[450] The link on batteries

[David McKenzie]

 23:09:52 up  3:23,  1 user,  load average: 0.40, 0.38, 0.40
Thu Oct 10 23:09:52 UTC 2013



On Thu, Oct 10, 2013 at 4:38 PM, John Foege <john.foege at gmail.com> wrote:

> 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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