House Battery Bank Upgrade

During the Bunbury Cruise last February I was not happy with Pachuca's electrical power situation.  I had left Fremantle with all batteries fully charged and two days later found myself short of battery power and forced to run the engine about 1 hour per day to maintain the voltage.  I knew that the house bank's four 230 a/h gel batteries that had been installed  in New Zealand in 2008 were getting long in the tooth and I would have to face the prospect of replacing them.

During the cruise I mentioned my power situation while visiting friends aboard their modern 11.6m boat  and was surprised to hear that they never worried about battery power: they left the marina with a full charge and that was it.  From memory, they do not augment their voltage with solar panels or a wind charger.  That sealed it for me: I would replace the house batteries during the coming winter.

I got a break in March Brenda's when son Brenda's Stephen purchased a battery analyzer, something  that had seen only in the hands of professionals.  We used it to check the house batteries and got the following results:

1. Forward stern battery

13.42V, charge 98% , ir=16.6 m/ohm, CCA 180 amps, Health 0%, REPLACE

2. Aft stern battery

13.34V, charge 98%, ir 3.7 m/ohm, CCA 800 amps, health 18%, REPLACE

3. Starboard cabin battery

13.46V, charge 98%, ir 4.0 m/ohm, CCA 735 amps, health 15%, REPLACE

4. Port cabin battery

13.26V, charge 98%, ir 6.4 m/ohm, CCA 455 amps, health 06%, REPLACE

The batteries were basically dead and it was a wonder that I had gotten any life out of them at all.  I had known that the 9 year old batteries needed replacing but it was good to confirm this before embarking on the replacement project.

I then did some research on lithium batteries and although their Total Cost of Ownership is lower than that of other battery types I was not too impressed with the high initial investment and did not want to deal possible charging issues, so AGM batteries it would be.  The boat had been set up in New Zealand using great ingenuity for four large batteries and high (920 a/h) total capacity and I wanted to keep that configuration.  

Two problems remained: (1) finding AGM batteries of a similar size that would fit in the boat, (2) finding someone to remove the old batteries and fit the new ones.  The batteries weight in the order of 75 kg (165 lb) and I was not going to risk my back by moving the batteries myself.

Fortunately Battery World in O'Connor had just what I needed.  I purchased 3 x Century C12-270DA deep cycle 270 a/h AGM batteries and 1 x Fullriver DC210-12 210 a/h AGM battery.  The Fullriver battery was required because the Century batteries were slightly taller than the gel batteries they were replacing, and would not fit under the boat's autopilot linear drive ram (3 mm too high).  And of great value to me was that their personnel would handle all of the installation at no extra charge.  The Century batteries cost $715 each and the Fullriver battery cost $679 yielding a total price of $2824.  I purchased the batteries  on 1 May 2017 and they were installed three days later.

 

Gel batteries under cockpit ready for removal

Lifting one of the gel batteries

Gel battery being unloaded using the handy plank

Bringing new Century AGM battery on board

I later made two visits to the boat to strap down the batteries.  This required some design work because three of the new batteries were taller than the old ones.  Even though Pachuca never rolled or was even knocked down during the circumnavigation I felt that I should keep up the standard of the boat as fit for blue water cruising anywhere.

New starboard battery

New port battery

Pachuca now had 1020 a/h capacity in the house bank vs 920 a/h previously.

I was extremely pleased with the service provided by Noel Brennan and his team at Battery World, O'Connor.  They were great to deal with in the planning, and performed a flawless installation.  I also did a spot check on the Net of the prices of the batteries that I was purchasing and theirs were consistently the lowest.

 

Under cockpit: Century in front, Fullriver aft, under autopilot linear arm