Re: Battery level tester.

From: Colin Dawson (nospam_at_cjdawson.com)
Date: 10/01/04 

Date: Fri, 1 Oct 2004 08:45:17 +0000 (UTC)

"John Fields" <jfields@austininstruments.com> wrote in message
news:lv8pl096em780iore37iasf69vo9a5d1j0@4ax.com...
> On Thu, 30 Sep 2004 23:27:22 +0000 (UTC), "Colin Dawson"
> <nospam@cjdawson.com> wrote:
>
>
>>In practice it works really well, except for
>>the Battery monitor, which is OK. until I add my laptop and it's hard
>>drive
>>make things go crazy.
>>
>>This is what I wanted to sort out, but I don't know how. My initial
>>though
>>was to add an ammeter so that when the load increases, it compensates for
>>the, but you've told me that won't work. So now, I don't know how to
>>compensate.
>
> ---
> I suggested several posts back that you repartition your meter or
> build a new one so that you have only three LEDs to contend with:
> green = OK, yellow = getting flat, and red = flat. If you chose to
> build a new one it could be arranged so that it would never blink and
> would always be on only either red, yellow, or green. It would take a
> single quad comparator, a voltage reference, and a handful of
> resistors to do that. If you're interested I'll draw you a schematic.
>
> --
> John Fields

Hi John.

The battery meter that I had before (built into a cigar lighter socket
thingy - with one plug and 4 sockets) worked exactly like that. It was
stable, but I wanted more information on the state of the battery. One of
the things that I'm trying to do is long exposure astrophotograhy. These
can last up to an hour per shot. I need to know if there's enough juice to
keep my kit running sweet for the entire shot, for that purpose 3 LED's
isn't enough. That's why I wanted 10 leds. It does work well, but I want it
to work better. And yes. I'm willing to make a new circuit, There's
another design issue that I need to sort out anyway, which I'll do on the
next version of the PCB.

Regards

Colin Dawson
www.cjdawson.com

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