Using Lead Acid Batteries in the Shack

User Notes Red-bordered illustrations are web links Links at the end of this slide show are to my website You re on your own. I am not responsible for you, your property, personal safety or the safety of anyone else, okay? 2

K8SV shack tour Discussion Topics for Today s Presentation Popular battery applications for ham radio The basics about lead-acid batteries Real world operating and batteries Safety Batteries for radio and other long duration applications Charging Storage Temperature Effects on Capacity & Service Life Battery capacity ratings Voltage drop considerations Batteries and hamfests Weblinks 3

K8SV Shack Tour 4

K8SV Shack HF Ops RS-50M FT-900 HRD Rig Control Palstar Tuner Ameritron AL811H 5

UHF / VHF FT-8800R IC-2100H BC Scanner 6

VHF/UHF Antenna Farm AR-270 vertical 6 elements on UHF 4 elements on VHF Discone for general use 7

HF Antenna Cushcraft R7 8

12 Volt Standby Power 3 X 12 Parallel 72 AH VRLA Batteries About 1 week with intermittent transmitting 9

Popular Lead-Acid Battery Applications for Ham Radio Base station standby power Repeaters Mobile Car, RV, ATV Portable / emergency Hand held radios Lighting Standby power source for remote sites Remote base Satellite receivers Repeaters PV (solar) systems Field Day! Click Pic for OH Rptr Map Emergency Ops 10

The Basics About Lead-Acid Batteries 11

Primary Ingredients of a Cell Three things are essential to making any cell There must be at least... 1. A Positive electrode (plate) 2. A Negative electrode (plate) 3. An Electrolyte A battery is comprised of a number of cells connected in series to operate the desired equipment at the required voltage 12

The Lead Acid Battery Lead-acid = 2.0 V per cell nominal + Lead peroxide in the positive plate - Sponge lead in the negative plate * Sulfuric acid diluted in water This presentation will focus on the maintenance free lead-acid battery, also called Valve Regulated Lead Acid (VRLA) 13

The Valve Regulated Lead Acid Battery Industry abbreviation - VRLA Commonly referred to as maintenance free Gel not a commonly used battery in U.S. AGM - electrolyte is absorbed in a fiberglass mat/separator Popular battery for many ham radio applications Non-spillable no mess! Expect about 5 years of service from these types of batteries 14

The AGM Electrolyte System Absorbed Glass Mat Starved Electrolyte System Electrolyte is absorbed in a fine, highly porous fiberglass mat. The mat also serves as a plate separator. No water additions needed No specific gravity measurements to take These batteries are NOT sealed Fiberglass Separator Material 15

The Difference Between Conventional Flooded and VRLA Batteries Flooded batteries lose water that has to be replaced periodically VRLA batteries are designed to not lose water VRLA batteries recombine oxygen and hydrogen to reform water VRLA pressure relief vent 16

Construction of a Small 2 Cell VRLA Unit Terminal Polypropylene Container Positive plate Negative plate Separator material Cutaway of a 2 cell VRLA module with components exposed 17

Real World Operating with Batteries 18

Safety 19

Safety Considerations Wear safety glasses when working with a battery Use insulated tools exclusively Observe polarity Use breakers or fuses on all battery circuits Mark and observe polarity on common colored wire RED = Positive BLACK = Negative Recycle all spent batteries properly they are not common trash 20

Short Circuit Current Many feel, Hey, it s only a 12 volt battery for my ham shack. What s the big deal? This is a 12 volt, 100 AH battery designed for long duration applications like running a station A shock hazard does not exist at 12 volts, however potential equipment damage and burns are a real concern 21

Batteries for Radio and Other Long Duration Applications 22

Batteries for Amateur Radio The VRLA battery is the most practical type of lead-acid battery for our use Non-spillable - attractive for portable/mobile/emergency ops 12 volt or 6 volt AGM electrolyte system 70 AH 20 hr. rate to 10.5 v 3.5 A continuous Figure 17 Assorted 12V AGM VRLA Batteries 23

You Say You Need Power? How Deep Are Your Pockets? Battery disconnects for battery strings at right Two battery strings, 24 cells (48V) each in parallel rated for a total of 8000 AH. This battery can deliver 1000 amps continuously for 8 hours until discharged to 1.75 volts per cell for a communications microwave site in Trinidad. 24

Charging 25

Charging Batteries Proper Charging is Important VRLA batteries are typically charged at 2.25 to 2.30 volts per cell (VPC) when in float (standby) service 12 volt batteries charge at 13.5 13.8V 26

Improper Charging Both under and over charging cuts life short Overcharge dries out and overheats the battery Undercharge sulfates the plates 27

Charging & Distribution Equipment Figure 21 West Mountain Radio PWRgate PG40S Backup Power System powers radios and trickle charges the battery simultaneously. Power supply, battery and distribution circuits required. 28

Storage Considerations 29

Storage Considerations During periods of storage off-charge, check voltage periodically and charge when necessary Store fully charged in a cool and dry location Store batteries in a charged state A fully charged battery will not freeze A battery tender is a good device to keep a battery charged during periods of storage 30

Effects of Temperature on Capacity and Life 31

Temperature and Its Effect on Service Life One of the biggest enemies of a lead-acid battery is high temperature Performance and service life is referenced to 77 F Service life is cut in half for each 15 above 77 F Performance (capacity) is enhanced above 77 F, but service life is reduced Performance is reduced below 77 F, but service life is extended 32

Capacity Ratings and Sizing Considerations But first, let s play true or false! 33

True or False #1-My 150 amp hour battery can deliver 150 amps for an hour, or 1 amp for 150 hours Discharge rates and time do not share a linear relationship #2-If 100 amp hours have been removed from a battery, then put 100 amp hours back in to fully recharge the battery Batteries are not 100% efficient! You must put about 115% back into the battery to fully recharge it. 34

True or False Lead-acid batteries have memory effect like NiCads Not true Maintenance free (VRLA) batteries will last 10 years Not true When maintenance free batteries get old you can add water to extend its life Not true 35

True or False Products on the market that state they can rejuvenate an old battery really do work Not true 36

Data Sheets Battery manufacturers establish the performance capabilities for their products Battery application determines battery design 37

Capacity Rating Criteria Ratings are based on several factors Operating environment - battery temperature Final Voltage the minimum voltage at which the connected radio can operate reliably Discharge rate amps required to support the radio Time - hours or minutes needed to operate the radio 38

Example of a Data Sheet C&D Deep Cycle Series Battery - DCS-100 VRLA design with AGM electrolyte system Deep cycle applications good for radio, emergency repeater power, lighting, etc. 1.90 VPC = 11.40V 1.80 VPC = 10.8V 1.85 VPC = 11.1V 1.75 VPC = 10.5V 39

Voltage Drop Voltage drop for DC should be considered Formula Voltage drop = 11.1 x loop x load / wire size Voltage drop = 11. x 20 x 11A / 6530CM (#12AWG) Voltage drop =.3739V So A 12V battery operating with 11 amps on transmit and 12.3V at the battery will have 11.92V at the radio Using #10AWG 12.06V at the radio 40

And Finally For used batteries it s buyer beware Service history is unknown Sometimes you can find a hamfest bargain Excessive container bulge indicates end of life Carry a volt meter. State of charge does not indicate capacity 41

Web Links To download a copy of this presentation in PDF format go to www.ricktressler.com/k8sv Click on the Downloads Page link 42