HPWREN Solar Power Relay Station Design - La Jolla and Rincon

This document describes requirements and final design for the solar system that supports the HPWREN's relay stations located on mountain-tops with line of sight into the La Jolla and Rincon Native American reservations.


Step 1: Power Requirements

We prototyped one system for this installation. The power requirement for this system is detailed below. It is important to not only understand the power consumption, but also the various voltage breakdowns and their associated power requirements. Additionally, it is important to acknowledge the fact that we want 24x365 uptime.

Implementation 1: Low Power
QuantityPartVoltageCurrentPower
1Lucent 802.11 RORs5v3A15 watts
2Hyperlink 1 watt Amplifiers12v0.42A5 watts
Total Power:5v at 3A
12v at 0.84A
25 watts
Adjusted Total Power:
(after 80% dc-dc converter efficency)
5v at 3.75A
12v at 1.05A
31.25 watts

Step 2. System Diagram

Below is a basic schematic diagram for a solar power system. In reality the load should have a DC-DC convetor on it to adjust and regulate the voltage coming from the batteries. However, if you know the tolerance range of the equipment you could always set LVD (low voltage disconnect) and HVD (high voltage disconnect) to the applicable limits. It is also important to remember this is a simple diagram and the battery array should have some blocking diodes so if one battery dies it doesn't kill all of the batteries. It is also very important to think about the voltage of the solar array and batteries as higher voltages tend to lose less power due to wire resistance. HVD is to protect the equipment should the batteries be disconnected accidentally. LVD is to protect the batteries so they will not be completely drained (it then reconnects when the batteries get recharge to a high enough level).

Step 3. Components

Below is a list of components we selected for our setup. Many solar companies have programs to calculate how many solar panels / batteries you need. They require several specific pieces of information:

  • Location (lat/long, elevation): N33.3 W116.9, 5000 feet
  • Continous Power Drain: 31.25
  • Prefered final output voltage(s): 12v
  • Physical Issues (pole-mount, roof-top, etc.): Pole Mount 4" (I.D.) schedule 40 (side of pole mount)

Additionally, we chose to go with a combined charge controller and load controller as opposed to aquiring each part individually.

Implementation 1: Equipment List
QuantityDescriptionManufacturerDistributorPrice
412v 94AH Gel Cell BatteriesCD?Solar Depot, Inc.
61 Paul Drive
San Rafael, CA 94903
(800) 822-4041
Shawn Moshfeghi
shawnm(at)solardepot.com
120.75 EA
4PV SX 80W 4.75A Solar Panels PV/SX-80USolarexSolar Depot, Inc.
61 Paul Drive
San Rafael, CA 94903
(800) 822-4041
Shawn Moshfeghi
shawnm(at)solardepot.com
374.25 EA
1Side of Pole Mnt 4-SX60-8 (MH/TS-UNI-TP/04)???Solar Depot, Inc.
61 Paul Drive
San Rafael, CA 94903
(800) 822-4041
Shawn Moshfeghi
shawnm(at)solardepot.com
217.50 EA
3Inter Mod WireKit Flex15" WR/SX-IM15???Solar Depot, Inc.
61 Paul Drive
San Rafael, CA 94903
(800) 822-4041
Shawn Moshfeghi
shawnm(at)solardepot.com
6.00 EA
1Output Cable 6ga 10' WR/SD-IP120???Solar Depot, Inc.
61 Paul Drive
San Rafael, CA 94903
(800) 822-4041
Shawn Moshfeghi
shawnm(at)solardepot.com
35.00 EA
1Add on terminal kit WR/SX-ATK???Solar Depot, Inc.
61 Paul Drive
San Rafael, CA 94903
(800) 822-4041
Shawn Moshfeghi
shawnm(at)solardepot.com
32.70 EA
1PS20 Chrg Reg 20A (with LVD & LCD & protective coating) PR/MS-PS20MCMorning StarSolar Depot, Inc.
61 Paul Drive
San Rafael, CA 94903
(800) 822-4041
Shawn Moshfeghi
shawnm(at)solardepot.com
155.78 EA
1Case for battery storage (weather resistant but vented) BE/AM-L16BB-8 AeromagAeromax
9520 East Lorna Lane
Prescott Valley, AZ 86314
520-775-0085
Fax: 520-775-0803
Solar Depot, Inc.
61 Paul Drive
San Rafael, CA 94903
(800) 822-4041
Shawn Moshfeghi
shawnm(at)solardepot.com
305.00 EA
8Battery Cables 2/0 gauge WR/SD-12-00TSolarexSolar Depot, Inc.
61 Paul Drive
San Rafael, CA 94903
(800) 822-4041
Shawn Moshfeghi
shawnm(at)solardepot.com
6.00 EA
1DCA-102 - 15 watt series, 12 volt input, 12 volt out at 1.2 A (86% efficent)International Power SourcesInternational Power Sources, Inc.
200 Butterfield Dr.
Ashland, MA
01721
Tel: (800) 226-2100
Fax: (508) 879-8669
75.00 EA
1DCB-101 - 25 watt, 12 volt input, 5 volt ouput @ 5A (%86 efficent)International Power SourcesInternational Power Sources, Inc.
200 Butterfield Dr.
Ashland, MA
01721
Tel: (508) 881-7434
Fax: (508) 879-8669
109.00 EA
14" I.D. schedule 40 8'6" poleSurplusEscondido Metal Supply
7:30am-5:00pm
760-747-3333
67.98 EA
Total Cost:(excluding tax+shipping)3031.96

Step 4. Final Design Diagrams

Implementation 1: Low Power

The work on this project was completed by Todd Hansen for NLANR. This work is funded in part by NSF Cooperative Agreement No. ANI-9807479

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