New Kyocera Solar Panel

Submitted: Sunday, Nov 16, 2003 at 02:08
ThreadID: 120232 Views:2562 Replies:15 FollowUps:0
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Hello all We have just recieved an email from bushtracker telling us that there is a new solar panel from Kyocera that has a better power curve, and is a significant improvement over the normal KC-120. The net effect is that it will produce more power in the hot weather. The new model is the KC-125G and it will cost an extra $50 a panel they are a 125w panel. Does anyone know about this and do we upgrade. we are also wondering if we should have 4 panels as we have only ordered 3 panels and 3 Gaston AGM Maintenance free batteries. the van is 21ft with double and three singles for the kids with the normal list of options. Any suggestions welcome? Rod
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Reply By: Noosa Fox - Sunday, Nov 16, 2003 at 02:10

Sunday, Nov 16, 2003 at 02:10
Hi Rod, Not knowing anything about the new solar panels, I would still be inclined to pay the extra and go for the lastest technology. As for the number I have 3 by 120watt on ours and we only ever run low on power when it is raining and very overcast for more than a day. It is no different to our solar hotwater at home, they both work great 99% of the time, and on those ocassions when the sun cannot get through the generator comes out on the van and to 240 switch goes on at home for the hot water. I would still stay with 3 panels, and if for some reason you find that you haven't got enough, an extra one can easily bne put on but I doubt that you will ever need it, because your new one will probably be putting in a lot more than than extra 5 watts that they are rated above ours. Brian
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AnswerID: 560128

Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:11

Sunday, Nov 16, 2003 at 02:11
Kyocera also have areasonable CDMA phone deal as well

AnswerID: 560129

Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:12

Sunday, Nov 16, 2003 at 02:12
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Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:13

Sunday, Nov 16, 2003 at 02:13
Kyocera data sheets indicate the 125-G module will produce a maximum of around 90 watts into a typical 12 volt 'van system. The data shows thermal performance marginally better than previously. As with ongoing industry trends efficiency is up - so there's more watts per square metre. And that's always handy if roof space is scarce. BUT - the apparent 5 watt increase over the 120 watt unit will only be realised if driving a voltage matching load. The 120 watt unit has a stated maximum output of 7.1 amps. The 125 watt units has a claimed maximum output of 7.2 amps. With a 12 volt system (say 12.6 volts) that's 89.46 watts and 90.72 watts respectively (at moderate temperature). That's 1.26 watts more - not 5 watts more. Heat losses will reduce this by about 0.4% per degree C - possibly a bit less for the 125 G but it's hard to pick from the graphs in the data. Summary. People jump to quite wrong conclusions about solar module outputs. Claimed wattage output is only obtainable when driving loads matching the voltage at which the max power output is shown. In this case that is 16.9 volts and 17.2 volts respectively. The claimed ouput (under controlled and somewhat improbable real-life conditions) can be achieved, for example via direct-driven water pumps, and by multiple power point tracking regulators. But not by the solar regulators fitted to any commercial Australian-built RV I am aware of. It actually says most of this in the specifications - but it's in techo-speke! If you upgrade you will pay about $40/watt - the going price is under $10/watt. Collyn Rivers
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Reply By: Tassietracker5 - Sunday, Nov 16, 2003 at 02:14

Sunday, Nov 16, 2003 at 02:14
Thanks for the reply Collyn, In simple terms from what i gather you said that it is only marginal gain of just over a watt. It doesnt sound worth it at 3 panels $150, and i always thought that with this sort of technologhy it got cheaper with new advances not dearer. Thanks again Rod
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Reply By: Luvntravln - Sunday, Nov 16, 2003 at 02:15

Sunday, Nov 16, 2003 at 02:15
Not speaking techo-speke or anything closely resembling such a foreign language, the bottom line recommendation is to stay with the 120 panels because a cost-benefit analysis fails to justify the increased cost. Correct? Thanks, Jay
AnswerID: 560133

Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:16

Sunday, Nov 16, 2003 at 02:16
On an output basis stay with what you have ..... the 120's. It might pay to check the physical strength of the new panels verses the old. If they are markedly stronger in construction I'd pay the difference and go the new. Anthony Explore this Great Land ...Do it Easy ...Tow a Bushtracker
AnswerID: 560134

Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:17

Sunday, Nov 16, 2003 at 02:17
I possibly need to make it clear that the 125 G Kyocera module can produce at least five more watts - but it can only do that with a suitable load (which is not a basic 12 volt system). The cause of the ongoing confusion is that the by far the largest single market for solar modules is water pumping in remote areas. By their nature, water pumps can take advantage of a solar modules' output characteristics: 12/24 volt systems cannot (unless fitted with a sort of 'electrical torque c onverter' called a multiple power point tracker ) that in effect shuffles volts and amps around to optimise usable watts. The short answer is - stay with the 120-watt modules unless spending most of your time where it's seriously hot (like plus 36 degrees most of the time).. Collyn Rivers
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Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:18

Sunday, Nov 16, 2003 at 02:18
Collyn, That's very interesting !! Is it similar to the new generation "inverter" air-con compressors that vary the voltage and frequency and ramp up/down ... to save power ? Anthony Explore this Great land ...Do it Easy ...Tow a Bushtracker
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Reply By: Luvntravln - Sunday, Nov 16, 2003 at 02:19

Sunday, Nov 16, 2003 at 02:19
Hi guys Sorry I wasn't clear. I do not have any panels right now so when I said "stay" with the 120 I meant "buy" the 120 as compared to the 125. Therefore, based upon your experience, what would you purchase for a new BT? The 120s or the 125s? Thanks, tgintl
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Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:20

Sunday, Nov 16, 2003 at 02:20
Anthony The Multiple Power Point Tracker is closer to a torque converter. It works like this. As you'll be aware a watt is definable as being one volt times one amp. Now for various and valid reasons a solar module typically produces its maximum power at about 17.0 volts. At that voltage an 80 watt module typically generates a max of 4.7 amps. Multiply 17 and 4.7 and you get 79.9 watts. Solar modules are vaguely constant current devices (which means the current does not vary much as voltage changes). At 12.6 volts it still produces about 4.7 amps. But multiply 12.6 by 4.7 and you only have 59.22 watts. That's the most you can get out of that module at that voltage. (In practice it will be up to 10% less due to temperature losses.) The modules will in fact produce a higher voltage than that 17, but current does start falling off above that point. At 18 volts it's likely to be about 4.5 amps. The MPPT is a dc-dc converter. It accepts whatever voltage is coming in (which is probably about 18 volts and reduces it to about 14.7 volts. The process increases the current available by the same percentage (less internal losses of around 10%). So what we are likely to get out of the MPPT is 14.7 volts but at 5.5 amp (minus 0.55 amps) = 4.96 amps. And 14.7 volts times 4.96 amps = 73 watts. You still suffer the same temperature losses, but even so the starting point of 73 watts is a lot better than a starting point of 59 watts. Big MPPTs are beginning to be used in big domestic systems where it's increasingly common to series-connect modules to 140 volts or so (to save voltage drop) and use an MPPT to bring that down to 24 or 48 volts. There are a few small MPPTs on the US market but at present they cost more or less what they save! The technology will however eventually be incorporated in smaller solar regulators. A litle bird has told me that one of my favourite solar regulators may have it by the end of next year. A vague analogy is that it's a bit like having a car with only (say) 3rd gear. That car will only be able to use its otherwise available power over a limited range of speeds and loads. A solar module is a bit like a one gear car, and an MPPT is like an automatic gearbox plus torque converter that makes the available power usable over a wider range. Trust this helps. Collyn Rivers
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Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:21

Sunday, Nov 16, 2003 at 02:21
Collyn, I see .... in a simplistic overview it limits voltage fall at a constant current thereby increasing watts available ..... Mmmmm ! Nice to own the patent on that one ..... especially as the price filters down to caravan use. Anthony Explore this Great Land ...Do it Easy ...Tow a Bushtracker
AnswerID: 560139

Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:22

Sunday, Nov 16, 2003 at 02:22
Anthony - almost spot on! Brecause volts time amps equals watts, 100 watts can be generated at 1 volt and 100 amps, 10 volts at 10 amp or 100 volts at one amp etc etc. Following this, the MPPT doesnt drop 17 volts down to 14 volts by losing energy, it sort of juggles it. In the process the volts go down, but as the conversion is very efficient, the amps go up. It's a sort 'conservation of energy' thing. Collyn
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Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:23

Sunday, Nov 16, 2003 at 02:23
Hi All, Just to add a little more to the MPPT debate. There is lots on the web about the technology. Just search on MTTP. Solar Boost in the US make a MPPT unit called Solar Boost 2000E. It is a 25A controller and is designed for RV use. solarsales.com.au have them on their web site. Cheers, Peter & Leigh
AnswerID: 560141

Reply By: Deleted User - Sunday, Nov 16, 2003 at 02:24

Sunday, Nov 16, 2003 at 02:24
Peter The problem with these units at the moment is that, in RV type sizes, their cost is much the same (or more than) the gain. Their is of c ourse a case for them even then if roof space is very tight. They are however gaining acceptance in big rural systems such as our own 12 kW/hr/day. Be wary of some of the claims made on the web. It's very easy to 'juggle the numbers' - by for example quoting the dc output at 12 volts instead of the probable charging voltage of (say) 14.0 volts. This is very often done and gives the impression the gain is 35% plus rather than the more realistic 20%. Collyn Rivers
AnswerID: 560142

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