Date: Thu, 4 Sep 2008 09:14:01 -0700
Reply-To: neil N <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: neil N <musomuso@GMAIL.COM>
Subject: Re: Did I hurt my Aux Battery?
In-Reply-To: <48BFF3EA.9020606@gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Thanks Mike.
D-oh!
I didn't mention that the DVD player was connected directly to 12V
with the supplied cigarette adapter. I didn't use the AC adapter.
And wouldn't you know it. I left the DVD's battery pack connected over
night! Took the battery down to 20% (11.x V) Oh well. Was planning on
doing that to charge it at the slower rate.
Neil.
On Thu, Sep 4, 2008 at 7:42 AM, Mike Elliott <camping.elliott@gmail.com> wrote:
> On 9/3/2008 9:35 PM neil N wrote:
>
> "[DVD player's]AC charger says 1.3 amps on it. Maybe I could measure the
> draw with my VOM."
>
> (Obligatory warning ON)
> You may need to measure this. Take care when measuring anything connected to
> 120 vac household current. Make sure you know what you're doing. (Obligatory
> warning OFF)
>
> Were the DVD player's AC charger/power supply 100% efficient, then it would
> take in 120 vac @ 1.3 amps from your house's wall outlet when it's working
> hard. If you're running that charger off an inverter, then that inverter
> (were it 100% efficient, which it isn't) will be pulling 13 amps from the
> battery's 12 vdc and outputting the needed 120 vac @ 1.3 amps to run the DVD
> charger. Roughly.
>
> One hour @ 13 amps is 13 amp-hours taken from the battery. Your two-hour
> movie would have required 26-ish Ah.
>
> --
> Mike "Rocket J Squirrel" Elliott
> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
> KG6RCR
>
>
>
> On 9/3/2008 9:35 PM neil N wrote:
>
>> Hi all.
>>
>> 2-3 years ago, I installed a smallish, sealed, 40-ish amp house
>> battery in my Westy. At time of purchase, I didn't note the battery
>> type. (deep cycle or AGM). I *think* it's a deep cycle, but am not
>> certain.
>>
>> My new "intelligent" battery charger: http://tinyurl.com/6jryzn
>> tops up the battery quite quickly at the 8 amp/deep cycle setting.
>> Coupled with the fact that the incandescant interior light and
>> portable DVD player drained it down to ~ 20% fairly quickly, I thought
>> it might only be "surface" charging. I charged it a second time. It
>> still charged back up quickly. (1/2 hour - 45 minutes).
>>
>> Is the fast charging a bad sign? I hope that using a standard charger
>> or vehicles alternator all this time, hasn't damaged the batteries
>> ability to hold a charge.
>>
>> Would it help the battery to hold a charge longer if I drain it down a
>> few more times and do a slow 2 amp charge?
>>
>> Is there an easy way to tell if the battery is deep cycle or AGM?
>> (that way I could knowingly use the right setting)
>>
>> FWIW, after the second charge, running ONLY the DVD player for 2
>> hours, drained it down to 60% or 12.3 volts (says the charger). I
>> don't know how many amps the DVD player draws. Nothing in the manual
>> or online. AC charger says 1.3 amps on it. Maybe I could measure the
>> draw with my VOM.
>>
>>
>> Thanks for any help,
>>
>> Neil.
>>
>>
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