Advanced Marine Electrics and Electronics Troubleshooting A Manual for Boatowners and Marine Technicians

need to be recharged before conducting the test

(a prerequisite for traditional load testing and

specific gravity tests with a hydrometer).

Conductance battery testers, such as those

listed in the sidebar, eliminate the need for

hydrometers and high-current-draw load

testers. They are the only safe means of deter-

mining the condition of sealed batteries. When

selecting a conductance battery tester, consider

the types of batteries it can effectively analyze

(e.g., flooded cells, gel-cells, AGM) and the

maximum battery rating in cold cranking

16 electrical systems troubleshooting

amps (CCA). Also be sure that the tester

matches the battery’s capacity. Marine batteries

often have a larger capacity than automotive

batteries (an 8D-sized battery, for example),

which some automotive testers cannot handle.

Midtronics is one of the leading compa-

nies involved in the development of these

instruments; I use a Midtronics Micro500XL

conductance tester, which costs about $800,

and have found it to be reliable. It has an

amperage rating that accommodates 8D-sized

batteries, which are common to the marine

Micro500XL, Midtronics, http://www.midtronics.com

DBA Analyzer, Newmar Power, http://www.newmarpower.com

BAT 121, Bosch, http://www.boschautoparts.co.uk

CRT-300, Alber, http://www.alber.com

Accuracy Plus, OTC, http://www.otctools.com

YA2624, Snap-on, http://www.snapon.com

CONDUCTANCE BATTERY TESTERS

To measure conductance, a tester sends a small signal

through the battery, then measures a portion of the pulsed

current response. This measures the plate surface avail-

able in the battery, which determines how much power

the battery can supply.

conductance

tester

impressed

voltage signal

current

response

signal

+ –

clamps connect

to battery

menu

digital readout

scroll up

and down

enter

code

printer

The Midtronics Micro500XL analyzer with IR-linked

printer.