What is a battery maintainer? Never had one.
gumbyred
a Battery Maintainer, is a small charger with Electronic Smarts in it.
Typically they have small current capacities, on the order of 750 mA on the bottom end,
to about 2.5 Amps on the high end of the scale.
I have several "Battery Tender" brand chargers, 750 mA, 900 mA, 1.25 A
the 750 mA is the last one that I bought, and it is on my 2001 Chevy Suburban keeping that battery up to snuff.
That truck sets for weeks at a time w/o being moved, and I went out a couple months ago to use it, and found the battery down to 9.6 volts. I was really pissed at myself over that one, I had forgotten to turn off the Garmin GPS the last time I drove the truck
Now, to the real difference in a "maintainer".
The charger monitors the battery voltage and when it gets up to about 12.8 to 13.0 volts ( varies by charger ), it shuts off Charging Mode, and just monitors the voltage.
when the battery falls down to about 12.3 volts, it turns on and starts charging again, and turns off the charger at 12.8+ volts.
On the Battery Tender brand, there is a LED that is RED when the charger is plugged in, and not on a battery, or the battery voltage is low.
That LED turns Green once it goes into "Monitoring Mode" and stays there unless something pulls the battery voltage down faster than it can keep the charge up
I also have a NAPA Deltran, and a Schrader Smart Charger. both are very good maintainers.
In addition to that, I have a very old 12+ years, heavy shop charger with a voltmeter on it, and 3 switch positions.
2A, 10A, 15A
in the 2A range, the voltmeter does not move, but it keeps the battery at 12.8 to 13.3 all the time.
in the 10A range, the voltmeter kicks a lot, jumps up to about 1/3 scale, and the drops off the Zero reading.
that battery is on my Toy Hauler and all the interior lights are 12 volts....
when a light is on, they change in brightness as the charger switches modes.
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