In over my head

[inetdog]

And a query touching on fundamentals - when you connect panels in series does it have to be AXBXCXY where Y is the controller and X is + to - and vice versa, or can it be AXY BXY CXY?

Houston, we have a problem....

Series means that you line up all the panels (electrically) with one loose + on one end, one loose - on the other, and with the one in the middle connected + to - and - to + to the outside two. The two loose ends are now connected to the CC (Y).

But you can only connect panels in series if they are reasonably close (~5%) in their Imp figures. That is why you have to find out those specs (or measure them) before making any design decision.)

If you connect all of the + together and to the + of the CC, and all of the - together and to the - of the CC, you have the panels in parallel. Which will also be fine IF the Vmp of the panels are all reasonably close (again within ~5%). (For a PWM controller, voltage mismatch of panels in parallel does not make a difference since they will all end up pulled to the battery voltage at the moment anyway.

Regarding the connection of the turbine, since it is only 200W, it seems a shame to dedicate a Classic to it. And one CC cannot usually handle both wind and PV at the same time. If the C35 does not actually dump the battery voltage down to the dump load, you can probably do well enough with it for the turbine. But a lot still depends on what type of control the turbine is expecting. The CC has to act to protect the turbine as well as to charge the batteries.

For proper wiring of two batteries in parallel, and a host of other good technical discussion, go to smartguage.co.uk.

[Tom Bradford]

Houston, we have a problem....

Only one?

Series means that you line up all the panels (electrically) with one loose + on one end, one loose - on the other, and with the one in the middle connected + to - and - to + to the outside two. The two loose ends are now connected to the CC (Y).

And if you have four panels? The middle two connected + to - and - to + to each other with one connected + to - on one side and the other connected - to + to the outer, with the outer having one + and one - 'loose'? Jeez, what ever happened to KISS?

But you can only connect panels in series if they are reasonably close (~5%) in their Imp figures. That is why you have to find out those specs (or measure them) before making any design decision.)

Are we talking in a perfect, Valinorish world here, so that if you connect panels with more than 5 imps difference you might not get perfection but you'll still get a large chunk of something? Or will having more than 5 imps difference loose an unstoppable hoard of imps onto an unsuspecting world? And how do you measure imps?

If you connect all of the + together and to the + of the CC, and all of the - together and to the - of the CC, you have the panels in parallel. Which will also be fine IF the Vmp of the panels are all reasonably close (again within ~5%). (For a PWM controller, voltage mismatch of panels in parallel does not make a difference since they will all end up pulled to the battery voltage at the moment anyway.

So perhaps it might be better to rebuild the frame and spend $500 on another couple of 80W panels to feed the C35 than $1,100 on the Classic.

Regarding the connection of the turbine, since it is only 200W, it seems a shame to dedicate a Classic to it. And one CC cannot usually handle both wind and PV at the same time. If the C35 does not actually dump the battery voltage down to the dump load, you can probably do well enough with it for the turbine. But a lot still depends on what type of control the turbine is expecting. The CC has to act to protect the turbine as well as to charge the batteries.

The C35 has a diversion control mode which I think is what you're referring to. We'd connect the turbine and the panels directly to the batteries in parallel and the C35 sucks out of the batteries and dumps anything they can't take when they're full that panels and turbine try to feed into them. I think that's how it works. Presumably we'd need diodes on the panel input lead at least to stop the battery and turbine try to make them glow in the dark.

For proper wiring of two batteries in parallel, and a host of other good technical discussion, go to smartguage.co.uk.

Thanks. When next I feel like a bit of S&M and the wife has a headache...

[Sunking]

Some follow-on: If we get this wind-turbine donated by a well-meaning member we will be required by community politics to utilise it. How would I do this?

Set it on the ground somewhere and let it rot. You woul dhave to construct a tower to clear everything by about 50 feet. Then it would still be about useless. YOu could build a brand new system for what the tower will cost with money left over. .

[Tom Bradford]

But you can only connect panels in series if they are reasonably close (~5%) in their Imp figures. That is why you have to find out those specs (or measure them) before making any design decision.)

If you connect all of the + together and to the + of the CC, and all of the - together and to the - of the CC, you have the panels in parallel. Which will also be fine IF the Vmp of the panels are all reasonably close (again within ~5%). (For a PWM controller, voltage mismatch of panels in parallel does not make a difference since they will all end up pulled to the battery voltage at the moment anyway.

OK, took a trip to the mountaintop in search of enlightenment - a trip made even more exciting by the fact that not only does duck-hunting season open today in New Zealand, it's also the weekend of our local hunting competition. Such is my opinion of the mental-state of the testosterone-soaked who enjoy scrambling around soaking bush for two days looking to kill inoffensive beasts who only want to be left alone that I harbour serious concerns as to whether they are fully aware that deer have not yet evolved to ride quad-bikes.

Bit I survived. Here's the geeky stuff:

Panels 1 & 2:

Pmax 80W
Warranted min power 76W
Voltage (Vmp) 17.6V
Current (Imp) 4.5 A
VOC 22.1V
ISC 4.8 (? - didn't note this)
Min by-pass diode 8A
Max series fuse 20A

Panel 3:

Rated max Power 85W
Open Circuit Voltage 21.86V
Short Circuit Current 5.19A
Voltage at Pmax 17.66V
Current at Pmax (Imp) 4.82A

Presumably voltage isn't a problem as it's within 5% however you look at it. As for Imp, 105% of 4.5A = 4.725A. 95% of 4.82A = 4.579A. If that doesn't satisfy the God of electricity could we mask out one of the cells on the 85W panel ((4.82/36)*35 = 4.686 Amp which is with the 5% range) or even two of the cells ((4.82/36)*34 = 4.55A) to keep the Classic happy?

Set it on the ground somewhere and let it rot. You woul dhave to construct a tower to clear everything by about 50 feet. Then it would still be about useless. YOu could build a brand new system for what the tower will cost with money left over. .

Aren't you being perfectionist? Sure it might need to be atop a 50ft tower if you want to wring every possible watt out of it but on this site it only has to be a meter above the top of our pole and it will be the highest thing for twenty miles in any direction - the highest thing for 2,000 miles in the direction the wind comes from - and nearly 2,000 ft above almost everything. In fact if it survives it would probably meet all our power needs with buckets to spare even at 50% efficiency. It would certainly be a lot easier to stick the thing up on a guyed 4m pole than it would be to rebuild the entire solar panel frame which has to be able to hold several square meters of solar panel in some serious winds.

Nice as it would be we have to start from where we are rather than from where we'd like to be.

[Sunking]

OK use the wind turd. But now you have to come up with a dedicated controller and diversion load, plus tower cost.

[Tom Bradford]

OK use the wind turd. But now you have to come up with a dedicated controller and diversion load, plus tower cost.

Well we could use the Xantrex on it IF we can use a Classic on the panels. And tower costs? Yes, But if you were one of thirty odd - to some degree or another - folk depending on this network for your internet would you rather put your hand in your pocket for $100 or spend a day hauling things up to a mountaintop, chipping holes in solid rock or cutting and welding railway irons?

[russ]

Just remember the warnings about the little turbine a year after installation when it has died a horrible death after all sorts of maintenance