C35 and micro hydro drain batteries!?

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System
System Posts: 2,511 admin
in Solar Beginners Corner #1
It's not solar, and it's not wind, but right now I wish it were either.

Im hoping someone can come to my aid... I've hit an impasse. I've wired my C35 up as a diversion charge controller, being fed 20 volts of dc from a perm mag motor and turgo runner. I can check the voltage at test point right before the batteries and see 20+- volts, but when I connect the system, my batteries read only 10+- volts, and this with no load being drawn from the system!?

The batteries were nearly fully charged when the experiment began.

I get the usual flashing green LED, but it never changes, and the batteries seem to slowly drain. It's 2X6volt batteries. I've run a positive wire from the turbine/motor to the batteries (with a disconnect in between) and the negative straight to the neg. battery term.

I believe I've wired it exactly as to the manual's instructions for a Diversion Load. Aside from my dump load (a 400 watt/120 AC block heater from a jetta, which seems to get warm/hot occasionally), where do I draw my DC loads from? The battery bank, or the controller's "Load+" & "Common Neg"?

So, batteries seem to be depleting even though the main line from the water wheel shows 20volts DC, the battery lugs show a wimpy 10 volts.
Also, I have no blocking diode between the motor and the battery bank... I thought the C35 took care of that?

Any help would be greatly appreciated!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,446 admin
    #2
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    Re: C35 and micro hydro drain batteries!?

    Is this an Alternator (AC) with 3 phase rectifier bridge (diodes)?

    Or is this a brushed generator (DC)?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #3
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    Re: C35 and micro hydro drain batteries!?

    "perm mag motor" sounds like it could be a brushless AC motor, OR is it a brushed DC motor? What voltage was the motor designed to work on? What was the current rating of the motor?
    Reason I'm asking, if it's a relatively small, high voltage motor, the windings will be of relatively fine wire which will greatly limit any current production when used as an alternator or generator. There may well be 20 volts from it's output, but is that 20 volts AC, or DC, and is there any usable current available? If AC, is there a rectifier between it and the charge controller?
    Also, what voltage is your battery bank? Sounds like a 12 volt system, but if it's down to 10 volts, the batteries are dead and MUST be recharged right away, by whatever means, or they will be rendered scrap. Hopefully it's not too late, and you can still save them. Leaving in a discharged state is a death sentence for lead/acid batteries. And I'm assuming these are lead/acid batteries?
    You say that "right before the batteries" you see 20 volts, yet the batteries are only showing 10 volts. Sounds like a disconnect there. Possibly a blown fuse between that test point and the batteries? If not, then there may be a broken wire, or otherwise a break in the circuit. It's also possible that one of your batteries has a shorted cell, so no matter how much charge you dump in, the voltage will never come up to where it should be, but that would not account for 20 volts just before the batteries, but only 10 volts on the batteries..
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  • System2
    System2 Posts: 6,290 admin
    #4
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    Re: C35 and micro hydro drain batteries!?

    Thanks for the prompt responses! It's a 200volt dc perm-mag treadmill motor directly coupled to turbine. at the end of the wire run, im getting 20+ volts(variable, depending on how much flow I give it...it can easily achieve 50volts or more)
    I cant help but think its in the controller. I used to use ACDelco alts. but was going through them rapidly, so tried switching to these perm-mag motors.
    I believe the batteries are fine (or *were*) as I charged them with ac charger prior to this install. I have no rectifier or blocking diode, and am basically running the motor straight to batteries with the C35 in between as a diversion controller. Im stumped! I read here somewhere that diversion setups are potentially problematic...
    There are no fuses between dc source and batteries.
    any suggestions?

    Thanks!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,446 admin
    #5
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    Re: C35 and micro hydro drain batteries!?
    Sisterlover wrote: »
    I believe the batteries are fine (or *were*) as I charged them with ac charger prior to this install. I have no rectifier or blocking diode, and am basically running the motor straight to batteries with the C35 in between as a diversion controller. Im stumped! I read here somewhere that diversion setups are potentially problematic...
    There are no fuses between dc source and batteries.
    any suggestions?

    I am not quite sure I understand "between" for the diversion controller... DC Generator to blocking diode (you should have one when the water flow tops or the generator slows down--otherwise the battery will try to run the motor backwards). Also--Fuse and wiring should be >1.25x your estimated maximum continuous current flow (i.e., 10 amp max current should be 12.5 amp rated fuse/wiring minimum).

    The diversion controller should be connected:
    • Battery->diversion controller->resistive heater/alternate load
    Double check your meter (put on your car battery and measure resting voltage, battery under load--head lights on, and battery under charge with engine running (should be from ~12.0 to 14.2 volt range).

    It does not make much sense the 20 volts and 10 volts... Unless you have small gauge wire running long distances (i.e., excessive voltage drop)--you should not see that wide of range from DC generator to battery bank.

    You can use a simple on-line voltage drop calculator to see how much drop you have (12 volt systems are very difficult/expensive to send a lot of current any appreciable distance).

    Regarding your battery... You really do not want to see it under 11.6 volts (20% state of charge resting voltage--no charge/discharge current for 3+ hours). And it should be ~12.7 volts (again resting voltage) when fully charged.

    And, you should read about batteries--They can be seriously damaged if undercharged:

    Deep Cycle Battery FAQ
    www.batteryfaq.org

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #6
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    Re: C35 and micro hydro drain batteries!?

    A 200 volt treadmill motor that's only turning fast enough to put out 20 volts, is going to be producing very little power in watts. The amperage is going to be VERY low. Same as if a 12 volt Delco alternator was only turning fast enough to output 1.2 volts. The power would be negligible. There may well be other problems, but that one I believe is a big one. And yes, as BB stated, if this is a DC brush type motor, you must have a blocking diode to prevent the battery discharging backwards through the motor when it's not turning fast enough.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #7
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    Re: C35 and micro hydro drain batteries!?

    Are the batteries in series? With fully charged batteries and a strong charge, you might well see an over charge at 10 volts if the are in parrall...

    ...just thinking out loud....
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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