48 volt load diversion control, high amperage

[elvar]

Hello

On this website http://www.otherpower.com/17page1.html is shown how the windmill is created from scratch, At the end when testing 3800 watts is the result at 48 volt in high winds. If I am correct, the amperage is 83.3.

I have started building my own windmill but should have asked the questions first... Better now than never!

I have seen several websites with the morningstar and Xantrex contols, but only able to handle up to 60 amper. What kind of diversion control is used to handle the output of this kind of windmill?

Elvar

[SamoaPower]

Judging from posts and comments on this site, most try either paralleling multiple controllers or building a single point or stepped switch, usually using relays. I cannot recommend either one.

It seems to be forgotten or ignored that the primary purpose of a controller is to provide a proper charge algorithm for the batteries. Secondarily, it provides protection against wind turbine runaway.

Multiple parallel controllers will mess up their battery charge algorithm at the risk of shortening battery life.

Bang-bang controllers only limit battery charging voltage with no suitable algorithm at all.

What I will do for my up-comming larger turbine, is to build a multiple FET switch to be driven by a PWM controller, a Xantrex C40 in my case. This will preserve the C40 charge algorithm while providing 150 Amps diversion capability.

[phil b]

Elvar, I use two Xantrex C-40 controllers on my mill. One is setup for diversion, while the other is set for load control. It seems to work fine.

"... build a multiple FET switch to be driven by a PWM controller, a Xantrex C40 in my case. This will preserve the C40 charge algorithm while providing 150 Amps diversion capability."

Samoapower, would you explain more of how you are going to do this? Sounds interesting.

[SamoaPower]

Phil,

I likewise use a pair of C40s set up like yours and as you say, it works fine. However, it still provides only 40A of diversion capability. The one used for load control doesn't enter the charging/diversion picture.

A high-current FET series switch is really quite simple. I'm surprised someone hasn't reported on this til now.

The normal controller diversion PWM output would be used to drive a high-side FET driver IC which in turn, drives low resistance FETs (perhaps 10) in parallel mounted on a small heat sink. Estimated power loss for this switch is quite low, maybe 5W because of the low PWM rate of a C40. A small handfull of parts will do the trick.

I don't like to supply schematics on designs I haven't tested yet but I will when tested.

[robl]

Hi all

I've been using a basic little home-made SSR to up the power of my Outback MX60 diversion circuit. Has worked well for a couple of years. To up the power add more Mosfets in parallel. Feel free to use the design in non-commercial settings. To retain my sanity (and to avoid having to justify my design decisions/omissions to all the experts) I will not be answering any questions about the design. If you can understand the schematic, go for it. There's a better quality pdf vrsion in my files area.

REgards

Rob

[elvar]

Thank you for the answers. Good to know that there are soloutions even tough I don't fully understand this (I am no expert at this). While searching the web I found one unit that might handle the output. Do you have oppinion on this unit? BTW I don't have other specifications for this unit than shown on this page

http://www.solarelectricsupply.com/Charge_Controllers/PV-2-Center/charge-control-center.html

Best regards

Elvar

[Sparky01]

Samoapower I am in the process of installing another 10ft turbine and presently using a C-60 charge controller. I have some 100A DC SSR's with intergral heat sinks,could I use the PWM output to run these? I have got 6 of these kicking around.

Thanks

[SamoaPower]

Probably, if they really are DC types but it depends on their specs.

You need to know the switching input voltage range and its switching frequency response. It needs to be able to switch at about 200 Hz.