Announcement

Collapse
No announcement yet.

Field Multimeter

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

  • #16
    My 2-cents worth

    Go with the Extech MA220 as it is a good quality meter. True it exceeds your needs at the moment, but you did say your first project which indicates you expect to grow the system or do other systems in which case the meter will grow with you. For $54 it is a heck of a deal

    In addition to being able to read DC amps up to 400 amps, more importantly is for battery systems you need to be able to read small DC voltages very accurately when measuring battery cell voltages down to 1/1000 of a volt.
    MSEE, PE

    Comment


    • #17
      Originally posted by john p View Post
      As for expensive multimeters lasting longer.. mabe they do mabe they dont. We have a big box of top of range Fluke multimeters perfectly destroyed mostly by electrical engineers
      John I am telling you for the last time, stay out of my garbage can or I will put a Restraining Order on you for being a stalker and have you arrested.
      MSEE, PE

      Comment


      • #18
        Ah ha so its you Sunking that is the culprit,
        Why is it its electrical engineers seem to know less about how to use multimeters correctly than even non electrical tradesmen. ??
        We have about 14 EEs at work in our dept and between them in about the last 2 yrs have totally destroyed more than 30 really good multimeters. To my knowledge the technicians about 30 of us a total of 5.

        I personally dont believe anyone needs to attempt to read battery voltages down to one tenth of a millivolt. I dont believe any multimeter used in the field will achieve that. And how does he check its calibration in the middle of nowhere in Africa??? I be willing to bet after it arives in Africa then to one of its destinations it be lucky to achieve a accuracy of better than 2 mv.
        Another thing his batteries are more than likely to be 12v not single 2v cells. its a 100w system even if it grows by a factor of 10 its still a small system and be most likely using a one or 2 parallel 12v batteries.

        Comment


        • #19
          MR SUNKING Question ... please tell me how you going to do this with that multimeter.. more importantly is for battery systems you need to be able to read small DC voltages very accurately when measuring battery cell voltages down to 1/1000 of a volt. It only has a claimed accuracy of plus and minus .8% at 4v????I know sometimes im more wronga than othertimes but to me at 2v that means about plus or minus 16mv. ????? Soin practical terms it cant give a reading at around the 2v voltage of better than 20mv??? when you are saying you need to read differences of .1 of 1mv. HMMMMMMMMMMMM

          Comment


          • #20
            Hurry up I need reply . And the person that is looking for way to measure DC amps may be interestd to know before he shells out over $100.
            As yet im not convinced any multimeter is ever going to be able to measure in the field battery voltages accurately better than plus or minus 10mv.

            Comment


            • #21
              Originally posted by john p View Post
              Hurry up I need reply . And the person that is looking for way to measure DC amps may be interestd to know before he shells out over $100.
              Why are you terminally ill? The Extech MA220 is $60 and one heck of a good meter for the price with more than enough accuracy for DIY solar. Heck even enough accuracy for a feld tech sweating details. Not quite enough for a train driver crunching numbers, but close enough for government work. Have a beer and relax, it is on me.

              Originally posted by john p View Post
              As yet im not convinced any multimeter is ever going to be able to measure in the field battery voltages accurately better than plus or minus 10mv.
              Then you have never used a Flike 170 or 77 series meters. They have .09 to .3% accuracy depending on model at .1 mv accuracy. so at 2 volts range is .9 to 6 mv accuracy which is less than 10 mv. For home DIY solar the user would like to read 2.xx1/2 accuracy but 2.x1/2 +/- digits is close enough.

              Bottom line is a low end Fluke is around $300 for .3% accuracy at 2 volts, while the Extech is $60 for .8% accuracy which is a heck of a good deal. You gotta spend $500 for a .03 % meter.
              MSEE, PE

              Comment


              • #22
                yes terminally ill im dieing of old age. only 40 years to go
                BUT BUT you said you needed to read the voltage of a cell to .1 of a mv , You have now proved my point it cant be done in the field.
                Those "super" accurate Fluke multimeters are NOT that accurate most of the time , FACT , They need constant calibration to keep those accuracies. At work its done every month , and they drift with temperature.
                So how is this man in deep darkest Africa in a remote village surrounded by head hunters and witch doctors ,and not even a MC Donalds to sustain him going to measure those cells to .1 mv as you say should be done??

                more importantly is for battery systems you need to be able to read small DC voltages very accurately when measuring battery cell voltages down to 1/1000 of a volt.

                Comment


                • #23
                  Originally posted by john p View Post
                  Those "super" accurate Fluke multimeters are NOT that accurate most of the time , FACT , They need constant calibration to keep those accuracies.
                  They only need calibrated once a year, and the following years are more just verification. Once they are set they do not drift any to speak of. That is why they come certified. and guaranteed for a year.
                  MSEE, PE

                  Comment


                  • #24
                    OK I will tell on Monday the electrical engineers to stop calibrating them every month Now the problem will be finding something productive for them to do to use the time it took to do the calibrating.
                    You still have not said how he is going to measure cell voltages with an accuracy of .1mv . That is the figure you say is importantBecause to measure that accurately the meter needs to be accurate to.01 mv as worst case.
                    That figure is hard to achieve with lab standard bench multimeters in temperature controlled rooms that cost us anyway about $2600. We have many of them as no hand held ones come close to those sort of accuracies.
                    HMM and why is their one of these meters in your rubbish bin with all the other hand held ones. How you destroy it ??, as no one here at work will say. its ok you can tell me I wont tell.

                    Comment


                    • #25
                      John you need 4-1/2 digits at 1% to measure any battery voltage from 2 volt cells up to whatever voltage say to 500. What is important is to be able to check voltage balance of individual cells. The Extech meter is a darn good meter for the DIY solar type. I am done with this.
                      MSEE, PE

                      Comment


                      • #26
                        sunking you somehow missed the point of what ive been trying to say about your claim you need to be able to measure cell voltage to an accuracy of.1 mv,. I still say that is pointless as no .one needs to be that accurate .secondly no one is going to measure that to that accuracy.thirdly no hand held multimeter is going to read that ACCURATELY the error IS ALWAYS going to be more than a FEW millivolt.

                        finally he is extremely unlikely to be using 2v cells, I willing to bet just about anything he is going to be using 12v batteries, Therefor he only needs simple AMP to an accuracy of about 1a and VOLTAGE TO 100mv

                        A SIMPLE MULTIMETER FOR$10 AND A SIMPLE SHUNT OR AMP METER CAN DO THAT. AND IF LOST OR STOLEN EASILY REPLACED

                        HE HAS SIMPLE NEEDS DOESNT NEED HIGH QUALITY EXPENSIVE ITEMS that can also look "interesting" to customs persons and possibly attract some form of duty payment.One day try visiting 3rd world countries not always easy to get some things into countriess for free. If he was in USA or similar I would agree get good measuring devices.

                        the end

                        he has most likely gone to another forum to get simple advice, not confusion
                        OH I remember now I gave simple good advice for his situation but far to much extra got added

                        Comment


                        • #27
                          Originally posted by john p View Post
                          OH I remember now I gave simple good advice for his situation but far to much extra got added
                          No John he wanted a clamp on meter from Extech 220MA, not a cheap china meter. $54 is not a lot of money for a meter. Have you got it now?
                          MSEE, PE

                          Comment


                          • #28
                            Yes I get it completely now,, Im now 100% sure his mall systems would be best insalled in remote areas in 3rd world countries with both cheap and simple analogue volt and amp meters. This way if a fault develpoped the users could contact him and he could possibly diagnose and offer advice to rectify the problem.
                            Yes I get it that he will not ever be measuring the voltage on individual cells.
                            Yes I get it that its not likely anyone on earth will ever own a hand held multimeter that can give a different voltage reading between 2.1864 and 2.1865. Any one that says you need to be able to read voltages accurately down to one tenth of a millivolt on individual 2v cells in a solar setup is in a world of their own. Even the electrical engineers here at work agree with this.

                            Comment


                            • #29
                              Originally posted by john p View Post
                              Yes I get it that its not likely anyone on earth will ever own a hand held multimeter that can give a different voltage reading between 2.1864 and 2.1865.
                              You are making that up, I never said 2.1234, I said 2.123 and 12.12
                              MSEE, PE

                              Comment


                              • #30
                                Sunking this time it seems I missread your post #16 .OOPS .MY MISTAKE
                                Somehow I looked at your1/1000v and read it to be one ten thousandth of a volt, and to make it worse so did 2 engineers at work, very bad, sorry

                                Comment

                                Working...
                                X