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unplugging battery to prevent drain? / battery recharging and maintenance tips?

I have a '97 Mazda Miata that I have retired from "commuting service" and only drive about once a week, for about 5 miles. I have noticed that the battery dies quite often and find myself having to use a booster pack to jump start it.



Would unplugging the battery when I'm not planning to drive the car help prevent power drain? If so, would I have to unplug both terminals, or would unplugging just the positive one do?



To the best of my knowledge, there is only one active drain on the battery: a factory-installed anti-theft LED blinker that I can't seem to turn off, even though the anti-theft system no longer works.



What are some other practices for preventing battery drain/properly maintaining a charge, short of daily driving?



Thanks!
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Comments

  • edited February 2009
    Consider the age of the battery. If it 3 to 4 years old, get a new one, that is about they normally last.
    The flashing LED will not drain a battery in that short of time. If you want, cut the wires on it.
  • edited February 2009
    Don't mess with the positive terminal at all. Just disconnect the negative and the battery will stay charged. Disconnecting is the only way to keep the battery going without a lot of effort.
  • edited February 2009
    You may want to consider a battery tender. A master kill switch located on the batt is another option. If you just disconnect, do the neg thermal. Some products to consider

    http://www.batterytender.com/

    http://www.sears.com/shc/s/p_10153_12605_02871219000P

    http://www.supertruckusa.com/products/99966_00.htm

    The palce for Miata info: http://www.miata.net/
  • edited February 2009
    I use a Battery Tender rather than disconnecting the battery. The Tender keeps the battery properly charged but won't overcharge it. There's one hooked up to the battery of my summer car right now.

    You really should drive more than 5 miles if your starting the engine. The engine and drivetrain need to warm up completely, and 5 miles isn't enough time. Five miles won't recharge the battery, either.
  • edited February 2009
    Even a reasonable trip once a week is plenty to keep a battery in good condition assuming the battery is good, the charging system is good and there is not abnormal dark load (the power used to keep things like the clock going). If you need more consider a battery tender or a solar recharger. If you really must disconnect the battery often, get a switch made for that use.
  • edited February 2009
    Once a week should be enough to keep your battery charged. You should get your battery tested for free at your local auto parts store.

    If your battery is fine, I recommend a battery tender.
  • edited February 2009
    If you really want to do this, don't disconnect the terminals. too much work disconnecting and reconnecting. As mentioned, a "kill switch", a switch put on the negative cable to open the circuit.
  • edited February 2009
    You are probably right about the alarm system being the problem. You could have a shop the specializes in alarm installations properly disconnect it and eliminate the drain. or, as others have suggested, install a switch in one of the battery cables.
  • edited February 2009
    This is the one I was thinking of. If you can disconnect a batt terminal, you can install one of these. Have you thought about the hassle of resetting the clock and radio stations ever time you power down?

    http://store.summitracing.com/partdetail.asp?part=sum-g1439
  • edited February 2009
    More important than loosing the clock and radio settings, a '97 is an OBD II engine computer. I expect that it will loose its memory when you disconnect the battery, and have to 'relearn' its normal parameters every time you restart the car. Since most cars require several start/warmup cycles to get dialed in, the system will never be quite dialed in.

    5 miles, a restart, and 5 miles home is not enough to charge your battery. That is probably why it is going dead. If it has gone dead several times, you are going to need a new battery, as maintenance free batteries won't tolerate deep cycling very many times.

    Some sort of battery tender would seem to be the best solution. If you park outside. a solar cell unit like they put on RVs while they are parked would be a good choice.
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