Emergency power

2

Comments

  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Stars

    Thank you Bill for the analogy about the stars which was helpful.

    There were some things you mentioned that I would like to clarify:
    What is a "bus bar" and a "Bus common point" and "Bus connection"? I believe you are referring to something like Power Distribution Block Bussman 16220-1 175 Amp (view)

    "it is better that they join back at the battery common point"
    -Are referring to a situation where I have a single 12V battery that is supplying multiple loads?

    Another question I have is that if I have to fuse for every branch of rays from the star (battery), would it be easier for me if I bought a West Mount Radio Rig Runner connected and fused to the 12v battery? I could probably use the bussman, but I don't know how they work and wire. I understand that this rig runner power distribution panel have many fuses built-in. Perhaps I won't need fuses to the loads going out from the rig runner since they are fused on that device. (ex. a load of an inverter, a couple of fused female cigarette plug adapter, maybe my handheld radio).

    rohanjcp
  • BB.BB. Posts: 28,084Super Moderators, Administrators admin
    Re: Stars
    rohanjcp wrote: »
    Thank you Bill for the analogy about the stars which was helpful.
    I hope that it was helpful... Analogies are frequently the cause of confusion--as further discussions end up confusing clarifications (are we calrifying the analogy, or the underlying fact...). :p
    There were some things you mentioned that I would like to clarify:
    What is a "bus bar" and a "Bus common point" and "Bus connection"? I believe you are referring to something like Power Distribution Block Bussman 16220-1 175 Amp (view)
    Bus Bar is historically a chunk of copper (or brass) bar that has drilled and tapped holes in it to attach "branch" circuits ("rays from the star").

    A common point, would be a more generic term meaning, in this case, the battery post--for example.

    The Bussman block you showed would be perfect for a ground return connection (no fuses).

    If you used such a block for the "+" positive connections, you would need to add fuses/breakers close to where the branch circuits leave the bus block.
    "it is better that they join back at the battery common point"
    -Are referring to a situation where I have a single 12V battery that is supplying multiple loads?
    This is a state of "being". Be the "battery"... ;)

    For example, one battery--the +/- posts are the common point for that battery.

    However, if you have, say three batteries in parallel. Normally, you would connect a heavy cable from each battery post to a "common point" or "Bus Bar"--Then attach your loads/chargers to that point.

    And there is a reason for this... Say you have your 3x battery bank. You attach a charger to battery #1 and your inverter to battery #3--and you have some wires connecting each battery post to its neighbor's post (standard parallel connections).

    When you charge the battery bank, battery #1 will have the lowest resistance to the charger (and therefore get the highest charging voltage and currents).

    And when you turn on your big inverter (load), battery #3 will provide the most current because the other batteries "see" the added resistance of the parallel interconnect cables.

    If you run the batteries to a "common point/bus connection", then all batteries see the same voltage/resistance, and therefore charge and discharge exactly the same.

    Batteries are very sensitive to voltage (their voltage points are set by chemistry, temperature, physics)--so they are naturally very close. When you add resistance (differing wire lengths between batteries and loads), it make them "out of balance"--So that "bad wiring" practices--will cause early battery failures.
    Another question I have is that if I have to fuse for every branch of rays from the star (battery), would it be easier for me if I bought a West Mount Radio Rig Runner connected and fused to the 12v battery? I could probably use the bussman, but I don't know how they work and wire. I understand that this rig runner power distribution panel have many fuses built-in. Perhaps I won't need fuses to the loads going out from the rig runner since they are fused on that device. (ex. a load of an inverter, a couple of fused female cigarette plug adapter, maybe my handheld radio).
    From an "electrical" point of view--where you place the fuse does not matter... However, from a physical wiring point of view--it matters a lot.

    Again, the fuses are there to protect the wiring from shorts.

    If you rely on the fuse in the devices to protect--then any wiring harness to ground shorts will catch your wiring harness on fire--and not blow the fuse in the device.

    Also, say you have several cigarette lighter outlets at the end of a 14 awg cable. You plug in your cell phone charger and it draws less than one amp (with internal fuse), not a problem...

    However, say you plug three 100 watt inverters. Each with a 15 amp internal fuse. You just put three of them on the end of a 14 awg cable--45 amps maximum current draw (and no blown fuses)--but the 14 AWG cable is only "safe" for 15 amps (because there was no fuse at the common battery connection.

    That is why I suggested something like these... Combined "bus bar" and fuse block... One heavy wire in (bus common point), and multiple branch circuits out--all protected by individual fuses.

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

    Hello Bill,
    Thank you very much for the clarifications. I now see that a rig runner with 4 or 5 fuses in it is not an excuse to skip adding fuses to the outgoing branches. Also, I see what you mean by buss bars.

    The opti fuse blocks that you recommended are a great idea. However I am a beginner and can only rely on you and my own research to get more answers. If I go to this route, I would have to ask more from your precious time with Q and A with questions such as which specific blocks do I have to get / how do I connect them / which fuse do I get / where do I connect them?

    I have diagram I made to illustrate what I have learned thus far. For my beginner's level now, I would like to take a step back and ask you 1st if my thinking is still on the right track or if I am confused somewhere. view

    If you believe the opti fuses are easier for me, I can change plans and go to that direction.

    Thank you.
    rohanjcp
  • mike95490mike95490 Posts: 7,969Solar Expert ✭✭✭✭
    Re: Stars

    http://www.smartgauge.co.uk/batt_con.html

    Site has a sketch (and a VERY informative article) of how to wire to buss bars
    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 ,

  • BB.BB. Posts: 28,084Super Moderators, Administrators admin
    Re: Emergency power

    rohanjcp,

    For a "simple" system--what you are doing is fine. The combined fuse block + bus connection is very nice--but certainly not needed for your starter system.

    And, this is your first project. Nothing you are doing currently will be "dangerous"--and you will learn what works well for you and what does not.

    You have purchased some nice products that will migrate to larger systems very nicely--After you have destroyed your first battery or two (and you will ;) )--you will be ready to "move up" to your next larger system.

    Feel free to ask more questions--there are a lot of us here that "share the load".

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

    Hello everyone,
    Thank you for your blessing in my 1 st experimental solar panel setup. Please forgive me if I am slow and if the question is repetitious. The good news is that I found and automotive website that sells various inline fuses with fuse holders. There are a couple of fuses and fuse holders that can do 8 AWG and 10 AWG wires. Can I ask about my wire sizing and fusing once more?

    1. Do I have the proper wire sizes in my diagram?
    diagram

    I don't know if I should have all of them 8 AWG wires or mixed:
    10AWG for the panels<->charge control
    8AWG for the battery<->inverter/loads
    ?AWG for the charge control<->battery

    2. The 2nd question is how much amp fuse should I get?
    for the battery<->inverter/loads
    and the charge control<->battery

    Using Tony's advice:
    "Generally, #10 wire would have an ampacity of ~ 30 amps."
    "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."

    Combined with Bill's advice:
    "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)."

    MY CONCLUSION- I was thinking of #8AWG wires and fuse for 1 size lower #10AWG=> 30-40AMPS.

    Thank you.
    rohanjcp
  • BB.BB. Posts: 28,084Super Moderators, Administrators admin
    Re: Emergency power

    You should be fine.

    In reality, you have wired your system about 2x heavier than just about any first timer out there--and properly fused it too.

    You can easily add to your panel size, and battery size -- as you out grow you current system without any problem.

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

    Thank you Bill and Mike for your postings.

    Today, I ordered a SAMLEX 300Watt pure sine inverter and a Concorde 40AH AGM battery. And my morningstar MPPT arrived from the mail today.

    I got a recommendation from the host of the site that it may be easier to fuse the system using breakers on a Midnite solar Big Baby Box. (image 1 2 3 4)

    I remember Bill mentioning about the breakers being better too. As you know, I am a beginner in electronics and would like the simpler way. I was hesitant of the concept of breakers but it looks like an inline fuse too. It looks like the breakers have 2 screws that you screw the wires/cables into. I will do some research and ask them for some clarifications and let you know.

    Thank you for reading.

    rohan
  • BB.BB. Posts: 28,084Super Moderators, Administrators admin
    Re: Emergency power

    Fuses or Breakers are fine (assuming properly rated).

    Breakers are nice because you can use them to switch off loads/sources when needed. (many times, you want to turn off the inverter when there are no loads--because it will keep idling and draw down the battery/waste power).

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

    actually i see no lengths given for the wire runs or did i miss that? if the wire lengths were not given then nobody can say without a doubt that what you have chosen for a wire gauge will be fine as that would not have been determined as of yet. can you redo the diagram of your system showing the distances the wire has to travel between each of those stages in addition to the gauge you wish to use? this would be termed as a run and the wire length will be doubled due to the fact you have 2 wires to run with, 1 being + and the other being -.
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    A diagram still in the works

    Hello Niel,

    Thank you for offering to view my diagram. I am still researching about breakers. Here is a diagram of where I think I might head to if I was to use breakers rather than fuses. It could be totally off since I am still researching. Also, I do not plan on distancing with long wires. This is for an emergency back up power purpose not relying on the grid and fuel, and not permanently installed (ie. it should be semi mobile).

    View new diagram in the works. (ps. if image is blurry, clicking on it once helps)

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

    the wiring seems ok and i hope i didn't overlook anything.
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Crimper

    Hello there. I just wanted to thank everyone so far (especially Bill) for all your support so far. I have mustered enough courage and information to be confident to make my major purchases: 80 Watt panel, 300W pure since inverter, 40Ah battery, and MPPT charge control.

    I wanted to physically see these 1st before making my final decision about using inline fuses or breakers on a Big Baby Box breaker enclosure. If I want light weight, I may go for inline fuses and if I want extra safety, I may go for the breaker.

    In the meantime, I bought 2 home depot dvds to learn about wiring: splicing, cutting, crimping.

    Also, I have some questions if you don't mind:
    1) Do yo know of any reliable crimper that can do 8 to 10 AWG? Most of the time, these are 2 different tools. (maybe this?)
    2) Do you know of any reliable wire stripper cutter that can do 8 to 10 AWG? Most of the time, these are 2 different tools depending on stranded or non stranded wires. (good but does not do 8 to 10AWG)
    3) When I went to HOME DEPOT, they have all sorts of cables and wires. I know I should get the copper wires that are good for the outdoor. Should I get 2 each of the singles or should I get the pairs such as 8AWG/2? The pairs seem to come with a 3rd wire.

    Thanks so much.
    rohanjcp
  • icarusicarus Posts: 5,108Solar Expert ✭✭✭✭
    Re: Emergency power

    As for a wire stripper for larger gauge wire,, I just use a sharp utility knife to strip #8 and larger wire. I find it easier for most wire gauges anyway. Unless you have a real need for a large gauge stripper,, I would stick with using a knife (carefully!)

    As for a crimping tool. This type of crimper works great for almost all guages,, #16 down to ~#02 Reliable, and if you shop around you can get a pretty good price. http://store.solar-electric.com/hacrtoforlal.html

    The two wire comes with a ground. Probably cheaper to go with the single conductors if you don't need the ground. On the other hand, running the 2 wire with ground might be easier.

    Tony
  • BB.BB. Posts: 28,084Super Moderators, Administrators admin
    Re: Crimper

    You are very welcome rohanjcp. We all started at the same place the first time out.
    rohanjcp wrote: »
    Also, I have some questions if you don't mind:
    1) Do yo know of any reliable crimper that can do 8 to 10 AWG? Most of the time, these are 2 different tools. (maybe this?)
    That is a cool tool--I have not used a large crimping tool before--it was always easier to write on a part drawing "Crmp Here" and let somebody else to it (I was a design engineer).

    You are really going all-out. NAWS has a mechanical crimper:

    trans_1x1.gif
    Hammer Crimp Tool for Large Terminal Lugs
    wind-sun_2041_6874483 This simple, inexpensive crimping tool can be used to crimp connectors on #8 through #3/0 AWG wire. Spring loaded pin locks in ...

    But it is only ~$15 cheaper than the tool you are pointing at.

    Realistically--Not many people go to this expense for a "simple" off-grid system--perhaps they should. I am very impressed!
    2) Do you know of any reliable wire stripper cutter that can do 8 to 10 AWG? Most of the time, these are 2 different tools depending on stranded or non stranded wires. (good but does not do 8 to 10AWG)
    I just use a pocket knife to strip the insulation--You do have to be careful not to nick the copper wire (can cause wire to break at nick).

    Something like this may work for slitting/stripping larger cables. Or this vendor.

    You might also look for a local electrical supply warehouse for these types of professional tools.

    Again--if you are not manufacturing/installing systems...
    3) When I went to HOME DEPOT, they have all sorts of cables and wires. I know I should get the copper wires that are good for the outdoor. Should I get 2 each of the singles or should I get the pairs such as 8AWG/2? The pairs seem to come with a 3rd wire.
    I am not sure Home Depot sells UV/outdoor single wire product. They do sell an outdoor/UV resistant cable with two wires and ground. Either ignore the extra ground wire, or attach it to the solar panel's metal framework (for a bit of extra safety--required by building codes).

    Or, if this is for portable use, use a outdoor rated extension cord (you can get down to 10 awg in many stores--and larger from an electrical supply house).

    I don't have a copy of the NEC to know which "SJO" or whatever is the correct insulation for outdoor/sun/wet/oil resistant type use you will need.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Bus bars
    mike90045 wrote: »
    http://www.smartgauge.co.uk/batt_con.html

    Site has a sketch (and a VERY informative article) of how to wire to buss bars

    Thank you mike for this link. It was very informative regarding multiple battery connections. By the way, is this the correct link? It does not mention anything about buss bars.

    And thank you Bill and Tony for your suggestions on crimping tools, wires, and more.

    rohan
  • BB.BB. Posts: 28,084Super Moderators, Administrators admin
    Re: Emergency power

    The "bus bar" common point would be the place where your +/- load connection is made (the two wires that come out of the battery).

    For method #3, where all of the batteries connect together--those points could be a big piece of copper where all of the wires connect (plus your load connections).

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

    Hello all,

    I had a creative idea that may aid in making my system a bit more portable.

    The scenario is: I wish to charge indoor first and to disconnect the wires after charging, and bring the battery ONLY into the house for AC use.

    Goal 1: no inverter outdoor since the inverter's manual says for INDOOR use only. Goal 2: less components during charging outdoor (no inverter) and only the battery to carry indoor. Goal 3: easy assembling and disassembling. Goal 4: 1 less set of wires and fuse (since the battery's wire and fused is used again indoor).

    Method: For my battery-to-inverter connection, I was wondering if it is possible to disconnect the battery-to-charge control fused connection, take the detached battery with exactly that same wire and fuse into the house, and use it for the battery-to-inverter connection indoors.

    Diagram:
    Is this setup possible?

    Thanks for reading.
    rohan
  • BB.BB. Posts: 28,084Super Moderators, Administrators admin
    Re: Emergency power

    Yes, you can do it--but with a couple warnings.
    1. Make sure you open and close the connections when there is no power flowing (panels in dark, inverter off--or at least unloaded). DC current is very good at welding connections (actually, DC current is much harder on switch contacts/breakers/fuses vs AC of the same or higher voltage/current).
    2. You may confuse the solar charge controller if you connect the charge controller to the battery when there is light on the solar panels... Virtually every manual I have read says to made the Battery to Controller connection first. And make the solar panel connections second. Most controllers probably use the battery voltage to run their internal controller/computer and sometimes setup the voltage (12 or 24 volt battery bank--for example). You probably want to make the solar panel Pluggable too--so you can connect it second.
    3. The inverter should work OK outside--as long as rain does not get to it, and you prevent condensation from entering the case.
    -Bill

    PS: If this is for an emergency type system... I would make it so that battery, charge controller, and inverter are in the same box. With a solar panel plug and AC outlet (and 12 VDC if needed).

    One of the great advantages with the solar emergency system is you can put it in the sun and charge it during the day--and use the AC/DC power anytime you need (day or night).

    Placing it all in one box (like Mike's example) with rain/weather protection keeps the system flexible--and there is no chance of breaking wires or equipment as you move the pieces around for day/night use/etc.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Posts: 7,969Solar Expert ✭✭✭✭
    Re: Emergency power
    BB. wrote: »
    Placing it all in one box (like Mike's example) with rain/weather protection keeps the system flexible--and there is no chance of breaking wires or equipment as you move the pieces around for day/night use/etc.

    In my "Monolith", with the PV panel lowered, the interior parts are protected from the weather, and in fact, I hose dirt off it in that condition, and it has withstood several rainstorms. I do make sure the 120V inverter is disconnected in wet conditions.

    Bit it's a bit big and bulky to carry around. Building it into a milk crate makes it a bit more portable

    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
    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 ,

  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Confused with fusing

    Hello all,
    Thank you for your continued feedback. I just finished reading the Morningstar MPPT charge control manual and it says to use a 25 amp fusing on the connection between the CHARGE CONTROL to BATTERY.

    I contacted their customer support asking them if I can use 8Gauge wires with 50amp fuse on the connection between the CHARGE CONTROL to BATTERY. I was advised I shouldn't use any fuses larger than what are specified in the manual and that it's ok to use a larger wire.

    Since I already bought 2 inline MAXI fuse holders (picture),

    I looked for a smaller maxi fuse blades for them. They only have 20, 30, 40, 50 and up. But I did find a new Maxi fuse product here, that is actually 25 amp.

    Would this maxi fuse holders with the 25amp fusing work? And I will use a 50 amp maxi fuse for the BATTERY to INVERTER connection.

    rohan
  • BB.BB. Posts: 28,084Super Moderators, Administrators admin
    Re: Emergency power

    It may just boil down to a personal choice--30 amp fuse vs 25 amp self reseting breaker...

    Given that this is a "fixed" installation (solar charge controller)--I probably would choose the 30 amp fuse because if it blows--it does it once because something is "broken".

    The the self reseting circuit breaker--It will keep trying to reset every minute or so. This kind of behavior (self reset) would probably be better on a plug or something where you know immediately what/why the circuit tripped.

    The 30 amp fuse should not be a problem. You have heavy enough wire that the wire will not "melt". If the controller fails internally--it will most likely be a lost cause whether there was a 25 amp or 30 amp fuse involved.

    But--in the end, they wrote 25 amp in the manual--and you cannot go wrong following the manual (most of the time anyways... ;) ).

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

    Thank you Bill for the response. Upon more research, I found out that radio shack has a 25amp maxi fuse.

    Today, my 85Watt solar panel arrived and it looks beautiful. I have some questions with the product's pictures below.

    View 1
    View 2

    1. There are so many screw connectors when I was expecting only 2. Can you tell me which exactly is the positive and which is the negative?
    2. Specifically, which of these do I connect the panel's 10AWG positive wire and the panel's 10AWG negative wire?
    3. How long of the wire should be stripped?
    4. Since the wires are stranded, when doing the stripped positive wire 1st, do I twist the wires up together and insert or should I loop them up like a u shape then insert?

    Thanks for reading. I believe I am getting there, thanks to all your help.

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

    hmm, i see - on the far left strip and + on the far right. the diodes may be for bypass/blocking. if you bought it new then i would assume there should be some documentation that came with it explaining things or at least pointing the way. if not tell us what 85w pv you bought (i'm not searching this whole thread for info) and did you get a meter and know how to use it? if the latter is no, but you bought one, then you will need to read the instructions carefully and educate yourself on how to use that meter, just to find out the output posts.:confused:
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Safety tips

    By the way, thank you Bill for these safety tips and precautions. Very thoughtful and kind of you to mention them.

    rohanjcp

    FROM BILL'S past posting:
    "Yes, you can do it--but with a couple warnings.
    1. Make sure you open and close the connections when there is no power flowing (panels in dark, inverter off--or at least unloaded). DC current is very good at welding connections (actually, DC current is much harder on switch contacts/breakers/fuses vs AC of the same or higher voltage/current).
    2. You may confuse the solar charge controller if you connect the charge controller to the battery when there is light on the solar panels... Virtually every manual I have read says to made the Battery to Controller connection first. And make the solar panel connections second. Most controllers probably use the battery voltage to run their internal controller/computer and sometimes setup the voltage (12 or 24 volt battery bank--for example). You probably want to make the solar panel Pluggable too--so you can connect it second.
    3. The inverter should work OK outside--as long as rain does not net to it, and you prevent condensation from entering the case.
    -Bill"
  • rohanjcprohanjcp Posts: 30Solar Expert ✭✭
    Meters

    Hello everyone.

    Thank you Niel for your feedback. You were right, the seller did not give me any manual at all for my Kyocera 85 watt solar panel (KC85TS). I did request for one and if they don't have any, I will ask them to instruct me the proper procedures.

    Also, of all the components I got, I forgot about the meter. I am assuming you mean the multimeter to measure voltage or the multimeter to track the battery power.

    I saw something about the Watt's Up Meter in this forum. Is that the one suggested? I mainly wish to keep track of the battery power so I don't go below 50%.

    Thank you for reading.

    rohan
    ps. Today I got the hammer crimper on the mail.
  • BB.BB. Posts: 28,084Super Moderators, Administrators admin
    Re: Emergency power

    I am the guy that keeps mentioning the Watt's Up and Doc Wattson meters--just because I have never seen anything else like them (cheap, small, lots of functions) for analyzing DC power usage.

    Other than what I have read--I do not have either meter nor have had any dealings with the retailer...

    One person here preferred the Watt's Up as more accurate (and had the functions he wanted for his system).

    There are a fair number of reviews out there--Google a few up and see what works for you.

    I would eventually pop for a real Battery Meter--really setup to monitor Lead Acid batteries (and does nice things like reset to 100% capacity once the battery is fully charged+equalized).

    But for a smaller system, the battery meters are probably overkill.

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

    Hi,

    I have a 65 Watt Kyocera panel and use an 85 amp/hour battery with a 7 amp charge controller. If you want to have an emergency station and use 120 volts AC, I would recommend getting a true sine wave inverter. Otherwise, you will find that the modified inverters create a lot of noise and many items will not tolerate this coarse of power production.

    Think of the battery as a big Watt bucket. If you pull 100 watts out, you will have to put about 125 watts back in. Charge rates should run about C10 to C20 or total battery capacity/ 10 or 20 in this example.

    I use Anderson Power Poles with 10 gauge wire. My next battery will be two 6 volts batteries that I will wire in series. This will provide lots of amp hours and allow you to split the weight up between two batteries.

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

    65w of pv will work ok (not within good charge range percentages) with an 85ah battery, but if you increase the battery capacity to about 220ah, there's no way you'd have enough current to properly charge the battery. the number of pv watts will need increased. you could roughly figure about a watt of pv for each ah of battery capacity at 12v and mind you that this is not a rule of thumb to go by in all cases as i'm only saying this as a rough idea for you. there isn't any good substitute for actual calculations. the general rule of thumb for most standard lead acid batteries, especially generic brands, would be a charge rate of about 5-13% of the total amp-hour battery rating based on about a 20hr rate unless the manufacturer would state otherwise. do know that many can take the higher rates, but even with that ok from the manufacturer, the farther it is above the 13% rate the higher the maintenance will be and a possible increased chance of failure for some more cheaply made batteries.
  • mike95490mike95490 Posts: 7,969Solar Expert ✭✭✭✭
    Re: Emergency power

    If the batteries are going to be periodically moved, can't the EQ cycle be lower power, as electrolyte mixing is NOT the sole responsibility of the battery gassing ? You would still need enough PV watts to recharge in 6 hours of sun, so batteries don't sit too low, too long, and sulphate.
    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

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