[450] The link on batteries

[John Foege]

I'm curious what the objective of this whole experiment is??

I could understand hooking up a deep-cycle gel cell marine battery or
something + a charging system + a 13.8V PSU = the link electronics /
transceiver would run 24/7 and have battery backup for power outages...

But, I'm just curious in general what the point of fooling around with a
step-down converter and a long line of AAs is?? I'm not understanding what
the idea is.

And, secondly, is it really a concern whether or not the link can run on
battery power? Or are you still thinking about Chris' suggestion of using a
big fat solar panel + a gel cell + charging system and making a portable
unit that can be hoisted up into a tree, etc. ?


On Thu, Oct 10, 2013 at 10:27 PM, David McKenzie <k1fsy at vhfwiki.com> wrote:

> I'm currently testing it with 8x generic AAs in series. So that's probably
> about 2500mA @ 12v. The raspi with wifi/soundcard running the link with my
> ssh session open is drawing around 275mA average from the batteries
> measured on the battery side of the dc/dc converter. It's been up for about
> 40 minutes and the batteries are reading a steady 12.01 volts. I don't know
> how long it will take before Vin < Vout (it just passes through lower than
> set voltage) will be enough to turn off but a back of the hand calculation
> of 2500mAh / 275mA = about 9 hours of run time.
>
>
> On Thu, Oct 10, 2013 at 12:05 AM, David McKenzie <k1fsy at vhfwiki.com>wrote:
>
>> no, ~5.6v (because AAs run hot) down to 5v.
>>
>> that's a LM2596 switching regulator board; Vin > Vout only. I have 10 of
>> them now. Supposedly something like 95% efficient. That's an 8-cell battery
>> pack I should load it up and give it another test.
>>
>>
>> On Wed, Oct 9, 2013 at 11:50 PM, John Foege <john.foege at gmail.com> wrote:
>>
>>> 4 AAs in series? 5.2V to 12V DC-DC regulator?
>>>
>>> Can you set it for 1.3V to 13V and run the batts in parallel?
>>>
>>> I'm assuming this doesn't make any difference in run-time due to either
>>> having a 1800 mAh 5.2V cell or a 1.3V 7200 mAh cell with the
>>> converter...unless I'm having a massive brain fart...
>>> On Oct 10, 2013 12:04 AM, "David McKenzie" <k1fsy at vhfwiki.com> wrote:
>>>
>>>>  Got the switching regulator modules from China. It ran for 3 mind on
>>>> those 4 nearly dead AAs :)
>>>>
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>
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