Charging a small battery

[SmoggyTurnip]

I want to put a small winch on my tail so that I can force the machine to furl when I want to shut it down.

I plan on using this battery to power it:

I never intended on using my system for charging batteries so I don't know much about it.  Can someone point me to a simple circuit for this job.  My generator is 3 phase,  1 volt/rmp (Phase voltage), 5.5 ohms phase resistance.

Should I rectify all 3 phases for this small job or just use one phase.

I assume I will have to use a step down transformer. I am thinking I might put the battery and charging equipment right on the frame to avoid running wires down the tower and use a remote control to operate it.

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[kitno455]

1. where are your rectifiers?
   
2. what sort of frequency (rpm) range do you get?
   
3. why is the unit horizontal on the tail instead of vertical on the yaw tube (easier to shroud)
   
4. why not keep the battery in the house on a charger, and take it outside when you want to use it?
   
   

allan

[SmoggyTurnip]

where are your rectifiers?

I don't have any rectifiers - the system is used for heating only.

What sort of frequency (rpm) range do you get?

0 to 67 hz.

Why is the unit horizontal on the tail instead of vertical on the yaw tube (easier to shroud)

Seems that the cable will be easier to hook up this way.

Why not keep the battery in the house on a charger, and take it outside when you want to use it?

I am considering doing that but it would be more convient if I didn't have to do that and I would also have to run heavy wire from the top of the tower (100ft) and out to where I want to hook it up.  This would give me a large voltage drop if I didn't use VERY big wire.  I also don't like being real close to the tower in high winds.

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[ghurd]

A tiny solar panel?

Like the $10 red HF 1.8W PV, change the wires to something better, weather-proof it, add a $2 PB137ACV controller, or a zener and regular diode.  Under $20.

G-

[willib]

I like ghurds idea  , a small solar pannel(with reverse blocking diode ) connected to the battery should keep it topped off till you need it.

you may not even need a charge controller , if your solar is small enough

[kitno455]

wait, are you saying you want to put the battery on the gen itself?

allan

[SmoggyTurnip]

Yes I was thinking about putting the battery on the gen itself.

I am not sure about the solar charging idea.  We only get about 2 useful hours of sun here in january.

.

[AbyssUnderground]

Youre not going to be manually furling every day though are you? If not then it has time to recharge. A 1.5w (125mA) panel should do the trick.

[SmoggyTurnip]

I think I will be manually furling alot just to make sure it works and to keep it from locking up.

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[AbyssUnderground]

Maybe a bigger panel will help then. How much power does the motor take? If its only low then you might not need much charging power.

[SmoggyTurnip]

The motor is 12 volts and will draw about 10 amps for about 10 seconds to furl and a little less to unfurl.  I would like to have things sized to be able to do this once a day.

.

[ghurd]

Well, 10A for 10 seconds X 2 = How many AH?

It wouldn't take much solar to keep up with that!

G-

[dinges]

Ghurd,

I thought you were better at math than this... Let me help you:

10. seconds = 10/3600 hour
    
10. A * 10/3600 = 0.028 Ahr/event.
    
    

This twice a day: 2 * .028 = 0.056 Ahr/day.

This is at 100% discharge of the battery. If one would settle for 50% maximum discharge:

.056 * 2 = 0.11 Ahr.

Q.E.D.

Next time you're facing a math problem you can't figure out, don't hesitate to ask.

[zap]

Three guys walk into an hotel and ask for a room with three beds. They just want to stay for one night. The clerk at the hotel tells them that the cost will be 30 euros. They pay 10 euros each and walk upstairs to their room. After awhile the clerk knocks at their door, apologizing for a mistake. He made them pay the high season price and not the low season one, and since it is now the low season, he must give them 5 euros back.

They are happy and appreciate the honesty of the man, so they tell him: "from these 5 euros we will just take back 1 euro each and we will give you the remaining 2 euros as a tip for your honesty". The man thanks the guys and returns to his desk.

Now, they paid 10 euros each (30 in total). They take back 1 euro each (3 euros in total). In this way the have paid 10-1=9 euros each. So in total they have now paid 9*3=27 euros. Plus the 2 euros tip given to the man we get 27+2=29 euros. Where is the missing euro?

S.E.G.

[Shadow]

Ha trick question... You cant say  'plus' the 2 euros given to the man, you must say 'minus' the two euros. As you did when you said "They each take back 1 euro" Then things work out.

[dinges]

Hmmm... Took me just 10 minutes to find it out...

"Where is the missing euro?"

Yes, lots of people are nowadays wondering whatever happened to the value of their money, during and after the transition period to the Euro...

[Ungrounded Lightning Rod]

Huh?

Since when is 0.028 Ahr a 100% discharge of a 7.2 Ah battery?  Looks more to me like about 0.077%.  You'd be able to cycle it almost 260 times and still only drain the battery 20%.

As for overrunning the panel's charging:  A 125 ma panel times say 5 solar hours would give you .625 Ah.  Let's cut that in half as a conservative estimate of the effect of mounting the panel facing zenith rather than the noon sun (because it's on the mill which yaws).  You get about .31 Ah of fresh power every day - enough to cycle the mill's tail over 11 times every day and still keep ahead of the charging.

You might want to think about a charge regulator or dump load to keep from drying out the sealed battery.  B-)

[dinges]

7.2 Ahr? Where you got that number from? I don't recall mentioning that battery capacity in my (tongue-in-cheek) reply. I've showed that a .11 Ahr battery is all that would be needed, given the requirements.

Try using one of these perhaps   :

http://www.anotherpower.com/gallery/dinges/slipstick

[RP]

Is that some kind of USB device?

;-)

[Ungrounded Lightning Rod]

7.2 Ahr? Where you got that number from?

It's printed on the side of the battery in the picture in the original article.  SmoggyTurnip said that was the battery he intended to use, unless we came up with a reason not to.

I don't recall mentioning that battery capacity in my (tongue-in-cheek) reply. I've showed that a .11 Ahr battery is all that would be needed, given the requirements.

Hmmm...  I didn't read it that way.  I didn't see anywhere in the posting where you assigned the computed Amphour value to the battery capacity.  Further, Smoggy had been asking whether this battery would do the job and the discussion had been about that.  Thus, when you said that one operation would fully discharge "THE battery" I had "the" pointed to the original 7.2 Ah battery, not a hypothetical just-big-enough-to-wag-the-tail-once dinko.

Now that we're all on the same page I think we can agree we're all saying his battery WILL do the job and the little panel will be more than adequate to keep it charged.  Right?

[willib]

Naaa thats a new memory stick device :-)