[MLB-WIRELESS] New Node to be

David Ashburner d_ashburner at hotmail.com
Thu May 18 12:52:50 EST 2006


>
> * Mark (IKD ILW etc.) has offered to purchase an 80 watt solar panel 
> and construct the power system.
> We'll monitor the performance over the first weeks to see exactly how 
> much more solar capacity is required.
> * A pair of 12V 100A/H battery have been purchased.
>

how much power is an interesting issue.  I look forward to see how much 
you can get out of the panel.

I'm assuming you are going to run the routers/radios from the 
batteries, they will be up 24 x 7
they probably draw less then the 1 amp the plug pack is rated at but it 
makes a good first pass estimating figure.

2 units x 1 amp x 24 hours = 48 Ah per day so your batteries could run 
the system for 4 days without sun. But it's the problem of not 
recovering full charge over a period of time that is going to be the 
hard one.

80 watt panel at say 18 volts gives you  4.4 amps for something like a 
max of 6 hours in VIC so you have a max of 2.4 amps charging for 6 
hours = 14 Ah
The battery will have to provide  48 - 12 = 36 Ah
I'm thinking you are going to go into deficit . Of course the AP's will 
probably draw a lot less than 1 amp each so it might do it.

One other thought is if the site is only for relaying data ( no AP 
access ) you could run one radio in WDS mode and configure a WDS link 
at either end. It would halve the available throughput but use half the 
power.






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