Professional BoatBuilder - December-January 2018

SYSTEMS: Battery Technology

36 PROFESSIONAL BOATBUILDER

SYSTEMS: Battery Technology

904 Buffaloville Rd., Dale, IN 47523 800-533-6901

http://www.thermwood.com

lead sulfate slowly morphs into large

crystals that cannot be recovered by

normal charging processes (this is the

sulfation mentioned above). However,

the pore structure in the Firey foam

is too small to allow the lead sulfate to

crystalize to this extent, rendering

these batteries more-or-less immune

to sulfation. I was skeptical of the tech-

nology but have since operated these

batteries in a partial state of charge for

months at a time, discharged them to

35% state of charge, and le them for

eight months without recharging

them. I then restored them to 100%

state of charge.

e carbon-foam plate grid is a

major step forward for lead-acid

batteries. Because the technology is

patented, these batteries are available

from only one company. Unfortu-

nately, I have found the quality control

to be somewhat uneven.

Aer more than a century of lead-

acid battery development, you’d think

we’d know everything there is to know,

but exciting discoveries are still being

made; lead-acid technology should

not be written o.

Ultracapacitors

For a decade various experiments

have been made with capacitors

embedded in lead-acid batteries. A

capacitor is a device that can absorb

very high energy spikes but with a

miniscule storage capability. In the-

ory, a capacitor/lead-acid combina-

tion can absorb high-rate charges in

the capacitor and then over time

dump the charge into the battery for

storage, maintaining a high average

state of battery charge and minimiz-

ing sulfation. e core application for

these batteries is in hybrid cars, with

the capacitors absorbing the high-

energy spikes from braking events.

e rst of these batteries, the Ultra,

is just now becoming available in the

U.S. from East Penn Manufacturing.

e jury is still out on whether this

represents a signicant step forward

in marine applications, where the

duty cycle will be very dierent from

that of a hybrid car.

foam. e carbon acts as the conduc-

tor of energy in and out of the battery

plate.

is foam results in some remark-

able changes in battery characteristics.

e normal consequence of discharg-

ing a lead-acid battery is to turn the

active material into lead sulfate. If the

battery is le in a discharged state, the

(this conducts the energy in and out of

the battery), into which is pasted the

active material (which absorbs energy

on charging and gives it up on dis-

charging). A Firey battery dispenses

with the lead grid in the negative bat-

tery plate and replaces it with foam

formed from carbon. e active mate-

rial is pasted into the pores in the

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