Groups > sci.electronics.design > #446602

Re: Battery charger with solar panel

From	rickman <gnuarm@gmail.com>
Newsgroups	sci.electronics.design
Subject	Re: Battery charger with solar panel
Date	2017-02-06 23:41 -0500
Organization	A noiseless patient Spider
Message-ID	<o7bj1s$pub$1@dont-email.me> (permalink)
References	(3 earlier) <o75ru6$h2c$1@dont-email.me> <o75s9v$h9p$1@dont-email.me> <o7699p$2a8$1@gonzo.alcatraz> <o7b5o8$usc$2@dont-email.me> <o7bgf7$nd2$1@gonzo.alcatraz>

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On 2/6/2017 10:55 PM, Jasen Betts wrote:
> On 2017-02-07, rickman <gnuarm@gmail.com> wrote:
>> On 2/4/2017 11:22 PM, Jasen Betts wrote:
>>> On 2017-02-05, rickman <gnuarm@gmail.com> wrote:
>>>> On 2/4/2017 7:35 PM, mike wrote:
>>>
>>>>>> And in Arizona we certainly don't lack for sunshine ;-)
>>>>
>>>> I believe that is only 1.5 watts.  That's barely enough to trickle
>>>> charge a car battery.  I've used a 2 watt, 15 volt wall wart to trickle
>>>> charge a car battery and that's just barely enough running 24/7.
>>>
>>> How can you tell it's just barely enough?
>>
>> You clipped my example.
>
> Huh? I quoted all that arrived here.
>
>> It would take a full day to charge a slightly run down battery.
>
> "barely enough" is, to my mind less than twice the self discharge rate.
>
>> If it was fully down it would take three days.
>
> If the vehicle can sit for 4 weeks (without the battery being fully depleted)
> and then recover on that charger in only 3 days, I'd say it's got
> at-least 8 times excess capacity (for for the task of preventing unattended
> discharge)

Yeah, well I'm not sure there is any meaning to that calculation.  This 
unit barely will put current into the battery.

>> I've measured the current it supplies and I see very little difference
>> when it is run down or fully topped off.
>
> That is not unusual in a constant-current charger.

Who said it was a constant current charger?  It's a tiny wall wart that 
barely charges the battery.  Even a 2 amp charger will fully charge a 
battery overnight.  This thing takes days because there is very little 
excess capacity compared to the minimum current required to keep the 
thing up.  But then again, I guess it is constant current considering 
that the battery always draws the full load it is capable of delivering. 
  It's a 15 volt power pack and once attached to the battery it never 
gets above 13.5 volts.  So it does put out a constant current under 
those conditions.

I don't think charging a lead acid battery is a zero sum game.

-- 

Rick C

Thread

Battery charger with solar panel gm <notmy@mail.com> - 2017-02-04 21:41 +0100
  Re: Battery charger with solar panel Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-04 13:49 -0700
  Re: Battery charger with solar panel Baron <baron@linuxmaniac.net> - 2017-02-04 21:39 +0000
  Re: Battery charger with solar panel rickman <gnuarm@gmail.com> - 2017-02-04 17:05 -0500
  Re: Battery charger with solar panel mike <ham789@netzero.net> - 2017-02-04 14:42 -0800
    Re: Battery charger with solar panel Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-04 16:00 -0700
      Re: Battery charger with solar panel mike <ham789@netzero.net> - 2017-02-04 16:35 -0800
        Re: Battery charger with solar panel Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-04 17:38 -0700
        Re: Battery charger with solar panel rickman <gnuarm@gmail.com> - 2017-02-04 19:42 -0500
          Re: Battery charger with solar panel Jasen Betts <jasen@xnet.co.nz> - 2017-02-05 04:22 +0000
            Re: Battery charger with solar panel mike <ham789@netzero.net> - 2017-02-04 23:26 -0800
              Re: Battery charger with solar panel rickman <gnuarm@gmail.com> - 2017-02-06 19:55 -0500
            Re: Battery charger with solar panel rickman <gnuarm@gmail.com> - 2017-02-06 19:54 -0500
              Re: Battery charger with solar panel Jasen Betts <jasen@xnet.co.nz> - 2017-02-07 03:55 +0000
                Re: Battery charger with solar panel rickman <gnuarm@gmail.com> - 2017-02-06 23:41 -0500
        Re: Battery charger with solar panel Jeff Liebermann <jeffl@cruzio.com> - 2017-02-04 18:17 -0800
          Re: Battery charger with solar panel rickman <gnuarm@gmail.com> - 2017-02-04 22:36 -0500
            Re: Battery charger with solar panel Jeff Liebermann <jeffl@cruzio.com> - 2017-02-05 01:03 -0800
  Re: Battery charger with solar panel Don Y <blockedofcourse@foo.invalid> - 2017-02-04 22:02 -0700
  Re: Battery charger with solar panel dakupoto@gmail.com - 2017-02-04 22:25 -0800
  Re: Battery charger with solar panel boB <boB@theresnoplacelikehome.com> - 2017-02-05 16:38 -0800

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