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Thread: GP300 Bricks - Question about batteries

  1. #1
    bushbabe No Longer Registered

    Default GP300 Bricks - Question about batteries

    Hi all..... this is my first post so pls bear with me. I am from Down Under and run a Cattle Station (Ranch to you Northeners). We use the GP300's for air to grond comms during mustering times. I have been wanting to upgrade the ol ni-cd batteries and have seen on "ebay" that there are ni-mh batteries available. I have a 6 bay rapid charger and was wondering if I can use the newer ni-mh in this charger. Bear in mind that our normal procedures is to put radios on charge overnight, use for around 5-6 hrs daily, then back on charge overnight for a few months at a time. To date the 1200mah batteries have coped reasonable well, but thought the 2600mah ni-mh batteries might be a good upgrade. Are there any real benefits to using Ni-mh........ other than I understand they don't have the memory glitch that Ni-cd's have.

    I have had these radios for years, solid as a brick. Tried some Vertex radios the other day, and don't hold a candle to the "Bricks". Oh... we use hiband VHF if that is of any interest. Our property is over 500,000 acres (not a misprint) and our paddocks average around 40,000 acres each. We use Tait TM8200 mobiles and a MSR2000 repeater to help get out there.

    Thank you for any help.


  2. #2
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    You are right, they don't have memory effect, and they hold more coulombs than a NiCd (more mAH). The chargers are already "smart" enough to know how to properly charge NiMH batteries.

    That type of repetitive use where the usage duration is about the same every day is exactly what causes the NiCd "memory" effect, so the NiMH should help.

    I used to love the old GP's - durable, good audio - even dropped one in a lake for about 20 mins one wild night, and 10 min with a hair-dryer fixed it nicely! :P

  3. #3
    bushbabe No Longer Registered

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    Many thanks for your quick response. Probably grab a few for next years work. Just a thought. We would like to be able to remotely turn on/off the repeater which is 20miles from here in inhospitable territory and is a pain in the **** to get to. What would be a good way of doing this..... no mobile phone coverage, so would have to be a radio link of soughts. Any suggestions.

  4. #4
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    It's your basic Anti-dickhead remote control system for a repeater.

    I'm working on something exactly like that right now. What I had planned to do was use a 2 channel cheap-*** Maxtrac and use the Horn/Lights MDC Call function to either 1) turn on/off a relay - pulse on, pulse off type, or 2) turn off a delay-relay for a time-out period, say 10-15 minutes. The repeater interface is either 1) a knockdown signal (ENABLE) going to the repeater controller or 2) a coffee-pot timer type relay to kill the mains to the repeater. This is rude and interface #1 sounds more elegant if there is such a control signal available. The repeater in question is a Quantar.

    I haven't designed the actual radio-to-repeater relay interface yet but it's on my LONG list of crap to do this lifetime.

  5. #5
    Will No Longer Registered

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    I found that the chargers for the GP300 can and do overcharge the batteries. I came up with a resistor change that reduces the problem. I can look that up, been a long time ago, if you need it. This is 1990's work!

    With the desktop, 'shoe' chargers the NiNh batteries work fine. Just do NOT leave the batteries in the rapid charger past the Complete cycle start more than an hour. The complete cycle still charges the battery and WILL overcharge the battery.