I am ready for technical advice...Yipee

IyaIya Solar Expert Posts: 32
Hello Guys,

After I have confirmed everything, I can now estimate a system.
I will be most happy for inputs. Thank u in advance.

Sun peak hours data for the work site is 4.6 hours /day. NASA data 1983 to 1993.

Location is at equator.
Tracker not worth using. Many tall trees surrounding the area.
Land clearing is 100 x 140 meters, perimeter all trees at least 20-25 meters tall. Not a hill top location. Flat area.
Ambient temp is 30* celsius average. Highest maybe 35*C at best.
Lowest will not hit 23* Celsius no matter what happen.
Humidity in tropical rainforest I think must be 95% at least.

User Load during sun light hours, feeding by Solar Panel direct.

25 watt Radio VHF thru 230V AC power supply, 4 hours. Estimated use RX,TX & stand By for 24 hours a day at 384 watts. Power supply loss included.
Sunlight powered 4 hours = 64 watts

100 watt SSB radio thru 230V AC power supply, 12 hours. Estimated use RX,TX & stand By for 24 hours a day at 725 watts. Power supply loss included.
Sunlight powered 4 hours = 120 watts
Battery powered = see under under no-sunlight

Oher possible use at 300 watts.

User Load using batteries or after sunlight hours

SSB radio at 8 hours = 241 watts

TV & Satelite decorder at 110 watts consumption ( 10% inverter loss included ) for 6 hours a day = 660 watts

All other portable electronics using chargeable batteries being charged at night = 350 watts.

LED base light connected direct to 48 volts battery bank ( probably 24 volts model wired in series ) at 150 watts for 12 hours = 1,800 watts

Other possible use at 300 watts.

Total consumption = 3,835 watts/hours

Battery bank will be 48V. Cable run will be quite long.
Useful sunlight will be based at 4 hours only
Charging to battery must be done in 3 hours + 1 hour for final absorbtion
Final PV power will be based on 3 hours of sunlight.

So I am calculating that I need a 1,800 watts panel if based with 1.4 factor.
20% battery charging loss
20% panel efficiency loss due to 75*C panel temp + etc + Etc

Whatever conservative calculation I am doing here, the surplus power I get is an insurance.

In worst case scenario of constant heavy rain, I will make ready 20amps x 2 constant current battery charger for real top up thru an emergency generator. I am using 20amps x 2 because the generator is only 3,500 watts. If I get a 40 amps unit, the surge is not friendly on the generator. So I plan to be easy on the generator.

I am keen to try Sanyo HIT 195 panel and will wire in series to get 138V maximum open circuit voltage. Since ambient at location will never go lower than 23* celsius ( only at night ) , it is very safe. 10 panels. Total will be 1,950 watts. Can use 9 panels because I want to get 138 volts.
However Sanyo HIT is only 2 years proven...How ????

I want the new Xantrex WX but I heard it is not out yet and won't be out so soon. If I use Outback, it is in some installation producing EMI. ??? How ??

For batteries, I will be using Yuasa 2V Traction battery. This is a 565amps at C5. For my use, it will be at least 610 amps battery. This is a forklift battery and rated at 1,800 cycles at 50% discharge based on C5. Price is cheaper than Surrette and locally available. Made in Japan.

Locally available panel is Kyocera and Sharp. Kyocera seems to rule and common.

Any advice, I will be most grateful. Thanks.

Kind Regards,


  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I am ready for technical advice...Yipee

    hello iya,
    lots of radios and this makes me wonder if this is for amateur radio as in a dxpedition or is it for some other radio capacity that'll be more longterm? (bb, i know that i should've checked on his location, but that may not tell the whole story) yes, i'm curious as to what the radio application will apply to. i didn't fully follow how you were calculating some of the loads as you list a total wattage and a max time of 4hrs and come up with a figure that equals less than watts/4hrs. i'm not going to comment on what you have figured too much until i am clearer on the system requirements, but figure on something else to back up everything just in case. this could be wind, water, or standard gennerators run by gasoline or propane depending on what is easier and available to you.
    on the wire run i'd also be curious just how far it will be going and did you figure the wire gauge needed/how? i ask because i have a sticky for a voltage drop calculator you can use that i helped in creating at the top of the general solar topics discussion area.
  • IyaIya Solar Expert Posts: 32
    Re: I am ready for technical advice...Yipee

    The site is for research geologist doing field work. So they need VHF to communicate among themselves for some radius around the camp.

    The SSB is to communicate with HQ some 1,000+ miles away.

    OOppss...you are right, I made a mistake on the VHF consumption. Thank you so much.

    It should be like this :
    I calculated the 25watt VHF in combine Rx,Tx and stand by mode for 24 hours to be at 16watts/hr or 384 watts per day. Thus 4 hours while being supplied by sunlight is 16watts x 4 = 64 watts.

    I also forgot to add the 20 hours it will be feed by the batteries after no effective sunlight. 16 x 20 = 320 watts. Lucky you spot it...thank you thank you so much.

    I am trying to separate day time use where sun light power is available as direct feed while having to calculate the extra power to do recharging for equipment consumption after no sunlight power production.

    Of course the priority is to recharge the batteries for the assumed 20 hours of no useful sunlight to power the panel.

    I know this is a little odd way of calculation but if I can advice the geologist to shift their working time with electronic equipment, while sun light is available, they can maximize their autonomy in rainy season. Working while sun light is available means they save about 20% if compared they have to use batteries. I mean the 20% is the battery charging loss.

    So the new calculation for total power is : 4,155 watts hour, instead of 3,835watts.

    There is a stand by generator of 3,500 watts. However the switch to solar panel from generator is because the place is so remote, sending fuel is a 2 days walk or by helicopter. So generator use is only in desperate situation.

    I want 48V batter bank is also because I can push the MPPT charger to run easier. With a 24V system and 2,000 watts panel, no single 60 amps MPPT charger can handle. I want to avoid a twin 60 amps unit. Not because of cost but in my experience with battery charger in twin/parallel application
    ( marine ), long term is not that good. Once one is out of "tune" a bit, the other charger get "fooled" too.

    I think I read that Outback can be set in Master & Slave mode for charging. If only one unit controls the logic of actual charging, it should be safe for me, otherwise two logics unit may actually interfere if one is out of "tune".

    The cable run length, honestly I can't say yet but I am looking at 20 meters at least from PV to MPPT and to batteries. Later for the distribution it will be much longer for the LEDs light. For 230V output from inverter, I don't really worry. Wire size I will follow your table later and will probably go one size up.

    Now my worry is the Outback if it may interfere with the VHF or SSB. The VHF probably a 430Mhz unit. I will check on it. The other worry is the Sanyo panel, which I just did a search is only 3 years proven, sorry not 2 years.
    If i choose the wrong PV, my client will kill me. The PV will be transported by helicopter and the charges is A-LOT.

    Thanks Niel. Would like to hear more advice where I can refine the sytem for better reliability.

  • mike95490mike95490 Solar Expert Posts: 8,207 ✭✭✭✭✭
    Re: I am ready for technical advice...Yipee

    Voltage trop caculator spreadsheet.
    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 Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I am ready for technical advice...Yipee

    very good that you are trying to get away from the generator and its costs, but we both know that it will be expensive with solar too. (much quieter with solar though) a rainy season will make the solar production very close to non-existant so you will be reverting back to the generator during that time period. wind and hydro are other possibilities that you made no comment on, but the hydro would be a more permanent type of an arrangement in most cases.
    as to the track record of the pvs, you will find that not too many of the companies existing now have been able to proveout the pv performances due to the pvs, or in some cases the companies themselves, not being around for that length of time. some of the companies have even cut back on the warranty they offer on the pvs(i think it applied retroactively). i believe kyocera is still offering a 25yr warranty and they have proven to make good on their warranty service. you did not mention if this is a longterm arrangement or one with a finite time limit for that location. or will you just take the pvs from location to location when the need arrises? i am assuming location to location because of your concerns of the pvs' lifespans.
    i also know you have done your reading here on the forum by the 138v into any of the current higher quality mppt controllers. yes the temps will keep voltages down somewhat, but all it would take to exceed would be an edge of cloud event when that batteries are full and little to no loads on them making a borderline scenario. i wouldn't design a system up that close to the limit area, but that's just me. others should make their comments on this too.
    that now brings to mind a question on how you will be mounting the pvs. will it be a trailer type of an arrangement or a more permanent thing that'll be torn down? will it be adjusted or adjustable for their angles? near the equator the general scenario is the sun rises in east, goes overhead, and then sets in the west and this will vary slightly depending on the time of the year too. this is tougher to have a single fixed angle for than compared to someone like myself, but if you had to pick an angle i suppose that single angle would be the pvs laying horizontally and looking straight up. oops, i forgot you mentioned a limited view due to the trees so this would apply to you with laying the pvs flat. i guess that takes some of the complexities out of it.
    the way to look at this would minimally be on a daily basis of watts consumed measured in watthours. knowing how much you need in a day and then dividing by the 4hrs of sun you have indicated would give the true power needed to be supplied per hour. i see you have compensated already for ratings and losses, which is good. this will give the the idea of how much pv to go with.
    well, ive rambled on in my thoughts too long so i'll stop now.
  • IyaIya Solar Expert Posts: 32
    Re: I am ready for technical advice...Yipee

    Hello Niel,

    Thank you for the reply. I have been having nightmares over the past few weeks trying to learn of PV and the MPPT charge controller. Bought a book from Australia Rainbow Company but its quite useless. The best info I got is from this forum, Outback , Nasa and a few universities PV FAQ database and research papers.

    I am not an engineer by education but DC charging for marine/yachts is my strong point since I been playing with it for the past 10 years. So I do not have a problem with understanding MPPT output side all the way to batteries and loss in cables. However I never knew PV panel is so fun to learn and the MPPT charger is such a beauty. I mean it is a beauty because the charging logic can be programmed to such an extend that it makes even the smartest marine battery charger look stupid...:p.

    The team who will need the solar panels are good friends, their boss is my best friend and I like challenges like this. Anything that add ups knowledge, I welcome very much.

    The problem is that in Indonesia, there are not many solar expert because the application is very limited. Solar tech here are more of salesman than engineers. The sytems I been offered are sub-standard in the way of the system efficiency calculation or suitable power. I was not informed of panel temp at 75*C will make output so much less. I also see their battery charging loss calculation too little. I also do not see time allowance for the last final absorbtion of the battery, which is time consuming in my experience with yachts battery banks. The geographic of the PV installation site was not even asked by the solar tech, how can they produce such a calculation ?

    I am conerned of PV lifespan because it is not cheap. If I need 10 of Sanyo 195watts, that is about US$11-12K internet price. The geologist team will move from one location to another. I expect at least 10 years real life span on the PV panels to make it a decent investment, 80% performance after 10 years I can live with.

    You are saying that 138V I am intending to wire is a bit risky if days are cloudy. The Sanyo 205, which is of the highest Voc at 68.8 volts is rated at 25*C , STC. In the installtion site, and with sun out regardless of rain or cloudy, temperature can not hit lower than 25*C. Is it not safe enough for my calculation ?

    Hydro is out of the question in this site. No real river close by, only a creek with very little water movement. Wind, maybe if we built a tower of 50 meters or more. That will cost a lot and the wind speed according to Nasa for 50 meter above sea level is only 1.7 meter per second by average. I have not look into the wind yet but the NASA numbers and on site report is not promising. This site is like 200-270 miles from the sea and with some hilly topography in between.

    Since this is the equator the sun declination is 23.5*deg (x2) degrees soltice to soltice. I can get the team do adjust the panel maybe everynow and then every month or so, or keep it flat.

    The installation for the PV, I really don't know yet but in most cases it will be just above ground at a height where they will need no ladder to clean the panels. Chest height ? I have to visit the site if I want to get a better picture. Wood would be definately be the main construction material for support of the PV panel. I never seen a big 150+ watt panel, I may want to make a hinge on them or something for the adjustment. I don't know yet. Now my work is based on imaginations....:confused:

    My plan is to first "play" with the panel once I buy them. My location is 5* degrees south of the equator, very similiar to the work site. From there I will think what I should improve.

    I hope I can get more input from others.

    Thanks Mike,
    I already downloaded the voltage drop calculator.

    Thanks for your time and advice Neil. Keep it coming.

  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I am ready for technical advice...Yipee

    yes, there are many of us that also enjoy the subject and we all learn everyday and from each other.
    you said, "You are saying that 138V I am intending to wire is a bit risky if days are cloudy."
    no, not just on a cloudy day, but the amplification of sunlight through refraction on the edge of a cloud. this could've been the only cloud in the sky so a cloudy day is not the right way of seeing it. the controllers are rated to a certain voltage and exceeding their ratings are not good. the open circuit voltage alone will exceed the controller's ratings. open circuit voltages are when no load is on at the time to pull current. increasing the current will start pulling down the voltage until you would see the rated vmp at the rated current imp if receiving the 1000w/m^2 strength of sunlight.
    now we did not address the energy conservation side of this either. the sideband radio is an efficient way of transmitting, but increasing antenna gain can allow a significant reduction in power levels. this could be a directional antenna, but in the case of a vertical antenna on the high frequencies the placement of a few 1/4 wavelength radials attached at the grounded point where the antenna is fed would help. for vhf radios operating fm, use the lowest reliable power level if it is adjustable. of course the increasing of the vhf antenna gain helps too, but if going for any distance you may need to also increase their height above the ground.
    there are also ways of reducing the need for lighting too so a check into the section on energy use and conservation would benefit you.
  • IyaIya Solar Expert Posts: 32
    Re: I am ready for technical advice...Yipee

    Wow....lucky I found this forum. Many thanks Niel on the 138V advice.

    Now, I am getting 68.8 volt as Voc at 25* Cecsius if I use the 205 watts PV.

    I do not know how much voltage loss I will expect from Outback for a 48V battery bank. At panel temp of 75 *C and 1 amp, I am looking at 57.7 volts.
    for Sanyo 205 watts PV. The Xantrex writes that +0.25V per cell and 1 V extra for equalizing, that means 64 volts for lead acid battery with 48V set up. No mention too on loss within the MPPT.

    I just downloaded a 215W Sanyo HIP-215NEH5.
    Its Voc is 51.5V and Vpm at 42V. This looks good for series connection and should be safe input at 103 volts. What do you think Neil ?
    I really like the solar PV thing, its so unique in is properties....:D.

    Thank you so much.

  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I am ready for technical advice...Yipee

    iya said,
    "Its Voc is 51.5V and Vpm at 42V. This looks good for series connection and should be safe input at 103 volts. What do you think Neil ?"

    looks good to me.:D
  • IyaIya Solar Expert Posts: 32
    Re: I am ready for technical advice...Yipee

    My my...Solar Panel is really so unique.

    That 215W seems to be European spec. All the on line retailers are either German or British based. I don't see any US retailers having them. The spec sheet put Sanyo Germany, not Sanyo USA like the 205 watts panel. I will have to write to Sanyo and see if they can take 36 *C ambient temperature.

    I just checked the US and German Sanyo website. 215watts is only shown in German website....hhmmm.

    I am trouble getting climate data for year 2000 and up. This area is not populated, my country weather data is not showing anything and they are also so broke and under funded. In 2002 there is a report of extreem weather some 200 miles away from work site and it registered 36*C out of the usual 32 *C for the last 50 years or so.

    Hhmmmm...solar panel you make me cry...:confused:... ha ha ha

  • IyaIya Solar Expert Posts: 32
    Re: I am ready for technical advice...Yipee

    Why would Sanyo make a 215 watts type with Voc of 51.5V and the smaller ones ( 180 - 205 watts ) at 68.8 V ?...:confused::confused:?? And then in the USA 215 watts panel not available in the US website.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I am ready for technical advice...Yipee
    Iya wrote: »
    Why would Sanyo make a 215 watts type with Voc of 51.5V and the smaller ones ( 180 - 205 watts ) at 68.8 V ?...:confused::confused:?? And then in the USA 215 watts panel not available in the US website.

    you may have to ask them.
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