panel 24V -125W for our Landcruiser...

ivan29
ivan29 Registered Users Posts: 8 ✭
in Caravan, Recreational Vehicle, and Marine Power Systems #1
Hello everybody,

We are a couple of French travelling in a Toyota landcruiser HZJ75. We left France in September 2012 and went East, Europe, Balkans, Asia, all the Stans, Mongolia and far East Siberia, we shipped the car from Vladivostock to Vancouver then when up North, spent 3 months in Alaska and now heading South East. Here you can have a look on our car and our trip: www.ikasfilm.com

We are actually thinking about fitting a solar panel on our roof, as the car is working on 24V I decided to keep everything in 24V:

2 x 12v aux. batteries with an automatic swich (so far those batteries get charge by the alternator).

1 compressor fridge Vitrifrigo C42, 31w nominal
1 Webasto diesel heater HL18D, 25w
LED lights, 3.5w
and 1 inverter 24V 220V (Yes Europe...) for the laptop 90W (and camcorder batteries but mostly when we are driving) .

Because of the room that we have on the roof we can only go for a 125W-24V monocrystallin panel... And 2x 12V will be way to big for the same power.
We found a panel on the web as no one around here (Canada, British Columbia) got smaller than 235W polycrystalline.

The panel is from Aleko (http://www.alekoproducts.com/ALEKO-Solar-Panel-125-Watt-24-Volt-Monocrystallin-p/sp125w24v-ap.htm), I tryed to get some information about it but get no luck, wonder if anyone know about this company and this product?
my biggest concern is about the shipping... I don't want to order a panel (even if the website is .ca) and get the panel hold by the customs.

If ever someone have an other solution that will be very appreciate, maybe an other place to by or a dealer in CA...

Thank you very much for your time, (excuse my french/english)

Ivan & Katia.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: panel 24V -125W for our Landcruiser...

    Welcome to the forum Ivan & Katia.

    That is a very odd and expensive panel. Normally a panel that small would be 12 Volt, but the specs indicate it is a true 24 Volt: the Vmp is 36. The cost of $2 per Watt is on the high side for sure. I've never heard of this company before, but that means little in the solar panel business these days; they come and go all too quickly.

    What I would wonder about is how much it will actually contribute to your power reserve. We don't know how large your batteries are in Amp hours, and probably they are just automotive type not deep cycle. But it's been working so far, yes?

    Your loads look like around 60 Watts DC with a variable inverter & AC load. Technically this panel should be able to offset that much while the sun shines on it (expect slightly less than 100 Watts in reality). You should also have a charge controller to prevent it from pushing the battery Voltage too high.

    And yes, buying things in Canada can be vexing. Especially in British Columbia (our motto: The Expensive Province).

    No doubt you are having much fun with the Canadian French, better known as joual or "gibberish". :D Some of the translations to English or real French can be hilarious.
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  • ivan29
    ivan29 Registered Users Posts: 8 ✭
    #3
    Re: panel 24V -125W for our Landcruiser...

    Thank you for answering,

    Sorry for don't giving you all the details...

    The aux. batteries are 2 x 12V AGM gel batteries of 850Amps each and 90A/H, so that make a pack of 24V / 1700Amps / 90Amps/hour.

    I choose a PWM controller, according to some of the retailers we don't really need to go for a MPPT controller as we only have 1 panel and it will work at the same tension as the batteries.

    I'm still trying to get in touch with the dealer...

    PS: Cariboocoot, as you are in BC, do you any other dealers?

    Thanks again.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: panel 24V -125W for our Landcruiser...
    ivan29 wrote: »
    Thank you for answering,

    Sorry for don't giving you all the details...

    The aux. batteries are 2 x 12V AGM gel batteries of 850Amps each and 90A/H, so that make a pack of 24V / 1700Amps / 90Amps/hour.

    I choose a PWM controller, according to some of the retailers we don't really need to go for a MPPT controller as we only have 1 panel and it will work at the same tension as the batteries.

    I'm still trying to get in touch with the dealer...

    PS: Cariboocoot, as you are in BC, do you any other dealers?

    Thanks again.

    Right; 90 Amp hour AGM's (not GEL - that is a different type of battery and not suitable for either use here). So the 3 Amps from this panel would be very minor charging: about 4% peak which is maintenance level. That is what you probably want here; enough to stave off discharge rather than replenish.

    You do not need an MPPT type controller for that panel as the stated Vmp will work with a 24 Volt system and PWM type controller.

    The solar dealers in BC keep changing as it is not a strong market. Our super cheap utility power makes grid-tie systems pretty much worthless, and that leaves the RV and off-grid markets which are rather volatile as they depend on people having disposable income. The last dealer I dealt with (and got a good deal from) here was Riverside Energy in Kamloops: http://www.riversideenergy.ca/
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  • ivan29
    ivan29 Registered Users Posts: 8 ✭
    #5
    Re: panel 24V -125W for our Landcruiser...

    Well,

    So far I didin't fit a "Amp-meter" but only a "Volt-meter" to be able to check if the alternator is working, so after driving (full batteries) we can read 25.6V and the aux. pack and we always be very careful about not going under 24V. So far we never had any trouble even during the winter (heater on during few hours) and we do have 24.6v / 24.8v in the morning before starting the car.

    I was thinking about a panel for, in case that we find a nice place and want to stay 3-4 or 5 days without starting the car (that will be probably in central and south America and definitely in summer time) , the panel could "recharge" the batteries not up to full but enough to use the minimum (fridge and LED so around 12A / 24h so 290w).

    If I understand correctly what you said, that will not be possible with "only" this panel. regarding the fact that if we start the car during 1 hour we got 30Amps...

    Thank again for helping us!

    Here is a pics of the inside of the car to give you an idea of how small it is: Attachment not found.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: panel 24V -125W for our Landcruiser...

    If we look at your loads of 60 Watts DC only and apply a time factor of 24 hours you'd get 1440 Watt hours. A little quick math and you can see that 125 Watt panel will never 'harvest' that much in a day that's only 5 hours of good sun. Maybe 1/3 as much.

    And if we look at that load demand against the battery capacity either the time factor is way off or the engine runs a lot: 90 Amp hours @ 24 Volts and 50% DOD is 1080 Watt hours. Neither of these calculations include any losses either.

    So if we look at what would normally be used to recharge 90 Amp hours @ 24 Volts we get this:
    9 Amps * 35 Volts (Vmp for a 24 Volt system) = 315 Watts of PV. That would be nearly 3X as much as that one panel, which as per above would be about right for the expected load.

    When it comes to that, three panels @ $250 each is $750 for 375 Watts. If you go with that kind of Watts you could buy a couple of 190 Watt panels for $436 http://www.solar-electric.com/topoint-jtm-190-72m-solar-module.html These would also work on a PWM controller (<20 Amps for two) and 24 Volt system.

    Maybe you want to visit Arizona for buying solar panels? :D

    P.S.: Your Land Cruiser is a bit larger than my 4Runner but definitely smaller than my E250 Ford.
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  • WillBkool
    WillBkool Solar Expert Posts: 35 ✭✭
    #7
    Re: panel 24V -125W for our Landcruiser...

    I bought an Aleko 190 watt 24 volt panel for $250 shipped. It turns out that it was manufactured by Eoplly. I have no problems with it, it is a fine panel.
    1220 Watts, 4 Evergreen 120 watt, 1 Eoplly 190 watt; 1 Sungold 200 watt; 2 175 Watt; M-Star 15A MPPT; C40 PWM; 6 105 AH AGM Configured to 315@24V
    Cotek 1500 watt/24v
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  • ivan29
    ivan29 Registered Users Posts: 8 ✭
    #8
    Re: panel 24V -125W for our Landcruiser...
    Cariboocoot wrote: »
    If we look at your loads of 60 Watts DC only and apply a time factor of 24 hours you'd get 1440 Watt hours. A little quick math and you can see that 125 Watt panel will never 'harvest' that much in a day that's only 5 hours of good sun. Maybe 1/3 as much.

    And if we look at that load demand against the battery capacity either the time factor is way off or the engine runs a lot: 90 Amp hours @ 24 Volts and 50% DOD is 1080 Watt hours. Neither of these calculations include any losses either.

    So if we look at what would normally be used to recharge 90 Amp hours @ 24 Volts we get this:
    9 Amps * 35 Volts (Vmp for a 24 Volt system) = 315 Watts of PV. That would be nearly 3X as much as that one panel, which as per above would be about right for the expected load.

    When it comes to that, three panels @ $250 each is $750 for 375 Watts. If you go with that kind of Watts you could buy a couple of 190 Watt panels for $436 http://www.solar-electric.com/topoint-jtm-190-72m-solar-module.html These would also work on a PWM controller (<20 Amps for two) and 24 Volt system.

    Maybe you want to visit Arizona for buying solar panels? :D

    P.S.: Your Land Cruiser is a bit larger than my 4Runner but definitely smaller than my E250 Ford.


    Well, before to be totally lost here was my calculation:

    Fridge: (vitrifrigo C42) 31W nominal, (run about 20 minutes per hour in summer) so 1.3A and so 8H out of 24H = 10.4A
    LED: about 3.5W, so 0.5A and about 5H per 24H = 2.5A
    Heater Webasto HL18D: 25W so 1.04A run about 3H (only in winter) out of 24H = 4.16A
    Laptop: 90W so 4.7A run 3H out of 24H = 14.1A (not everyday)

    Of course the heater doesn't run in summer and the fridge run a lot less in winter but I guess taking the extremes make sure that I will not under estimate our need.

    So that give us a consumption of 31.16A on 24V so 748W per 24H.. am I right?

    I don't understand your 1440Watts... but maybe all my thinking is just not working in a good way...

    Thanks for taking time to teach me.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: panel 24V -125W for our Landcruiser...

    The 1440 Watt hours is based on 60 Watts average load over 24 hours. The hours part is important.

    Things can get a bit messed up when you switch between Amp hours and Watt hours. In general Amp hours are used for battery sizing and sometimes for DC only loads, but Watt hours are usually used for loads either AC or DC. The reason is that Watts is the actual amount of power used by the load, and the Amps it draws to produce those Watts worth of work will vary with the Voltage level of the system: as it goes down the Amps go up.

    32 Amps at 24 Volts is 768 Watts, but there's no time factor here so you do not have a quantity of electrical power. If that 768 Watts is drawn over 24 hours (and it wouldn't be because it is not all always on) it would be 18,432 Watt hours!

    Take the refrigerator for example: 31 Watts but only on 1/3 of the time so 31 * 8 hours = 248 Watt hours (numbers assumed to be accurate but may not be).

    3.5 Watt LED on for 5 hours = 17.5 Watt hours.

    Heater at 25 Watts for 3 hours = 75 Watt hours.

    Laptop at 90 Watts (unusually high for a laptop) for 3 hours = 270 Watt hours.

    Total power used in 24 hours: 610.5 Watt hours. Note this makes a lot of assumptions and is probably not entirely accurate: there's no inverter consumption or conversion efficiency for AC loads for example.

    On a 24 Volt system that should be 25.4375 Amp hours used (note use of lowest system Voltage; this is a 'fudge factor' to make sure system stays healthy). If we were to plan a battery bank for that and 25% DOD it would be roughly 100 Amp hours @ 24 Volts. Yours is 90, which is pretty close to that and with enough luck and an occasional engine run there's no doubt it will work.

    Not entirely accurate, but clearly not too far off either. :D
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  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    #10
    Re: panel 24V -125W for our Landcruiser...

    Things will get much clearer if you get your units right. This is a load analysis, so stick to Wh/day. For instance the fridge (if it really is a 31W compressor) would be 31W * 20/60 * 24h/d = 248Wh/day. This is either a very very good fridge or the numbers are wrong. I have one rather like it in our RV and it draws 75W at about one third duty, thus about 600Wh/day. And thats when the temps are cool. Ive seen it draw a good deal more.

    Any kind of fridge is a demanding load for solar. Assuming we take your fridge estimate of 250Wh/d, a solar panel on a flat surface is limited in its output for two reasons, a) off angle, b) inadequate airflow. Thus lets say we get an end to end yeild of 1.5Wh/Wp. That means you need 175Wp pv just for the fridge. With adequate storage this could be reduced, but space is constrained for that as well.

    Before you go any further you need to know what your realistic Wh/day total figure is for the four seasons.

    I presume the bulk of your roof is taken up with roof rack, otherwise a bigger panel would fit. For this reason, dont just buy any old panel. You want the highest efficiency one you can lay your hands and cash on. Something in the 20% efficiency region, will get the most watts per square meter of roof space.
    ivan29 wrote: »
    Well, before to be totally lost here was my calculation:

    Fridge: (vitrifrigo C42) 31W nominal, (run about 20 minutes per hour in summer) so 1.3A and so 8H out of 24H = 10.4A
    LED: about 3.5W, so 0.5A and about 5H per 24H = 2.5A
    Heater Webasto HL18D: 25W so 1.04A run about 3H (only in winter) out of 24H = 4.16A
    Laptop: 90W so 4.7A run 3H out of 24H = 14.1A (not everyday)

    Of course the heater doesn't run in summer and the fridge run a lot less in winter but I guess taking the extremes make sure that I will not under estimate our need.

    So that give us a consumption of 31.16A on 24V so 748W per 24H.. am I right?

    I don't understand your 1440Watts... but maybe all my thinking is just not working in a good way...

    Thanks for taking time to teach me.
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


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  • ivan29
    ivan29 Registered Users Posts: 8 ✭
    #11
    Re: panel 24V -125W for our Landcruiser...

    Thanks for explaining,

    Well just to make sure I'm not wrong with my estimation, here is the specs of the fridge: Attachment not found.

    So if I understood, the panel 24v-125W will only give us around 144Wh/d (with ideal conditions) so that wil never cover our need and only give us a few hours more of autonomy?

    Ivan.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #12
    Re: panel 24V -125W for our Landcruiser...
    ivan29 wrote: »
    Thanks for explaining,

    Well just to make sure I'm not wrong with my estimation, here is the specs of the fridge: Attachment not found.

    So if I understood, the panel 24v-125W will only give us around 144Wh/d (with ideal conditions) so that wil never cover our need and only give us a few hours more of autonomy?

    Ivan.

    That's right.

    As for loads based on specifications given, don't count on them to be accurate. The real amount used by a refrigerator is highly variable due to temperature and usage. But it seems to be working so far, and that's good.
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  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    #13
    Re: panel 24V -125W for our Landcruiser...

    Well, then those danfos compressors have come along way. Mine is maybe 8 years old, and its a bigger unit, but 250Wh/day is nonetheless a real acomplishment, for a upright fridge.

    But as Coot says often these specs are written for certain 'normal' ambient conditions. And once the vehicle temp goes up the consumption increases. Lets face it vehicles get rather warm sometimes. I think you will never be able to be 100% solar in such tight space constraints. Unless you could add some fold out type panels on ground mount frames or something, but i just think your space has got you as far as it is going to. That you can fit and run a fridge in such a small space it itself an achievement!
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


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  • ivan29
    ivan29 Registered Users Posts: 8 ✭
    #14
    Re: panel 24V -125W for our Landcruiser...

    Thank you very much for your time and help.

    I think, the best for us is just to leave it like that, so far we never had any trouble but because we have time and nice inside space to work on the car and also because the prices droped since the last time I had a look we though it could be the good time to add a solar panel.

    It is definitely not worth to invest now for us and for this particular case, lets wait an other couple of years and find a smaller and double/triple more efficient panel....

    Thank you all again and maybe see you on the road...

    Ivan & Katia.
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  • animatt
    animatt Solar Expert Posts: 295 ✭✭✭
    #15
    Re: panel 24V -125W for our Landcruiser...

    One thing I think important to mention.

    If your refridgerator consumption numbers are anywhere near accurate, it means your laptop is using a significant amount of you daily power. I am not sure what your needs are for your pc or if even those 90watt figure is accurate. I would doubt that as well. Probably much lower consumption on the laptop.


    As I say it depends but a laptop for internet browsing, watching videos, document editing and other lighter tasks can be done on laptops that use maybe 10-15watt when running. Which makes a big difference to power consumption if your numbers are correct. That single change could save you 40% of your energy budget. which makes powering from limited roof space much easier.

    Conservation is key.


    I am using a small 11.6" laptop(fine for me but maybe not everyone). When on battery power. Justing typing this post on full screen brightness, wifi on, no other cables or drives connected, reported energy usage of about 6.7 to 7.1 watts. Turning screen off for a few seconds drops usage to 4.7 watts. if screen on with a smart phone charging power usage goes to a whopping 10 watts. Granted that is not a major task, but this laptop does save me a bit of juice. most of the time this computer is just doing light work anyways.

    artificially maxing out my processors power consumption while charging smart phone via usb port maxes power consumption out at ranging from 13.0 to 14.2watts.

    My computer was picked because it will be with me offgrid and as stated above CONSERVATION is KEY.
    Just something else to think about.
    animatt
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  • ivan29
    ivan29 Registered Users Posts: 8 ✭
    #16
    Re: panel 24V -125W for our Landcruiser...

    Thanks for that animat,

    my numbers for the laptop are from the main power charger adaptater:

    INPUT AC 100V-220V ~1.5A & OUTPUT DC 19V 4.7A (I figure 19x4,7= 89.3w) but I maybe wrong?

    We use our laptop for video editing... it's a 16" dual quad core, 8GO ram and it's almost of the time running at 80-90% (adobe première / avid / after effect...)

    If ever we don't use the laptop and only the fridge and LED, according the fact that will be in central America so very hot outside lets guess that the fridge will be running more than in winter of course but even when we where in Mongolia in the Gobi desert last July (40-45°C and no aircon in the car), it never ran more than 20mins per hour so that mean, ~250wh for the fridge and ~130wh for the LED so a total of 380 watt hour.

    Here, the panel I could fit on the roof will only give us 144watt hour, just enough to cover the LED consumption...

    So far we only had to stay during 6 days without starting the car (in Uzbekistan, May, 25°C-30°C) with only the fridge running, and we didn't pass the limite of the 24V on our "voltmeter".

    I still wonder if installing the panel (about 350CA$) is worth it?

    Ivan.
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  • animatt
    animatt Solar Expert Posts: 295 ✭✭✭
    #17
    Re: panel 24V -125W for our Landcruiser...

    I may have missed it but do not see where you get 130wh for LED light. A led of 3.5w running 24 hours a day would be 24 x 3.5 = 84 waa hour. You could have various Led lights but still probably not at 130wh.

    One 3.5w Led light for 5 hours would be 17.5wh.
    So your purposed solar panel could supply alot more than the LED lighting. Atleast how I see it.

    animatt
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  • CDN_VT
    CDN_VT Solar Expert Posts: 492 ✭✭✭
    #18
    Re: panel 24V -125W for our Landcruiser...

    Ivan & Katia ,

    HI There ,I follow you on I8MUD . Where are you now (in BC) ? Im also in BC till Wednesday then off to USA for Courses.
    I have the BJ60 in camper mode also.
    So for this Solar Idea , I also have one built for mine , Im using 200W panels with a MTTP morning star 15 that kept my danfoss fridge freezer working all winter in test mode. The entire setup for testing was in our greenhouse , panels/controller /fridge .


    Now as I read your Setup , your taking 24 volts , converting it to 230Vac and then using converters to 18Vdc for the computers .. 2 conversions is wasting power . I would & do use a few voltage converters from 24Vdc to 18-20 Vdc for the computers & 24Vdc to 5Vdc for the phone charging .. Much smaller amount of conversion wasting ..

    My system test proved that I could keep the food frozen & not drain the battery's.


    VT on Vancouver Island till next week

    Edit add:
    Nice to have the AC inverter for shavers & trimmers etc , But I don't see the need to use the inverters just to charge a phone or run a computer ..
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  • AuricTech
    AuricTech Solar Expert Posts: 140 ✭✭
    #19
    Re: panel 24V -125W for our Landcruiser...

    Of your vehicle's roof area, what are the actual dimensions of the area(s) you can dedicate to photovoltaic panels? It may be that a larger number of smaller panels will make the most effective use of that area (if, for instance, you can fit a pair of 60W 12V panels (wired in series) over here, and another similar pair over there, that would give you a nominal PV array of 240W/24V). Play "TETRIS" on your available roof space, using various panel sizes, to see how best to maximize your planned PV system's performance.... ;)
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  • ivan29
    ivan29 Registered Users Posts: 8 ✭
    #20
    Re: panel 24V -125W for our Landcruiser...
    AuricTech wrote: »
    Of your vehicle's roof area, what are the actual dimensions of the area(s) you can dedicate to photovoltaic panels? It may be that a larger number of smaller panels will make the most effective use of that area (if, for instance, you can fit a pair of 60W 12V panels (wired in series) over here, and another similar pair over there, that would give you a nominal PV array of 240W/24V). Play "TETRIS" on your available roof space, using various panel sizes, to see how best to maximize your planned PV system's performance.... ;)

    Hello,

    actually we can only fit a single panel between the windshield and the roof rack

    I don't want to fit a second one on the spare wheels as it will be a pain to take it out when ever we need.

    Thanks.
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