Catalina 350 International Association

I currently have 4 golf cart batteries for my house bank and am considering adding 2 more to give me additional battery capacity. Has anyone added an additional 2 golf cart batteries and if so how did you mount and wire them in?
Thanks
John
Hull 484

Most of us who add a battery (or pair) use the compartment just forward of the OE battery compartment under the port settee.

I am not a fan of using wet cell batteries inside-- much prefer AGM's, as they do not out-gas and are a lot "cleaner" particularly when located under cushions in the main saloon. Have used Lifeline AGM batteries on our last three boats.

You can either join them in parallel with one of the existing banks, or use the original batteries as one battery bank and the new ones as the other. Have also seen them routed through a simple Perko ON-OFF switch to the OUT post of the main battery disconnect.

John
You currently have two pair in series and each pair wired in parallel. Wire your two new batteries in series, then wire them in parallel with the other two pair. If your existing batteries have some age on them it is recommended to not mix and match batteries in one bank if there is much age difference.
Rick
Sea Breeze

i approached this a bit different. I replaced my pair of 4D's with 4 golf cart batteries. I wired all 4 in parallel to form one large house bank. I added a group 27 battery under the port settee as a starting battery in case the house bank wouldn't start the engine. So far that's never happened. The house bank is battery 1 on the selector switch and the starting battery is #2. I can still combine them if needed viva the ALL position on the switch. The only extra wire needed with this approach is a negative jumper from the house bank to the starting battery.

Ken,

A little more explanation for those contemplating 6 VDC batteries: They are wired in series, then parallel.

So one starts by wiring each pair of 6 VDC batteries in series (positive of one to negative of the other) to form a "12 VDC battery that happens to be housed in two cases".

Then each new "12 VDC battery" is wired in parallel with the other "new 12 VDC battery".

Then the positive to the house comes from one "12 VDC battery" and the ground to the other.

Brett, thanks for clarifying that. If you need a visual, here's what it looks like -

Make sure the inline fuse between the battery charger and battery is the right amperage. We found out the hard way the inline fuse was undersized and blew without us knowing.

We have a 40A charger and the previous inline fuse was also 40A. (You would think that's correct: 40A charger needs a 40A fuse. It's not - it's wrong.) When the fuse blew the charger kept running and looked like it was charging the batteries. We realized something was wrong because the battery monitor was showing battery voltage dropping even thought the charger was running at 100 pct.

Reading the charger manual showed the inline fuse for our charger and wire size should have been an 80A fuse. Strong enough to handle any surges from the charger and sized to blow if the battery wires begin to overheat.

I am on my second set of 4 Interstate 6 volt golf cart deep discharge batteries. In another post about batteries going back to 2006, I learned of the 6 volt replacement and switched to the first set in 2008. I needed help to remove the 2 4D original batteries, but put in the 6 volt replacements myself. In June of 2016 I replaced them with another 4 and keep up the water level monthly. They have been great, but I have a slip and the boat is plugged in with the charger turned on. When we cruise, I only use one bank of 2 X 6 volt batteries at a time so that the other is in reserve to start the engine if the first one has been discharged too much. I have never been on the hook for more than 24 hours without running the engine for an hour to recharge the batteries. On the Hudson River and Long Island Sound, there are not many days where one does not need to motor a bit, so my batteries are mostly kept up. I recommend the switch to the golf cart type 6 volt batteries. They are easy to handle, seem to last very long and in my case negate the need for a starter battery.
Richard
C 350 # 111
Three Sheets

Greetings from Chicago!

Due to medical issues I chose not to launch the good ship "Tranquil" this summer. Several years ago I followed the 6 Golf Cart Battery advice + 1 start battery - great advice! I disconnect all and fill with distilled water for the winter. Checked on her yesterday as she will soon go thru another winter until I can launch her Spring 2021 and 5 buckets of damp rid worked great!

Question: Do I need to/is it advised to hook up the batteries now and charge them for a couple of hours and then re-winterize them for the upcoming Chicago winter? or Can I leave them as is and hook back to to re-charge next Spring? Will charging them now make a difference?

Thanks
Teri Weber

tranquil wrote: ↑Sat Sep 19, 2020 9:14 am
Question: Do I need to/is it advised to hook up the batteries now and charge them for a couple of hours and then re-winterize them for the upcoming Chicago winter? or Can I leave them as is and hook back to to re-charge next Spring? Will charging them now make a difference?

Thanks
Teri Weber

In a word, YES they will benefit from a charge now and at least once while in storage. If discharged, batteries can FREEZE.

Start by measuring voltage, so you know level of discharge.

Fully charge them-- shore power or portable generator powering either a separate charger or your built-in charger. Will likely take 6 or more hours.

Let us know what beginning voltage is.

You will know when they are charged, as the charge rate (amps) drops off to below 5 amps.

Dock Holiday sits 280 miles north of Chicago in beautiful Green Bay. It’s COLD up here in the winter. Each fall I fully charge the batteries and shut all systems off. Every spring we show up with almost full Battery power. Super easy.

Thanks to all for the responses! Definitely will go back and charge. Thanks again!

I had a three battery system on a 1981 Seidelmann 30T which I sold after buying Flagship hull 314 which is in Tampa Bay. I would top off with distilled water, full charge the batteries, and then (here's the trick ) disconnect the positive cables from each of the batteries to limit parasitic loses. You could do both positive and negative cables for insurance. I would reconnect the positive terminals just before splashing in the Springand and start the diesel engine in the very cool April without any charging or other assistance. I thought it was a miracle. Good luck to all our northern boaters.

Mike Cronin
Flagship #314

AND, before disconnecting anything, label the wires and take pictures so you will know what goes where!