Charger Inverter on Narrowboat issue

Discussion in 'EMC Matters' started by Nigel M0NDE, Jul 17, 2019.

  1. Nigel M0NDE

    Nigel M0NDE New Member

    I have a narrowboat and have had a Stirling 3.5Kw charger inverter installed.
    On 40m I have noise S7 which appears when the boat is connected to the marina 240V supply. The noise every 20 Khz. This is a modern charger/inverter. Unplugging the shore line removes this regular noise.

    I need a plan of attack.

    My boat is near Rugby

  2. Peter Torry

    Peter Torry New Member

    Morning Nigel,
    It would appear that you are receiving noise from the inverter at the switching frequency in use e.g. 20kHz. As it is a new install I suggest that you contact the installer and request their assistance with filtering and correct bonding. The manufacturer of the inverter may supply line filters that will alleviate the issue if not the supplier should be able to help.

    It would be wise to undertake some investigation yourself using a portable receiver, amateur or broadcast, to ascertain if the interference is present at other times from the inverter and its associated wiring. Does the inverter just charge the batteries or does it supply the boat with 230v AC? As the noise goes away when the shore line is removed I would suspect the inverter noise is being radiated by that connection and a suitable filter at the inverter should fix the issue. Do check if there is any interference on other frequencies even with the shore line disconnected as this will give an overall view of the situation.
    Good luck with solving the issue.
  3. Nigel M0NDE

    Nigel M0NDE New Member

    Thank you Peter for your reply. The inverter charges batteries and provides mains when marina supply not present. I do have one more bond connection to add from the case to the boat body, though I am not hopeful this will resolve the issue. I have contacted the supplier, no reply yet and again I am a bit pessimistic about that. I do have some torroids as recommended in one of the RSGB seminars I think last year on EMC. I will experiment with these to try and reduce if not eliminate some of the problem. My motorhome charger is so noisy I just turn it off when I wish to work HF so the boat at least has gaps between the noise!

    73 Nigel M0NDE

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