Wiring mixed panels for radios

cris

Hi,
I am installing 2 radios for internet in a off grid situation. The radios are Ubiquity Powerbeam M5 400 and each require  24V, 0.5A Gigabit PoE and Max. Power Consumption 8W. 
I have 3 Solartech 85 W, 12 V. , 5.15 A panels and 1 Sharp 80W, 12V, 4.7 A panel.
To get 24 V I need to connect 2 panels in series.  I would also like to connect 2 in parallel to maximize Amp.  Can I do that?  What would it be the best wiring for this system?  
I also have several 40A, 12 V batteries.  I am thinking to make a bank of 2 in parallel and 2 in series.  Would this work and be sufficient for this system?  I live in sunny central and California with at least 6 hr/day of sun in the winter. 
I imagine I need to get a controller for 24 V.  (I have a morning star for 12 V but imagine it won't work, right?)
Thank you,

Photowhit

First, you might check to see that the radios can handle the voltage range of unregulated 24 volt system, roughly 23-30 volts.

2 strings of 2 solar panels would work fine, you will lose a tiny bit with the 85 and 80 in series. And the 2x2 battery bank should also be fine assuming the batteries are all the same type and capacity. They system is also reasonably well balance, the 4 panels should put out about 10 amps at 24 volts normally with a peak of about 13 amps on cold winter days or about 12.5% charge rate normally.

Some Morningstar charge controller can be used either as 12 or 24v. Not sure what you have, it may be as simple as hooking up to your battery bank first, and some may have a dip switch or electronic interface.

cris

Thanks Photowhit.  I read that the radios need a constant 24V.  I am hoping the controller will do this?

BB.

Here is a company that makes DC to DC for POE powered systems:

http://tyconsystems.com/index.php/dc-passive

Otherwise, contact your Ubiquity re-seller and see what they recommend... I could not find any detailed specifications.

-Bill

mike95490

cris said:

Thanks Photowhit.  I read that the radios need a constant 24V.  I am hoping the controller will do this?

The Charge controller supplies power to charge the batteries.  It is not a stable voltage, when the battery is low, you see 23V, while the battery is approaching full charge, it can be 28-30VDC.

Estragon

You might find a variable 12v input to stable 24v POE injector easier to find (mobile/marine markets) than 24->24v. You would also be able to use the 12v controller.

BB.

See post #4 above for wide range dc input to fixed dc output poe supplies.

- Bill