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The Projects Forum Working on an electronics project and would like some suggestions, help or critiques? If you would like to comment or assist others with their projects, this is the place to do it.

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  #11  
Old 11-04-2011, 10:51 AM
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thatoneguy thatoneguy is offline
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Originally Posted by labhelp View Post

The problem with the internal adjustable charging circuit is that when the battery bank is full I don't wan th turbine to stop outputing, I want it to ouput to a load (two lightbulbs) if the are on. If they are off I would have to add a dump to handle the excess power.
Often they simply turn the power into heat. Through BIG resistors, think "Pringles Potato Chip Can" size, with fins, and more than one. They send excess to a dump load, which is good in winter, but counteracts A/C or natural cooling in the summer.
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  #12  
Old 11-04-2011, 03:04 PM
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Is there really a need to "dump" power? I mean, the you could just let the turbine spin without putting a load on it. Maybe the term "dump" has just become a term for any excess power beyond what the charging system needs.

Aren't we really looking to use any and all available power in some clever way? I'd say lighting is the way to go, since incandescent bulbs are designed to handle heat and you get great visual feedback in addition to free heat. It wouldn't be too tough to build a "bargraph" type load that could light up an increasing number of bulbs as the excess power level increases with wind. And then it could ratchet back to keep a reasonable load on the turbine as the wind slows.

Are your batteries lead-acid? The simplest charge controller is a constant voltage controller, for instance built around the LM317. It'll take your batteries to full charge and then cut current to a trickle. It's not ideal, but easy to DIY. Constant voltage is less ideal of a strategy with other battery chemistries.
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  #13  
Old 11-04-2011, 08:13 PM
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Originally Posted by wayneh View Post
Is there really a need to "dump" power? I mean, the you could just let the turbine spin without putting a load on it. Maybe the term "dump" has just become a term for any excess power beyond what the charging system needs.

Aren't we really looking to use any and all available power in some clever way? I'd say lighting is the way to go, since incandescent bulbs are designed to handle heat and you get great visual feedback in addition to free heat. It wouldn't be too tough to build a "bargraph" type load that could light up an increasing number of bulbs as the excess power level increases with wind. And then it could ratchet back to keep a reasonable load on the turbine as the wind slows.

Are your batteries lead-acid? The simplest charge controller is a constant voltage controller, for instance built around the LM317. It'll take your batteries to full charge and then cut current to a trickle. It's not ideal, but easy to DIY. Constant voltage is less ideal of a strategy with other battery chemistries.
The resistors are used when there is a lot of wind, enough to have the batteries charged, and run everything hooked up to it, and then extra. The resistors are used a "braking load" to keep the turbine from spinning too fast.
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  #14  
Old 11-09-2011, 09:17 PM
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Quote:
Originally Posted by wayneh View Post
Is there really a need to "dump" power? I mean, the you could just let the turbine spin without putting a load on it. Maybe the term "dump" has just become a term for any excess power beyond what the charging system needs.

Aren't we really looking to use any and all available power in some clever way? I'd say lighting is the way to go, since incandescent bulbs are designed to handle heat and you get great visual feedback in addition to free heat. It wouldn't be too tough to build a "bargraph" type load that could light up an increasing number of bulbs as the excess power level increases with wind. And then it could ratchet back to keep a reasonable load on the turbine as the wind slows.

Are your batteries lead-acid? The simplest charge controller is a constant voltage controller, for instance built around the LM317. It'll take your batteries to full charge and then cut current to a trickle. It's not ideal, but easy to DIY. Constant voltage is less ideal of a strategy with other battery chemistries.
Battery is a typical battery like for a boat motor. I'm not sure the exact model off the top of my head. The LM317 is intriguing to me. Do you have any documents on how they are used and/or example circuits?
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  #15  
Old 11-09-2011, 11:34 PM
wayneh wayneh is offline
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Just Google the datasheet and start there. You'll find a number of application circuits. You'll want to find one that uses transistors for higher current, since one LM317 by itself can only handle an amp or two at most.
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  #16  
Old 11-10-2011, 12:00 AM
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One problem I am running into a lot online is that most charge controllers only allow for:
1. Charging the battery
2. Diverting to a dump

I want the added feature of if the battery is full, divert power that is coming from the turbine to the load (3 light bulbs) if they are turned on otherwise divert power to the load
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  #17  
Old 11-10-2011, 12:44 AM
wayneh wayneh is offline
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Please clarify. Sorry if I've missed this. I understand that you have 3 loads; the battery, some light bulbs, and something else?

You want to supply turbine power to these with a priority scheme, something like the load first, battery charging second, and the light bulb dump third?
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  #18  
Old 11-10-2011, 12:59 AM
labhelp labhelp is offline
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Close, I have a load which is my lightbulbs and I am planning on adding a dump.

I want to supply power to the battery first, if the battery is fully charged I want the power going to the load
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  #19  
Old 11-10-2011, 01:05 AM
wayneh wayneh is offline
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OK, so the priority is battery until charged, then lightbulb load if turned on, and then dump any power in excess of charging or lightbulb.

Would you expect the load to not function unless the battery is charged? The "usual" arrangement is to give the user what he wants - power at the load - as often as possible.
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  #20  
Old 11-10-2011, 01:44 AM
labhelp labhelp is offline
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Correct

I want the load to function even when the battery isn't fully charged
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