Re: switching

On Thu, 26 Jun 2008 18:04:07 -0700 (PDT), lilipot@[EMAIL PROTECTED]
 wrote:

>On Jun 26, 6:23 pm, Peter Bennett <pete...@[EMAIL PROTECTED]
> wrote:
>>
>> Use a relay - that's an electrically controlled switch.
>>
>> There is probably no need to switch both positive and negative
>> terminals - using an SPDT switch in the positive leads would likely be
>> sufficient.
>>
>> An output of a PIC probably won't drive a 5 amp relay directly, so you
>> would have to have the PIC drive a transistor or small relay, which
>> would drive the large relay.
>>
>> --
>> Peter Bennett, VE7CEI
>> peterbb4 (at) interchange.ubc.ca
>> GPS and NMEA info:http://vancouver-webpages.com/peter
>> Vancouver Power Squadron:http://vancouver.powersquadron.ca
>
>would there be anything else beside a relay?
>that would require energy only when switching is required?
>
>Li

Another thought: Is there any reason you can't just connect the two
batteries in parallel, and to the load.  You will get the same total
run time as you would using one battery, then switching to the other
when the first is discharged.

In many applications, it is recommended that all available batteries
should be connected and used/charged in parallel, rather than
discharging part of the battery bank, then switching to the other
part.  This (use all in parallel) will generally result in a smaller
depth-of-discharge of all the batteries, increasing their life (since
depth-of-discharge is what usually kills rechargeable batteries.)

 
-- 
Peter Bennett, VE7CEI  
peterbb4 (at) interchange.ubc.ca  
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca