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Battery charger noise

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  • #16
    Re: Battery charger noise

    I thank you CW for your information.
    Where is the lithium-ion decal located on your single chargers?

    I think the two I have are first generation with the lithium-ion identifier on the lower front left side.

    I have a newer unit coming it has the lithium-ion identifier on the upper left side. I'll open it up to compare as soon as it arrives.

    I took a 20 amp L/C multiple stage EMI filter and wired it up to allow me to plug in the charger. I added a mix-31 split bead on the cable going from the circuit board to the battery terminals that the battery slips into.

    I also lined the top orange cover/case with metal tape but I did leave the ventilation holes open. Hmm I wonder if I build a Faraday cage I can squelch the radiating noise? I sense another project on my list.

    I plugged in the battery and as soon as the evaluation ended and the green light flashed indicating charging is happening I also heard the noise. I have an ICOM IC7700 and the display showed the noise too.

    I did notice though, plugging the unit in an outlet not on the same circuit breaker as the radio station the noise was considerably lower but still very obvious.

    I then used a Grundig G6 portable SWL radio and tuned it to 550AM. The buzzing was obvious but nothing like it was without the added stuff I installed.

    I walked around the house trying to hear the noise and if I go +/- 10 feet from the actual charger the noise is gone.
    Now, I know ALL electronic devices have near field noise...for you non electronic types go place an AM radio set to the top of the band not on a radio station and listen to the noises ....

    For example stand right next to a LCD or plasma TV and yikes...then slowly move away from it. At approximately 12" to 24" away the noise should [hopefully] be gone! Well maybe further for plasma TVs as they are awful noise generators!!!!

    Light dimmers, microwave ovens, computer displays even your direct TV or dish receivers are all noisy.

    According to the FCC part 15 the manufacture has specific guidelines regarding unintentional radiators...but that's getting too technical for this discussion.

    So..what now? Well For those of you that are Amateur Radio Operators [Hams]. simple ensure you're not charging any batteries when on the air. If you hear such noise and it's not from may be time to visit your neighbor and ask them to charge their tools at a different time.

    Oh, wheel chair, scooter, electric mower chargers are also extremely noisy and present lots of dirty buzzing back into the AC power lines. Then that noise will radiate from the power lines and you have all sorts of interference.

    Using a Timewave ANC-4 does not help

    If anyone can gain access to a schematic diagram of the charger I'd appreciate a copy. On the circuit board there are obvious filtering components not installed!!!!!

    Thanks to those of you who tolerated this topic. I'm confident this answered some questions other Hams here have been thinking about these chargers. Don't forget DeWalt, Milwaukee, Porter Cable, Harbor Freight, Black& Decker, Craftsman chargers are very similar in design.

    Finally those of you with quiet chargers I envy you.

    I am on 14.178mhz Monday through Friday at 2300utc KA7GKN
    If your license permits, stop by and I can play back a recording of my specific noise.

    Cactus Man


    • #17
      Re: Battery charger noise

      KA7GKN DE KF2VA,

      With the exception of my 12-volt LiIon charger (for the compact drill/driver), none of my other charger are designed for both NiCad and Lithium... at least there is no indiction or decal stated such.

      At the moment, I'm wondering WHY my charger back in Painted Post didn't emit, or at least my IC751A didn't pick up on any RFI. I think I went through more effort there (trying two different antenna's as well as no antenna and several attenuator/preamp settings.) While here in Binghamton I do not have my station setup, I just use the 706 with a shortwave-listing portable antenna... it picked up a LOT of noise.

      When I return next week, I will take this same SWL portable with me to test again. The "loop", which is my primary antenna in Painted Post, is extremely quiet and perhaps that, and the fact that it's probably about 30 feet or so high, may have isolated it from the RF emitted from the charger. I do know that when using the old dipole, it picked up everything in the neighborhood, and once I switched to the loop, all that went away. (my delta-loop is very efficient and I've worked a pretty good share of the planet on my 100 watts... including New Zealand. )

      Here on the 706, I was using a deep-cycle battery... so the "same circuit" scenario didn't enter into the equation. I did try the charger at around 20 ft away and it was on a different circuit than the first test; but then again, I was running the rig off the battery, so no direct circuit connection.

      I'll also check the model number... I bought these at various times and perhaps that particular charger was the first one.




      • #18
        Re: Battery charger noise

        I wonder what would happen to the RFI if the charger and/or radio receiver(s) were plugged into a good surge suppressor that has some RFI hash noise filtering.

        Please note this and other similar models can be purchased well below the MSRP price.


        • #19
          Re: Battery charger noise

          Thanks Woussko but I described a "better" LC type filter in a post earlier and no joy!

          Without metal shielding and proper filtering all devices with switching power supplies etc. radiate interference.

          As a side bar I chuckle when I tell a kid he's using a walki-talkie and he says uh-uh it's a cell phone!

          By the way the guy who invented the walki-talki back during WW2 lived in Sun city AZ ..retired, recently passed away. He was also a Ham Radio Operator

          I expect the "newer" model single charger to arrive here early next week so I'll report back if it is any different. My single chargers are
          BD0734 CS0852

          Cactus Man


          • #20
            Re: Battery charger noise

            On an Amateur Radio site discussing this in their RFI forum a
            fellow indicated he's experiencing this same phenomenon
            with his Ryobi battery charger.
            I suspect they have similar electronics under their cases.

            I have yet to receive the newer charger in the mail yet so nothing else to report right now.

            Cactus Man


            • #21
              Re: Battery charger noise

              Get a cup of coffee this is going to be long.......

              The "newer" Ridgid charger arrived yesterday. I'll try to provide as much information and attempt not to be over confusing......

              I have three single chargers. They are different generations, meaning different production runs or evolutions. I also suspect they have contracted with different OEMs to make their charger boards.

              I'll try to provide data from each unit and then you decide if this is just a waste of time in attempting to address EMI electrical interference generated by them.

              They all required a torx security bit to open them.

              Original charger..

              model 140276001
              serial G0502
              9.6V-18V 4.1A

              on the bottom of the case it lists batteries it will support and does not identify lithium-ion batteries. It only identifies Ni-cad batteries.
              The front decal does not have any lithium-ion markings. It also has two clocks showing max-HC and compact battery charging times. On
              the front lower left it only says "RAPID MAX"

              Internal stuff: circuit board numbers 860231001 01
              C101, L101 AC filter OK
              C102 L102 MISSING no filtering!!!!!
              Circuit board is highly populated!

              Newer charger..

              model R840091
              serial BD0734
              9.6v-18v 4.1A

              on the bottom of the case it lists batteries and indicates R840084 [lithium-ion] battery is OK as well as all older nicad batteries odd though it does not list the 18v 3AH battery..I suspect this was made before that battery was introduced. As the charger is rated at 4.1AH it does charge the 3AH battery properly.

              The front decal has "lithium-ion, Ni-Cad, RAPID MAX" displayed on the lower left front. it also has two clocks showing compact battery and max-HC charging times

              Internal stuff: circuit board numbers HF-06-94V0
              C101, L101 AC filter OK
              C102, C103, L102 missing no filter
              circuit board is quite populated

              My newest charger...

              model R840091/140276010
              serial CS1016
              9.6v-18v 4.1A

              on the bottom of the case it does list all nicad batteries and the R840084 [18v 1.5AH] and R84008 [18v 3AH] lithium-ion batteries.

              the front decal does not have the charging time clock displays. The upper right side has "RAPID MAX, multi chemistry, Li-ion/Ni-cd"
              And, obviously placed below where the battery is inserted instead of a warning label they placed a large logo label "RIDGID"

              Internal stuff: circuit board numbers 260017003 VER 1.1 3-25-2009
              4 CEM-94vV0 E231305
              C1,C2,L1 AC filter OK
              C9,L2 missing no filter
              circuit board is sparsely populated

              The newer charger makes me believe all the "charging information" is regulated by the lithium-ion battery's internal control board.

              The 18V 3AH battery model R84008
              has stamped on its base "use only with R849001 chargers"

              OK so what does all this mean?

              Well, as RIDGID's battery technology evolved so did their battery chargers.
              NONE of their chargers have worthwhile EMI filtering...I'll do a brief editorial here....

              Typically a manufacturer submits a product to UL/CSA for safety testing and then the FCC to determine if it stays within the parameters of Part 15.

              Once certified/passed they get the "oky-doky labels and proceed to manufacturing the product..... This is where the bean counters step in as they ask the engineers.."how can we cut costs"???
              The most painless component cut is filtering so they remove a capacitor here a choke coil there and the product still works..they save 25 cents a unit ...the bean counters are happy!

              The engineers figure the filters reduce EMI and the odds of a charger interfering with an an Amateur Radio Operator or other device is maybe 1 in 500,000 so no foul!

              I strongly believe the FCC and other regulatory agencies pull production run devices without notice during the production run unannounced to verify compliance!

              I do not see any ISO9000 or FCC certification what so ever..
              Now this may not be a big deal as many devices are not submitted but we all know switching power supplies are notorious for generating interference!!!!


              The older chargers MAY charge your lithium-ion batter as I indicated earlier as the battery has an internal control board.....would I do that?

              The next generation and of course newest chargers are OK for ALL their batteries.

              It would have been nice if they upgraded their dual charger for lithium-ion batteries as I do like the blowers to keep everything cool while operating. Oh, the internal heat sinks are large so actually over heating during charging is quite unlikely unlikely unless there is a catastrophic problem.

              None of this solves the EMI question I initially posted but it was very interesting to follow the evolution of the charger.

              I'm still trying to figure an easy way to reduce/eliminate the EMI...
              I do not run the chargers when operating my radio station, but I can't control everything the neighbors do unless I can offer them a painless and yeah free fix for something the manufacturer should have done at the get-go!

              I'd think a 3 wire grounded AC power cord with a proper EMI filter circuit [a complete design] would easily address the EMI it generates. I am really surprised that a two wire polarized cord is acceptable ...then again the exterior case is all plastic so it's electrically shielded to ensure the user does not get zapped.....A metal case or internal shielding properly grounded, a three wire cord, and proper filtering is ideal but likely it will never happen!

              Ridgid has not provided any schematic diagrams for any of their chargers as they claim "proprietary information"

              Cactus Man
              Last edited by cactusman; 07-09-2010, 12:57 PM.


              • #22
                Re: Battery charger noise

                Well a nice surprise here....

                I finally had an opportunity to charge a battery with the newest charger
                the one that says "multi-chemistry" on the top left and in the front it says "RIDGID" where on the older single chargers it has a warning label.

                I sat the radio next to my Ham Radio [ICOM IC7700]
                and not a peep of EMI/RFI noise!!!!! It's quiet!!!!!

                without any schematics I'm unable to determine why it's quiet and the others are not!

                I refer you to my post prior discussing the three chargers I inspected.

                I'm tempted to retire all my older chargers and invest in another one or two of the newer ones.

                Cactus Man


                • #23
                  Re: Battery charger noise

                  I saw a bit of this thread when it was first posted. It's something that I was surprised about, when I realized that this hasn't been discussed before on here really that I can remember. Very good thread, Cactusman.

                  I have 4 different Ridgid chargers that (sort of) all cause this to happen. And, when I say "cause this to happen", I mean that these chargers, when operating, cause my FM radio to have excessive amounts of static/interference.

                  I have 3 different Ridgid 9-18 volt chargers that all do this. I have an '05 original ni-cad charger, and then two different lithium-ion-generation chargers, one from '07 and one from '08. Then, I also have a 24 volt lithium charger - however, this 24 volt charger does not do this at all.

                  When I have batteries on the 18 volt chargers, you can audibly hear them cycle through charging "blocks", where they take a second or two to build up a charge in the capacitors (I'm presuming), and then a second or two where it then "dumps" this charge into the battery. It then repeats this in random, variable "blocks" until the battery is charge. Well, that's my lay-mans, non-engineers version of what I hear.

                  So, when it goes through that point where it builds up a charge in the capacitors, there is an audible buzzing coming from the charger. When this happens, any FM radio that I have within about a 30 foot viscinity has the signal over-ridden by a heavy static buzz/interference, where the signal is cut out. This seems to happen on all available FM signals, within the whole FM range, and no matter how close the FM signal is coming from - some radio stations are 60 miles away, while the closest local station, with an extremely strong signal, has it's transmission tower only about 4 miles away.

                  This happens on an indoor radio, on my small Ridgid compact MaxSelect battery-powered radio, or on my Grundig/Eton emergency radio (those yellow battery/crank-powered radios). If I move the radios about 25 to 30 feet away, the interference weakens and eventually drops off. It is so bad and audible over the speakers, that I have gotten used to not having the radio on when I'm charging batteries. It's been like that since I got each of my chargers. Again, the only exception is that my 24 volt XLi charger does not do this at all.

                  My solution to solve it? Well, I wired my whole house up for just about everything just after we bought it - I've got DSL, RCA-audio, computer AV, surround-sound speaker wiring, outdoor speaker wiring, etc., wired throughout and all over/through our house. I'm planning to put a small pair of speakers out in my garage in the rear ceiling corners, and will wire it in with all of the other stuff connected to our home theatre receiver. I have a nice high-end Harmon Kardon AVR 3550 HD receiver, with dual-zone capability. I'll wire my garage speakers into this, same as how I have the back-deck speakers wired in (with some nice JBL N24AWII outdoor speakers). Then, with a volume-control dial in the garage, I can just hit play on my computer's audio files, and listen to it in the garage; and/or, just turn on the radio on the AV receiver, and I can then have an AM/FM feed piped through into the garage also.