Announcement

Collapse
No announcement yet.

New idea for Tank circuit

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • New idea for Tank circuit

    I have done a lot of reading about tank circuits and relays etc, and a lot of people say that the relay in the circuit may not react quick enought in order for the voltage not to drop.

    I have a PX-70 and an ITPS, work superbly, cannot fault it as i wanted a really small footprint and the opus was just too big.

    Anyway here is my idea, have the Yuasa 0.8-12 or similar, have a resistor in between the 12V contonous between my main battery and the tank battery.

    If i decide to stop the car for some petrol, surely i can have a switch instead of a relay which switches the power to the computer to solely run of the tank battery? Basically the switch act before the resistor?

    Would this work? And if so does someone know where in the UK online i can get the right battery and the right resistor?

    Thank you all in advance

  • #2
    Oh and i though i better add that the computer will work after i switch the car off, i.e. off of the voltage solely from the battery as i have heard some peeps have probs with ITPS wanting to see 13something Volts.

    Anyway will the 0.8-12v show more than 12V? I dont want to add the diode as i have heard this will drop the voltage and i think the ITPS is right on its limt

    Comment


    • #3
      probably too small of a tank battery. you need a diode to prevent the starter from sucking power from the tank battery when the car is cranking.
      CarPC install is starting to come along again...

      Comment


      • #4
        Originally posted by adrian_uk17
        a lot of people say that the relay in the circuit may not react quick enought in order for the voltage not to drop.
        Worked for me. Tank batt is a 5Ah model from Rat Shack. Standard Bosch relay disconnects power between main batt and tank when starter wire in steering column is charged. It hasn't failed once. Even after running the comp for 1/2 hr, then starting the car.

        Your idea looks good, but the whole manual switch idea is too.... manual. Spend a couple of bucks on a relay and see if it works for your setup.
        http://www.jeepmp3.com/
        CarPC Stolen. Starting over.
        Ne1 recognize the avatar?

        Comment


        • #5
          PatO - we have a 12v 4Ah battery that we're trying to use as a Tank. I'm not sure how to create the tank circuit. How should we connect it? How do you recharge your battery when it's not acting as the primary?
          DashPC - The Linux Car (since 1999).

          Dash LCD, Via Epia, GPS, XM, OBDII, DSSC Shutdown Controller.

          As seen in the book Geek My Ride

          Comment


          • #6
            You can do it with two relays & no diode, just use the first relay(tank relay) to connect your tank, triggered by crank signal, & have the first relay also trip the second(main interrupt), which momentarily interrupts your main power wire, this double trip covers the latency in the relay switching. The trick is to have the second relay re-engage (main power) before the first disengages. You can do this by having the second relay powered by grounding one solenoid terminal to the accessory lead, which will drop to ground during crank & return to power immediately after releasing the key, & therefore releasing the second relay & restoring main power. The first relay can be delayed with a Pac tr-27 or similar, & you can set it to be delayed for up to 25 min.s & the benefit here is that the delay here will cause the tank to remain connected for that period of time to top off the charge on the tank. this works well with smaller tank batteries that don't need more than that to be charged for the next time, & are really only being used strictly as a tank battery & not an aux power source as well...

            with this there is no voltage drop through a diode, & there is never a time that the pc has even the slightest split second of power loss throughout the transitions. I could draw a diagram, but it would be a pain to upload it, I may be able to next week......but it's pretty simple if you think about it.........whole thing should cost around $35, with the delay timer being around $25 of that, there are ways to use a small capacitor to delay the primary relay release long enough too.........& then the whole thing comes in at $10-$15 tops...........but that won't charge the tank at all. the third way to do this, & the best way if you want your tank circuit to charge throughout the whole ign. cycle each time is to have the first relay latch upon ign, & stay activated throughout the ign cycle, then when the main interrupt relay is activated while cranking & then released the tank relay stays on until you turn the ign. off, you can also use a delay circuit here to allow your pc to run on the tank for a period of time after the ign is turned off if desired....

            I hope this makes sense to you & if I can put a wiring diagram up I will, if there is anyone out there who understands this & has the ability to display diagrams here please feel free to do so.............
            MY NEWEST INSTALL:modded infiniti fx with big screen

            first windows carpc install........my liquid cooled LVDS screen :D

            Comment


            • #7
              I understand what you're saying for the most part. We're trying to implement a Tank circuit into our DSSC startup/shutdown controller.

              We'd like to get input from you guys on what we should add and how you'd like for us to implement it.

              Your guys' thoughts?
              DashPC - The Linux Car (since 1999).

              Dash LCD, Via Epia, GPS, XM, OBDII, DSSC Shutdown Controller.

              As seen in the book Geek My Ride

              Comment


              • #8
                Why wouldent a simple setup like this work?
                Attached Files
                1990 Jeep Cherokee
                2000 VW Golf TDI 4dr
                2005 VW GTI MKIV - SOLD

                Comment


                • #9
                  Originally posted by turbocad6
                  You can do it with two relays & no diode, just use the first relay(tank relay) to connect your tank, triggered by crank signal, & have the first relay also trip the second(main interrupt), which momentarily interrupts your main power wire, this double trip covers the latency in the relay switching. The trick is to have the second relay re-engage (main power) before the first disengages. You can do this by having the second relay powered by grounding one solenoid terminal to the accessory lead, which will drop to ground during crank & return to power immediately after releasing the key, & therefore releasing the second relay & restoring main power. The first relay can be delayed with a Pac tr-27 or similar, & you can set it to be delayed for up to 25 min.s & the benefit here is that the delay here will cause the tank to remain connected for that period of time to top off the charge on the tank. this works well with smaller tank batteries that don't need more than that to be charged for the next time, & are really only being used strictly as a tank battery & not an aux power source as well...

                  with this there is no voltage drop through a diode, & there is never a time that the pc has even the slightest split second of power loss throughout the transitions. I could draw a diagram, but it would be a pain to upload it, I may be able to next week......but it's pretty simple if you think about it.........whole thing should cost around $35, with the delay timer being around $25 of that, there are ways to use a small capacitor to delay the primary relay release long enough too.........& then the whole thing comes in at $10-$15 tops...........but that won't charge the tank at all. the third way to do this, & the best way if you want your tank circuit to charge throughout the whole ign. cycle each time is to have the first relay latch upon ign, & stay activated throughout the ign cycle, then when the main interrupt relay is activated while cranking & then released the tank relay stays on until you turn the ign. off, you can also use a delay circuit here to allow your pc to run on the tank for a period of time after the ign is turned off if desired....

                  I hope this makes sense to you & if I can put a wiring diagram up I will, if there is anyone out there who understands this & has the ability to display diagrams here please feel free to do so.............
                  Wow. Someone's put a lot of thought into this!
                  My setup has one relay - normally closed which connects the two batteries in parallel. It opens when the key turns to the start position. It works for me (and a few others on this board).

                  Why it works is another question. Could it be that the two batteries together have enough power that they would normally run a computer during a start? Possibly. However, cbergeron, it may be worth your time to invest a couple of dollars in a relay to test this out in your ride. At the very least, it seems that this concept hasn't been fully explored and your results would help solidify the idea of an ideal tank circuit...
                  http://www.jeepmp3.com/
                  CarPC Stolen. Starting over.
                  Ne1 recognize the avatar?

                  Comment


                  • #10
                    Originally posted by cbergeron
                    PatO - we have a 12v 4Ah battery that we're trying to use as a Tank. I'm not sure how to create the tank circuit. How should we connect it? How do you recharge your battery when it's not acting as the primary?
                    Using WebDog's diagram, replace the diode with a relay. The circuit should be normally closed - that is, the two batteries will act as one all the time, unless the car is starting.

                    In the case of a Bosch (automotive) relay, you'll want to have the 85 going to the battery, 86 going to the starter switch in the steering column, 30 going to the + on the main batt (heavy guage wire), 87a going to the + on the secondary batt (heavy guage wire), 87 open, and the negative on the secondary batt going to ground.

                    Then hook your computer up to the secondary batt as you would a primary battery.
                    http://www.jeepmp3.com/
                    CarPC Stolen. Starting over.
                    Ne1 recognize the avatar?

                    Comment


                    • #11
                      The main reason for using two relays instead of one is to be able to fully disengage the tank with the ign off so it can't be totally drained if the pc hangs. if a lead acid battery is allowed to become totally discharged it cuts its remaining life roughly in half. If this happens more than just a few times the battery is pretty much junk, unless you use a deep cycle...........besides, I just happen to like relays & timers..there just so electromechanical & everything...
                      MY NEWEST INSTALL:modded infiniti fx with big screen

                      first windows carpc install........my liquid cooled LVDS screen :D

                      Comment


                      • #12
                        You guys might want to go thru THIS thread. It covers a lot of ground.
                        MikeH

                        Comment


                        • #13
                          Why hasn't anyone just replaced the diode (in the basic tank) with a P-channel MOSFET with the gate conntected to the drain? I'm probably missing something critical, but I think current can reverse from drain to gate, but not from drain or gate to source. Is that right? Anyone?

                          Comment


                          • #14
                            Power MOSFETs often have schottky diodes in them for transient voltage supression when driving inductive loads. This will allow reverse current flow.

                            KyferEz
                            TheCarPCStore.com - Power Controllers (SDC), Inverters, Tank Circuit, GPS, OBDII, CarPCs, and more!
                            PSU Wattage Calculator
                            Electronics Calculators
                            Copper Wire Data

                            Comment


                            • #15
                              Maybe it is just because I'm such a huge noob...

                              What about using a UPC backup power unit to cover the power during the crank. My air conditioner used to knock out the power to my computer when it went on, and the APC unit unit fixed my problems.. I'm sure this wont work but being a noob it seemed like a good idea to me.

                              http://apcmedia.apcc.com/resource/im...t/BE500Ufl.jpg
                              Volvo 850 GLT

                              Comment

                              Working...
                              X