Date: Mon, 3 Oct 2011 06:08:39 -0700
Reply-To: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Subject: Re: Vitrifrigo: two corrections to my earlier post
In-Reply-To: <637FAB95FEA14BD1A037CDD5211FEBFC@troyb5bff49d63>
Content-Type: text/plain; charset=windows-1252; format=flowed
One source:
"What size charger should I buy?
"A properly sized charger takes into account battery capacity and the
time interval between charges. In applications where cycling is
infrequent, such as weekend RV users, or infrequent or seasonal trolling
motor usage, a charger with an output current rating between 10 and 13%
of the battery's rated 20-hour capacity will suffice. In applications
where battery recharge must be accomplished within 8 to 10 hours, a
three stage, automatic charger, rated at 20% of the battery capacity,
may be required.
"Example: A good charging rate for a battery with a 20-hr capacity of
225 amp-hr is about 22 to 29 amps. You can of course go slightly higher
or lower depending on what is available on the market."
See <http://www.trojanbattery.com/Tech-Support/FAQ/Charging.aspx>
--
Jack "Rocket j Squirrel" Elliott
Bend, Ore.
1984 Westfalia. A poor but proud people.
1971 "Ladybug"-brand utility trailer ca. 1972 from a defunct company in
San Clemente, Calif., now repurposed as The Westrailia.
On 10/02/2011 10:09 PM, Troy wrote:
> <<2. That Dennis Haynes explained to me that I was not doing my deep-cycle
> battery any favors by recharging it gently. Turns out that batteries
> such as this want a charge rate of 10% to 16% of their rated A/h
> capacity (Trojan sez 10% to 13%), and my DC > DC charger's 7A charge
> setting was not idea. I remembered that I had the older version of the
> charger, with the "hi/lo" switch and flipped it to the "hi" setting,
> which results in somewhere (I say "somewhere" because the charge current
> varies) between 10A and 18A, which fits the charge requirements of the
> battery perfectly.>>
> Interesting, but I would like a more detailed explanation as to why. You
> said "batteries such as this", which I will infer to mean deep cycle
> batteries. This would mean that a 125 amp hour battery could want as
> much as 16.25 amps, which seems really high to me. By the same logic a
> 250 AH battery would want 32 amps. I don't think I have ever seen a
> battery charger go this high, short of the booster setting (55amps).
> Seems to me the wisdom over the years favored lower amps over a longer
> period of time, and is certainly much safer too. I do recall reading in
> a solar controller manuals about the dangers of equalization, which
> generate amperage up around 15 or so. They warn about possible battery
> explosion. (Blue sky manual) I guess I would just like to have a more
> detailed explanation as to why. Why is 10 to 13% ideal? What's going on
> internally? What are the dangers, what are the benefits?
> I still have yet to hook up my auxiliary 125 amp hour battery, so have
> the opportunity to use some heavier gauge wire if it is truly of
> benefit. My plan was to hook up a heavier gauge (4 gauge) wire from the
> alternator to the starter, which is the weakest link in the system. This
> in turn will allow for faster (higher amperage) charging as well, if it
> fact there is a benefit to this. I still have yet to hear a clear-cut
> explanation as to why, and there seems to be opinions for both sides.
> Can anybody back up the info with some facts please, and perhaps a
> source for your info? Rocket referred to the Trojan manual, and this at
> least is a credible source. More info please...
> Troy
>
>
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