Solar panel selection

**intelliGEORGE** · 12-09-09, 11:42 PM

I am setting up a solar rig and was looking for advice from some experienced persons.

What I need to know is what size panel do I need, will I require anything else such as regulators and battery charger? If so what would be the spec.

Object is to charge a 20Ah SLA battery and power 12v devices.

Total current draw on the 12v devices is approx 1.5Amps Peak.

Thanks in Advance.

**Joey** · 13-09-09, 05:37 AM

Originally Posted by intelliGEORGE

I am setting up a solar rig and was looking for advice from some experienced persons.

What I need to know is what size panel do I need, will I require anything else such as regulators and battery charger? If so what would be the spec.

Object is to charge a 20Ah SLA battery and power 12v devices.

Total current draw on the 12v devices is approx 1.5Amps Peak.

Thanks in Advance.

Normally it's recommended to only draw down these batteries to about 50% if you want any sort of extended life from them , but you could safely draw 1.5amps from that battery for 8 hrs without doing any damage.

Basically you are drawing 12v x 1.5a = 18wh , a 40W panel would come close to covering this usage while adding back some charge to the battery in good conditions.
A basic 12V 5amp regulator would be fine .

A lot depends on whether this supply is needed 24/7 or how many hours per day or night it's needed , if not critical the panel size could be smaller and the battery drained even further down to about 80% max occasionally as long as it is recharged quickly.

**intelliGEORGE** · 13-09-09, 09:34 AM

Well it has to be 24/7. During the sunlight hours the system needs to run off the panels, then battery when there isn't. If need be I can bump the battery up to a 40Ah one.

I'm running a CCTV camera, IR spotlight and an indutrial NextG modem/router.

**Joey** · 13-09-09, 04:10 PM

Originally Posted by intelliGEORGE

Well it has to be 24/7. During the sunlight hours the system needs to run off the panels, then battery when there isn't. If need be I can bump the battery up to a 40Ah one.

I'm running a CCTV camera, IR spotlight and an indutrial NextG modem/router.

Ok then , 40AH is a much better option , if you want to be sure this will keep going all the time even on rainy days with virtually no direct sunlight you will need at least a 60W panel , It will be overkill in on clear sunny days but necessary when it's not , on average you will get about 3amps at 12 volts from this panel.
The same 12 volt 5 amp regulator will cover it , any excess will be shunted away when the battery is fully charged.

All of this stuff is readily available from Jaycar

**Chimp** · 13-09-09, 09:37 AM

interested in this also for a site that has no power, that needs cctv and a simple security system putting into. (its not that critical to have a system out there but it would be nice.)

Ill let George finish up and if my questions arent answered by then, ill ask away.

**intelliGEORGE** · 13-09-09, 10:02 AM

Chimp if you have questions, by all means ask away. I just need to get a good combo of panel/regulator and charger.

I will be using an IP camera coupled with a nextG modem for connectivity on rural properties using a 900mm 6dB 850Mhz antenna.

Another model I will be building will be for WLAN, where labor for cable will exceed the cost of wireless.