[C320-list] totally shot D-4 Batteries

[Troy Dunn]

Hi all-

Way too much ground to cover in an e-mail thread.  But I’ll mention the
high points.

As of two years ago, FLAs were still the most cost effective for most.
That being said, LiFePO4s were definitely gaining on FLAs, I suspect by now
IF you are designing an entire system from scratch, LiFePO4 is now the
obvious choice.   Unfortunately most 320 owners aren’t ripping out their
entire electrical systems and starting over so that doesn’t really
apply….for most.

AGMs always come in dead last for energy (watts) per dollar spent.   They
do have some significant advantages over FLAs like a slightly higher depth
of discharge, and the ability to go to more significant heel angles without
worrying about spills etc.  , and obviously not have to water them is
pretty nice too.  One downside of AGMs is they are the least forgiving to
abusive cycling.   Take them way down into their discharge depth
consistently without getting them back to a full 100% charge and they will
rapidly lose capacity.  FLAs are slightly more forgiving and of course
LiFePO4s live for this kind of punishment.

I went with 4 GC2s (the FLA kind) and a group 27 backup battery.   That’s
464 Ah (232 Ah usable)  for the house which is a really healthy number for
us with tons of margin.   We generally wake up after a night at anchor with
85% SOC.  The thought of dealing with those 4Ds still makes my back hurt
thinking about it.   For those still needing to move 4Ds the best approach
is to slide a shorter 2x4 under the handles and then have two people lift
the battery.   It's still heavy but more manageable this way and when done
this way simplifies getting the battery out of the salon.

I have since added a watering system to the batteries which helps with the
watering process but it’s still a chore that has to be done.

Installing GC2s is not a straightforward process for most since it's
unlikely you will be able to get the to fit without modifying the battery
compartment.   There are pictures of all that DIY fun in my gallery.

Ultimately there are so many variables and so many user types of the C320,
reccomending a battery replacement is really difficult without knowing a
lot more about cruising habits, battery management skills, and of course
how much enjoyment one gets from boat projects vs cruising.

FWIW

Troy Dunn
Hull #514