Emergency power

rohanjcprohanjcp Posts: 30Solar Expert ✭✭
I am a beginner and would need some guidance and recommendation. I would like to setup a solar panel based backup emergency power kit for my home. I get about 4 hours of sunlight a day but I only need the power for emergency. I have no background in electronics but took the effort to read Emergency Power for Communications for Ham Radio Operators.

I'm looking at the 50W-65W solar panel range such as in the Kyocera KC-65T 65 Watt 12 Volt Solar Panel and had a couple of questions. I feel it is better to get these panels with long warranty than the cheaper solar kits at Harbor Freight with less than 5 years warranty.

I would like to use this setup to mainly charge my:
-Duracell DPP-600HD Powerpack 600 Jump Starter & Emergency Power Source with Radio
-My HAM radio Yaesu FT60R handheld radio desktop charger.
-My MAHA AA/AAA battery chargers
-A 12v dc water boiler

Can you help me to get my bearings with regards to what I think I need to buy?
-In terms of the solar panel- if my choice is ok
-I am interested in the morning star charge controller if you recommend them. It seems that this charge controller allows me to connect the solar panels to the charge controller and to the load directly without a battery in between.
-I am interested in the most appropriate and affordable inverter.
-I am curious if I need a digital multimeter.
-Maybe a battery too?

Thank you so much for all your help.

rohanjcp
[email protected]
«13

Comments

  • icarusicarus Posts: 5,108Solar Expert ✭✭✭✭
    Re: Emergency power

    You realize of course that using solar for emergency power is WAY more expensive thatn using a generator?

    As we say here all too often,, do the math. Calculate your loads to last watt/hour, then you will know where to start.


    From there you can do some sizing and using some efficiency curves to see what you really need. Consider how much reserve battery you will need, and how long before you can get back on line on average. (Most people consider a 50% discharge of any battery system to be the maximum permitted if you expect the batteries to last).

    For a rough number for efficiency, I like to use 50%. In other words for every 100 watt hours of solar power capacity you have, the average you are likely to get out of a battery into an ac outlet is ~50 watt hours. So for your example, if you had 50 watts of panel, for 4 hours (of 100% sun!) you would get a gross of ~200 wh out of the system gross. Calculating all the efficiencies would net you ~100 wh, enough to run a 15 watt CFL for ~5.5 hours.

    As I said,, do the math and it will begin to give you some answers.

    As for your hardware requirements,,, most of the questions can't be answered until you have done the math. As for inverters, consider whether or not you need true sine wave or if you can live with modified sine wave. Sensitive (expensive) electronics often don't like modified sine wave, and you risk sending them up in smoke.

    Start with the battery capacity you need, then work backwards to figure out how much panel you need to keep it charged, how much controller etc.

    Tony

    PS Bill will chime in with "real" numbers, but they seem to come close to my 50% rule.

    PPS. I don't know what a 12 vdc water boiler is, but what I do know is that any heat generating appliance will draw considerable wattage, and in the kind of system you are talking about, it would be prohibitive. I suggest a small camp stove to heat water.
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    Tony/Icarus has the basics down pat... Nothing to add on that side of the discussion (unless you want me to point to the solar PV calculator--not really needed yet).

    The 12 volt travel heater--don't bother. Get a multi-fuel camp stove or an emergency stove that can burn fuel tablets or can fuel. Even a solar oven of some sort would probably be more useful.

    Solar power is, usually, to "expensive" and "hard to get" to waste on tasks that can be done other ways.

    Next, the Duracell power station... I would suggest that you "build your own"... All it has is a 28 Amp*Hour (12 volt?) AGM battery, a cheap 600 watt inverter, and battery charger (plus a radio, etc.).

    The 28 amp*hour battery can only run the 600 watt inverter at full load (600 watts) for:

    28 AH * 12 volts * 50% (max batt disch) / (600 watt * 1/85% eff) = 16.8 minutes (rough estimate) Fix below:

    28 AH * 12 volts * 50% (max batt disch) / (600 watt * 1/85% eff) = 0.238 hours

    or:

    0.238 hours * 60 min per hour = 14.28 minutes (rough estimate)


    And the thing weighs ~30 lbs.

    You would be much better off building/configuring your own... Pick a battery that supports your needs (and probably lasts longer than the 1-2 years that the Power Station may last), uses a real True Sine Wave inverter (better for electronics, motors, and radios). And a real 3-4 stage AC battery charger (allows unit to be plugged in and kept fully charged--also has a fast charge mode where you can plug into an emergency generator if handy).

    Lastly, with a good solar panel (sized to your needs) and a good solar battery charger with a remote battery temperature sensor for best battery life and most charge "pumped" into the battery.

    Lastly, take a look at the Honda eu1000i or eu2000i generator with 5-10 gallons of fuel (siphon from car, or use fuel stabilizer). The eu1000i is about the same weight (~29 lbs), and will run 1/4 rated power (225 watts) for 8 hours on 0.6 gallons of fuel). Maybe a propane powered genset would be a good option for an emergency field station trailer (including hot water, cook top, fridge, etc.).

    Solar is best when you are using it full time for 9+ months out of the year--for emergency use (and 1 day a month testing)---it is pretty bulky and expensive for the amount of power you will get. Also, solar panels are thin pieces of glass--portable solar panels can get easily damaged.

    In the end, first fully understand your loads and needs, then work backwards to decide the power source(s) that will fill your needs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Emergency power

    there's too much here to address in one post, but generally you can piece together something workable for 12v as even the ht should be able to charge from a 12v source. i'm not sure of which maha chargers you have, but if yours run from 120vac then there should be chargers available to use from 12v rather than 120ac so as to eliminate the need for an inverter. a battery and a charge controller should be used with the pv and must be sized according to the loads you'll need to run and the pv's ability to properly charge the battery. fuses/circuit breakers and switches should be utilized to shut down power and to protect from mishaps.
    using electric to heat anything is asking for trouble so i wouldn't do it. please do some reading up here in the forum to learn more of what you are doing and what you can do, not just what you want to do. you can continue your questions here along this line as it's basically your thread to pursue knowledge for.
    1st step is to know what you want powered and for how long using 12vdc. work on this while you read.
  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    Re: Emergency power
    rohanjcp wrote: »
    I get about 4 hours of sunlight a day but I only need the power for emergency.

    Do you ever expect to have a cloudy/rainy/no sun in an emergency ? If you have a 3 day emergency, you may only have one day of sun to recharge with.

    Bigger battery, and a plug-in charger for it. Run your radio off 12V battery, you loose effiency when you recharge it's internal cells.

    Will the repeater you use have power, or are you going from handheld - handheld ?
    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 ,

  • jacobsjacobs Posts: 72Solar Expert ✭✭
    Re: Emergency power

    My older model MH-C777 Maha charger works fine on 12vdc. With 12 volt input, it won't charge 12 volt batteries but it will charge 9.6 volt batteries. If you need to charge 12 volt batteries, you need to use the wall wart.
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Basic question about AC and DC to all

    Hello everyone. It looks like my 1st step is to calculate my energy requirements. I just bought a killawatt and am not sure how to use it yet. And I have a basic ac vs dc question. Lets use my Rapid Desktop Cradle Charger for my Yaesu FT60 handheld HAM radio as an example.

    According to its ac adaptor it says:
    INPUT: AC 120V 60Hz 20W
    OUTPUT: 16V 900mA

    But when I look below the cradle itself, it too has some specs:
    INPUT: DC 12V - 16V
    POWER: 15W
    OUTPUT: DC 8.4V - 1A

    And when I use a KILLAWATT reader, I get:
    Voltage:120VAC
    Amps: .14A
    Watts:12

    My questions then is, which one do I follow to determine my solar power needs?
    Also, is since the device uses dc, can I use it with a dc adaptor without any inverter when I buy a solar setup?

    As you can see, I am very confused but I am sure this 1st step would help to point me to the right direction.

    Thank you.
    rohanjcp
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Emergency power
    mike90045 wrote: »
    Bigger battery, and a plug-in charger for it. Run your radio off 12V battery, you loose effiency when you recharge it's internal cells.

    Hello mike,
    Yes I am anticipating that in an emergency it would be difficult to gather solar energy. Perhaps a couple of hours only in a 3 day period. This is the reason I would like to get a larger 60W panel to charge my simpler non energy hogs devices: So that I can gather a lot of wattage within a short amount of time. I figure a 60 watt panel is quicker than a 10 watt panel.

    "Bigger battery, and a plug-in charger for it. "
    I did want to ask clarification on your advise. How do you mean by the quote above? If you are suggesting me to use a plug in charger to run the radio from a bigger capacity battery, I believe it is possible. I have a DC car cigarette plug exclusive for the radio that allows me to operate the radio. If my guess is correct, all i need is a connector to the battery bank that allows me to operate the radio.

    "Run your radio off 12V battery, you loose effiency when you recharge it's internal cells. "
    Did you mean it is better to run it as mentioned above rather than recharge the AA batteries and use them on the radio?

    Thank you.
    rohanjcp
  • icarusicarus Posts: 5,108Solar Expert ✭✭✭✭
    Re: Emergency power

    Watts are watts are watts.

    Watts a a unit of electrical power, measure in watt hours or kilowatt/hours.

    Voltage times amperage equals watt

    Watts divided by voltage equals amperage.

    Watts (as a measure of power) don't care how you get there,, large amps, low voltage, or high amperage, low voltage.

    So in your example, your .14 amps @ 120 volts=16.8 watts

    16.8 watts from 12 volts would be 1.4 amps X 12 volts = the same 16.8 watts

    Label specs list the maximum draw, the kilowatt meter will give you the real world draw over time,, measured in Watt/hour, Kilowatthours, which is what you really need to know when "doing the math" and sizing any system.

    Tony
  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    Re: Emergency power
    rohanjcp wrote: »
    Hello mike,
    Yes I am anticipating that in an emergency it would be difficult to gather solar energy. Perhaps a couple of hours only in a 3 day period. This is the reason I would like to get a larger 60W panel to charge my simpler non energy hogs devices: So that I can gather a lot of wattage within a short amount of time. I figure a 60 watt panel is quicker than a 10 watt panel.

    "Bigger battery, and a plug-in charger for it. "
    I did want to ask clarification on your advise. How do you mean by the quote above? If you are suggesting me to use a plug in charger to run the radio from a bigger capacity battery, I believe it is possible. I have a DC car cigarette plug exclusive for the radio that allows me to operate the radio. If my guess is correct, all i need is a connector to the battery bank that allows me to operate the radio.

    "Run your radio off 12V battery, you loose effiency when you recharge it's internal cells. "
    Did you mean it is better to run it as mentioned above rather than recharge the AA batteries and use them on the radio?

    Thank you.
    rohanjcp

    "Bigger battery, and a plug-in charger for it. "
    Get a much larger battery, car sized (group 24 or group 27) 100AH deep cycle battery, a 120VAC 3 stage charger for it. and you can run at least 50 hours continous with it.

    Recharging your little batteries from your big battery will loose a lot of efficieny, run the radios off the big battery with a car cig lighter adapter.
    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 ,

  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Emergency power

    many hts can be charged from a 12v source be it in a car or a solar arrangement. the wall wart's output is at 16v, but the charger circuit itself can take from 12v to 16v. if the wall wart's output plugs into the charger circuit with a connector then it's possible to put a connector on a switched and fused pair of wires from the solar system arrangement of pv, cc and 12v leadacid battery. this will not have to go through an lvd circuit. most ccs do need a battery and i'm not sure of that particular cc, but the sunsavers i have used as straight regulators without a battery with success.
    edit to add: if the 120vac charger you have would need cut and spliced and you're not comfortable in doing that then the optional car adapter/charger would work. this would mean wiring up a cigarette lighter receptical to your 12v leadacid battery in your solar system.
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Re: Emergency power

    Hello Bill (BB),

    Thank you so much for your helpful and detailed replies. I too am from the bay area and am happy to know I have a neighbor in this forum.

    I was wondering if you can help me replicate you calculation below. I tried many times and got these numbers instead:

    28AH x 12V= 336 x 50% discharge= 168
    /
    600W x 1.177eff=705.88
    =0.238?
    BB. wrote: »
    28 AH * 12 volts * 50% (max batt disch) / (600 watt * 1/85% eff) = 16.8 minutes (rough estimate)


    As you suggested I will probably configure my own setup.

    rohanjcp
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    Sorry,

    0.238 hours * 60 min per hour = 14.28 minutes

    Also, in my previous calculation, I forgot to do the 0.85 part of the math (inverter efficiency) so I got the 16.8 minutes.

    By the way, at such high discharge rates (draining the entire battery in 1/2 an hour)--The 28 Amp*Hour rating (which is typically based on a 20 hour discharge rate) will be much less.

    I will fix the previous post.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    To everyone: RE fuses and circuit breaker
    niel wrote: »
    fuses/circuit breakers and switches should be utilized to shut down power and to protect from mishaps.

    Newbie asking everyone for their input for setting up a kit for a 65W solar panel:

    Thank you neil for bringing up fuses and breakers. From my book reading the author mentioned this a number of times. He seemed to emphasize in making sure there is a fuse in the line of the battery (or or close to the battery, i don't recall).

    Is this very hard to do? Do i need to cut and splice or do i simply clamp these fuses on? I am getting the impression that the charge controller is not enough and that fuses/breakers are the next step in what I need to know.

    The reason I am confused is because I've seen suggestions where:
      You add 2 fuses positive and negative
    1. Then there was another suggestion where you add a fuse between the panel and the charge controller and another fuse between the charge controller and the battery
    2. Then there is a distribution panel by West Mountain that have fuses built in to them. All these leads me to wonder if the line from the battery to the loads need a fuse as well.

    If anyone can help me to clarify on this, I would be very much grateful.

    rohanjcp
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    Fuses and breakers are designed to protect the wiring only...

    Fuses and breakers are not intended to "save" a device if it starts drawing too much current. There may be circuits inside the device to do that--but the external fuses are not designed for this function.

    Where to install a fuse...

    Look at the wiring and decide where the "excess current" can originate from. For a battery powered system, that is almost always from the battery itself.

    So, for every wire that "leaves the battery", there should be one fuse/breaker that protects the wire from excess current. Imagine a short anywhere in the length of the wire to ground--could be near the fuse at the battery--or it could be all the way at the end device.

    Normally, do not put a fuse in the "return" or negative lead too... The idea is, once a fuse blows--the circuit is "safe". If you have a fuse in the positive and negative lead, then you could have situations where the negative fuse pops first... This kills the device--but leaves the positive wire "hot"--which could still spark/short to another negative ground wire or grounded metal object.

    Usually, the manuals for your devices (charge controller, wind turbine, inverter, etc.) have wiring diagrams with recommended wire sizes and fuse ratings. Normally, you will not go wrong if you follow the recommendations.

    For more complex examples of solar RE systems--take a look at the Outback Wiring Diagrams... Really helps you to see how it all goes together safely.

    With any system, there are complications where you need to add fusing for other situations (more than two strings of solar panels in parallel... A large fuse in the battery lead to the bus bar, etc.).

    Some of the issues get pretty complex (type of wire, size of wire, how it is run, in conduit, outside, wet, UV, etc.)--It can take quite a bit of reading and questions to figure out the requirements and make the system safe (not always the same thing).

    Short answer--ask lots of questions and get local help when needed.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Purchasing

    Hello everyone,
    I am considering to purchase the following for my 1st solar setup. Do they look like a good choice in your opinion?

    Here's what I have on my shopping list:

    1. Kyocera KC-65T 65 Watt 12 Volt Solar Panel (view)
    2. Morningstar SunSaver 15 Amp MPPT Solar Charge Controller(view)
    3. 10/2 cable for panel to charge control (view) and connector (view)- still researching how to fuse
    4. ~34 AH battery concord- I only have about 4-5 hours of chargeable time and don't need high capacity yet.
    5. Samlex 300 Watt 12 Volt Sine Wave Inverter- seems to be the affordable pure sine inverter (view)
    6. Voltmeter- this one from Equus got great reviews (view)
    7. DC to DC converter to use my AA/AAA maha charger using its cigarette plug. I just don't know how a deep cycle battery bank accepts a cigarette plug input.- still researching


    My biggest project from here would be to research fuses and wires.

    rohancjp
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Wiring

    Thank you BB. Your detailed information has been extremely helpful.
    rohan
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    rohanjcp,

    For for this sized system, there is really not much danger if you follow basic good wiring practices--just like DC wiring for a car or boat. And keep the battery away from children's fingers and metal objects.

    The big issue is knowing the correct wire gauge (AWG--American Wire Gauge). The NEC (National Electric Code--which you can buy at the local electric contractor supply or even some libraries may have one)... Wouldn't you know it--I just went to the Peninsula Library Catalog and it is down--so I cannot find a copy right now.

    Just for a rough idea, a 14 awg house type solid (or stranded) wire is rated for 15 amps. So, protect it with a 15 amp fuse or breaker, and draw no more than 80% of the fuse/breaker rating (15*0.8=12 amps).

    And, actually the update code does allow a 14 awg circuit to have a 20 amp breaker/fuse...

    For a 300 watt inverter, roughly, the maximum current will be:

    300 watts * 1/85% eff * 1/10.5 volts min batt=33.6 amps maximum

    Here is a link with some numbers from a NEC wiring table (remember, different insulation, conduit, conduit fill factor, wetness, ambient temperatures, all go into determining "safe" practices--for your setup--the first approximation of this table is fine--plus NEC is pretty conservative in its ratings--so any mistakes will be small with respect to your system).

    If we look at the table, 10 or 8 awg wire will be fine for your setup.

    Fusing, find the next size up fuse from:

    33.6 * 1/0.80 max circuit rating = 42 amp fuse/breaker (or 50 amp next standard size).

    So, looking at the NEC wiring table, that would be an 8 AWG wire (buy it by the foot from Home Depot).

    Notice, as you start "adding" all sorts of safety factors, the size of the wiring (and costs) start to rise. In reality, a 10 awg wire (for a short DC run) would be just fine for your setup... I doubt you are going to put the wire in conduit or run it in a very hot location--plus, at least with this sized battery, you are not going to be running 300 watts very long (~15-30 minutes maximum before the battery dies).

    For fusing/breakers... Probably start with fuses and fuse holders from the local automotive store. Some places that specialize in Automotive Stereo systems (the ones that those young "whipper-snappers" install in their cars have some very nice larger distribution fuse holders for good prices. A marine store may also have a selection too.

    For the Solar Panel--the Kyocera 65 watt is a fine pick/match with your 34 amp*hour battery.

    The solar charge controller--Morning Star MPPT 15 amp--is a very nice, high end charge controller... And frankly, unless you are planning on "growing" this system later or want the computer interface (both perfectly justifiable reasons to buy the MS MPPT)--It will not provide much advantage in this smaller system over a less expensive PWM controller.

    When wiring the system together... "Home Run" all of your various connections (charge controller to battery, inverter to battery, 12 volt lighter socket to battery, even technically a built in panel volt meter--if you have one--to the battery).

    And, at the battery, either use a long screw where you can attach all of the connections... Or use a heavy piece of cable (like the 8/10 awg for your inverter) to go from the battery to a fuse distribution panel or a "chunk" of metal/stud/screw/nut where all of the wires can join safely. And from that point, each wire that leaves should have an appropriate rated fuse inline--as close as practicable to the battery--in the positive feed line.

    And, in reality for this small of system... You probably don't need a fuse in the 8/10 awg wire to the inverter if you keep the leads short and well supported/insulated. The Inverter probably has an internal fuse, and this small of battery probably cannot output enough current into a short/failed inverter to really cause much damage.

    If you run a cigarette lighter plug 10' from the battery--then having an inline fuse in the positive lead near the "bus connection" would be a good idea (fuse size based on the wire awg).

    Lastly, reasonable expectations... Unless you have a specify need for high current and a short duration (say a portable electric drill)--I would size the average load of your system for about C/10 discharge rate for maximum sustained operation. That would be:

    C/10 = 34 Amp*Hour / 10 = 3.4 amps
    3.4 amps * 12 volts = 40.8 watt average load

    And since we suggest that you only run the battery to 50% level of discharge, then a 10 hour discharge rate to dead battery, would be 5 hours of 40 watt discharge.

    For the AGM batteries, they do warrent them down to 20% State of Charge--so that would be 8 hours of useful load.

    Looking at that level of load, a 300 watt inverter might be a bit of overkill--unless you also plan on sharing the inverter, for example, for use on your car (with battery clips).

    I hope that this all helps.

    -Bill

    PS: For smaller wire sizes, here is another table. Notice that for a 14 awg wire, they rate the wire from ~30-45 amperes in free air. But at the top of the chart, they have bundle deratings (16 wires in a bundle, derate by 50%)--which gets you closer to NEC (15 amps).

    Also, when running wires longer distances, and especially at lower voltages (like 12 volts DC)... The voltage drop can really interfere with equipment operation.

    For example, I can run an extension cord for 100' and get a 5 volt drop at the end... 120 V - 5 V = 115 volts -- my stuff will run just fine...

    Run 12 volts with a 5 volt drop, 12-5=7volts, no 12 vdc device will run at that low of voltage.

    So, the wiring drop calculator (excel spreadsheet) is very useful to understand how much drop there is between your sources and your loads--to help ensure "happy operation".
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Fusing

    Hello Bill,

    As usual, every time I see your postings I am closer to achieving my goals. Thank you so much for your kind information.

    With regards to fuse installations, I finally was able to see that it is very simple and easy to do. This youtube video shows that it's just a matter of screwing it in to the proper places:
    Video (here)

    May I ask for some clarifications?-

    *Does a jumper cable simply mean a short wire?
    *I noticed that in the video, he is connecting the fuse between the panels and the charge control. And like you said, he only fused the positive lead. Do I need a fuse between the charge controller and the battery too? I will probably not fuse the battery to the inverter since the inverter has an internal fuse. And it only has 1 ac input.
    *I need a Voltmeter to make sure the panels are working right and to keep track of the battery state of charge- which do you think is better? this one from Equus got great reviews (view) or this one (view)
    *Is this device what connects my battery bank to my 12V electrical appliances? 12 V Battery Clips w/12 V Power Outlet RPPSAPS (image here) and (product here)

    Again, thank you for all your help. I will go to the hardware store now to see the 8 AWG wire, the fuses (fuse holders), and maybe the fuse distribution panel.

    rohanjcp
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    Sorry, I cannot "stay to answer your questions right now"... But I wanted to point to our host's website for some ideas on bus bars and various pieces to connect your solar hardware together.

    The parts here may be a bit large for a small system... But it will help you understand the intent when buying the parts and connecting everything together.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Posts: 5,108Solar Expert ✭✭✭✭
    Re: Fusing
    rohanjcp wrote: »
    Hello Bill,

    As usual, every time I see your postings I am closer to achieving my goals. Thank you so much for your kind information.

    With regards to fuse installations, I finally was able to see that it is very simple and easy to do. This youtube video shows that it's just a matter of screwing it in to the proper places:
    Video (here)

    May I ask for some clarifications?-

    *Does a jumper cable simply mean a short wire?
    *I noticed that in the video, he is connecting the fuse between the panels and the charge control. And like you said, he only fused the positive lead. Do I need a fuse between the charge controller and the battery too? I will probably not fuse the battery to the inverter since the inverter has an internal fuse. And it only has 1 ac input.
    *I need a Voltmeter to make sure the panels are working right and to keep track of the battery state of charge- which do you think is better? this one from Equus got great reviews (view) or this one (view)
    *Is this device what connects my battery bank to my 12V electrical appliances? 12 V Battery Clips w/12 V Power Outlet RPPSAPS (image here) and (product here)

    Again, thank you for all your help. I will go to the hardware store now to see the 8 AWG wire, the fuses (fuse holders), and maybe the fuse distribution panel.

    rohanjcp


    Just to jump in for Bill for a bit,

    A Jumper is generally a short piece of wire.
    Second, in spite of the fact that the inverter has a fuse, I would also provide on between the battery and the inverter, sized for the smallest wire size in that run.
    Third, you should get a good digital volt/ohm meter. You really can't work with this equipment without one.
    Fourth, while you could use the clip on connector for small loads directly from the battery, I wouldn't suggest it. The clamps don't handle large current well, and the chances of reversing the cables and burning something up are considerable. In addition, the "lighter plug" is not fused.

    I would only use a hardwired 12vdc lighter plug for things light cell phones, or similar small loads. If you have extensive 12vdc loads consider using a different system to connect you loads, such as different configured plug/recepticle combinations, or Anderson polarized connectors.

    Good luck,

    Tony
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    Tony answered fine...

    My only small quibble--a fuse on a short cable (aka "jumper") to the inverter. If you can find a place for it, and it is not too expen$ive--it is fine. Especially if you are using 10 or 8 awg wire.

    However, with your small battery and heavy cables, they will not probably overheat anyway (battery may not even blow a 50 amp fuse). And, if the cable is properly mounted and protected (so that it cannot flex/cut/short)--adding the fuse is just another point of cost and failure for a small setup.

    Cars, for example, do not usually have a fusible link (aka fuse like piece of wire or metal) between the battery and the starter... It is assumed that the battery cannot output much more energy than the starter itself draws.

    If, however, you had several full sized (100 amp*hour or so) batteries in series and/or parallel--then a 50 amp*fuse between the battery bank and the inverter would be pretty much a requirement.

    If you look at the alternate wiring/current link I posted in the PS, you will see that an 8 awg wire is rated to run something between 75 and 100 amps (before the insulation melts). And it would probably take more current for the wire itself to melt/fail...

    But, if you decide to add a fuse/breaker--it won't hurt anything either.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Wires and fuses- Anderson Power pole

    Thank you Tony and Bill,

    For your input on fuses and wires. I did go to the local hardware shop (Home Depot) as well as 2 auto shops. They also had many kinds of wires too. The Home Depot shop had so many fuses and circuit breaker that I got confused and when I explained to the staff they said go to the auto shop.

    The auto shop experience was a bit better. They had this "primary wire" that sold as a single cable but not as a pair. Their largest size was 10AWG. As for the fuse, Kragen had the ATP, MINI, AGC, and the MAXI type but no fuse boxes. I tried to explain but they were also confused.

    Here's the solution I figured. Upon my research, I found a website that provides fusing with anderson power poles. I watched videos about installing these and they sound simple enough. What do you think of this setup?
    *ATC Style Fuse Holders with Powerpoles-(Gauge: 10, Amps: 40)-(view)
    *Same but with Ring terminals(view)
    *ATC Style Inline Fuse Holder - 10 Gauge- (view)
    The fuses for these 3 items can be found- here

    I like this setup a lot because I can see which fuse to get. I also like the fact thta the fuses can be removed and replaced easily. I just need to ask them if's ok to crimp and install anderson power pole to any cigaretter lighter run appliances I have.

    I also noticed from the same website that there is a way to connect the AGM battery to a female cigarette plug: here

    Thanks for reading.
    rohanjcp
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    I have always loved the Power Pole stacking connectors... But I could never use them in my designs as they where always too small (12-15 amps maximum). And the larger devices are physically, very large.

    Anyway, if you like to make the stuff "pluggable"--even the high current items (battery, inverter), look here for Power Pole, and around here for large fuses/fuse holders/breakers.

    The folks that make their car stereo system way too large... Have some very nice fuse blocks. Here is one company (don't know anything about them or their products) with some very useful fuse blocks+bus bar assemblies. May be too large for your application--but for 90% of what people need for small off-grid solar--they are hard to beat (adding connectors everywhere adds costs and complexity to a system if it will never be disassembled during day to day use).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Fusing

    Thank you Bill and Tony for your feedback.

    I now understand that a jumper is a short piece of wire. I would now like to ask about fusing the panels to the charge control / fusing the charge control to the battery / fusing the battery to the inverter. Since these are 3 different topics, I will start asking with the first one. Which of these 2 fuse holder option is the proper procedure?

    For my solar panels to charge controller, I am thinking of using 10 AWG wire and a fuse of 40amp.

    Connection:
    65 Watt 12 Volt Solar Panel- 3.75amp
    CONNECTION TO
    Solar Charge Controller

    My guess:
    BUY WIRES: 10 AWG primary wire 2 colors from an autoshop
    BUY FUSE: 40amp ATC from autoshop
    BUY FUSE HOLDERS:

    1-ATC Style Inline Fuse Holder with no anderson power poles view - 10 Gauge
    (I don't know how wire loops work, I assume that the wire is inserted inside the loop.)

    or

    2-ATC Style Fuse Holders with Powerpoles view (Gauge: 10, Amps: 40A) (I assume that I need an anderson power pole on the solar panel and another power pole on the charge controller side, which sounds rather inefficient)

    PS. I appreciate Bill's reference to the host of this site. Unfortunately, their email support have not been responsive to my queries and I don't know exactly which fuse/breaker to choose from with too many choices.

    Thank you for reading.
    rohan
  • icarusicarus Posts: 5,108Solar Expert ✭✭✭✭
    Re: Emergency power

    Rohan,

    The wire loops that you cite are just loops of wire with the fuse holder in the loop. You have to cut the loop so that you have two ends to wire into your circuit.

    Remember that all fusing (or breakering) should be designed to protect the SMALLEST wire size in the circuit. If the expected load is BIGGER than the capacity (ampacity) of the wire, then the wire is too small and should be up-sized.

    In your small application fusing the wire(s) from the panel(s) to the controller is generally not needed, but there should be a fuse between the battery and the controller of the proper size as noted above.

    Between the inverter and the battery should also be fuses,,, with the proper fuse size for the wire. You are on the right track with the ATC type fuse holders. You can simply hardwire these to your feed wires using appropriate connectors,,, such as wire nuts, (not recommended) or split bolt connectors, crimp lugs or terminal blocks. You don't need Anderson connectors at every wire joint. The point is to make a mechanical connection that will carry the amperage load, and the physical strain of the wires. What you are wanting is a connection that won't work loose over time, and won't heat up because of a poor conductive joint. You also have to insulate the connections with tape, or heat shrink, or enclose them in a proper covered box to prevent fires and shorts between one conductor and another. (Check you local regs if it matters to you that you are being 100% NEC or CE correct!)

    Generally, #10 wire would have an ampacity of ~ 30 amps. http://www.cerrowire.com/default.aspx?id=46

    I personally prefer the biggest wire I can afford, (or that will physically fit the requirements) and I usually try to use a wire 1 size bigger than normal, and fused for the smaller size. For example #12 wire will carry 20 amps. I would use it and fuse it with 15 amp fuses.

    Tony
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    You really don't need to follow NEC for a small home/portable off-grid system... But it does not hurt to follow the basic requirements (automotive fuses, I am pretty sure, don't meet NEC requirements).

    I would tend to use "bolt together" connections (ring lugs and such)--just cheaper and easier for a simple system. You may put a set of plugs on something you need to move (like to disconnect the inverter). Your choice.

    NEC, as I showed with another wiring rating list--is pretty conservative and fusing to an NEC wire list is just fine.

    If you are not going to move the system around much--you can also use solid or stranded wire from the local home center too (sold in colors and by foot/meter).

    And for a small--first time experimental system--fuses are fine. Breakers would be a nice touch for the next system (with 1-3kWatts of solar panels and a huge battery bank)... But would be a waste on a small system (other than perhaps one between the inverter and the battery--so you can shut down the inverter when you want--or substitute a heavy switch).

    I am sorry that our host did not respond to your emails... None of us here (other than the Admin WindSun) are connected with their business. We are just posters and a couple volunteers to help control spam and minor moderation of posts/threads.

    This forum is here to help answer many of the questions that new (and experienced) users have with solar power. None of us can speak for NAWS.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Emergency power

    I am new here too, and was going to try building solar panals myself. Do they work as well as store bought one. thanks Alison s
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    Alison S,

    Short answer is that home built solar panels will not work as well (20%-50% lower output) or last as long (water infiltration causing corrosion, etc.) as a good quality silicon (mono or poly-crystalline) photo voltaic solar panels (larger panels will have 20-25 year warranty).

    Anyone that sells "books" online to build your own solar panels should be looked upon with great suspicion.

    If you want to build a panel of a few tens of watts as a science project--great! Have fun.

    If you are building a system that you want to have work without any maintenance (other than battery maintenance and replacement) for the next 20+ years--don't bother building your own PV panels.

    However, if you want to do something with solar hot water? The "store bought" panels are usually much cheaper than silicon panels (pv panels ~$3-$5 per watt for larger panels, smaller panels up to $10 per watt; hot water panels ~$0.50 per watt equivalent). But also lend themselves to home built projects (if you have the skills, time, and materials at a good price).

    What is it you would like to do?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Fusing

    Hello Bill and Tony,
    Thank you for your detailed explanations. They were very helpful.

    The staff at the host site was able to respond to my inquiry and suggested an 8AWG wire for the inverter connection. (#8 cable with 3/8" ring terminals for the Samlex 300W invtr)

    I honor Bill's and the staff's opinion that I need 8AWG for the inverter. I also honor Tony's opinion that the "fusing should be designed to protect the SMALLEST wire size in the circuit." The dilemma I have is that do ALL 3 sets of wiring need to be the same wire size (#8AWG) or can I have a #10AWG (solar panels wiring / charge control wiring) with #8AWG (inverter wiring)?

    I am now battling between 2 setups:

    All CONSISTENT 8AWG wiring:
    Solar Panel To Charge Control- 8AWG wire
    Charge Control To 12VBattery- 8AWG wire and Heavy duty 8 gauge fuse holder with 80 amp MAXI fuse - 75 amp Powerpolesview
    Wth
    12VBattery To Inverter- 8AWG wire and Heavy duty 8 gauge fuse holder with 80 amp MAXI fuse - 75 amp Powerpolesview

    Or
    INCONSISTENT 8AWG wires with 10 AWG wires:
    Solar Panel To Charge Control- 10AWG wire
    Charge Control To 12VBattery- 10AWG wire with ATC Style Inline Fuse Holder - 10 Gauge view
    12VBattery To Inverter- 8AWG wire and Heavy duty 8 gauge fuse holder with 80 amp MAXI fuse - 75 amp

    Thank you for reading.

    ps. To propel me forward, I have purchased the Morningstar MPPT charge controller.

    Next purchase:
    65WATT Kyocera solar panels
    300WATT SAMLEX inverter
    3/8" ring terminals for inverter view
    Hammer Crimp Tool For #8 AWG through #4/0 AWG Terminal Lugs view
    #8AWG cables view
    2 pieces connector view
    2 pieces lock nuts view view
    34 or 40AH concorde battery
    Fuses (to be determined)
  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Emergency power

    The way to "thing about fusing" is to think of a "star" with rays coming from a center point...

    The battery + / + bus bar is the center point with lots of amperage available. Each ray of the star is going to a different device. Connects to the +/Bus common point, goes up to 18" max (one spec. I have read--nothing magic about 18"), insert a fuse/breaker that will protect that gauge of wire (8, 10, 12, 14, 18, etc.) and the wire goes on to the destination.

    Repeat for each major branch "ray" from the center point.

    The reverse is done for the wires coming back to the center - / Bus connection. The wire gauge back must be at least as large as the + wire and fuse wire going out. All the return wires (of multiple gauges) come back to the common point... Just without any fuses (no fuses in the return leg is a standard--fusing both + and - leads is a waste of money and can create a dangerous situation... - fuse blows, but the positive lead is still not and can short elsewhere.

    You can run one heavy 8 awg wire everywhere--but it is usually not a good idea... Waste of money, may still need fusing at the individual loads, and you may have interactions between loads (charge controllers can be confused by the electrical noise cause by AC inverters when sharing the same wire--it is better that they join back at the battery common point--that way noise is not shared between devices/circuits--the battery basically swamps them all to near zero noise).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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