
After all the charging problems we had on our June cruise, we decided to replace all our house batteries. Here are the six new Dyno batteries sitting in the main cabin of Phoenix, ready to be lowered to the engine room.
As readers of this blog know, we had continual problems with charging our batteries on our June cruise due to a few worn-out batteries in our house bank. It goes without saying that we should have replaced the 5-year-old batteries before we left Anacortes, but we thought we’d be able to get by a little longer before we shelled out our cash. Batteries are one of the major expenses on a powerboat. At any rate, Jim recently made a trip to Anacortes to buy new batteries and replace the bad ones.
We had thought about replacing only the three batteries that tested bad, but additional research led us to conclude that we would be better off replacing all six of the house batteries. Even though three of the batteries tested okay, they were 5 years old too!
Jim ordered six new Dyno GC2 6-volt deep discharge batteries from Fisheries Supply in Seattle and asked to have them placed in will-call so that he could pick them up on his way from Bend to Anacortes.

On his way to Anacortes, Jim stopped at Fisheries Supply in Seattle to pick up the six new batteries. Here they are in the back of the car. They are Dyno 6-volt deep discharge batteries.
The new batteries had to be hauled down to our boat from our car in the marina parking lot. It’s a long walk, which can be difficult when the tide is low because the ramp from the parking lot to the dock can be really steep. Jim checked the tide predictions and waited to move the batteries to our boat when the tide was high and there was a fairly level ramp.
Many thanks to friend Bob from down the dock for his help in getting the batteries from the car to the dock and onto the boat. These puppies weigh 70 pounds apiece! Also thanks to Mel at Specialty Automotive in Bend for the loan of a battery-carrying strap, which was a big help in loading the batteries in Seattle.
To prepare for the new batteries, the first step was to clean out 11 years of accumulated junk at the forward end of the engine room. And then the inverter/charger had to be temporarily removed to get it out of the way.

There was lots of accumulated junk in the forward end of the engine room that had to be cleaned out to make room for the new batteries and new battery distribution system. The tan colored “snake” in the center of the photo is one of the coolant lines for the Webasto hydronic heating system.
In order to get the six old batteries out of the engine room, Jim had to wrestle them up to the floor of the main cabin. Then he took them off the boat and stored them on the dock while he put in the new batteries. Finally, they had to be hauled back to the car for recycling. Fortunately we discovered that Les Schwab in Anacortes will recycle batteries, so he didn’t have to drive far to dispose of them.
Moving the new batteries to the engine room from the main cabin was much easier…gravity helped a lot! The 6-volt batteries are grouped into pairs so they can be wired to make 12 volts, and each pair of batteries is stored in its own box. We use Hydrocaps on our batteries. They function to re-convert battery gases into liquid that is returned to the battery, reducing the frequency that water must be added to the batteries.

This photo shows one pair of the new batteries in its storage box. The red and black caps on the tops of the batteries are the Hydrocaps.

Once the new batteries were in, Jim had to clean up the rat’s nest of wiring that was the high current distribution system.
As part of the project, the original battery charger that came with the boat had to be removed to make way for a new battery distribution system. We had left this charger in place, but it was never used because we added an inverter/charger to use for charging. We’ll keep the original charger on board for backup.

The silver box at the left side of the picture is the original battery charger that came with the boat. It was removed to make way for the new battery distribution system.
After the new batteries were in place, Jim worked on revising the battery wiring to change the existing spoke pattern distribution system to a daisy chain configuration. We are making this change because the spoke configuration had resulted in one pair of the house batteries discharging disproportionally and boiling off the electrolyte of those two batteries. The daisy chain fashion should result in the six batteries discharging more evenly. Note that the daisy chain configuration has the positive cable out of one end of the daisy chain and the negative cable out of the other end.
The photo below shows the new positive distribution system. It has two new bus bars. The big bus bar at the top of the frame is where the big loads (DC panel and Webasto heater) meet the big sources (engine alternator, batteries and charger). The small bus at the lower left is for accessories (heater fans and echo chargers). At the time Jim was working on this project, he ran short of big red cables and had to temporarily wire the system using two black cables that he had on hand. Next time we’re on the boat, he will replace the black cables with the proper red cables.
Finally, Jim tied down the new wiring and labeled the big cables to tidy up the engine room. So glad to be done with this project!
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Jim
good looking job. I will remember you next time I change out batteries.
Bob
Hey Bob,
Thanks for the compliment. The only batteries I’m gonna change for a while are the ones in my flashlight.
Jim
We also had DYNO batteries on Bearoness 2 that we purchased from fisheries, and we were very happy with them. However, we didnt need to change any wiring, just had to change the battery boxes. The big DYNOs and the new boxes fit in the same space as the old ones.
Hope your batteries are as satisfactory as ours were.
Joe
Thanks, Joe. This is our third set of Dyno batteries and we’ve been happy with them too. We got 5 years out of the last set and hope we’ll get the same service life with the new ones!
Oh my goodness! What a project. The airplane battery is smaller than a cars. Those things are huge. Thanks for the update.
Hi Bonnie,
Yes, this was quite a project, and that’s the reason Jim went up to the boat by himself…it would have been almost impossible to live on the boat during all that’s involved in moving batteries in and out…plus we would never have been able to keep the kitties out of the engine room. As far as the size of the batteries compared to a car or airplane…the batteries in airplanes (and cars) are primarily used for starting the engine. These six batteries that we replaced are our “house” batteries, which supply power to our boat’s systems similar to the power supplied to a house by the power company. As far as starting our boat’s engine…we have two additional batteries that are dedicated just for starting the engine. Thanks for your note!
Of course! Silly me, should have realize you use those batteries is such a different way. Glad it is over and you can have some fun later this month.