[C320-list] Lithium vs. golf cart

[Bruce Heyman]

Hi Jack,
All good points and considerations. 
I'm not an expert but trying to become one.   
I've removed my two 10 year old 4D wet cells that don't owe me a penny.   I
was going to just simply replace them as I already have a "spillover"
charger for the emergency start battery, high output alternator with
external regulator, Link 10 battery monitor and 30 amp AC charger.    
Just looking at the battery spec sheets and seeing how the LiFeP04's can
accept the charge at a very high rate for an extended period of time and
they can be used down to zero remaining AMP Hours without running them
(doing this will shorten the number of total cycles but it is still an
incredibly high number fp cycles).  It seems like they might justify the
extra cost and spending my children's inheritance..  I've been trying to
figure out how many amp hours could actually be fit into our battery space.
The batteries can be mounted in almost any orientation so my guess is you
can fit at least 800 AMP Hours in there and unlike wet cells you can use all
of the amp hours.   With that kind of capacity it becomes very realistic to
be able to use an inverter and run things like microwaves.
I was working with one of the techs at West marine and believe it or not he
was encouraging me to not buy chargers/inverters and LiFePO4's that are
marine(ized) and focus on the large number of products that are coming out
for home solar which have driven the prices way down.   However, the lowest
cost option for you has to be to go with the golf cart batteries!
Agree, it is an interesting puzzle.
Bruce

Bruce Heyman
Somerset #671   San Pedro (LA) California
-----Original Message-----
From: C320-list <c320-list-bounces at lists.catalina320.com> On Behalf Of Jack
Brennan via C320-list
Sent: Wednesday, February 22, 2023 7:44 PM
To: C320-list at catalina320.com
Cc: Jack Brennan <jackbrennan333 at outlook.com>
Subject: [C320-list] Lithium vs. golf cart

So the four group 24s I have right now are not doing the job, and I'm
debating golf cart vs. possibly lithium before I pull the trigger on
batteries.

I'm not an expert by any means; I'm just throwing out some numbers to see
what other people on the list think as a way to clarify my thinking.

The cost: I can get four good-quality Duracell golf carts, about 450 AH,
from Sam's Club for less than $450. Two decent lithium 100 AH batteries will
cost me maybe a grand, plus I'll need a 20 amp DC to DC charger to move the
alternator amps from the start battery to the lithium.

I have 320 watts of rigid solar that can give me 20 AH on a perfect day for
either golf carts or lithium. The Ahs will of course shrink over time with
the golf carts as the rate of acceptance slows, but pretty much stay at 15
or 20 forever with the lithium.

I also have the standard Hitachi 50 amp alternator on my Yanmar 3gm30. That
can give me 50 for a short period and then a diminishing amount on golf
carts as the rate of acceptance slows, but 20 for a longer time with lithium
if I use the DC to DC charger.

I probably use 80-100 AHs a day while cruising, between the fridge, anchor
light, my CPAP machine, music,  a movie, etc. Solar will replace that on a
sunny Florida day with golf carts, but only some of it if it's cloudy. A
couple of hours of motoring would fill the gap.

With lithium, as I understand it, it will accept everything the alternator
and the solar throw at it. So it works really well, cloudy or sunny. You're
topped off quickly, especially if you motor some.

So my question is this: Given the limits on alternator and solar charging,
how much difference does it actually make whether I go with golf carts or
lithium? Is it just an issue of whether your battery bank is topped off at 2
p.m. or 5 p.m.?

I know there are other considerations. You save about 200 pounds of
displacement with lithium. They also appear to last much longer with proper
treatment. On the other hand, I could buy three sets of golf carts for the
price of two 100 AH lithium batteries.

An interesting puzzle.

Jack Brennan
Sonas, 1998 Catalina 320
Tierra Verde, Fl.









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