Battery charger effects on guitar electronics

Discussion in 'Tele-Technical' started by spellcaster, Aug 2, 2021.

  1. spellcaster

    spellcaster Tele-Holic

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    I've got a Thinline partscaster with one unfinished thing to resolve. I've been building in wireless transmitters into my partscasters, but I'm looking for some advice with someone who has more electronics expertise. In the past, I'd install battery boxes, so I could remove the rechargeable battery, charge it up, and then reinstall and play. In this particular guitar, there wasn't an easy way to rout in a battery box, so I built the rechargeable battery in and planned to be able to recharge it in the guitar.

    What I'm unsure about is how the recharger will affect the wireless transmitter....Do I need to physically decouple the transmitter board from the battery when the charger is in operation? I can, if necessary, install an extra switch to disconnect the transmitter board when the battery's being charged, but life would be simpler if I don't need to worry about it. Any thoughts on whether the transmitter board might be harmed if I don't decouple it?
     
  2. Peegoo

    Peegoo Poster Extraordinaire

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    It should not be a problem because the charger supplies voltage to the battery at a level near the battery's rated voltage. For example, a typical 18650 lithium cell is rated at 3.7 volts and charges at 4.2 volts.

    If your transmitter is digital and sensitive to over-voltage conditions, you could incorporate a simple precision curent limiting circuit between the battery and the transmitter.

    If the transmitter has an on/off switch, the off position disconnects the battery (and the charger) from the transmitter. So there's that.

    Back in the 80s I built a wireless transmitter into a Strat, and I used the truss rod as the transmitter antenna. A small spring in the neck cavity made contact with the truss rod adjuster in the end of the neck and that's how the signal got to the rod. Worked great.
     
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  3. spellcaster

    spellcaster Tele-Holic

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    This is a fairly old, and I assume primitive, wireless system....a Samson VHF transmitter and receiver. So, no digital circuitry, I don't think, but the lithium ion battery and the lithium battery charger are 9 volts....Not sure how that affects the charging rates you mentioned.

    By the way, this project has come full-circle. When I started the build, I was on FDP (Reep) and you were the one who suggested the truss-rod antenna idea to me when I was undecided how to do an antenna. So, I've done the same thing to connect to the heel truss road in the vintage Fender neck.

    [​IMG]

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  4. Fendereedo

    Fendereedo Poster Extraordinaire

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    That looks great, really lovely.
     
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