I am confused (again)

rake1
rake1 Solar Expert Posts: 173 ✭✭
in Solar Beginners Corner #1
I am looking at changing my system from my two controllers to one TS-60, but am concerned that this setup is putting full power to the batteries all the time and the controller is only dumping the excess above my setting of 14.7. In other words I am never in the proper float stage of 13.1 as the wind turbine is always putting something into this set up day and night.
Tell me I am wrong but it looks like a direct connection to the batteries to me.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: I am confused (again)

    The TriStar when set up as a diversion controller still operates for Absorb and Float stages. It just operates differently.

    In the standard mode the controller monitors battery Voltage on its output and turns off the input, so to speak, to maintain the Voltage set point for the charging stage.

    In diversion mode the controller monitors battery Voltage on its input and turns on the output to maintain the Voltage set point for the charging stage.

    In either mode it goes through Bulk, Absorb, and Float. It simply functions differently while doing so. Standard: disconnect power source when Voltage starts to go high. Diversion: connect dump load when Voltage starts to go high.
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  • rake1
    rake1 Solar Expert Posts: 173 ✭✭
    #3
    Re: I am confused (again)

    So if this is in float 13.1v and dumping and my trimetric meter showing 15v, I should be able to read with my clamp meter about 13.1v at the battery give or take a bit due to surface charge. And the amps going into the battery greatly reduced compared to what is going to the TS-60. AM I RIGHT? Just trying to understand and make sure my system is working correctly. My Batteries are way to much Money to take it for granted.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,631 admin
    #4
    Re: I am confused (again)

    I don't know how any specific controller manages "float" when in shunt mode... It could, for example, turn on the shunt at 13.8 volts and turn it off after a few seconds (more or less) at 13.1 volts, then repeat the cycle.

    It also could send an "off/on" cycle in a PWM format (pulse width modulation)... Say every 10th of second the shunt turns on for 50% of the cycle, then turns off, and at the next 1/10th second cycle decides that the average voltage is still high and is on 75% of the cycle, etc..)...

    My guess you will need a meter (or even a scope) to figure out how this is working (there may even be more programmable options to affect the shunt power behaviour).

    Obviously, the type of load you have will matter... If it is a resistor with a transistor switch--A fast PWM cycle is best for the battery bank.

    If you are running a pump motor as your primary dump load, then you don't want the pump and relay switching 10x a second. You would prefer a 1 minute cycle or something similar...

    Also, with shunt controllers, it is always possible that something could fail--Nominally, you would set up second shunt controller that could take over if the first fails (controller or load for example). And/or an alarm if something goes wrong (over charging the battery bank). And over charging battery bank can cause all sorts of problems.

    I am not sure I understand the Trimetic showing 15 volts and measuring 13.1 volts... Something does not sound right. Both should measure the same voltage--But if you have a wildly varying battery bank voltage (say PWM controlled shunt) it is possible for two different digital meters to read different voltages (sampling error, how they sample/average/RMS the voltage). But I would not expect that high of difference between two meters. Of course, you could just turn off the shunt (or even leave it on 100%) and see what the two meters read (steady state DC voltage).

    Also, if your shunt load is too small, then it is possible for the charging source(s) to overwhelm your dump load... You could use the second (backup) controller to add dump capacity if needed (in rare events of too much charging current).

    -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 ✭✭✭✭
    #5
    Re: I am confused (again)
    rake1 wrote: »
    So if this is in float 13.1v and dumping and my trimetric meter showing 15v, I should be able to read with my clamp meter about 13.1v at the battery.

    If your batteries are in float @ 13.1 volts, you measure 13.1 volts on the battery terminals, but your Trimetric is showing 15 volts - - - either something is wired wrong, or the Trimetric is out of wack.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #6
    Re: I am confused (again)
    BB. wrote: »
    I am not sure I understand the Trimetic showing 15 volts and measuring 13.1 volts... Something does not sound right. Both should measure the same voltage--But if you have a wildly varying battery bank voltage (say PWM controlled shunt) it is possible for two different digital meters to read different voltages (sampling error, how they sample/average/RMS the voltage). But I would not expect that high of difference between two meters. Of course, you could just turn off the shunt (or even leave it on 100%) and see what the two meters read (steady state DC voltage).
    -Bill

    Some meters built into CCs display the equivalent voltage at normal temperature while actually measuring and delivering the corresponding temperature corrected voltage. Not sure if the trimetric has a temp sensor that might be causing it to read a temperature very different from nominal, causing a large voltage correction.

    The different reaction of the two measuring devices to a waveform with lots of ripple is more likely to be the cause though.
    SMA SB 3000, old BP panels.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #7
    Re: I am confused (again)
    waynefromnscanada wrote: »
    If your batteries are in float @ 13.1 volts, you measure 13.1 volts on the battery terminals, but your Trimetric is showing 15 volts - - - either something is wired wrong, or the Trimetric is out of wack.
    Or he assumes they are in float ( 13.1 is low ) and they have never reached the absorb voltage.
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  • rake1
    rake1 Solar Expert Posts: 173 ✭✭
    #8
    Re: I am confused (again)

    Guys I think I am confusing everyone including myself LOL, my question was if the batteries are in float but I am getting to many amps coming it then the TS-60 will dump the excess above the float setting of 13.1 correct. What I am asking is the TS-60 only dumps at 15v (my setting) what happens to the other amps from 13.1v to 15v when it starts to dump? Also if in float shouldn't my batteries voltage also read the same as the float voltage but allowing for a surface charge of course. I am just trying to understand how a battery stays in float with all this extra power coming into the system.
    How does a charge controller restrict amps to a battery? Where does the extra power coming in from a solar panel or a wind turbine go? When my ts-60 dumps I know where this power is going.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: I am confused (again)

    It doesn't actually 'restrict' Amps to the battery, it diverts (hence the term "diversion controller") some of the power to the dump load. It can do this because the dump load is a lower resistance than the battery, so if it is active as part of the circuit more current flows through that path. If you were to measure things separately you would see:

    Float Voltage at the battery. "Full" current coming from the charge source. "Partial" current (enough to maintain Float Voltage) going to the battery. The difference between the two going to the dump load.

    You normally do not see this because that's not the way things are wired up. It would require separate Ammeters for the charge source output, the connection to battery, and the connection to the dump load.

    And the Voltage coming from the diversion controller will be pulsing in accordance to the need to keep the battery at Float level, meaning the V at the dump load will be rapidly changing difficult to get an accurate measurement of. It doesn't actually matter, though.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #10
    Re: I am confused (again)
    rake1 wrote: »
    Guys I think I am confusing everyone including myself LOL, my question was if the batteries are in float but I am getting to many amps coming it then the TS-60 will dump the excess above the float setting of 13.1 correct. What I am asking is the TS-60 only dumps at 15v (my setting) what happens to the other amps from 13.1v to 15v when it starts to dump? Also if in float shouldn't my batteries voltage also read the same as the float voltage but allowing for a surface charge of course. I am just trying to understand how a battery stays in float with all this extra power coming into the system.
    How does a charge controller restrict amps to a battery? Where does the extra power coming in from a solar panel or a wind turbine go? When my ts-60 dumps I know where this power is going.

    Read the full TS-60 manual (available online). The dip switches do not set a single diversion point voltage, they set a combination of Bulk, Absorb and Float voltages (Bulk will current limit until the Absorb voltage is reached):
                   Absorb       Float     Eq
on-on-off      15.0         13.7      15.3    
on-on-on       Custom       Custom    Custom
Table 6.3 Standard Diversion Charging Programs

    When a solar charger limits current, it just is not produced by the panels. If you try to use a standard charger with a wind turbine, without a separate diversion controller and load, the turbine will see a reduced load and may spin out of control.
    SMA SB 3000, old BP panels.
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  • rake1
    rake1 Solar Expert Posts: 173 ✭✭
    #11
    Re: I am confused (again)

    This makes more sense to me the difference in resistance. So I always thought that the dump load was only activated when(in my case 15v) the voltage hit 15v then it dumped. But am I reading this correct that the TS-60 is actually dumping long before that if I am in float. Ex if set at 13.4 in float ts-60 starts dumping at 13.5v?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #12
    Re: I am confused (again)

    Yes; it regulates the Voltage at the battery by "virtually" varying the resistance of the dump load via switching it on and off rapidly. Otherwise it runs through the same charging stages with the different Voltage set points. The change between standard regulation and diversion regulation is as I described; shutting off the source of power vs. draining off excess power.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #13
    Re: I am confused (again)

    And don't confuse yourself thinking about the "surface charge voltage" you mentioned. For the purpose of this thread, it's not part of the process.
    13.7 volts will be 13.7 volts, surface charge or no surface charge. In this discussion it matters not what if any "surface charge" exists.
    Surface change is another topic for another day.
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  • rake1
    rake1 Solar Expert Posts: 173 ✭✭
    #14
    Re: I am confused (again)

    I will take some reading at the camp next time just to satisfy myself. Thanks for the clarification on all of this.
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