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variable radiant oscillator and battery logging

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  • variable radiant oscillator and battery logging

    Hi there fellow experimenters!
    Below is my latest project.


    the leads on the right ar for charge and run batteries, and the three leads on the top are for using different coils. There are three leads because in forced oscillation there is a common positive for the trigger and the drive coil

    I will do my best to upload a schematic of the exact parts. For now all I can say is that it is hooked up close to the circuit I posted in The two controls on the front are to vary the trigger resistance. The top one is a 5k potentiometer, and the bottom is a 6 position switch wired in a way that each click adds 5k to the resistance allowing me to vary the resistance from 0 to 30k ohms. The meter is a simple panel mount with 0-2A range. and at the moment I am using MJE3055's because I simply have hundreds.

    What I am planning on doing is using the computer monitor feature of my Radioshack multi-meter to graph the charging and discharging of batteries to see the difference over time and to also see the difference between charge rates (hence the variable setup). I also have a cap dump setup using an arduino relay shield that i want to try and record. I will be doing this with three or four different batteries just for learning sake ....I have a 12v 9ahr.... 12v 7ahr.... 12v 100ahr car battery and egc2 6v golf cart batteries. Though I do not know if this is able to charge the golf cart batteries ...would probably take months, but we will see.

    Anybody out there that has done some discharge test... what is the best rate for accuracy? I figure discharging a 100 amp hour battery in one hour would probably not be a good representation of the battery. I was thinking aiming for a 24 hour discharge would be ok. But i do not know for sure so if there is a recommended rate to accurately gauge the capacity without harming the battery please let me know.

  • #2
    C20 is the standard discharge rate... capacity/20 = discharge amps per hour. this is for deep cycle batteries. should be higher like c50 for car and lawn tractor batteries.

    Tom C

    experimental Kits, chargers and solar trackers


    • #3
      Thanks tom. I thought thats how it went but just double checking with the masters.
      going to be getting everything set up and then probably run one test every other day for the next few weeks. Looking forward to learning.


      • #4
        Hi all. Hey , thanks for sharing this.



        • #5
          First discharge

          This graph is the first discharge of my 8 Ahr battery. It was not charged prior to the test because it was already at 12.78 and I wanted to test out everything. I am going to run a charge on it with a normal charger set "to the turtle" to fill it up as much as possible then run this test again before trying a oscillator charge. So this graph is basically a test and the next will be my "baseline" for a hot charger. disch graph.jpg

          The sample rate was at 2 seconds and the start to end time was (5:22:30pm at 12.78 V) to (12:49:34am 12.00 V) so 7 hours 27 minutes and 4 seconds of run time. The load I have it running through is 3 x 100ohm resistors (10w rated) in parallel that reads 33 ohms on my radio shack meter. At the beginning of the run it was pulling about 380 miliamps. 400 mA would be the C20 rate so I was about as close as I could get. If my math is correct I pulled 2.85 Ahr from the battery. I only discharged to 12.00V honestly because my meter kept beeping every twenty minutes and it was driving me that I have a test run and know that no fires will result I am going to relocate the setup and run the longer full length test. the meter will not shut off when hooked to a computer but for some unknown reason will beep about every twenty minutes so if anyone by chance knows how to shut that feature off on the true rms radioshack meter PLEASE let me know.


          • #6
            Here is the circuit

            The three connections on the top represent the connector that allows me to swap coils. I did not represent the battery connectors as it would make it more complicated to look at...but it is just the connections for positive and negative of each battery wired to 4 spring loaded terminals on the side so I can quickly add any wires I need to connect the batteries or use the alligator clips in the pic. The roatary switch in the ciruit is wired with 5K resitors so that each succesive click adds another one in series and with the switch all the way down it is a short into a 5K pot allowing the 0-30k in the ciruit i only drew 4 resistors on the rotary switch but there are actually 5.for fine tuning I have a 14 turn trim 10k pot between base and emitter.circuit.jpg

            currently running the hot charger now and will upload a graph of the charge when its done.


            • #7

              started at 12.33V and reached a peak of 14.72V before the charger showed a full charge. It then dropped to 13.30 and stayed there for a few minutes so i disconnected. I will update, after a day of sitting, what the final resting voltage is on it after the "hot" charge. It took 1 hour and 50 minutes from the start of the charge to the time it turned off.


              • #8
                Can anyone point me in the direction of a good free plotting software? The graph on the meter software is not easy to use and once I save the data it can no longer view it as a graph. I know excell can do it but I do not have excel at the moment. I have downloaded several plotting programs but they seem to run on nuclear physics. The data is a simple column with the time and a column with the voltage reading.


                • #9
                  first charge with the oscillator

                  charge 200ma 20v b1.jpg

                  START TIME: 18:09:58 12.27 V
                  FINISH TIME: 07:35:01 13.57 V
                  RUN TIME : 13:26:03
                  Pulse frequency on scope 3Khz

                  I had the power supply set at 20 volts and tuned it to 200ma. after a rough calculation I used up 4 watts for 13.5hrs (close enough for an idea of whats going on) that equals up to 54 Watt hours of energy OUT of the supply. This brought the battery from 12.27 to 12.57. The 12.27 was the resting voltage after a few days since I discharged it. Just realized I forgot to upload the discharge so I will do that in a bit.

                  EDIT: I could have probably kept charging for longer but when i looked at the meter software and see that around 13.4 volts it started to increase its rate of climb. that led me to believe thats as much as it was going to absorb and it was starting to overcharge the plates. after a rest period and a discharge i will be doing the same setup again with 20v and 200ma to see if that increase starts to happen at a higher and higher voltage showing that it is improving the least that's what I am thinking.
                  Last edited by Bradley Malone; 03-04-2017, 10:28 AM.


                  • #10
                    here is the discharge after the charge with a normal hot charger

                    I used a normal battery charger to charge the batt as high as it would in "turtle" charge mode.
                    the graph here is the discharge through the resistive load averaging 400ma. The graph doesn't show the starting voltage because it dropped so quickly but after the charge i let it rest for a few days and started the discharge at (21:57:36 12.98 V) and turned it off at (07:19:13 11.91 V). I meant to stop it at 12 volts for consistency but obviously I failed at that. So a run time of 9.21.37...
                    so to try and straighten up all this data i have sparatically thrown around.

                    After a full charge with off the shelf charger, and a few days of rest,

                    DISCHARGE #1
                    resting voltage : 12.98V
                    discharged through 33ohm load to average 400ma (C20 rate for 8Ahr)
                    run time of 9hrs 21mins 37secs
                    ending voltage 11.91V
                    average the voltage and you get 12.445...divide by 33 for average current = 377ma.
                    (ma) x (time) = Ahrs..................(.377) x (9.3hrs) = 3.507 Ahrs
                    (Ahrs) x (avg voltage) = Whrs.....(3.507) x (12.445V) = 43.65 Whrs
                    3.507Ahrs 43.65Whrs
                    disch 2 after hot charge.jpg

                    few days of rest

                    CHARGE FROM OSCILLATOR
                    START TIME: 18:09:58 12.27 V <---resting voltage
                    FINISH TIME: 07:35:01 13.57 V
                    RUN TIME : 13:26:03
                    Pulse frequency on scope 3Khz
                    power supply set to 20v
                    oscillator tuned to draw 200ma
                    4 WATTS 52.92 Whrs
                    charge 200ma 20v b1.jpg
                    will wait for a few days of rest and then discharge to see any changes in the graph from the hot charged run.