Posted by michel.capel (michel.capel@…>)
Alan,
That’s what I would do in your current situation and maybe not
connect the new starterbattery to the shore charger, but just to the
alternator. In cars that works fine, so why not in a boat. These dry
cells have a very low rate of self-discharge, so even when the boat
is not used for a while, you should be able to crank the engine. Ans
you could make an emergency switch to use the house bank to crank
the engine.
In my F33/35 I put two big batteries (165 amphrs each) in the bilge
just aft of the centreboard case. I glassed in 4 platforms in the
bilge so the tops of the batteries would sit just below the
floorboards. Below the batteries there was still space for bilge
water to slosh around. I also had to cut the middle piece out of the
2x2 teak beam that supports the floorboards above the battery
location. I used a piece of aluminum U-beam and 4 bolts with wing
nuts to make an easily removeable floor beam inlay. They were
conventional lead/acid batteries, big and cheap. I could not very
well access them, so I was sloppy with adding water in time. Still,
these batteries were in good shape after seven years. Once they even
went under (fresh) water when I had a badly leaking stern gland.
My starter battery was located higher up under the saloon seat and
had a switch so it could double up as emergency battery for the nav
lights and VHF.
michel
— In FreedomOwnersGroup@yahoogroups.com, Alan Kusinitz
<akusinitz@…> wrote:
Thanks. The current starter battery is exactly the same gel cell
as the two that form the house bank. However it would be true that
it has had lower use and different recharging both from the
alternator and the shorepower charger. I didn;t realize this was an
issue. So from what you say it is less then ideal to move it to the
house bank. On the other hand its a cheap upgrade versus all new
batteries so I may proceed until I really need to replace these in a
few years. In the long term I’d like to replace them with different
physical size batteries that could be placed in the middle upper
portion of the bilge to lower the weight a bit (currently under the
quarter berth).
Alan
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----- Original Message ----
From: michel.capel <michel.capel@…>
To: FreedomOwnersGroup@yahoogroups.com
Sent: Tuesday, May 22, 2007 9:40:14 AM
Subject: [FreedomOwnersGroup] Re: Mixing Battery types?
Alan,
Batteries that were charged and discharged along different
schedules
in the past should better not be combined in one group. The
charger
will use the worst battery (highest internal resistance) as a
reference for the automatic charging programme and thereby degrade
the good batteries in the group quickly to the level of
performance
of the worst battery. Usually the starter battery is in better
shape
because it’s hardly used and immediately recharged after short use.
Possibly, your starter battery has thin plates for high amp
cranking
and your house batteries have thicker plates for deeper cycling.
This asks for different charging times in the different charge
phases. Combining these types of batteries in one group confuses
your charger and may result in less than optimal charging.
I would keep your starter battery and add a second house bank if
that’s possible (you then have three charge groups) If that’s not
possible, I would follow your plan and live with the idea that I’m
maltreating some of the batteries. In a few years, you could
replace
the whole house bank into a group of identical age and type
batteries.
— In FreedomOwnersGroup@ yahoogroups. com, “Alan”
<akusinitz@ …>
wrote:
When I purchased my F33 there were 3 group 27 gel cells. 2 in
the
house
bank one for the starter. These seem to be in good shape. I want
to
increase my house bank and I plan to move the starter gel cell
to
add
it to the house bank and buy a new starter battery.
In the interest of weight reduction my plan is to buy a smaller
starter
battery. To ensure adequate cranking capacity but lowest weight
an
optima battery seems a good choice (spiralcell AGM). My
alternator
regulator can support different batter types in each bank but my
shorepower xantrex charger can not. I don’t see any reason why
charging
an AGM using a gel cell profile would be a problem (although the
opposite would be) or why combining banks occasionally (both on
battery
switch) would be a problem.
Does anyone disagree?
Thanks,
Alan F-33 Hull#51 1982 SEAPR