Leave an unplugged battery charger connected to lead-acid battery?

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BetaB4 wrote:

Hi, If you have a smart charger with electronic brain, it is OK to leave it on all the time.
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That would be my suggestion too. Just buy a new smart charger. In the grand scheme of things, especially when you're talking about boats, they don't cost that much. Also, if proper charging gets you some extra battery life, it could pay for itself,
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NO
EJ in NJ
BetaB4 wrote:

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BetaB4 wrote:

The self-discharge rate of the battery will be magnitudes greater than any discharge back through the rectifiers of the charger.
Very surprising that your charger doesn't switch to trickle charge mode once the battery is charged. Even the cheapest chargers nowadays do that, i.e. "http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumberE005" "http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumberf783"
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SMS wrote:

A trickle charge is supposed to compensate for self-discharge. The 2-amp trickle of those chargers will be magnitudes greater than self-discharge.
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Thanks all.
Based on what everyone wrote, I've been looking for an "automatic" battery charger. I checked Harbor Freight and one person suggested.
Here's the instruction manual for one Harbor Freight battery charger:
http://www.harborfreight.com/manuals/66000-66999/66783.pdf
On Pages 8 and 9 of the manual, it talks about not leaving the charger on and the possibility of the battery overheating with the charger on. So, I'm a little confused. Does the automatic shutoff actually work or not?

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wrote:

Check out any of the Sure Charge family as sold by Northern Tool. I keep my generator plugged into one, 24/7. It starts when I need it and has for the past 9 years [Same battery]. http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?storeIdi70&productId128&R128
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Thanks, but that wouldn't work for me. I need a battery charger for recharging a boat battery (that operates the electric motor) after running the battery down during a fishing trip. And, I sometimes need to be able to leave the charger on for a week or more without it overcharging the battery. So, I need a battery charger that will recharge fairly quickly but can be left on the battery.
starrin wrote:

http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?storeIdi70&productId128&R128
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BetaB4 wrote:

I think the problem is that the Chinese engineers hired an English major to write the manual, and the author tried to make sense of it in a hurry.
Page 9 makes it sound as if the 10A mode is not regulated. That's the one where you have to keep an eye on it.
It says in the auto mode (apparently 2A), you can go away, and it will turn on only as needed.
I'm curious about the note of Page 8: "This charger is not recommended for batteries with a built in Hydrometer eye. The reading of the built-in eye will conflict with ammeter readings."
I imagine what it means is that you should ignore the eye while charging because tiny gas bubbles from charging could make the eye read falsely.
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that'l be a first.
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On Sat, 23 May 2009 13:50:31 -0500, AZ Nomad

Chinese English Major - not an engineer or scientist or anyone with knowledge of both the product and English - so you get Chinglish.
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