Naracoorte power supply issues again

From Peter VK5BE
Today, 23/3/24 Nick and I attended at the Naracoorte repeater site and found the following.
  • The standby current on the 12 volt power supply was reading 3.5 amps.
  • Switching off the mains power to the power supply resulted in the battery dropping to 11 volts when the repeater was in standby.
  • This suggested that the battery was faulty (It also felt quite warm)
  • We then replaced the 15 Amp Tait power supply with another that was not set to limit the output current.
  • The battery was then removed from circuit, resulting in the repeater running entirely off the mains powered supply.
  • We noted that the volts now remain constant under load at 13.5 volts.
  • The total load on the supply seemed quite high, reading 12 amps when both links and the 2m repeater were transmitting.
  • Site was left running on mains power only, with no battery back-up.

Note from John VK5DJ

Things misbehaved again on Sunday. Signals were passing through on the links but the Repeater itself was either not responding or weak with hum. My conclusion is that the power supply is not able to supply the 12 amps required without a battery filling in the gaps.

For the moment Tony and I have successfully turned off the VK5RNC repeater transmitter but allowed Alan VK5ZLT to continue to have access to the 2M system through the links at Naracoorte.

In the meantime Peter has found a better battery charging system and a source for a replacement battery. As it is the Naracoorte Amateur Radio Club (NARC) Repeater he will speak to Ross and propose a possible solution.

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