Date: Wed, 21 Apr 2010 15:36:10 -0700
Reply-To: "Mike \"Rocket J Squirrel\"" <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "Mike \"Rocket J Squirrel\"" <camping.elliott@GMAIL.COM>
Subject: Re: charging aux battery: too much of a good thing?
In-Reply-To: <vanagon%2010042118234256@GERRY.VANAGON.COM>
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Phil Zimmerman wrote:
> On Tue, 20 Apr 2010 15:11:51 -0700, mark drillock <mdrillock@COX.NET> wrote:
>
>> Today I was able to fire up my 3 battery system for the first time. A
>> dedicated 125 amp hour deep cycle was added...
>
> ..... I was surprised to see the meter reading over 60 amps going into the
> battery when I first started the engine even though the battery was fairly
> full. This quickly tapered down over a few minutes to a steady 25 amps. I
> wonder if maybe I have too much charging?
>
> .....I am measuring 14.5+ volts at the alternator which I believe is pretty
> common with modern vehicles but I wonder how good it will be for the battery
>> long term.....
> That seems too high for a "float charge" but
>> I don't know how it will be in practice. Anybody know? Suggestions?
> -----------------
>
> Hi Mark,
>
> Wow... now thats a dedicated aux battery for a Italian Gelato Refer.... darn
> near the size of Karls D4 Battery under his rear seat! I now have a serious
> case of Battery envy!
>
> Which side of the engine is the Battery mounted and how did you hang that
> 80 lbs monster in there?
>
> What type of Cell... Wet, AGM or Gel?
>
> The previous posters have hit most the salient stuff I know, other than
> operating a Battery at elevated temps in the engine compartment...
> Higher than ambient (meaning room temp) temperatures can kill a battery by
> 50% to 75% of its expected life-time. Anything to keep the battery cool(er)
> will help.... IMHO
>
> Alternator Charging is pretty much limited to 'Bulk' charging. A float
> charge is really never reached while running on the Alternator... With the
> Fridge running... that 14.5 volts will be somewhat dissipated as heat and
> in line-losses... keeping your battery safe from overcharging. I would be
> more concerned with over-heating than overcharging... but, the devil is in
> the details in battery charging.
>
> Might be worth the time and effort to put a temperature probe on the battery
> to measure its temperature while Underway and Charging. See what the temps are?
>
> regards
>
> Phil Z.
> Campbell River, BC
> -----------------------
Your top-shelf chargers have a temp probe you screw to a battery
terminal so they can compensate for temperature.
--
Mike "Rocket J Squirrel" Elliott
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Westrailia: (Ladybug Trailer company, San Juan Capistrano, Calif.)
Bend, OR
KG6RCR
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