wildebus
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100/50 for £250 sounds a very nice deal.. last time I looked they were nearly twice the price of the 100/30 ones.
Solar panels 260w each
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wildebus
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Absolutely. Think it is 700W rated?
Fisherman
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wildebus
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Good Stuff.
As an aside, I was up on my roof this morning checking some measurements .... I am probably going to add another 150W of Solar to the roof with in-filling, so more than 50% more. So actually a fair bit more than I thought. But now I have to decide do I upgrade the controller?
If I get maximum harvesting, by not upgrading I would be loosing 115W worth of power, which is a fair amount to lose, but for how long would I be loosing it in a typical day? will be interesting to see actually, and I can always upgrade at a later point if I think wasting too much
(definately not going to run extra cable to a extra controller. too fiddly and awkward to run).
As an aside, I was up on my roof this morning checking some measurements .... I am probably going to add another 150W of Solar to the roof with in-filling, so more than 50% more. So actually a fair bit more than I thought. But now I have to decide do I upgrade the controller?
If I get maximum harvesting, by not upgrading I would be loosing 115W worth of power, which is a fair amount to lose, but for how long would I be loosing it in a typical day? will be interesting to see actually, and I can always upgrade at a later point if I think wasting too much
(definately not going to run extra cable to a extra controller. too fiddly and awkward to run).
wildebus
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100/30 is 880W at 24V
it can make a lot of sense to have a 24V setup instead of a 12V one. cabling can be thinner as current is lower; solar controllers work out cheaper (if you were on a 24V system, not only would you not have to upgrade the 100/30 controller, but you could have used a 100/20 controller instead (580W on 24V)).
But there are other complications, which is why 24V is less common despite the benefits.
Nabsim
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Depends where you intend being David, if in UK and all year round it probably makes sense to over panel but keep controllers as is. Reduce the 5 months power negativeGood Stuff.
As an aside, I was up on my roof this morning checking some measurements .... I am probably going to add another 150W of Solar to the roof with in-filling, so more than 50% more. So actually a fair bit more than I thought. But now I have to decide do I upgrade the controller?
If I get maximum harvesting, by not upgrading I would be loosing 115W worth of power, which is a fair amount to lose, but for how long would I be loosing it in a typical day? will be interesting to see actually, and I can always upgrade at a later point if I think wasting too much
(definately not going to run extra cable to a extra controller. too fiddly and awkward to run).
wildebus
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not in your situation.
You can potentially mix 12V and 24V panels on the same controller when they are connected in series. So a 24V panel plus a 12V panel will create a 36V panel setup, just like you can have 3 12V panels in series to make a 36V array.
you cannot connect different voltages in Parallel without massively compromising the output, so that is never a practical option.
This shows the difference between 3 12V panels in Parallel vs 3 12V panels in series (which could, as mentioned, be a 12V + 24V Panel)
seriesvsparallel by David, on Flickr
As an aside, you see the current on the series array is much lower than the parallel array.
But .... remember a "12V" panels voltage can be higher than 20V, and a "24V" panel can be higher than 40V.
The only way to combine your three panels (2 x 24V plus 1 x 12V) is in Series, and when you bear the PV voltages in mind, that makes the array >40V + >40V + >20V, so the total is over 100V and therefore you could not use the 100/50 controller in that setup.
What you COULD potentially do is get the 150/45 Controller instead. That is a 650W Controller, so above your total theoretical maximum of 620W on the 3 panels.
BUT ... and this is a very BIG BUT .... when you add the voltages together in a SERIES setup, the way the current works is you take the lowest current value of all the controllers as the maximum Input Current. So you will be effectively downgrading the 260W panels to more like 200W panels and you could in fact end up with LESS power overall by adding on the 100W panel, incredibly enough. If it were a 130W panel, then it would be a different story.
Your only real option is a different controller for the 100W panel.
As an example, I mentioned I am looking to add more panels onto my setup? These will be panels just a third the size, so the current is much lower than the existing one. My only option for that reason is to add them in Parallel (as they are all "12V" panels, that is fine).
But even then I am losing wattage from the bigger panels as the smaller panel also has a slightly lower max voltage (losing around 4W per 90W panel, so not massive enough to worry about in my case, but if it were say 20W or 30W per panel, it would be a different story).
wildebus
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yup. this is why I will not change, at least for a while and see how much I could really be missing out on (probably not much. It is remarkable how many folk think a 100W panel will give them 100W whenever it is light).
merl
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Gotta watch for shading when you start bunging panels in series too, A bit of a shadow over part of one of your panels and it'll compromise the output from that whole array.not in your situation.
You can potentially mix 12V and 24V panels on the same controller when they are connected in series. So a 24V panel plus a 12V panel will create a 36V panel setup, just like you can have 3 12V panels in series to make a 36V array.
you cannot connect different voltages in Parallel without massively compromising the output, so that is never a practical option.
This shows the difference between 3 12V panels in Parallel vs 3 12V panels in series (which could, as mentioned, be a 12V + 24V Panel)
seriesvsparallel by David, on Flickr
As an aside, you see the current on the series array is much lower than the parallel array.
But .... remember a "12V" panels voltage can be higher than 20V, and a "24V" panel can be higher than 40V.
The only way to combine your three panels (2 x 24V plus 1 x 12V) is in Series, and when you bear the PV voltages in mind, that makes the array >40V + >40V + >20V, so the total is over 100V and therefore you could not use the 100/50 controller in that setup.
What you COULD potentially do is get the 150/45 Controller instead. That is a 650W Controller, so above your total theoretical maximum of 620W on the 3 panels.
BUT ... and this is a very BIG BUT .... when you add the voltages together in a SERIES setup, the way the current works is you take the lowest current value of all the controllers as the maximum Input Current. So you will be effectively downgrading the 260W panels to more like 200W panels and you could in fact end up with LESS power overall by adding on the 100W panel, incredibly enough. If it were a 130W panel, then it would be a different story.
Your only real option is a different controller for the 100W panel.
As an example, I mentioned I am looking to add more panels onto my setup? These will be panels just a third the size, so the current is much lower than the existing one. My only option for that reason is to add them in Parallel (as they are all "12V" panels, that is fine).
But even then I am losing wattage from the bigger panels as the smaller panel also has a slightly lower max voltage (losing around 4W per 90W panel, so not massive enough to worry about in my case, but if it were say 20W or 30W per panel, it would be a different story).
wildebus
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That is quite correct. I deliberately ignored any pros and cons in my post, otherwise you end up going on and on (even more!). Parallel needs thicker cables, less voltage loss on series, harvesting starts sooner, etc etc. Gets boring zzzzz
Post was purely about the maths and technicalities of it, which is the primary factor. If that says one way won't work, then the rest is irrelevant.
1 Cup
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Thanks guys good information. . does any one want used panels and controller ?.lol. So 3 24 v 260w watt panels, it is then as they fit nicely on roof too.
What Controller from victron will do 780w at 24 volts ?????? The extra panel and fittings are £250 so not this side of our holiday. Will my controller hold out in the coming good weather ? ......
What Controller from victron will do 780w at 24 volts ?????? The extra panel and fittings are £250 so not this side of our holiday. Will my controller hold out in the coming good weather ? ......
wildebus
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You already have the perfect controller for that ... 100/30 -.880W at 24V.
wildebus
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When you start getting into bigger arrays like like, it is worth considering multiple controllers.