Xantrex C40

[brokengun]

Alright, so I've read the manual for the Xantrex C40 and I'm still confused. Basically, I have one Optima Yellow top battery and a 7 foot homebrew wind turbine (12 volt) to charge it with. I just want to make sure not to overcharge the battery or deep cycle it too much. It says that the C40 can only work in one mode at a time, so if I want to use it to regular my load I need one and I need another to regulate charge? Is this correct or could I get away with just using the one to charge?

Anyone out there done something like this with the Xantrex C40?

Sorry, this is probably a pretty easy question but I've done some research and I am still uncertain.

[electronbaby]

Yes this will work.

Only one controller is needed.

Make sure you set it up for Diversion load control. Use it with an appropriately sized dump resistive load.

Wire the turbine directly to the restifiers, and then directly to the battery.

The diversion load controller will start sending power to the dump load when the battery approaches full charge. This is how it regulates battery charge.

Do not use it in charge control (PV) mode for a wind turbine. You will kill it quickly.

[electronbaby]

meant to say rectifiers.

[Flux]

I suspect he is also thinking of the low volt disconnect mode when he mentions not letting the batteries cycle too deeply.

You need one as a diversion controller for dealing with the charge but if you really need the low volt disconnect then you do need another.

If you are around to manage the load you can get away with the LVD but if it is some remote installation then you may need the second controller.

Flux

[SparWeb]

Yes you do need two.  I thought it said so explicitly in the manual somewhere...  There are a lot of details in there, but no "big picture", nor a one-page summary of the live-or-die rules.  

Somewhere hidden in the manual is the 80% rule; have you found that yet?  For wind you should only use it to divert 32Amps, even though as a solar charge controller it's rated for 40.  Go figger.

Always feel free to ask about this stuff.  

[ADMIN]

Yes, everyone did get this correct....you can use the C40 in PV mode, diversion mode, or LVD mode, but not at the same time.

A word of warning though: Are you building the Otherpower 7 foot turbine? I fly that one, and I just checked the Doc Wattson meter for you -- my peak was 53 amps over the winter. That was in 80 mph winds, but would for sure fry a C40.

ADMIN

[kenputer]

I don't think it will fry the C-40 but it will over charge your batteries, it can handle 32 amps as a dump controller so any extra amps would be driven into the batteries as the C-40 could'nt drain the extra charge.

Thats the way I understand it.

Ken

[Flux]

Yes if the dump load is chosen correctly that is right, the controller will be limited to the dump load current but the battery will overcharge and this has to be taken into account when deciding the size of mill the C40 can deal with.  May be ok with flooded cells if the volts go up in an occasional gust for a few seconds but it may trip inverters off and the C40 is slow to respond anyway and for some this is an issue even within the rating.

Sealed batteries wouldn't tolerate this overcharge.

Flux

[electronbaby]

The most important part, if using the c40 in diversion mode, is to size the dump correctly.

I have used and set up many c40's. Most for PV applications, and in charger mode, but probably 6 or 7 in diversion mode with wind, and have caught every one of them on fire from over voltage. They are too slow to respond, and this is why we have moved on to either building a controller to suit the specific needs, or using another brand that has much lower hysteresis.

If using sealed batteries, the over voltage could really ruin your day (and your bank). Flooded cells can take a little more abuse.

[coldspot]

"by electronbaby"

   "using another brand"

Myself and others I'm sure would like to

know more about this.

 So please add more info

thanks