Hydro choices, location and turbine type

[mike90045]

.......I'm going to call IOTA and have them explain a little more how the charger works.

It's a simple DC switcher supply.   Voltage comes in, is rectified to DC,  oscillator converts to AC, @ 1-4 KHz (small efficient transformer) and the output voltage fine tunes the osc to regulate the voltage.   No regulators on heat sinks that only  waste heat.

If the input runs short of power, the output gets throttled back.

My problem with the Iota, is that it is more of a Power Supply, and not a battery charger.   It does get enough voltage to bulk charge, but not enough to absorb, unless you are not using any power.
  And at 48V, it's 15 A capacity is light for a 400ah battery bank (needs 40AH really)   But it's better than a boot to the head.

[Jedon]

Thanks for the info!
So I have a 200AH bank ( 8 6V golf cart batteries ) and am feeding it DC not AC so I guess the rectifiers aren't doing anything.
My question is how does the charger deal with lower input voltage?
Does the output decrease with the input voltage regardless of current?
So it wants 108V AC minimum but I give it ( loaded ) 109V DC ( but that's 71% of 109V AC or 78V? http://www.bcae1.com/voltages.htm ) ? If so then it doesn't seem like it should even be working but it is.
How can I measure the current coming out of the charger? I tried it with my DMM but it backfeeds from the battery bank, ZAP!

[sailawayrb]

misspoke - I mean the water controller,  need a 4" valve to gracefully shut off flow when the batteries are full, to conserve my pond for the next rainy day.  And some way to not break the valve while it's operating.

Mike, here are a couple other 4" butterfly control valve options:

http://www.murrayequipment.com/dyncat.asp?SGroup=Butterfly Valves 4 Inch

Electric is about $900 and pneumatic is about $300.

You may need to type "Valves 4 Inch" after the above URL to get there.

Here's a 6" pneumatic for $275:

http://cgi.ebay.com/Hayward-6-inch-PVC-Butterfly-Valve-Comp-4-ACT-Mac-/190367568274?pt=LH_DefaultDomain_0&hash=item2c52ca9192

Bob B.

[Jedon]

It has been pointed out to me that I've been reading current wrong, I had the DMM configured right but was reading across + and - instead of inserting into circuit, whoooooops!
Time to re-measure.

[mbryner]

  

[Jedon]

I called IOTA and they said performance falls off as voltage decreases and that if I was feeding it DC it wanted more like 130V instead of the 106-114V I'm feeding it.
I asked about perhaps bypassing the rectifiers on the alternator and feeding the charger wild AC and they said that would probably work better so I'll give that a try.

[Jedon]

Before trying this I contacted the maker of the hydro and he said I can't do that because it's 3 phase.
Now what?

[mike90045]

enjoy the watts you have !   go back and re-tune and keep the batteries charged

[Jedon]

Hehe well yes I am enjoying the watts but I'm hungry for power!
Just like German-Chinese food, 1/2 later you are hungry for power :-D
Next step is gathering a lot more data and accurately this time.

[Jedon]

I measured using the correct method this time, putting the meter in the circuit instead of across it.
From hydro at shed: 1.88a at 112.4v ( 211 watts )
Out of IOTA: 3.56a at 50.7v ( 180 watts )
So the charger is being 85% efficient which seems about right?
My guy feeling form our house power usage is that 180 watts seems about what we are getting, about enough to break even most of the time.
Now I can go futz with the alternator and see how much more power I can eek out of it.

[mbryner]

Not understanding why you can't send out wild AC three-phase from that alternator head?   211 watts is not too much to think about making your own "power supply".   If you want the most out of your hydro you'll need to increase the voltage to your batteries.   50.7 V is never going to get them really charged.     Your alternator must have a rectifier in it that can be removed.   At least if you put a 2:1 transformer inbetween the wild AC and a new rectifier you'd get around 112.4 / 2 = 56 V, correct?    Eliminate the IOTA charger and run that DC direct to the batts.   Use a C40 for dump load.   Maybe I missed something?

Marcus

[mobile_bob]

i agree with Marcus, 52volts isn't going to charge the batteries and if they are flooded cells there isn't enough to stir the electrolyte
either. i am not sure why the charger cannot get a bit higher output than what it is.

even a 48 volt switch mode power supply generally can be adjusted higher than 52volts and would be more efficient too boot.

not sure i would be happy until i got the voltage up to around 57.6vdc and have the capability to go to  maybe 62 for equalization.

maybe a bit more tweaking/tuning is in order?  recheck all connections, voltage drops etc.

bob g

[Jedon]

Marcus, I'll keep my eye out for an affordable transformer, that's maybe what I should have done to begin with.
Bob, the IOTA outputs 56.6V but when I connect it to the batteries it goes down to what the batteries were at plus a little, 3.6 amps isn't enough to raise the voltage of my 200AH bank much I guess. I'll measure again later today when the PV panels bring the voltage up to 53 or so. 
For now I still need to run the generator in the evening so that gets the voltage up to 58 and I can equalize when needed.