Date: Sun, 29 Jul 2007 22:28:09 -0700
Reply-To: Michael Elliott <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Michael Elliott <camping.elliott@GMAIL.COM>
Subject: Re: Deep Cycle Batteries
In-Reply-To: <vanagon%2007073000363016@GERRY.VANAGON.COM>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Proper charging of a deep cycle wants a proper two- or three-stage
charger (better). Good solar controllers do it, too. If I leave a
campground in the morning w/o first charging up the battery w/ the
panels, and rely on the alternator to charge the battery, drive a few
hours, then check the state of charge, the battery monitor generally
reports that I'm still 4 to 7Ah short of a full charge. This is with an
adjustable alternator set to higher than stock voltage -- about 13.6V
when temps are cool, 13.4V after driving for a while. Such voltages are
too low to bring the deep cycle to full charge. Our controller applies
current until the battery reaches 14.1V then chokes back the current to
hold it there. After the controller is able to hold 14.1V with less than
an amp for more than two minutes, the monitor declares the battery full.
These alternators are not so smart. But I'm not complaining -- getting
into camp with a battery that is 90% full is good enough for our use.
And, as John said, Dennis knows his onions when it comes to this stuff.
--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR
Geza Polony typed:
> Sorry to have hijacked this thread with my own aux battery probs, but I hope
> there's enough general info here for others to use.
>
> Interesting:
>
> On Sun, 29 Jul 2007 21:24:32 -0600, John <vanagonvw@GMAIL.COM> wrote:
>
>> if you
>> invest in true deep cycle batteries, and don't use a three stage charger
>> to keep them topped off, you are not getting the max life out of it, and
>> in fact, are never getting it "filled up" in the first place. It may say
>> 100aH, but without the proper charge rates and controlled currents, you
>> won't see those numbers in real life. These are not 'starter' batteries,
>> and are not made to be bulk charged, with a constant dump of current
>
> In other words, just putting the Optima (or whatever) in and connecting it
> to the relay, etc., is NEVER going to be enough to keep it fully charged?
> That sounds like the problem here--it's never quite fully charged. (This
> goes back even before my mishap with the espresso maker.) So to really get
> the max out of a deep cycle battery, you have to use a separate charger?
> I'll try it but sure seems like a PITA to have to do.
>
> If they're not made to be charged "with a constant dump of current," then
> how can you connect them to our typical alternator/relay systems to good effect?
>
>
>> Just wanted to point that out....Dennis knows of what he speaks. Those
>> who are paying for true deep cycle batteries, who want to take care of
>> their investments, and get the most out of them, would do well to do
>> some web work, and get the details on how to best take care of them.
>>
>> HTH,
>>
>> John
>
> Thanks, good post!
>
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