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Old Mar 20, 2005, 08:52 PM
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Smooth Spanky's Avatar
Detroit, Michigan
Joined Oct 2004
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Question
When to re-charge field battery?

I recently bought a new hobby battery (12V) to power my panel in my field box (starter, etc). Being curious, I put the voltmeter across the battery poles and it measured 12.8V with no load. At what voltage should one of these batteries be re-charged?

Thanks!
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Old Mar 20, 2005, 09:43 PM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
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Quote:
Originally Posted by Smooth Spanky
I recently bought a new hobby battery (12V) to power my panel in my field box (starter, etc). Being curious, I put the voltmeter across the battery poles and it measured 12.8V with no load. At what voltage should one of these batteries be re-charged?

Thanks!
Ask 10 people and you most likely will get 10 different answers. Many so called experts state that 12.2 volt is approximately 50% charged. It is reallyy best not to deep cycle most inexpensive gell cell batteries that are not relly designed for deep cycle useage.
Back when I flew glow a lot I charged mine weekly sometimes every few days.. Most of my e power field power source 12 volt batteries get charged weekly just to keep them toped off.
http://www.batteryuniversity.com/parttwo.htm

Charles
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Old Mar 22, 2005, 09:27 PM
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Detroit, Michigan
Joined Oct 2004
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Charles:
Hey, thanks for the information and for the web site. What type of charge rate would you use, that is, would you overnight charge?

Thanks again!
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Old Mar 22, 2005, 09:53 PM
Southern Pride
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Haralson County GA. USA
Joined Oct 2004
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Quote:
Originally Posted by Smooth Spanky
Charles:
Hey, thanks for the information and for the web site. What type of charge rate would you use, that is, would you overnight charge?

Thanks again!
The stsndard overnight charge rate is C/10 or 10% of the batteries capacity which for a 7Ah would be 700 mAh / 0.70Ah. Most chargers designed for thes batteries are around 500 - 600 mAh . I have a Hanger 9 one which has an LED which dims as the charge rate cuts back,simple and effective.

Charles
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Old Mar 22, 2005, 10:33 PM
Registered User
Perth, Australia
Joined Mar 2004
872 Posts
If you can find a dc power supply that can put out a steady 13.2v - 13.4v you can leave the charger on all the time when its not in use. The important thing, as everydayflier states is to make sure you dont put too many amps through it when charging, C/10 is a good rate.

If your charger is putting out more than this, a large resistor in series can reduce it. I have used a auto light bulb in series with the battery to limit the current .

Unlike Nicads and Nmhi and lipo batteries, Lead acid batteries in general deteriorate more quickly whilst not in a fully charged state. So its a good idea to recharge it immediatly after use and keep them that way to get max life expectancy.

Ron...
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Old Mar 22, 2005, 11:29 PM
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I usually charge mine with my Triton as soon as I get home from the field. I had heard that they don't like to be left discharged.

So far, so good.

Adam
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Old Mar 22, 2005, 11:39 PM
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Austin, TX, USA
Joined Feb 2001
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Quote:
Originally Posted by everydayflyer
10% of the batteries capacity which for a 7Ah would be 70 mAh / 0.070Ah.
Slight decimal correction: 7/10=0.7 Amps.
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Old Mar 22, 2005, 11:59 PM
Southern Pride
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Haralson County GA. USA
Joined Oct 2004
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Quote:
Originally Posted by Bob Baker
Slight decimal correction: 7/10=0.7 Amps.
Noted and corrected
I guess that comes from charging to many batteries of less tha 1000 mAh, atleast I got the C/10 part right..

Thanks,Bob

Charles
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Old Mar 23, 2005, 06:05 AM
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Dundas, ON Canada
Joined Feb 2001
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Quote:
Originally Posted by Cas123
Unlike Nicads and Nmhi and lipo batteries, Lead acid batteries in general deteriorate more quickly whilst not in a fully charged state. So its a good idea to recharge it immediatly after use and keep them that way to get max life expectancy.

Ron...
Yup - they sulphate badly when not maintained at a full charge.

Rob
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Old Mar 23, 2005, 06:29 PM
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Detroit, Michigan
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I'm now duly educated and aware of the fact that I'm doing things completely wrong! I'll be charging my battery when I get home tonight!! I learn something everyday if I'm not careful, thanks again.

Smooth
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Old Mar 24, 2005, 08:13 AM
Baptised Heathen
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Bundaberg, Qld, Australia
Joined Jun 2002
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You have to be carefull about learning stuff everyday. I try not to because I'm crammed so full of useless information now there's not much room left up there.
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