELL for me. The second one I'll let you know about.
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    Harbor Freight Tools sells a clone of that first product, that I bought, it was so dim as to be un-useable. It was thrown away.

    Thank you for the reference, but my wallet is on the Solsum.
  • BrettBrett Registered Users Posts: 19
    Re: First time solar, have questions

    I went shopping for a 90AH battery today, and finally found one that exactly fit the bill, for $220. The salesman then pointed to a set of 4 batteries they had on sale, CSB GP-12400.

    The sale price was $40 each, so I bought all 4. Their manufacture dates are all the same, Feb 2010, and they all read the same voltage, 12.8V, straight from their boxes. I also bought 3 pairs of #6AWG battery cables, 1 foot long.

    I've never heard of these batteries before, but after looking at the internet price listings, they certainly are expensive. I hope that means these are decent quality.

    I plan to charge them as two separate pairs, giving me 80AH instead of my target 90. The price per AH was certainly better than the one larger product.

    Is there some sort of battery switch that could allow me to NOT juggle cables back and forth? Thank you.
  • mike95490mike95490 Solar Expert Posts: 9,324 ✭✭✭✭✭
    Re: First time solar, have questions
    Brett wrote: »
    .......Is there some sort of battery switch that could allow me to NOT juggle cables back and forth? Thank you.

    Boating supply houses have battery selector switches, about 4" round, red plastic, they come in 2 flavors, Make before Break, and Break before Make.
    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 ,

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: First time solar, have questions

    They're all much like this one from Blue Sea: http://www.solar-electric.com/basw1300amp.html
    Good option.
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