Xantrex wiring diagrams

[dlenox]

Hello All,

Thanks for the wealth of information here!

I recently received my Xantrex XW-6048 inverter and was looking through the wiringing diagrams in the installation manual.  I noticed a distinct difference in how they recommended the DC output from source (solar/wind).

For solar DC connection both the + and - from the solar panels essentially connect to a solar charge controller, the output from the charge controller then connects to the common + and - in the DC distribution panel.

For wind turbine DC connection the + goes directly to the DC distribution panel while the - goes to the diversion load controller.  The + and - output from the diversion controller only gets connected to the diversion load.  This - (from the wind turbine) never gets connected to the common - in the DC distribtution panel.

What would be the rational for this?  I am connecting wind turbine and so don't care about explaination of solar connection.

(For reference here is a link to jpg showing wind turbine wiring diagram extracted from installation guide: http://www.briery.com/wind_turbine/documents/Xantrex%20XW%20Wiring%20Diagram_121.jpg)

Dan Lenox

[Flux]

This doesn't affect your inverter at all but there are normally differences between solar and wind controllers.

Wind generators need to be connected permanently to a load. The normal procedure is to connect directly to the battery and use a diversion controller to dump excess power to a dump load once the battery reaches the set voltage.

This method works perfectly well for solar, but with solar you can work in a different mode. As the panel voltages are limited you can just switch the panel on and off with a series pwm switch and that will regulate the charging voltage perfectly well and it saves the cost of a rather expensive dump resistor.

Most controllers can be connected for series pwm ( solar only) or for diversion for wind or wind and solar. Usually they can also be connected as a low voltage disconnect to protect batteries against excessive discharge.

They can only be used in one mode, you have to choose that to suit your charging source. If you need low volt disconnect then you need another device connected as a charge controller.

This doesn't affect your inverter in any way but you seem to have diagrams for an overall scheme. Inverters go direct to the battery ( usually they take too much current to via a low volt disconnect but that can be arranged if needed)

Probably best to download the manual for one of the Cx controllers then you will see how they can be connected to suit different needs.

Flux

[Ungrounded Lightning Rod]

Also:  Some solar controllers work by shorting the input, not letting it hang open.

Solar panels can be shut down by shorting them, with no ill effects.  The current is limited by the number of photons striking the panels - a shorted panel produces little more current than a loaded panel.  The power generated ends up as heat, mainly in the panels - much as it would if the panels were disconnected but still sitting in the sun - though a bit less is emitted as infrared in the shorted case.  Because the panel already dumps 4/5ths or more of the incident sun's power as heat while operating under load, dumping the rest as heat is not a big deal for it.

Shorting a mill when it is spinning produces a monstrous, long-lived, overcurrent, as the energy stored in the momentum of the blades is converted to heat in the coils, wieing, and controller's semiconductors.  Also:  If the wind is strong and the genny too small, shorting the mill may not bring it to a stop, causing the overcurrent to last indefinitely.  While shorting a (lift-type) mill is good for keeping it nearly stopped (with the blades in aerodynamic stall), bringing it down from speed by overloading it may burn out (or burn UP) the controller, the diodes, the generator, or even the wiring.

[dlenox]

ULR & Flux,

I understand the need for the diversion controller in a wind turbine setup, and I understand that most modern controllers can also be used as 1) charge controller 2) load controller 3) diversion controller.

I have seen other diagrams where both the + and - from the rectified turbine output go to the batteries and the dump controller is parallel to the battery bank.

My question really has to do with the way that the Xantrex wiring diagrams shows specifically how the negative (-) from the turbine rectifier only goes to the dump controller, and nowhere else.

Dan Lenox

[Flux]

Sorry, I didn't quite get the significance of the question.

The Jpg is not good enough for me to see the detailed connections. If I get some spare time I will load the original pdf and see if I can read it.

I tend to build my own control gear and I don't always have detailed knowledge of commercial circuits. There are lots of minor details that don't look too relevant but even minor deviations can sometimes cause problems as small volt drops occur in odd places. That looks a fairly extensive scheme and grounding may be quite critical but until I can actually see what they have done I shall make no further comment.

Flux

[boB]

I wonder if she (the woman that did this drawing) forgot to tie that negative to

the bus negative ??  That might be the simple answer ?  I see the other C40 or

C60 negative terminal going to the diversion load box I think, which I ~think~

would be OK if the negative was connected to the battery negative as well.

boB

[DanB]

I probably missed this somewhere in this thread but it's seeming like some people are not grasping your problem and others are making it too complicated or both.

The wind turbine connects directly to the batteries (or the DC bus bar)

The diversion controller also hooks directly to the batteries and controls a heater that's correctly sized for the charge controller (if its a 40 amp controller then your heater should draw about 40 amps at most - or at least the amount of power that needs to be diverted).

The wind turbine should not be directly connected to the charge controller in any way.

[Flux]

I agree with boB, they seem to have left the negative link out in that drawing but even the pdf is not much better than your jpg.

I presume that you would be expected to use the diversion controller manual for detailed connections rather than that very generalised scheme.

Flux

[Ungrounded Lightning Rod]

Yep.  The diagram is in error:  The mill is hooked to the diversion load but only the + side is hooked to the battery +, while the mill/diversion controller's - side is floating.  There's no way for the mill to charge the batteries.  It only drives the diversion controller.

Without the batteries to clamp the mill's output, once the unloaded peak voltage is higher than the full-charge voltage setpoint it fools the diversion controller into thinking the batteries are overcharged.  This the controller turn on the load, which keeps the mill from picking up speed and coming out of stall.  So it spins dog-slow.

[dlenox]

All,

Thanks so much for the time, I thought that the drawing looked to be in error and thought that I would put it to the experts in this group.

I have contacted Xantrex concerning ths issue.

Dan Lenox

[Ungrounded Lightning Rod]

please let us know their response.

[dlenox]

All,

I finally got confirmation back from Xantrex on this issue.

They stated "The drawing is incorrect.  You will need to connect the Negative from the turbine to the common negative in the power distribution panel. Thanks for bringing this to our attention.".

I am a bit surprized that they do not have an engineer sign off on the wiring diagrams before they publish them...

Thanks for all the comments.

Dan Lenox