Author Topic: 48V air x charging a 24v battery?  (Read 650 times)

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fabieville

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48V air x charging a 24v battery?
« on: March 03, 2017, 12:20:47 PM »
Can i used a 48v air x wind turbine to charge a 24v battery. The air x has a built in 48v charge controller and i am wondering if connecting the dc output wires to the 24v battery bank will it commence charging? Or does it need 48v battery to activate the circuit or will it detect the 24v battery as been too low than the 48v battery and still commence charging trying to bring up the 24v battery which in theory would not reach up to 48v so the air x would just be always in a charging mode?


dnix71

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Re: 48V air x charging a 24v battery?
« Reply #1 on: March 03, 2017, 04:45:18 PM »
It will probably overcharge a small battery. I have a 48v AirX with the controller removed. It was hooked up to a large 12v array and overcharging was never an issue. I had a Turnigy watt meter connected and the highest output I ever recorded was in a thunderstorm gale gust (198 watts). Most of the time less than 5 watts was the norm.

Ungrounded Lightning Rod

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Re: 48V air x charging a 24v battery?
« Reply #2 on: March 03, 2017, 06:30:01 PM »
Note that hooking it to a lower voltage battery will slow it down and cause the airfoil to be very inefficient.

Running it without the regulator on a 24V battery may give you significantly more than twice the power you'd get loading it down by doing the same into 12V, and running it into a 48V battery, which is what it's designed for, will be far better still.

Running with the regulator into the wrong voltage will confuse the regulator greatly.

You might want to see if you can get a switching regulator brick that gives 14ish volts from line power and feed it the wild rectified AC from the deregulated Air x (rectified to combine the phases).  Switchers do a raw rectification to pulsing DC and then run a buck converter from there.  They will often run - efficiently - at a wildly broad range of input voltages (beyond nameplate ratings on the low end), trading voltage for current as appropriate to make the load get as much of the energy as possible (and keeping the switcher itself cool).

fabieville

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Re: 48V air x charging a 24v battery?
« Reply #3 on: March 03, 2017, 08:23:43 PM »
I have a 48v AirX with the controller removed. It was hooked up to a large 12v array and overcharging was never an issue.

I am planning to remove my controller then have just 3 phase ac coming down.

When you had your 48v air x controller remove i want to know is how many wires you had coming from your stator coil, is it 3?
Reason why I asked is because all of them that i see on the net is 3 wires coming from the stator coil going to the rectifier block but in my 48v one i have 6 sets of wires going to the recitifer block. I notice that they are 3 different wire sizes also.

They are configured this way. 2 of the wires are kiss together going to one set of diodes, another 2 is also kiss together going to a next set of  diodes and the next two wires remaining each of them go to the 2 remaining set of diodes.

I am kinda confused as to why there is so many wires coming from the stator? also they are 3 different sizes. Why is this so?
Also when you pulled out your controller, did you then connect your 3 wires coming from your stator coil directly to the brushes so you could feed the 3 phase AC voltage through the slip ring?

I am trying to figure out a way to utilize all of my 6 wires and get 3 phase from them so that i can connect them to the 3 brushes after removing out the controller circuit  but whenever i used all of them there is a binding up of the turbine and it creates a shorts. If I leave out one of the wires by not kissing it with one of the phases then it doesn't happen but would i lose some current/voltage doing this and if so which wire would best to leave out, the smallest gauge one? Is there a way to use all 6 wires and get 3 phase coming out?
« Last Edit: March 03, 2017, 08:29:54 PM by fabieville »

dnix71

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Re: 48V air x charging a 24v battery?
« Reply #4 on: March 04, 2017, 05:12:37 PM »
The AirX I have was bought from someone here who did the mod. With the controller removed you only have 2 wires out, rectified dc, so I'm assuming there is a full wave bridge inside somewhere and that fed the controller.

Adriaan Kragten

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Re: 48V air x charging a 24v battery?
« Reply #5 on: March 07, 2017, 02:06:37 PM »
If the generator has a 3-phase winding, it has three coil bundles. Every coil bundle has several coils connected in series. One coil bundle has two coil ends so three coils bundles have six coil ends. Sometimes one of the coil ends of a certain phase is connected to one of the coil ends of the two other phases such forming the internal star point. The other three coil ends are guided outside the generator. So in this case, the winding can only be rectified in star. If all six coil ends are guided outside the generator, one has the choise to rectify in star or in delta. Normally all six outcoming coil ends have the same wire thickness. If you measure the Ohmic resistance, you will find that only two wires are connected to each other and you will find the same resistance in between three pairs of wires. Rectification for star or for delta is explained in my free public report KD 340.

If the six wires have a different thickness, I think that you don't have six separated coil ends. Probably the three thickest wires are the main wires. If you measure the same Ohmic resistance in between each of these wires, the wires are connected in star. From the other three thinner wires, one may be connected to the star point. If this is true, you will measure half the Ohmic value in between this wire and the three main wires. The other two thinnest wires may be connected to a thermo-couple to measure the coil temparature.

Ungrounded Lightning Rod

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Re: 48V air x charging a 24v battery?
« Reply #6 on: March 08, 2017, 11:39:50 AM »
If you measure the same Ohmic resistance in between each of these wires, the wires are connected in star.

No, you can't tell by any measurements you can apply to (just) the three wires whether they're connected star or delta.  (The y-delta equivalence is a fundamental rule of electronic circuitry and appears in, for instance, the Univerity of Michigan's Electrical Engineering walk-around-the-lab final exam.  B-) )

You have to dig deeper to see what's actually going on.  (Like by tracing the winding interconnects and finding the Y-point joint.  Or by finding continuity to one of the other three wires - the hypothetical Y point - and determining the resistance between it and each of the main wires is half the between-main-wires resistance.)

Adriaan Kragten

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Re: 48V air x charging a 24v battery?
« Reply #7 on: March 09, 2017, 01:41:54 AM »
It is true, if only three wires are coming out of the generator, then you can't determine if the winding is connected in star or delta by measuring of the Ohmic resistance. However, if four wires are coming out of the generator and if you measure the same resistance in between three wires and half the resistance in between the fourth wire and the other three wires, then the winding is connected in star. To be absolutely sure you must open the generator and follow the path of the wires in between all coils.

Internal connection in delta is almost never done for a generator if the winding is rectified as it results in a strong increase of the unloaded sticking torque because of circulating higher harmonic currents (see KD 78).

Using of a 48 V wind turbine for a 24 V battery makes that the Pmech-n curve of the generator shifts to the left a lot and this results in a bad matching in between rotor and generator and therefore in a much lower Cp of the rotor and in a much lower output (see KD 35 chapter eight). If the generator has a two layers winding, it should be possible to connect the first and the second layer in parallel in stead of in series. This halves the voltage and doubles the current and the matching is kept the same. Modification of the winding this way is described in chapter 4 of my free public report KD 341. However, an existing battery charge controller which is designed to limit the charging voltage up to about 55 V for a 48 V battery can no longer be used if the battery voltage is reduced to 24 V. I describe a battery charge controller for a 24 V battery in the free manual: "Manual of a 27.6 V, 200 W battery charge controller" which you find at the bottom of the list with KD-reports on my website.
« Last Edit: March 09, 2017, 02:10:44 AM by Adriaan Kragten »