Professional BoatBuilder - April-May 2018

APRIL/MAY 2018 7

LETTERS

device Calder cites o er the charging

capacity mentioned at idle speed when

setting or retrieving an anchor, or enter-

ing/departing the slip (Calder’s exam-

ples)? Even if it can, that energy must be

converted from the engine to electricity,

and for smaller engines and sailing auxil-

iaries it seems as if the necessary horse-

power may be unavailable unless running

connections are not bolted and are

therefore more vulnerable to high-resis-

tance scenarios, overheating, etc., which

could be exacerbated by lithium-ion

battery charging. However, similar con-

ditions occur frequently on vessels run-

ning HVAC systems, water heaters,

clothes dryers, and galley stoves.

Finally, will the new alternator-type

batteries are, as Calder said, “ready for

prime time” in our maritime environment.

Mark Lenci

Natick, Massachusetts

To the Editor:

As usual, Nigel Calder’s article, this

one on lithium-ion battery installations,

was very illuminating.  e points regard-

ing alternator and wiring (over)loading

are especially important for those design-

ing and installing these systems.

It’s worth noting that conventional

gaseous  re ghting agents including

FM-200 and Novec 1230 are among the

least e ective to deal with lithium-ion

battery  res. In the Material Safety Data

Sheets (MSDSs) for all lithium-ion bat-

teries I’ve encountered, these agents are

conspicuous by their absence, and a

Federal Aviation Admin istration analy-

sis of  ghting lithium-ion battery  res

gives them very low marks.  It appears

that the most e ective agents, according

to those FAA reports (https://www. re.

tc. faa.gov/pdf/systems/May13Meeting/

Hill-0513-ExtinguishmentofLithium

Batteriesrev2.pdf ), are water, dry chem-

ical, foam, and CO 2 , none of which are

common in the recreational marine

industry for the automatic protection

of battery banks, so there will be yet

another learning curve here. Comparing

LiFePo MSDSs to those of lead-acid/

AGM batteries, it’s debatable which is

worse.  e latter’s MSDSs list, among

other things, thermal runaway, explo-

sions, leaking sulfuric acid, and release

of explosive hydrogen gas. Yet, most

cruising vessels have at least two banks

of those batteries. It would be interesting

to know the preferred approach for lith-

ium battery bank installations: Should

they be contained in a  re-resistant

enclosure? Is that any more necessary

than for lead acid batteries? What type

of  re ghting technology is best?

Regarding shore-power cables, I’ve

encountered overloading, and melting

of conventional legacy NEMA as well

as SmartPlugs. I’ve also routinely run

120/240V, 50-amp services (legacy and

SmartPlug) at a continuous 45–48 amps

hour a er hour with no cause for con-

cern.  e cables are designed to carry

this load, but as Calder notes, the

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